Cytoplasmic Light Chain Research Articles

The expanding clinical and genetic spectrum of DYNC1H1-related disorders

Abstract Intracellular trafficking involves an intricate machinery of motor complexes including the dynein complex to shuttle cargo for autophagolysosomal degradation. Deficiency in dynein axonemal chains as well as cytoplasmic light and intermediate chains have been linked with ciliary dyskinesia and skeletal dysplasia. The cytoplasmic dynein 1 heavy chain protein (DYNC1H1) serves as a core complex for retrograde trafficking in neuronal axons. Dominant pathogenic variants in DYNC1H1 have been previously implicated in peripheral neuromuscular disorders (NMD) and neurodevelopmental disorders (NDD). As heavy-chain dynein is ubiquitously expressed, the apparent selectivity of heavy-chain dyneinopathy for motor neuronal phenotypes remains currently unaccounted for. Here, we aimed to evaluate the full DYNC1H1-related clinical, molecular and imaging spectrum, including multisystem features and novel phenotypes presenting throughout life. We identified 47 cases from 43 families with pathogenic heterozygous variants in DYNC1H1 (aged 0-59 years) and collected phenotypic data via a comprehensive standardized survey and clinical follow-up appointments. Most patients presented with divergent and previously unrecognized neurological and multisystem features, leading to significant delays in genetic testing and establishing the correct diagnosis. Neurological phenotypes include novel autonomic features, previously rarely described behavioral disorders, movement disorders, and periventricular lesions. Sensory neuropathy was identified in nine patients (median age of onset 10.6 years), of which five were only diagnosed after the second decade of life, and three had a progressive age-dependent sensory neuropathy. Novel multisystem features included primary immunodeficiency, bilateral sensorineural hearing loss, organ anomalies, and skeletal manifestations, resembling the phenotypic spectrum of other dyneinopathies. We also identified an age-dependent biphasic disease course with developmental regression in the first decade and, following a period of stability, neurodegenerative progression after the second decade of life. Of note, we observed several cases in whom neurodegeneration appeared to be prompted by intercurrent systemic infections with double-stranded DNA viruses (Herpesviridae) or single-stranded RNA viruses (Ross-River fever, SARS-CoV-2). Moreover, the disease course appeared to be exacerbated by viral infections regardless of age and/or severity of NDD manifestations, indicating a role of dynein in anti-viral immunity and neuronal health. In summary, our findings expand the clinical, imaging, and molecular spectrum of pathogenic DYNC1H1 variants beyond motor neuropathy disorders and suggest a life-long continuum and age-related progression due to deficient intracellular trafficking. This study will facilitate early diagnosis and improve counselling and health surveillance of affected patients.

Clinical characteristics and prognosis of newly diagnosed multiple myeloma patients with FGFR3 gene mutations

Objective: This study aimed to investigate the influence of FGFR3 gene mutations on the clinical characteristics and prognosis of patients with newly diagnosed multiple myeloma (NDMM) . Methods: A total of 198 patients with NDMM admitted to the Department of Hematology in Jiangsu Province Hospital between January 2016 and February 2023 were retrospectively analyzed. Next-generation sequencing and cytoplasmic light chain immunofluorescence with fluorescence in situ hybridization were performed for all patients. The prognostic significance of FGFR3 mutation and clinical features were analyzed using the Log-rank test and Cox proportional hazards model. Results: Among 198 patients, 28 carried the FGFR3 gene mutation. These patients had significantly lower serum albumin levels, higher β(2)-microglobulin levels, advanced Revised International Staging System stages, more frequent occurrence of t (4;14) , and shorter median progression-free survival (PFS) time (28 months vs 33 months, P=0.024) and overall survival (OS) time (54 months vs undefined, P=0.028) than patients without FGFR3 mutation. Additionally, patients carrying either FGFR3 mutation or t (4;14) had lower PFS (30 months vs 38 months, P=0.012) and OS (54 months vs undefined, P=0.017) than those without. The Cox proportional hazards model identified FGFR3 mutation as an independent risk factor for PFS and OS. Conclusion: FGFR3 gene mutation was an unfavorable independent prognostic predictor for NDMM.

