Normal Serum Free Light Chain Research Articles

Understanding the Constraints and Optimization of Serum Immunofixation Electrophoresis and Serum Free Light Chains for Detecting Monoclonal Proteins: A Single-Center Experience.

Introduction Serum immunofixation electrophoresis (SIFE) and serum free light chain (SFLC) assay are imperative investigations in diagnosis and follow-up of multiple myeloma (MM). SFLC assays are reported to have higher sensitivity than SIFE. However, discrepancies have been reported between them. The current study was aimed at assessing concordance and discordance between SIFE and SFLC results in MM. Methods A total of 450 observations of both SIFE and SFLC were obtained from treatment-naive and follow-up MM patients. Results One hundred and twenty-nine (28.7%) values were observed as discordant, that is, positive SIFE with normal SFLC ratio or negative SIFE with abnormal SFLC ratio ( p -value < 0.00001). Proportion of discordance was higher in SIFE positive-SFLC normal cases than SIFE negative-SFLC abnormal cases. Discordance was more frequent in follow-up cases. Conclusion Negative SFLC alone may not be reliable for MM follow-up. Algorithm may be based on SFLC measurements on each follow-up till attainment of normal SFLC ratio. Once SFLC normalizes, follow-up may be done with SIFE. If SIFE is positive, further follow-up with SIFE may be initiated.

Patients with IgM Monoclonal Gammopathy of Undetermined Significance (MGUS) or IgA with an M Band < 1.0 g/DL Have the Same Low Risk of Progression to Lymphoplasmacytic Neoplasm (LPN) As Those with IgG MGUS and an M-Band < 1.5 g/DL

Background Patients with MGUS can progress to LPN. Non-IgG subtype and the size of the M-band are known to correlate with the risk of progression. Consensus guidelines recommend that patients be monitored on an annual basis, but that IgG MGUS with an M-band < 1.5 g/dL, and a normal serum free light chain ratio is at low risk and can be managed with less intensive monitoring. There are limited data on the risk of progression to LPN in non-IgG MGUS with small M-bands. Methods Kaiser Permanente Northern California (KPNC) is a large integrated health care system serving more than 4 million members representative of Northern California residents. We identified a cohort of 3,303 KPNC health plan members who had at least one serum protein electrophoresis (SPEP) performed between January 1997 and December 2006 and extracted follow up data through December 2016. We excluded those with an M-Band > 3 g/dL, absence of a confirmatory immunofixation, or LPN before through 3 months after initial SPEP. The primary end point was progression to LPN, defined as multiple myeloma (MM), non-Hodgkin's lymphoma, or amyloidosis, and identified via an integrated tumor registry and, in the case of amyloidosis, by clinic diagnosis. Findings The median age of this cohort was 73 (IQR 63-80), 54.5% were male, and the ethnicity of this group was White 66.9%, Black 17.2%, Asian 6.7%, Hispanic 7.7%, and others 1.6%. Sixty six percent had an IgG gammopathy and 73% of gammopathies were < 1.0 g/dL. Overall, there were 2.1 (2.0-2.3) progressions per 100 patient years. The number of progressions per 100 patient years for an M-band < 1.0 g/dL, 1.0-1.5 g/dL, and 1.5-3.0 g/dL were 1.4 (1.2-1.6), 3.5(2.9-4.1), and 6.6 (5.5-7.7) respectively. As can be seen in the Figure, the cumulative risk of progression to LPN was clinically similar for patients with an IgG ≥ 1.5 g/dL and IgA ≥ 1.0 g/dL and considerably increased compared to those with an IgG gammopathy < 1.5 gm/dL, IgA gammopathy < 1.0 g/dL, or an IgM of any size. Discussion It has been estimated that there are several million individuals in the United States with MGUS. Following a patient with MGUS indefinitely is a financial burden and creates a substantial psychologic burden for the patient. Others have found that the effect of an MGUS diagnosis on quality of life is greater than a new diagnosis of symptomatic MM. Therefore, identifying additional categories of MGUS that could be assigned to a low-risk category could potentially diminish the burden and stress of ongoing monitoring. Limitations of our study are that, owing to the period from which our cohort was accrued, and the nature by which they were identified, free light chain levels were not obtained, bone marrow biopsies were done infrequently, and modern advanced imaging was not performed. In the modern era, many of our cohort would likely be identified with more advanced neoplasia such as smoldering or frank MM accounting for the higher rates of progression compared with other published reports. We found that during much of the period covered by our study, the clinical diagnosis of Waldenstrom's Macroglobulinemia was used in a non-discriminatory manner. We therefore limited our definition of progression only to those subjects developing frank malignancy that qualified for inclusion in our tumor registry rather than the less rigorously defined entity of "Waldenstrom's Macroglobulinemia.". This likely accounts for the lower risk of progression to LPN among our cohort with IgM gammopathy than has been described elsewhere. Conclusion Patients with either IgM MGUS of any size or IgA MGUS with an M-band < 1.0 g/dL have an equivalent clinical risk of progression as patients with an IgG MGUS < 1.0 g/dL and should potentially be assigned to a low-risk category to decrease the burden and stress of ongoing monitoring. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

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An Analysis of M-protein in Plasma cell Dyscrasia Patients Identifies that IgG Lambda Subtype is More Commonly Associated with Normal Serum Free Light Chain (SFLC) Ratio.

The determination of monoclonal protein (M-protein) by SPE, IFE and SFLC assay is fundamental in the diagnosis of Plasma cell proliferative disorder (PCPD). In the present study, we seek to assess the diagnostic performance and concordance of these three techniques in un-treated PCPD patients. All new patients with dysproteinemia and/or suspected PCPD were included in this retrospective observational study. The baseline parameters were retrieved from electronic medical records. SPE was performed on gel electrophoresis system; monoclonal component was identified by IFE. SFLC assays were performed by nephelometry using a latex-enhanced immunoassay. Total 402 patients of PCPD were included (10.9% of MGUS/SMM and 89.1% of multiple myeloma). The combination of SPE + rSFLC (ratio of kappa/lambda light chain) and SPE + IFE + rSFLC was able to detect M-protein across all subgroups of patients. In 61 patients, rSFLC values were within normal range (54.5% of MGUS/SMM and 10.3% of MM) and was more commonly seen with IgG lambda M-protein (57.4% vs. all-others). The median dFLC value, among these patients, was higher for MM than MGUS/SMM patients (23.8 vs. 14.4mg/L, respectively). The combination of SPE and rSFLC can be reliably used to detect M-protein in PCPD patients. In a small subgroup of MM patients, despite the presence of an intact immunoglobulin (M-protein), the rSFLC is not abnormal. Historically, these patients should respond better to treatment. However, a further follow-up analysis with more number of such patients would be advantageous for better understanding.

Early Serum Free Light Chain Response after High-Dose Melphalan and Stem Cell Transplantation Predicts Hematologic Response in AL Amyloidosis

Introduction Immunoglobulin light chain (AL) amyloidosis is a rare disease caused by a clonal plasma cell dyscrasia producing monoclonal light chains that misfold and form amyloid fibrils which can deposit in a variety of tissues and organs. This deposition of amyloid fibrils can lead to progressive organ impairment, multi-organ failure, and death if left untreated. High-dose melphalan and autologous stem cell transplantation (HDM/SCT) is known to improve patient outcomes with hematologic complete responses (CR) rates of 25-67%. Hematologic CR is currently defined as the absence of monoclonal protein in serum and urine by immunofixation electrophoreses and normal serum free light chain ratio (FLCR). Studies have shown that even among patients achieving a normal FLCR after initial therapy with HDM, persistent elevation of the involved FLC (hiFLC) predicts poor prognosis. Serum half-life of FLCs is approximately 2-6 hours, even with diminished glomerular filtration rates, and could be a tool for early treatment response evaluation. We sought to determine the extent to which early FLC responses after HDM/SCT predict hematologic complete response (CR) at 6 months. Methods We analyzed patients with AL amyloidosis who underwent HDM/SCT from 2012-2019 at Boston Medical Center. Exclusion criteria included death within 100 days, lack of FLC data at any time point, pre-SCT normal FLC concentrations and ratio, and chronic renal insufficiency (serum creatinine &amp;gt;1.3 mg/dL) with a normal FLC ratio. All subjects received a total of 140-200 mg/m2 melphalan IV in equally divided doses on days -3 and -2. Stem cells were infused on day 0. FLC measurements were obtained early in the peri-SCT period (&amp;lt; 1 month), at 6 months, and at 12 months after HDM/SCT. The patients were evaluated for response according to the consensus response criteria at 6 months. Statistical analysis to compare CR at 6 months and early post-SCT free light chain levels was performed by Chi-square with significance considered at p&amp;lt;0.05. Results Of the 113 patients with AL amyloidosis treated with HDM/SCT during the specified time period, 32 were excluded (4 died within 100 days of SCT, 15 had normal FLCs pre-SCT, 5 lacked data, and 8 had chronic renal insufficiency (Cr &amp;gt;1.3 mg/dL) with normal FLCR. A total of 81 subjects (females=30) were analyzed. Median follow-up from SCT was 27.6 months (range, 6-145). Median time of early post-SCT FLC measurement was 8 days (range, 7-30). Median age at diagnosis was 58 years (range 30-79) and the iFLC was lambda in 81.5% (n = 66) of patients. Median number of bone marrow plasma cells was 10% (range, 1-50). The mean absolute involved FLC was 196 mg/L ±221 prior to SCT, 60 mg/L ± 77 in the early post-SCT period, 92 mg/L ± 152 at 6 months post-SCT. In early post-SCT period, 39.5% (n=32) had iFLC &amp;lt;20 mg/L, 28% (n=16/57) had dFLC&amp;lt;10 mg/L, and 84% (n=48/57) had normal FLCR. Early post-SCT dFLC &amp;lt;10 mg/dL and early post-SCT iFLC &amp;lt;20 mg/L were statistically associated with prediction of hematologic CR at 6 months (p=0.025 and p=0.001, respectively). However, early post-SCT normal FLCR was not associated with predicting hematologic CR at 6 months. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of early post-SCT iFLC &amp;lt;20 mg/L, dFLC &amp;lt;10 mg/L and normal FLCR to predict hematologic CR at 6 months are presented in table 1. Conclusion This study concludes that achievement of dFLC &amp;lt;10 mg/L and iFLC &amp;lt;20 mg/L in the early post-SCT period is associated with prediction of hematologic CR at 6 months. Early post-SCT dFLC &amp;lt;10 mg/L could be considered a tool for early evaluation of treatment response following HDM/SCT in AL amyloidosis. Key words: immunoglobulin light chains; AL amyloidosis, HDM/SCT Disclosures Sarosiek: Spectrum: Research Funding. Sanchorawala:Caelum: Research Funding; Prothena: Research Funding; Celgene: Research Funding; Takeda: Research Funding; Proclara: Other: advisory board; Abbvie: Other: advisory board; UpToDate: Patents &amp; Royalties; Oncopeptide: Research Funding; Regeneron: Other: advisory board; Caleum: Other: advisory board; Janssen: Research Funding.