Validation of the prognostic value of the Mayo MASS and R2-ISS staging systems in patients newly diagnosed with multiple myeloma: A single-center study

Objective: To evaluate the prognostic value of Mayo MASS and R2-ISS staging systems in patients newly diagnosed with multiple myeloma (MM) . Methods: A total of 371 patients newly diagnosed with MM in Jiangsu Province Hospital were included in the study. Cytoplasmic light chain immunofluorescence with fluorescence in situ hybridization (cIg-FISH) was performed to detect cytogenetic abnormality. Clinical characteristics were combined to analyze the disease stage and evaluate the prognosis. Results: There were 37 (10.0%), 264 (71.0%), and 70 (18.8%) patients in R-ISS stage Ⅰ, Ⅱ, and Ⅲ, respectively. The median progression-free survival (PFS) times were 37, 25, and 14 months (P<0.001). The median overall survival (OS) times were not reached (NR), 66, and 30 months (P<0.001). There were 71 (19.1%), 140 (37.7%), and 160 (43.2%) patients in Mayo MASS stages Ⅰ, Ⅱ, and Ⅲ, and the median PFS times periods were 43, 27, and 19 months (P<0.001), and the median OS times were NR, NR, 35 months, respectively (P<0.001). There were, 23 (6.2%), 69 (18.6%), 222 (59.8%), and 57 (15.4%) patients in R2-ISS stages Ⅰ, Ⅱ, Ⅲ, and Ⅳ, respectively. The median PFS times were 47, 31, 25, and 15 months (P=0.001), and the median OS times were NR, NR, 49, and 55 months, respectively (P<0.001) . Conclusion: Based on the R-ISS staging system, Mayo MASS, and R2-ISS prognostic staging system incorporated 1q21+, which allows a better stratification. However, the proportion of stage Ⅲ patients in Mayo MASS and R2-ISS staging systems is relatively high, which is considered related to the high incidence of 1q21+ and ISS Ⅲ in the Chinese population.

The patterns and diagnostic significance of the lack of surface immunoglobulin light chain on mature B cells in clinical samples for lymphoma workup.

Surface immunoglobulin (sIg) light chains are not always detected on mature B cells. This may present as a challenge for clonality determination in clinical flow cytometry. To explore the mechanism and diagnostic significance of sIg negative mature B cells, we retrospectively studied 14 cases of sIg negative reactive B-cell lymphocytosis and 89 cases of sIg negative mature B-cell lymphomas. The expression patterns of sIg and cytoplasmic immunoglobulin (cIg) light chains were studied by flow cytometry using both monoclonal and polyclonal antibodies. These 14 cases of sIg negative reactive B-cell lymphocytosis were proven to be polytypic based on cytoplasmic light chain studies. In 89 cases of sIg negative mature B-cell lymphomas, we described four distinct patterns of abnormal light chain expression including partial or complete loss of sIg or cIg, suggesting different underlying mechanisms. This study represents the first reported series of body or cystic fluids where reactive B cells do not have detectable sIg, arguing strongly against making a diagnosis of B-cell lymphoma based on lack of sIg in mature B cells. Since the lack of sIg does not always predict clonal/neoplastic mature B-cell proliferation, further cIg evaluation should be performed when sIg expression is not detected in mature B cells. The lack of both sIg and cIg in mature B cells may serve as a reliable surrogate clonality/neoplastic marker.

Influence of the number of high-risk cytogenetic abnormalities on the clinical characteristics and prognosis in 360 patients with newly diagnosed multiple myeloma

目的探讨初诊多发性骨髓瘤（MM）患者的高危细胞遗传学异常（HRCA）数目对临床特征及预后的影响。方法选取2013年11月至2020年9月江苏省人民医院收治的360例初诊MM患者，应用胞质轻链免疫荧光结合荧光原位免疫杂交（cIg-FISH）技术检测患者的HRCA，并结合患者的临床资料进行分析。结果360例患者中，无HRCA、1种HRCA、2种HRCA、3种HRCA的患者分别为120例（33.3％）、175例（48.6％）、61例（16.9％）、4例（1.1％）。依据HRCA数目将患者分为无HRCA组、1种HRCA组、≥2种HRCA组，三组患者的R-ISS分期、血红蛋白、白蛋白、骨髓浆细胞比例、诱导治疗后疗效差异均有统计学意义（P值均<0.05）。Cox比例风险回归分析显示，髓外病变（P＝0.018）、HRCA≥2种（P＝0.001）、未行自体造血干细胞移植（P<0.001）是影响患者无进展生存的独立危险因素，乳酸脱氢酶≥220 U/L（P<0.001）、HRCA≥2种（P＝0.001）、未行自体造血干细胞移植（P＝0.005）是影响患者总生存的独立危险因素。生存分析显示，无HRCA组、1种HRCA组、≥2种HRCA组患者的中位无进展生存期分别为28、22、14个月（P＝0.005），中位总生存期分别为未达到、60个月、30个月（P＝0.001）。结论HRCA数目≥2是影响初诊MM患者生存的独立危险因素，HRCA数目越多，肿瘤负荷越重，进展及死亡风险越高。

Relevance of polyclonal plasma cells and post-therapy immunomodulation in measurable residual disease assessment in multiple myeloma.

Immunophenotypic profile and post-therapy alteration in antigenic expression were evaluated in normal, reactive, and aberrant plasma cells (NPC, RPC, and APC) for impact on measurable residual disease (MRD) assessment in multiple myeloma (MM). Samples from non-MM staging marrow (n =30), Hodgkin's lymphoma (n =30) and MM (n =724) were prospectively evaluated for expression profiles of NPC, RPC, and APC using antigens recommended in consensus guidelines. Polyclonal NPC-RPC demonstrated aberrations for all antigens evaluated with a higher frequency of aberrancies in post-therapy samples compared to treatment naïve samples (p <0.001%). Immunomodulation in APC was observed in 79% of post-therapy samples with a change in expression of 1, 2, and ≥3 antigens in 19.9%, 15.6%, and 43.5% samples, respectively. In 13.4% of samples, APC showed no aberrancy and aberrant status was assigned based on cytoplasmic light chain restriction (cyLCR) alone. 9% samples with an admixture of NPC and APC displayed normal cytoplasmic kappa to lambda ratio (cyKLR) when the percentage of APC of total PC (neoplastic plasma cell index, NPCI), was below 25% and 50% for kappa and lambda restricted cases, respectively. The panorama and high frequency of antigenic aberrations on polyclonal PC signify the importance of MRD assay validation on a large cohort under normal and reactive conditions. Frequent Immunophenotypic shifts in APC re-confirm the redundancy of baseline immunophenotype for MRD evaluation. Small clones of APC may be missed by assessment of cyKLR alone and therefore, surface marker aberrancy supported by cyLCR is required for definitive assignment of residual APC.

Rare presentation of kappa light chain proximal tubulopathy with fibrillar aggregates

Abstract Introduction/Objective Patients with dysproteinemias may show a spectrum of renal alterations due to organized deposits of excess immunoglobulins, including primary amyloidosis, myeloma cast nephropathy, monoclonal immunoglobulin deposition disease, and light chain proximal tubulopathy (LCPT). Among the least common is LCPT, which shows ultrastructural cytoplasmic light chain inclusions with crystalline morphology or rarely fibrillar aggregates. We present the case of a patient with LCPT with fibrillar aggregates that is the only such case registered in our large academic surgical pathology electronic database. Our aim is to increase understanding and recognition of this rare variant. Methods/Case Report A 73-year-old man presented with 540 mg/day proteinuria, serum creatinine 5.73 mg/dL, platelets 178,000/cc, and 20% plasma cells in his bone marrow biopsy specimen. Kidney needle biopsy cores examined by light, fluorescent and transmission electron microscopy (EM) showed kappa light chain cast nephropathy and kappa LCPT with fibrillary aggregates, the latter requiring unmasking of kappa epitopes using pronase-treated paraffin sections. Congo red stain was negative. By EM, proximal tubules contained intracellular bundles of tightly aggregated fibrils with mean fibril diameter of 7.7 +/- 1.6 nm. Individual bundles were variably shaped as round, oval, spicular or irregular blobs. Fibrils were not seen in glomeruli. Results (if a Case Study enter NA) NA Conclusion This rare presentation of LCPT with fibrillar aggregates reinforces the utility of renal biopsy diagnosis that includes careful ultrastructural examination of renal tubules. In the absence of EM, the unique fibrillar organization of these cytoplasmic light chain aggregates would otherwise go unrecognized.