Comparing measures of hematologic response after high-dose melphalan and stem cell transplantation in AL amyloidosis

Hematologic complete response (hemCR) in AL amyloidosis requires absence of monoclonal protein by immunofixation electrophoreses (IFE) and normal serum free light chain ratio (FLCR). Recent literature suggests that an involved free light chain (iFLC) <20 mg/L or difference in free light chains (dFLC) <10 mg/L may more accurately predict outcomes after treatment. We evaluated overall survival in 340 patients treated with high-dose melphalan and stem cell transplantation (SCT). Of 305 patients evaluable 6 months after SCT, 90 (30%) achieved hemCR, 132 (43%) dFLC <10 mg/L, 118 (39%) iFLC <20 mg/L, and 176 (58%) normal FLCR. Of 215 patients without hemCR, 65 (30%) had dFLC <10 mg/L and 86 (40%) had normal FLCR. Overall survival (OS) in those achieving dFLC <10 mg/L or normal FLCR without hemCR was inferior to those achieving hemCR (p = 0.013 and p = 0.001). OS was not significantly different in patients achieving iFLC <20 mg/L without hemCR compared with hemCR (p = 0.243). Of those with hemCR, OS was not significantly improved if dFLC <10 mg/L was also achieved (p = 0.852), but OS was improved for those with hemCR who also attained iFLC <20 mg/L (p = 0.009). Multivariate analysis demonstrated absence of monoclonal protein in IFE and iFLC <20 mg/L as independent predictors of survival. Attainment of hemCR remains a treatment goal, although achieving iFLC <20 mg/L may also predict improved OS.

P0204PREVALENCE AND PREDICTIVE FACTORS OF BIOPSY-PROVEN NEPHROPATHY RELATED TO MONOCLONAL GAMMOPATHY

Abstract Background and Aims The prevalence of monoclonal gammopathy (MG) and kidney disease increases with age. When a patient present with both conditions, it is often necessary to perform a kidney biopsy in order to rule out a Monoclonal Immunoglobulin-Related Nephropathy (MIRN) that may require a specific therapy that targets either an overt hematological malignancy or a MG or Renal Significance (MGRS). The aim of our study was to identify factors that predict the presence of MIRN in this setting. Method This retrospective monocentric study included all patients who underwent a kidney biopsy between 2007 and 2018 with concurrent presence of GM, as defined by positive serum immuno-electrophoresis and/or Bence-Jones proteinuria. Results 328 patients were included, representing 11.8% of all kidney biopsies performed in our center during this period. Indication of biopsy was renal failure (eGFR &amp;lt;60ml/min/1.73m) in 77.4% of cases and/or proteinuria (urine protein-to-creatinine ratio &amp;gt;0.5g/g) in 75.9% of them. Median (IQR) serum creatinine was 155 μmol/L (111-233), eGFR 37.5 (22-56) ml/min/1.73m, serum albumin 29.5 (24-35) g/l. Median age was 67 (57/75), the M/F ratio was 198/130, diabetes mellitus was present in 21.3% of cases, hypertension in 53.1%. Kidney biopsy revealed that nephropathy was related to MG in 91/328 patients (27.7%). Myeloma cast nephropathy and AL amyloidosis were the most common histopathological subtypes (36 and 34% respectively), followed by monoclonal immunoglobulin deposition disease (15%) and cryoglobulinemic glomerulonephritis (8%). Patients with MIRN had more severe renal function impairment with median (IQR) serum creatinine of 176 (119-307) vs 149 (108-216) μmol/l (p=0.003) and heavier proteinuria, 3.9 (2.2-8.2) vs 2.0 (0.9-5.2) g/g (p&amp;lt; 0.001), when compared to non-MIRN patients. Hematological malignancy was diagnosed in 83 cases (25,3%) (Multiple Myeloma in 62, non-Hodgkin Lymphoma in 6, Waldenström Macroglobulinemia in 6, Chronic Lymphoid Leukemia in 6, Plasmocytoma in 3). Among them, MIRN was diagnosed in 51 (61%) cases but tumoral lympho-plasmocytic infiltration was observed in 9 (11%) cases. In this subgroup of patients, no laboratory test could predict the presence of a specific nephropathy. Among patients with no hematological malignancy (n=245), MIRN was diagnosed in 40 cases (16%) to confirm MGRS diagnosis. The markers that were most commonly associated with the presence of MGRS were positive Bence-Jones proteinuria (OR 4.7; 95%CI 2.2-10.3; p&amp;lt; 0.001), abnormal serum Free Light Chain (FLC) ratio (OR 4.2; 95%CI 1.7-10.7; p&amp;lt; 0.001), and serum electrophoresis spike &amp;gt;1.5 g/l (OR 5.9; 95%CI 2.6-13.5; p&amp;lt; 0.001). However, none of those markers had sufficient power to formally predict the result of the biopsy, as positive (PPV) or negative (NPV) predictive values were 36/41/45 % and 89/86/88 % respectively. Conclusion Almost one-third of patients with MG and kidney disease referred to our Department have biopsy-proven related nephropathy. Although negativity of Bence-Jones proteinuria and a normal serum FLC ratio are frequently associated with the absence of MGRS, kidney biopsy, beyond its diagnostic and prognostic interest, remains the most discriminating test.

Pyrophosphate (PYP), and Hydroxymethylene Diphosphonate (HDP) are Reliable and Readily Available Tracers for use in Bone Scintigraphy for the Diagnosis of Transthyretin Cardiac Amyloidosis (TTR)

3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) is the most validated tracer for detecting cardiac amyloidosis with bone scintigraphy. PYP and HDP are more readily available in Australia, and considered possible alternatives. We sought to examine experience using HDP and PYP at the Victorian and Tasmanian Amyloidosis Service. 69 patients diagnosed with TTR underwent bone scintigraphy. TTR was confirmed on direct biopsy in 25, including 12 cardiac; and/or genetic studies confirming TTR mutations in 5; and/or on clinical phenotype (older male with isolated HFpEF ± carpal tunnel releases), with echocardiographic features (IVSD >12 mm) and elevated cardiac biomarkers in 57. Six underwent bone marrow biopsies demonstrating <5% plasma cells and Congo red negative, thus AL was excluded. All but one had normal serum free light chain (SFLC) ratios. Cardiac MRI confirmed amyloidosis in 25. Tracers used were: HDP in 61, PYP in 6, and 1 each for DPD and MDP. 65 demonstrated cardiac uptake. For negative scan patients, one had normal cardiac biomarkers with no clinical evidence of amyloidosis but positive for Met30 mutation, thus deemed an asymptomatic carrier; another had normal echocardiography with isolated biopsy-proven gastrointestinal disease; another had isolated biopsy-proven bladder disease with normal cardiac biomarkers. The final patient had bone scintigraphy using methylenediphosphonate (MDP), which was falsely negative. MDP is not validated for detecting cardiac amyloidosis. HDP and PYP are sensitive tracers to detect cardiac amyloidosis. MDP should not be used. SFLC measurement is essential. For those with abnormal SFLC, biopsy and referral to an amyloidosis service to exclude AL is recommended.