MM-340: Plasma Cell Neoplasm in the Central Nervous System: A Case Report

Context Plasma cell neoplasms are a heterogeneous group of diseases involving clonal plasma cell production, secreting monoclonal proteins. Usually, these are conditions that occur in the bone marrow, and involvement in the central nervous system (CNS) is a rare event, affecting about 1% of patients and with unfavorable prognosis. Early diagnosis is indispensable for the initiation of appropriate therapy. Objective The present work aims to describe two cases of patients with plasma cell neoplasms with infiltration in the CNS. Design Case report. Setting Case report with emphasis on laboratory diagnosis performed in a private laboratory of clinical analysis. Patients or Other Participants Case 1: Male patient, 58 years old, previous diagnosis of monoclonal gammopathy IgA, previous plasmocytoma in the sternal region, recurrence with orbital and sacral plasmocytoma treated with cyclophosphamide, thalidomide, and dhimhasone, and refused autologous bone marrow transplantation. He was hospitalized for seizure investigation. Case 2: A 51-year-old male patient with a previous diagnosis of MM; after autologous bone marrow transplantation, he sought medical service with a febrile peak 10 months after transplantation. Clinical evaluation and imaging tests showed multiple sparse lytic lesions in the vertebrae and other permeative bodies distributed throughout the skull cap. Presented with headache and visual turbidity. Interventions Case 1: The CSF sample was collected for cytological analysis, which showed 65% of cells with aberrant plasma cells. Immunophenotypic analysis demonstrated the expression of CD38++ CD138+ plasma markers, sIg-kappa+ cytoplasmic light chain restriction and phenotypic aberration. Case 2: Cytologic analysis detected 95% of aberrant plasmocytes and CFS immunophenotyping, presenting 94.4% of lambda monoclonal plasmocytes. Results Case 1: The patient underwent intrathecal treatment; however, there was progressive worsening and death. Case 2: Polychemotherapy was performed, and the patient had a satisfactory clinical response. Conclusions Clinical symptoms related to the involvement of the CNS in plasma cell neoplasms can be confused with symptoms due to hypercalcemia, hyperuremia, and paraproteinemia, making the laboratory analysis of CSF of paramount importance for proper diagnosis. Pathological cells have aberrant cytological characteristics; therefore, confirmation through immunophenotyping is essential, being a sensitive and quick-to-perform test for diagnostic confirmation. Plasma cell neoplasms are a heterogeneous group of diseases involving clonal plasma cell production, secreting monoclonal proteins. Usually, these are conditions that occur in the bone marrow, and involvement in the central nervous system (CNS) is a rare event, affecting about 1% of patients and with unfavorable prognosis. Early diagnosis is indispensable for the initiation of appropriate therapy. The present work aims to describe two cases of patients with plasma cell neoplasms with infiltration in the CNS. Case report. Case report with emphasis on laboratory diagnosis performed in a private laboratory of clinical analysis. Case 1: Male patient, 58 years old, previous diagnosis of monoclonal gammopathy IgA, previous plasmocytoma in the sternal region, recurrence with orbital and sacral plasmocytoma treated with cyclophosphamide, thalidomide, and dhimhasone, and refused autologous bone marrow transplantation. He was hospitalized for seizure investigation. Case 2: A 51-year-old male patient with a previous diagnosis of MM; after autologous bone marrow transplantation, he sought medical service with a febrile peak 10 months after transplantation. Clinical evaluation and imaging tests showed multiple sparse lytic lesions in the vertebrae and other permeative bodies distributed throughout the skull cap. Presented with headache and visual turbidity. Case 1: The CSF sample was collected for cytological analysis, which showed 65% of cells with aberrant plasma cells. Immunophenotypic analysis demonstrated the expression of CD38++ CD138+ plasma markers, sIg-kappa+ cytoplasmic light chain restriction and phenotypic aberration. Case 2: Cytologic analysis detected 95% of aberrant plasmocytes and CFS immunophenotyping, presenting 94.4% of lambda monoclonal plasmocytes. Case 1: The patient underwent intrathecal treatment; however, there was progressive worsening and death. Case 2: Polychemotherapy was performed, and the patient had a satisfactory clinical response. Clinical symptoms related to the involvement of the CNS in plasma cell neoplasms can be confused with symptoms due to hypercalcemia, hyperuremia, and paraproteinemia, making the laboratory analysis of CSF of paramount importance for proper diagnosis. Pathological cells have aberrant cytological characteristics; therefore, confirmation through immunophenotyping is essential, being a sensitive and quick-to-perform test for diagnostic confirmation.