Monoclonal Gammopathy of Undetermined Significance (MGUS): Indications for Pre-Diagnostic Testing, Subsequent Diagnoses, and Follow-up Practice

Introduction: MGUS is generally an incidental finding in the diagnostic work-up for clinical signs and symptoms suggestive of lymphoplasmacytic malignancies (multiple myeloma, light chain amyloidosis, and Waldenström macroglobulinemia), which are relatively rare (<35,000 annual new cases in the US). While much is known about the natural history of MGUS, information regarding the pre- and post-diagnostic part of MGUS patient care is lacking. Our study objectives were to determine the following: 1) indications for monoclonal protein testing; 2) subsequent diagnoses found for those indications; 3) specialty of ordering clinicians; 4) follow-up patterns after MGUS diagnosis.Methods: We identified MGUS patients residing in southeastern Minnesota who were diagnosed from 2011-2014 and followed at the Mayo Clinic. Medical records were reviewed to confirm the diagnosis and obtain relevant clinical data. Laboratory tests and visits were identified using Current Procedural Terminology-4th edition (CPT-4) codes from billing data. We defined a follow-up visit as: 1) any face-to-face encounter linked to MGUS diagnosis 30 days after the date of MGUS diagnosis regardless of whether ancillary test was performed or not; and 2) MGUS-specific tests or laboratory tests linked to an MGUS diagnosis claim performed without a face-to-face encounter. Based on the Mayo Clinic MGUS risk stratification model, we classified our cohort into either low-risk or non-low risk. Criteria for low-risk used were: serum monoclonal protein <1.5 g/dL, IgG subtype, and normal serum free light chain ratio. Follow-up patterns were analyzed according to year of diagnosis, demographics, and the specialty of clinicians performing the follow-up.Results: 330 MGUS patients were included in the study. The median age at diagnosis was 73 years (range, 21-98) and most were males (59.7%). The common indications for monoclonal protein studies were neuropathy (19.6%), kidney disease (13.6%), anemia (12.7%), bone symptoms/signs (12.7%), cutaneous disorders (5.8%), congestive heart failure (4.8%), and hypercalcemia (2.7%). The most common subsequent diagnoses for these indications were neuropathy not otherwise specified (NOS;100%), chronic kidney disease NOS (35.5%), anemia of chronic kidney disease (19%), osteopenia/osteoporosis (45.2%), congestive heart failure NOS (57.1%), and dermatitis NOS (100%), respectively. The practice specialties that most commonly diagnosed MGUS were internal medicine (31.3%), neurology (13.7%), nephrology (10.3%), family medicine (6.1%), and hematology (5.8%).Low risk MGUS comprised 44.8% of the cohort. After a median follow-up of 53.5 months (range, 13.0-77.4; IQR, 40.8-77.4), the total number of follow-up visits was 937. Majority (85.5%) of the visits were a combination of office visit with laboratory testing, while the rest were either office visit (11.2%) or laboratory tests (3.3%) only. The distribution of patients by mean interval between visits was: every <6 months (7.9%); every 6-12 months (19.4%); every 13-24 months (15.2%), and every >24 months or no follow-up at all (57.6%). The follow-up patterns did not change significantly (Kruskal Wallis; P=0.6759) over time (Figure 1) and were similar when age groups were compared (Figure 2; P=0.1328). However, males were followed more frequently than females (P=0.0365). Among patients 80 years and older, 32.1% continued to be followed at least once every 2 years (Figure 2). Hematologists were more likely than non-hematologists to follow MGUS patients regardless of the risk category (Figures 3-4). Among low risk patients, 31.1%, 22.2%, 20.7%, and 19.1% had at least one follow-up during years 2, 3, 4, and 5, after MGUS diagnosis (Figure 3).Conclusions: Approximately 1/3 of MGUS diagnoses were made during the evaluation of signs and symptoms not related to lymphoplasmacytic malignancies. The subsequent diagnoses found were a wide variety of common diseases. Most MGUS diagnoses were made by general internists, neurologists, and nephrologists. Follow-up practices varied between hematologists and non-hematologists. Nearly 1/3 of the oldest old patients continued to have follow-up, despite limited life expectancy. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Light chain multiple myeloma with normal serum free light chain: report of one case and review of literature

目的 探讨血清游离轻链正常的λ轻链型多发性骨髓瘤的实验室特征与临床意义。 方法 报道1例血清游离轻链水平及比值正常的λ轻链型多发性骨髓瘤，采用免疫比浊法、免疫固定电泳等对患者血清及尿液进行综合分析，并复习相关文献。 结果 患者正常免疫球蛋白水平下降，骨髓中出现大量异型浆细胞。免疫固定电泳：微量λ型，血清蛋白电泳无M带，本周蛋白阴性。血清游离轻链水平及比值正常。诊断为λ轻链型多发性骨髓瘤。 结论 血清游离轻链正常的轻链型多发性骨髓瘤实验室表现与非分泌型多发性骨髓瘤虽有相似之处，但有区别，免疫固定电泳有助于两种疾病的鉴别。

Immunoglobulin heavy light chain test quantifies clonal disease in patients with AL amyloidosis and normal serum free light chain ratio

Background: Serum and urine immunofixation electrophoreses (SIFE/UIFE) are used for clonal detection in plasma cell dyscrasias, while serum free light chain (sFLC) testing provides quantitation of clonal disease. Up to 20% of patients with light chain (AL) amyloidosis may present with normal FLC ratio (FLCr).Methods: We assessed the diagnostic, quantitative and prognostic potential of serum heavy light chain ratio (HLCr) in 199 untreated patients at initial evaluation.Results: An abnormal HLCr was found in 37.2%, abnormal FLCr in 81.9% and positivity by SIFE/UIFE in 94% of patients. HLCr together with SIFE/UIFE identified clonality in 94% patients; the combination with FLCr yielded 100% sensitivity. An HLCr abnormality was significantly over-represented in normal compared to abnormal FLCr group (63.9% versus 31.3%). HLCr did not predict overall survival (OS) (log rank, p = 0.09), while an abnormal FLCr was associated with decreased OS (log rank, p = 0.03). The combined use of both ratios trended toward increased OS in the abnormal HLCr/normal FLCr group (log rank, p = 0.11; Wilcoxon, p = 0.04). On multivariate analysis, HLCr was not predictive of OS, whereas an abnormal FLCr was associated with shorter OS (HR = 1.7, p = 0.04).Conclusions: The HLC assay has potential as a supplemental test to quantify monoclonal protein in patients with normal FLCr results.

Heavy/Light Chain Quantification Identifies Clonal Plasma Cell Disease in Patients with AL Amyloidosis and Normal Serum Free Light Chain Ratio

Background: Serum and urine immunofixation electrophoreses (SIFE/UIFE) are routinely used for detection of clonal immunoglobulins (Ig) in AL amyloidosis. Serum free light chain (FLC) assays (Freelite®, The Binding Site Ltd., Birmingham, UK) have significantly improved the management of patients with AL amyloidosis by providing quantitative measure for the detection and monitoring of clonal plasma cell disease. However, up to 20% of patients with AL amyloidosis may have uninformative serum free light chain values.Objective: To assess the quantitative potential of serum Heavy/Light Chain (HLC) pairs (Hevylite®, The Binding Site Ltd., Birmingham, UK) assay in identification of clonal plasma cell disease in AL amyloidosis.Methods: One hundred and ninety-nine untreated patients with AL amyloidosis were included in this study. Patients with multiple myeloma or B cell lymphoproliferative diseases associated AL amyloidosis were excluded. Serum sampleswere obtained at initial evaluation and stored at -20°C. SIFE/UIFE were performed at the time of sample collection. HLC pairs were assessed by the Hevylite® assay. HLC κ/λ normal ratios (HLCR) were: 1.12-3.21 for IgG κ/λ; 0.78-1.94 for IgA κ/λ; and 1.18-2.74 for IgM κ/λ. FLCs were assessed by the Freelite® assay; FLC κ/λ normal ratio (FLCR) was 0.26-1.65. In 103 cases, FLC testing was performed at the time of sample collection; 96 cases were tested at The Binding Site. Vital status of patients was obtained from either medical records or Social Security Death Index. Follow-up ended in June 2014.Results: An abnormal HLCR was found in 74 (37.2%), an abnormal FLCR in 163 (81.9%), and SIFE/UIFE positivity in 187 (94%) of 199 patients with AL amyloidosis. Of 36 patients with a normal FLCR, 23 (63.9%) were noted with an abnormal HLCR compared to 51 (31.3%) patients in an abnormal FLCR group (P = 0.001). In total 186/199 (93.5%) patients with AL amyloidosis had abnormalities in either HLCR or FLCR, compared to 187/199 (94%) of patients who were SIFE/UIFE+ (Table 1). The combined use of both FLCR and HLCR yielded quantifiable information in 93.5% of cases; the use of both tests in combination with SIFE/UIFE identified plasma cell clonality in 100% of patients. Seventy-two cases presented with an abnormal HLCR for a single isotype and 2 in multiple Ig isotypes. In all cases, involved LC type of abnormal HLCR matched LC type identified by SIFE/UIFE. None of 12 cases that were negative on the SIFE/UIFE presented with an abnormal HLCR, however, all showed abnormalities in FLCR.Table 1Comparative efficiency of FLCR, HLCR and Serum/Urine Immunofixation in AL Amyloidosis patients.SIFE/UIFE+ (n=187)SIFE/UIFE- (n=12)HLCR+/FLCR+51 (27.2%)-HLCR+/FLCR-23 (12.3%)-HLCR-/FLCR+100 (53.5%)12 (100%)HLCR-/FLCR-13 (7%)-Overall survival was similar in patients with and without abnormal HLCR (Log rank p=0.092; Figure 1), whereas patients with an abnormal FLCR had a significantly inferior overall survival compared to those with a normal FLCR (Log rank p=0.027; Figure 2). Combined use of both HLCR and FLCR demonstrated a trend toward superior overall survival in a group of patients with an abnormal HLCR / normal FLCR (Wilcoxon p=0.037; Log rank p=0.107; Figure 3).Conclusions: The Hevylite® assay provided information in addition to other laboratory tests for clonal plasma cell disease in AL amyloidosis. The combined use of the HLCR and FLCR provided quantifiable information in 93.5% of patients. The use of both assays in combination with SIFE/UIFE detected clonal disease in all patients. HLCR has potential to quantify clonal disease in patients with uninformative FLCR results. An abnormal HLCR was not predictive of overall survival, while an abnormal FLCR was, in this series of patients. Combined use of HLCR and FLCR could be beneficial in prognostication of outcome in AL amyloidosis. [Display omitted] [Display omitted] [Display omitted] DisclosuresMcConnell:The Binding SIte: Employment. O'hara:The Binding Site: Employment.