MM-359: Pattern-Based Identification of Normal and Aberrant Plasma Cell Compartment across a Spectrum of Plasma Cell Proliferative Disorders Using Multiparametric Flow Cytometry

Context The discriminative power of various antigens for delineating normal plasma cells (NPC) from aberrant plasma cells (APC) is variable; thus, understanding of the multiparametric flow cytometry (MFC)-based PC compartment is crucial for reliable PC characterization across various PC proliferative disorders (PCPD). Objective The expression profile and patterns of currently used immunophenotypic (IPT) markers were assessed for their ability to differentiate NPC from APC across the spectrum of PCPDs. Design This is a prospective analysis of patients diagnosed with PCPD (per standard IMWG criteria). Setting Tertiary care cancer center. Patients A total of 900 patients with diagnosis of PCPD were evaluated (MM: 724, PCL: 15, SMM: 12, MGUS: 42, Plasmacytoma: 54, Amyloidosis: 31, POEMS: 22). Interventions Bone marrow aspirate from cases (n=900) and controls (n=30) were processed per consensus guidelines from the Euro-flow protocol. An aberrant PC cluster was defined by >30 plasma cells with light chain expression beyond the range of control samples (0.26 to 3.08) and/or aberrant immunophenotypes (≥3). Main Outcomes Measures 1. Utility of cytoplasmic light chain restriction and 2. Most useful combination of markers to discriminate NPC from APC. Results All cases were segregated into three groups: cases with 1. only APC (n=181); 2. with both NPC and APC (n=574); or 3. only NPC (n=145). The PC compartment was solely characterized by light chain expression and IPT aberrancy in 36.22% (n=326) and 21.88% cases (n=197), respectively (p Conclusions Assessment of cytoplasmic light chain expression by MFC is essential for demonstrating clonality in cases with all normal or all aberrant PC. Pattern-based recognition is a useful parameter that identifies aberrant PC reliably in the majority of cases with co-existing NPC and APC, especially in setting of smaller clones of APC, which are likely to be missed by light chain assessment alone.

Novel Single Panel Method for Minimal Residual Disease Detection for Plasma Cells By Flow Cytometry

Introduction: Advancement in myeloma therapy has significantly improved outcomes including minimal residual disease (MRD) negativity that may be a surrogate for overall survival. We describe an assay using a single 10-colour panel to detect minimal residual disease (MRD) in plasma cell neoplasms to a level &amp;lt; 10-5. Methodology: Bone marrow aspirate specimens for this MRD assay must be from the first pull of 1.0 to 1.5 mL of bone marrow. A 1 in 10 dilution of the bone marrow is prepared and run on the instrument using a WBC count from the following calculation to determine the volume of specimen to process: For the MRD method, a corrective factor of 4 has been empirically determined to provide a sufficient number of cells to achieve the goal of 10-13 million viable cells during analysis. The required volume of bone marrow is added directly to Versalyse (Beckman Coulter) with 10% bovine serum albumin (BSA) in a bulk RBC lysis step. The cells are incubated for 15 minutes at room temperature while rocking. The cells are centrifuged and the following antibodies are added (Table 1): The cells and surface antibodies are incubated for a total of 20 minutes, specimen is gently vortexed at 10 minutes. Intracellular staining is achieved using the IntraPrep Kit (Beckman Coulter) using our standardized laboratory process. Cells are suspended in approximately 2mL of RPMI 1640 with 10% FCS. The specimen is loaded on to the Navios EX flow cytometer (Beckman Coulter)and data is acquired at approximately 5000 to 10000 events per second. The Navios EX is not capable of collecting more 1 700 000 events at acquisition when all 10 fluorescent detectors are in use plus light scatter detectors, so the specimen is repeatedly reloaded a total of 7 or 8 times. All data files are opened in Kaluza (Beckman Coulter) and merged in to a single file. This large data file is then imported in to the analysis template and analyzed for plasma cells. Analysis: A pilot of 20 specimens from patients with varying plasma cell disorders have been analyzed. Half of these specimens contained populations of monoclonal plasma cells. Ranked in order of smallest to largest (Figure 1): The smallest clone detected at 10x10E-4 is comprised of 1311 events. If a theoretical lower limit of quantitation of 50 events or 5x10E-6 in 10 000 000 total cells analyzed is required, this method will meet this criteria .Notably, all bone marrow specimens of adequate quality (not clotted, non-hemodilute) required less than 1.5mL of bone marrow to achieve &amp;gt; 10 000 000 nucleated cells in the final analysis. Analysis is complex using several dozen plots. Plasma cells are identified using CD38 and CD138. Gated plasma cells are analyzed for the immunophenotype of CD56, CD117, CD27, CD45, CD81 and cytoplasmic light chains simultaneously using n-dimensional radar plots (Figures 2, 3a, 3b): Qualitative results can be calculated from adjusted gates (Table 2): Conclusion: This rapid, high-sensitivity assay for immunophenotypically abnormal and clonal plasma cells requires low volumes of bone marrow. Results are ready in approximately 4 hours which is a distinct advantage and sensitivity can be shown to reach 5 X10-6. Disclosures Foley: Amgen,CelgeneJanssen: Honoraria. Mian:Takeda: Consultancy, Honoraria; Sanofi: Consultancy; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy.