Prognostic Implications of Oligoclonal Bands in Patients with Multiple Myeloma:Its Development per Se did Not Confer the Prologation of Survival

Background: Multiple myeloma (MM) is characterised by the production of monoclonal immunoglobulin (Ig) and clonal proliferation of neoplastic plasma cells in bone marrow. The emergence of oligoclonal bands (OB) in serum and/or urine immunofixation electrophoresis (IFE) that is different to that observed at diagnosis has been reported with varying frequency in patients with stem cell transplantation (SCT) or favourable response to chemotherapy, although its prognostic relevance remains unclear. Here, we retrospectively analysed clinical records and results serial serum and/or urine IFE to determine the frequency, clinical characteristics and prognostic impact of OB that developed after treatment. We also analysed the effects of OB on the results of free light chain (FLC) assay that may affect the stringent CR (sCR) criteria proposed by the IMWG.Patients: We retrospectively reviewed 180 patients with MM admitted to the Department of Hematology/Oncology at Kameda Medical Center, Kamogawa, Japan, from January 2006 to May 2014.Seventeen patients were excluded from the analysis due to lack of appropriate follow-up data.Method: An OB was defined as the presence of a serum and/or urine IFE monoclonal spike that was different from the original myeloma protein in heavy and/or light chains, as well as a different IFE migration pattern. IFE was performed at least every three months after obtaining very good partial response (VGPR) and then until the disease progression or relapse was confirmed. Overall survival (OS) and progression free survival (PFS) were analyzed in 173 MM patients by the Kaplan–Meier method, and differences between the curves were calculated by two-sided log-rank test. Free light chain (FLC) and minimal residual disease measurement by multicolour flowcytometory (MFC) were performed to evaluate the response to treatment.Results: Myeloma response more than VGPR and CR were achieved in 87 (53.3%) and 54 (33.1%) patients, respectively. None of the patients with less than PR developed OB, and OB developed in 36.3% (12/33) and 51.9% (28/54) of the patients with VGPR and CR, respectively. Among the 30 patients who received SCT, 18 patients (60.0%) developed OB, whereas only 12 of 133 patients who did not receive SCT developed OB. The emergence of OB was significantly higher in patients receiving SCT (P < 0.001). The median PFS of the patients with and without OB were 79.4 months and 19.2 months (P = 0.028), respectively, and those of OS did not reached and 41.1 months (P < 0.001), respectively (Figure 1). However, if patient response was limited to CR, median PFS and OS of patients with and without OB were not significantly different between the two groups (79.4 months vs. 80.1months, respectively, P = 0.646; and not reached and not reached, respectively, P = 0.776; Figure 2). OB was observed in 60% of patients after SCT, and in 36.6% of patients more than VGPR without SCT (P<0.001). In the patients who received SCT, the presence of OB was not associated with either PFS or OS (20.0 months vs 44.7 months, P=0.543 and not reached vs not reached, P= 0.739, respectively; Figure3). We also analyzed the association between residual myeloma cells assessed by the MFC in the patients who achieved CR according to the development of OB. Although the patients with OB showed slightly lower levels of residual myeloma cells than those without OB (2.49 x10-4vs 4.15 x10-4), there was no significant difference between the two groups (P= 0.054). As the presence of OB may result in an abnormal serum FLC kappa/lambda ratio, we examined the association of FLC kappa/lambda ratio and development of OB in 28 patients who achieved CR. Abnormal FLC kappa/lambda ratio was observed in 10 (35.7%) and 4 (15.3%) patients with and without OB, respectively, among those with CR (P = 0.118). Conversely, OB was detected in 10 of the 14 patients with an abnormal FLC ratio (71.4%) versus 18 of 40 (45.0%) with a normal serum FLC ratio (P = 0.164) among those with CR.Conclusions: In conclusion, we showed that the emergence of OB occurred exclusively in patients with favourable myeloma responses (more than VGPR) and was associated with prolonged survival. Patients with OB appeared to have fewer residual myeloma cells compared to those without OB. However, its development did not confer an additional survival benefit among the patients who achieved CR. In addition, it is possible that the emergence of OB affects the sCR response criteria proposed by the IMWG. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Serum immunoglobulin free light chain and heavy/light chain measurements in POEMS syndrome

POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome is a rare plasma cell dyscrasia. Nearly all patients present with a λ-restricted monoclonal gammopathy. Most patients with POEMS syndrome have been reported to have a normal serum free light chain ratio (sFLC-R), but the underlying mechanism is still unclear. We assessed the serum free light chains in 83 patients with newly diagnosed POEMS syndrome. The clinical and laboratory data associated with this disorder were collected to identify factors affecting sFLC-R. Fifty-six patients (67%) showed elevated serum free λ light chains, but only 11 patients (13%) had an abnormal sFLC-R. A comparison of patients with and without abnormal sFLC-Rs indicated that the latter group had more common splenomegaly and worse renal function. However, the introduction of an extended renal range for sFLC-R did not dramatically improve the diagnostic value of sFLC-R in these patients. Further analyses identified a correlation between the serum free κ light chain and the uninvolved immunoglobulin in patients with an IgAλ clone, implying that the activation of polyclonal immunoglobulin production could mask the presumed skewing of the sFLC-R induced by the underlying monoclonal gammopathy. Therefore, a serum heavy/light chain (sHLC) assay was performed in a subset of patients with stored serum samples available, and the prevalence of abnormal sHLC ratios was high in these patients. In summary, the overproduction of polyclonal immunoglobulin accounts for the high frequency of normal sFLC-R in patients with POEMS syndrome. The sHLC assay may provide unique information about this disorder.

Minimal Residual Disease in Multiple Myeloma

Minimal Residual Disease in Multiple Myeloma

The Serum Free Light Chain Assay Allows Earlier Detection of Relapse/Progression of Multiple Myeloma After Autologous Hematopoietic Cell Transplantation

Abstract 4466 The International Myeloma Working Group (IMWG) guidelines use serum free light chain (SFLC) response criteria only in multiple myeloma (MM) patients without measurable M-protein in serum or urine and to satisfy stringent complete remission (sCR) criteria. Current response criteria use changes in intact immunoglobulin measured by serum protein electrophoresis and immunofixation (SIF). The role of the SFLC assay during follow up of MM patients with measurable intact immunoglobulin after autologous hematopoietic cell transplantation (auto-HCT) is not well defined. In order to assess the role of the SFLC assay (Freelite; The Binding Site Group Ltd, Birmingham, UK) during the follow up of MM patients (with measurable M protein in serum or urine), and its role in detecting relapse compared to SIF test, a retrospective analysis of 20 MM patients after melphalan 200 mg/m2 conditioned first auto-HCT was conducted. Patients were followed for a median 15 months (range 3–36 months) between 2008 and 2011. Each patient had both the SFLC assay and SIF performed every 3 months at each routine clinic visit. No patient had renal failure (defined as serum creatinine 2 mg/dl or more). No patient deaths occurred during the follow up period. Two groups were identified. 10 patients without relapse had the following characteristics: median age at HCT 55 years (range 46–68 years); median time from diagnosis to auto-HCT 6.5 months (3–18 months); Durie-Salmon stage IIIA (n=7), stage IA (n=3); IgG kappa (n=5), IgG lambda (n=5); response to HCT very good partial remission VGPR 1 (n=5), CR1 (n=3), and sCR1 (n=2). All patients without relapse maintained a normal SFLC ratio (0.26–1.65) after HCT with negative SIF (n=5), or stable SIF (n=3) and in 2 patients (who were on lenalidomide maintenance), the SIF became negative 12 months and 18 months after HCT. 10 MM patients relapsed after auto-HCT: median age at HCT 55 years (range 46–68 yrs); Durie-Salmon stage IIIA (n=9), IA (n=1); IgG kappa (n=4), IgG lambda (n=2), kappa (n=2), lambda (n=1), IgA kappa (n=1); median time from diagnosis to HCT 8 months (range 4–28 months); response to HCT VGPR1 (n=7), CR1 (n=3). In all the patients who relapsed, the SFLC ratio became abnormal (&lt;0.26 or &gt;1.65) at a median of 3 months (range 3–12 months) before any other test detected relapse, (including SIF, bone marrow biopsy) and the SFLC ratio remained abnormal and continued to worsen over the follow up period. Salvage chemotherapy was begun at a median of 3 months (range 3–12 months) after the SFLC ratio became abnormal after confirmation of relapse by current approved methods (elevation of SIF or bone marrow biopsy). In follow up after HCT, 5 patients who relapsed developed an abnormal SFLC ratio (&lt;0.26 or &gt;1.65) without a concomitant increase in SIF and these patients had bone marrow biopsy confirmation of relapse (25% increase of plasma cells from baseline). In one patient, the SFLC ratio became abnormal at 3 months post HCT with negative SIF, and negative bone marrow biopsy at 3 months after HCT and multiple extramedullary plasmacytomas were found at 4 months after HCT accounting for the relapse. Conclusion: Abnormal SFLC ratio allowed earlier detection of relapse/progression of MM after auto-HCT even in those with measurable M protein in serum and urine and not only in light chain MM but also in those with intact heavy chain immunoglobulins compared to SIF and this can be critical for earlier intervention with salvage strategies. There are currently no guidelines for use of the SFLC assay in follow up of MM patients with measurable serum and urine M protein. The serum free light chain assay should be used concomitantly with serum protein electrophoresis and immunofixation in the follow up of MM patients after auto-HCT. Disclosures: No relevant conflicts of interest to declare.

Comparison of Immunofixation, Serum Free Light Chain, and Immunophenotyping for Response Evaluation and Prognostication in Multiple Myeloma

To investigate the impact of immunophenotypic response (IR) versus complete response (CR) and CR plus normal serum free light chain (sFLC) ratio (stringent CR) in elderly patients with multiple myeloma (MM) treated with novel agents. From a total of 260 elderly patients newly diagnosed with MM included in the GEM05>65y trial, 102 patients achieving at least a partial response with ≥ 70% reduction in M-component after the six planned induction cycles were simultaneously analyzed by immunofixation, sFLC, and multiparameter flow cytometry (MFC) immunophenotyping; this population is the focus of this study. Forty-three percent of patients achieved CR, 30% achieved stringent CR, and 30% achieved IR. Patients in stringent CR showed no significant survival advantage compared with those in CR, whereas patients in IR showed significantly increased progression-free survival (PFS) and time to progression (TTP) compared with those in stringent CR or CR; this was confirmed by multivariate analysis (hazard ratio, 4.1; P = .01 for PFS). Discrepancies between the three techniques were relatively common. Notably, in all seven patients achieving IR but remaining immunofixation positive, the M-component disappeared in follow-up analysis. In contrast, MFC-positive patients who were immunofixation negative (n = 20) showed a tendency toward early reappearance of the M-component (median, 3 months). Similarly, in five of 11 stringent CR but MFC-positive patients, symptomatic disease progression was recorded at a median of 13 months after induction. Achieving an IR translates into superior PFS and TTP compared with conventional CR or stringent CR. These techniques provide complementary information and thus, an effort should be made to refine response criteria in MM.

Macroglossia – Not Always AL Amyloidosis

AbstractAbstract 5007 Introduction:Amyloidosis is characterized by extracellular deposition of abnormal insoluble fibrillar proteins. The two most frequent systemic amyloidoses are the light-chain (AL amyloidosis) and familial transthyretin (ATTR) forms. Clinical presentations often vary between the two types. Macroglossia is viewed as pathognomic of AL amyloidosis, and has not previously been described in patients with hereditary TTR amyloidosis. Here, we describe two cases of systemic amyloidosis with macroglossia in which immuno-electron microscopy diagnosed ATTR in one and AL in the other. Case Presentations:A 61 year old woman presented initially to her general internist with weight loss, difficulty swallowing, and tongue numbness. Her clinical exam revealed macroglossia and peripheral neuropathy. Tongue and axillary lymph node biopsies demonstrated amyloid deposits by Congo red staining. There was no evidence of renal, cardiac or other vital organ involvement. She had no evidence of a plasma cell dyscrasia with negative serum and urine immunofixation electrophoresis, normal serum free light chain concentration and ratio as well as polytypic plasma cells in the bone marrow. Immuno-electron microscopy using gold-labeled antibodies was performed on the tongue biopsy. The fibrils were immunoreactive with anti-TTR but not anti-kappa, anti-lambda, or anti-AA antibodies. DNA sequencing identified a known amyloidogenic T60A TTR mutation in exon 3 of chromosome 18, confirming the diagnosis of ATTR with amyloidotic polyneuropathy and macroglossia. The second case involved a 59 year old man with renal insufficiency. He complained of fatigue, weight loss, and tongue swelling. Physical examination was significant for macroglossia and submandibular gland enlargement. Tongue biopsy demonstrated amyloid deposits by Congo red staining. As in the previous case, markers of plasma cell dyscrasia with clonal plasma cells in the bone marrow, blood, and urine were absent. Immuno-electron microscopy of the tongue biopsy documented antibody reactivity to lambda light chain and not TTR, kappa light chain or AA proteins, confirming the diagnosis of AL amyloidosis. He subsequently underwent treatment with high dose intravenous melphalan followed by stem cell transplantation achieving a good clinical response sustained for 2 years to date. Discussion:While macroglossia is thought to be pathognomonic of AL amyloidosis, we report a case of macroglossia with fibrillar ATTR amyloid deposits diagnosed by immuno-electron microscopy. This is contrasted with a clinical presentation consistent with AL in which routine laboratory testing failed to identify evidence of a plasma cell dyscrasia. In both cases, electron microscopy demonstrated immunoreactivity for the fibrils of a single pathogenic protein. The first case was confirmed by DNA sequencing, and the second had a typical response to anti-plasma cell chemotherapy, in spite of the lack of identifiable markers of disease. Disclosures:No relevant conflicts of interest to declare.