Detection of del(17p13) among newly diagnosed multiple myeloma cases using cytoplasmic light chain immunofluorescence combined with FISH and its clinical significance

To detect chromosomal aberrations by using cytoplasmic light chain immunofluorescence with fluorescence in situ hybridization (cIg-FISH), and to explore the correlation of del(17p13) with clinical characteristics, drug response and prognosis among patients with newly diagnosed multiple myeloma (NDMM). Clinical data of 198 cases of NDMM was collected. cIg-FISH and a specific probe (TP53) were used to detect karyotypic abnormalities in bone marrow samples derived from the patients. Correlation between karyotypic abnormalities and clinical data was analyzed. Nineteen of the 198 patients (9.6%) were found to have a karyotype involving del(17p13). The overall survival (OS) and progression-free survival (PFS) for patients with or without del(17p13) was significantly different (P<0.01). No significant difference was found in OS and PFS between patients carrying a del(17p13) on bortezomib and non-bortezomib regimen (OS: P = 0.873; PFS: P = 0.610). cIg-FISH is a simple and convenient method for the detection of karyotypic anomalies in multiple myeloma. Del(17p13) is an indicator for poor prognosis for multiple myeloma patients. Bortezomib cannot improve the survival disadvantage of del(17p13).

Utilizing Multiparametric Flow Cytometry to Identify Patients with Primary Plasma Cell Leukemia at Diagnosis

Utilizing Multiparametric Flow Cytometry to Identify Patients with Primary Plasma Cell Leukemia at Diagnosis

Comparison of minimal residual disease in multiple myeloma patients detected by 8-color panels and next generation flow cytometry

目的比较8色组合和二代流式细胞术（NGF）检测多发性骨髓瘤（MM）患者治疗后微小残留病（MRD）的敏感性。方法分别建立一组检测胞膜抗原CD45、CD38、CD138、CD19、CD56、CD117、CD81和CD27的8C-Mem组，及一组检测胞膜及胞质抗原CD45、CD38、CD138、CD19、CD56、CD27、cκ和cλ的8C-Cyto组，将8C-Mem组和8C-Cyto组合成的8C-2tubes组，3组采用Diva软件分析浆细胞胞膜抗原表达与胞质轻链表达，统称8色组合；NGF是采用Infinicyt软件将8C-2tubes组两管数据融合，进一步分析浆细胞各抗原的表达。以20名正常对照和76例治疗后达完全缓解的MM患者骨髓样本进行检测与比较分析。结果NGF组合识别异常浆细胞（aPC）和克隆性浆细胞（cPC）的阳性率均为88.2%（67/76），一致率为94.7%（72/76），cPC的中位值为0.3530%，均为胞质轻链限制性表达，NGF检测的敏感度为0.0003%。8色组合中，8C-Mem组、8C-Cyto组和8C-2tubes组MRD阳性率分别为84.2%、85.5%和86.8%，均低于NGF的88.2%（P<0.001）；8C-Cyto组和8C-Mem组MRD阳性率低于8C-2tubes组（P<0.001），8C-Mem组MRD阳性率低于8C-Cyto组（P<0.001）。NGF敏感性和特异性优于8色组合，8色组合中8C-2tubes组敏感性和阴性预测值、特异性和阳性预测值及准确性最高，缺点是获取数据太大，采用Diva软件分析耗时长，效率低；其次是8C-Cyto组，8C-Mem最低。结论反应浆细胞克隆性的胞质轻链较胞膜抗原更特异，胞膜抗原异常表达不能完全代表cPC，建议胞膜抗原和胞质轻链同时检测，有条件者优先选择NGF，8色组合中建议选择8C-Cyto组。

Immunophenotypic Heterogeneity of Polytypic Plasma Cells and the Impact on Myeloma Minimal Residual Disease Detection by Multiparameter Flow Cytometry.

Flow cytometry is widely used for minimal residual disease (MRD) detection in plasma cell myeloma (PCM). Recently, an increasing number of studies have demonstrated that polytypic plasma cells (PPCs) display greater immunophenotypic variation than previously appreciated. Our aim was to further characterize the immunophenotype of PPC in this setting. PPC in 102 bone marrow specimens (93 MRD-negative post-treatment PCM and 9 negative initial evaluations for plasma cell neoplasm) were evaluated by 10-color flow cytometry. Frequency of CD19, CD27, CD28, CD56, CD117, and CD138 expression was assessed. All cases showed CD27 and CD19 positivity. CD117 was uniformly negative. Percentage of CD138 expression was variable with one negative case (<20% expression). Percentage of CD28 and CD56 expression was variable and included 11 CD28+ cases as well as 38 CD56+ cases. Forty-two percent (43 of 102) cases showed atypical expression of at least one marker with 36 cases (35%) showing atypical expression of a single marker and 7 cases (7%) showing dual atypical marker expression (CD56+/CD28+). Considerable immunophenotypic variation exists in PPC. The assessment of cytoplasmic light chain distribution, in conjunction with surface marker expression, is recommended to avoid diagnostic inaccuracy in MRD evaluation. © 2019 International Clinical Cytometry Society.

A Case of Mature B-cell Neoplasm with Light Chain Clonality Confirmed by Cytoplasmic Light Chain Expression Using Flow Cytometry

A Case of Mature B-cell Neoplasm with Light Chain Clonality Confirmed by Cytoplasmic Light Chain Expression Using Flow Cytometry

Neospora caninum cytoplasmic dynein LC8 light chain 2 (NcDYNLL2) is differentially produced by pathogenically distinct isolates and regulates the host immune response.

Neospora caninum is the causative agent of bovine neosporosis. A N. caninum cytoplasmic dynein LC8 light chain (NcDYNLL) protein was characterized in this study. Cytoplasmic dyneins, including DYNLLs, belong to the microtubule minus-end-directed motor proteins and are involved in many cellular processes. Previous microarray studies revealed that NcDYNLL was downregulated in the non-pathogenic clone, Ncts-8, when compared with the wild-type NC1 isolate. The present study showed that DYNLLs from different species are highly conserved (>85% identity), and the NcDYNLL belongs to the DYNLL2 family. NcDYNLL2 and Toxoplasma gondii DYNLL2 have identical amino acid sequences, although they are slightly divergent at the genetic level (89% identity). NcDYNLL2 was cloned and expressed in Escherichia coli and purified. NcDYNLL2 was identified in soluble and insoluble fractions of tachyzoite lysate. As expected, soluble NcDYNLL2 was lower in the Ncts-8 lysate when compared with that of NC1 isolate. NcDYNLL2 release by the tachyzoites was low; however, it was increased when tachyzoites were treated with either calcium ionophore or ethanol. The data indicate that NcDYNLL2 may be actively secreted at low levels, but the secretion was upregulated by agents that also augment microneme protein secretions. Immunostaining of NcDYNLL2 in isolated and intracellular Neospora tachyzoites showed a diffuse distribution pattern. Furthermore, rNcDYNLL2 was internalized by the host immune cells and stimulated tumour necrosis factor-α) and interleukin-12 (IL-12) production by murine dendritic cells. Taken together, these results suggest that NcDYNLL2 is a secretory protein that cross-regulates host immunity.

Analysis of HSP27 and the Autophagy Marker LC3B+ Puncta Following Preoperative Chemotherapy Identifies High-Risk Osteosarcoma Patients.