The Relationship Between Serum Free Light Chain Levels and Urine Protein in Patients with IgG or IgA Myeloma.

Abstract 1810Poster Board I-836The serum free light chain (SFLC) assay is often though to be a replacement for the cumbersome process of 24-hour urine collection for monoclonal protein estimation (http://www.freelite.co.uk/initialinvestigationpro-24.asp; accessed 16 July 2009) despite evidence suggesting that SFLC estimation cannot replace urine protein quantification (Singhal et al. Blood 2007; 109:3611-2). We studied results from patients with IgG or IgA myeloma if all the following criteria were satisfied: concomitant SFLC and 24-hour urine specimens analyzed, no oligoclonal proteins, no diminished free light chain levels (involved or uninvolved). The aim was to study the correlation between SFLC and 24-hour urine total protein (24UTP), 24-hour urine monoclonal protein (24UMP) and urine immunofixation electrophoresis (UIFE). Only concordant abnormal SFLC ratios were considered abnormal (Singhal et al. Blood 2009; 114:38-9). 558 samples in 114 patients were identified. SFLC ratio was abnormal in 242 and normal in 316 (including 2 discordant abnormal). UIFE (available in 540) was negative in 290. The proportion of samples with normal SFLC ratio decreased as 24UTP increased (P<0.001): ≤200 mg - 75% of 243, 200-500 mg 33% of 129, 501-1000 mg - 24% of 54, and >1000 mg - 6% of 32. Similarly, the proportion of samples with normal SFLC ratio declined as 24UMP increased (P=0.001): ≤200 mg (including negative) - 41% of 145, 200-500 mg 4% of 28, 501-1000 mg - 0% of 14, and >1000 mg - 0% of 15. SFLC ratio was normal in 84% of samples with negative UIFE and in 26% of samples with positive UIFE (P<0.0001). Among the 47 samples with abnormal SFLC ratio and negative UIFE, the 24UTP was 47-288 mg (median 112). 24UMP was 35 mg in 1, “faint” in 1, and no restricted bands were seen in ther remaining 45. The table shows the relationship between UPEP, UIFE and SFLC amongst the 540 samples where all 3 tests were available. The presence of any restricted band on UPEP, even if too small to quantify, was considered positive.n=540Positive UPEPNegative UPEPPositive UIFENegative UIFEPositive UIFE22228Negative UIFE17273Abnormal SFLC ratio1725918447Normal SFLC ratio6724266243If a positive UPEP is considered the “gold standard” evidence of the presence monoclonal light chains in the urine, the sensitivity of UIFE in detecting urine monoclonal protein is 93% and that of an abnormal SFLC ratio is 72%. On the other hand, if a positive UIFE is considered the “gold standard” evidence of monoclonal light chains in the urine, the sensitivity of an abnormal SFLC ratio in detecting urine monoclonal protein is 74%. These data, obtained from a much large number of homogeneous clinical samples, confirm our previous observations (Singhal et al. Blood 2007; 109:3611-2) that an abnormal SFLC ratio cannot consistently predict the presence of either non-specific or monoclonal proteinuria. Fortunately, the proportion of urine samples with large aounts of non-specific or monoclonal proteinuria that is associated with normal SFLC ratios is small. The sensitivity of the SFLC ratio in detecting urine monoclonal protein is less than that of UIFE. The SFLC assay cannot replace 24-hour urine collection in clinical practice without compromising patient care. Whether a less cumbersome technique such as a spot (random) urine protein-creatinine ratio - used in conjunction with the SFLC assay - can avert the need for 24-hour urine collections in myeloma patients remains to be investigated. DisclosuresNo relevant conflicts of interest to declare.

UK Myeloma Forum (UKMF) and Nordic Myeloma Study Group (NMSG): guidelines for the investigation of newly detected M‐proteins and the management of monoclonal gammopathy of undetermined significance (MGUS)

Avon Haematology Unit, Bristol Haematology and Oncology Centre, Bristol, Department of Haematology, St Helier Hospital, Carshalton, Surrey, UK, Department of Haematology, Sahlgrenska University Hospital, Gothenburg, Sweden, Department of Medicine, Malmo University Hospital, Malmo, Sweden, Division of Immunity and Infection, University of Birmingham, Birmingham, Department of Clinical Biochemistry, Frenchay Hospital, Bristol, Department Haematology, University College, London, Glasgow Western Infirmary, Glasgow, UK, Department of Haematology, NTNU/St Olavs Hospital, Trondheim, Department of Haematology, Ulleval University Hospital, Oslo, Norway, Department of Haematology Aalborg Hospital, Aarhus University Hospital, Aalborg, Denmark, and Myeloma UK.