Chemotherapy-induced autophagy is a proposed mechanism of chemoresistance and potential therapeutic target in osteosarcoma. We evaluated heat shock protein 27 (HSP27) and autophagy-related proteins as predictors of pathologic treatment response and prognostic markers among osteosarcoma patients who received standard chemotherapy. We analyzed 394 tumor specimens (pre-treatment, post-treatment, and metastases) from 260 osteosarcoma patients by immunohistochemistry for cytoplasmic light chain 3B (LC3B)-positive puncta, sequestosome 1 (SQSTM1), high mobility group box 1 (HMGB1), and HSP27 expression. The staining percentage and intensity for each marker were scored and the extent to which marker expression was correlated with pathologic response, relapse-free survival (RFS), and overall survival (OS) was assessed. LCB3+ puncta in post-treatment primary tumors (50%) and metastases (67%) was significantly higher than in pre-treatment biopsy specimens (30%; P = 0.023 and <0.001). Among 215 patients with localized osteosarcoma, both pre-treatment [multivariate hazard ratio (HR), 26.7; 95% confidence interval (CI), 1.47-484; P = 0.026] and post-treatment HSP27 expression (multivariate HR, 1.85; 95% CI, 1.03-3.33; P = 0.039) were associated with worse OS. Lack of LC3B+ puncta at resection was an independent poor prognostic marker in both univariate (HR, 1.78; 95% CI, 1.05-3.03; P = 0.034) and multivariate models (HR, 1.75; 95% CI, 1.01-3.04; P = 0.045). Patients with LC3B+/HSP27- tumors at resection had the best 10-year OS (75%) whereas patients with LC3B-/HSP27+ tumors had the worst 10-year survival (25%). Neither HSP27 expression nor the presence of LCB3+ puncta was correlated with pathologic treatment response. Our findings establish HSP27 expression and LC3B+ puncta as independent prognostic markers in osteosarcoma patients receiving standard chemotherapy and support further investigation into strategies targeting HSP27 or modulating autophagy in osteosarcoma treatment. Mol Cancer Ther; 17(6); 1315-23. ©2018 AACR.

The utility of multiparametric flow cytometry in the detection of primary effusion lymphoma (PEL).

Primary effusion lymphoma (PEL) is a rare B cell lymphoproliferative disorder that arises predominantly in body cavities causing malignant effusions. The incidence of PEL is very low, accounting for approximately 4% of all HIV-associated non-Hodgkin lymphomas. PEL has also been described in elderly patients and after solid-organ transplantation. It is associated in all cases with human herpes virus 8 (HHV8). We describe a case of PEL in a 88-year-old HIV-negative woman who presented with progressive dyspnea and moderate right-sided pleural effusion without significant lymphadenopathies or other effusions. The cytological study of the pleural fluid revealed a dense proliferation of large plasmablastic cells. A six-color multiparametric flow cytometry immunophenotyping study was carried out, and revealed 45% of large in size and high cellular complexity cells positive for CD45 (dim), CD38, CD138, CD30 and HLA-DR; and negative for CD19, CD20, cytoplasmatic CD79a, surface and cytoplasmic light chains Kappa and Lambda, CD3, CD4, CD5, CD7, CD8, CD28, CD56, CD81, and CD117. In situ hybridization for EBV-encoded smalI RNA was negative and immunohistochemistry for Kaposi sarcoma herpesvirus (HHV8) confirmed the diagnosis of PEL. Our results confirm that flow cytometry bring useful data in the diagnosis of large-cell lymphomas involving body cavities. © 2018 International Clinical Cytometry Society.

Cytoplasmic Immunoglobulin Light Chain Revelation and Interphase Fluorescence In Situ Hybridization in Myeloma.

The cytogenetic analysis of plasma cell myeloma (PCM) allows stratification of patients so that prognosis may be determined and appropriate therapeutic options can be discussed. Owing to the patchy nature of the disease in the bone marrow (BM), the low proliferative activity of plasma cells and the cryptic nature of some PCM-associated cytogenetic changes, karyotypic analysis in this disease should be augmented with targeted interphase fluorescence in situ hybridization (FISH). Immunofluorescent revelation of cytoplasmic immunoglobulin light chains, together with interphase FISH (cIg-FISH), allows the identification of plasma cells within a sample so that they may be scored preferentially. This is particularly useful in situations where there are only a small percentage of plasma cells in a sample. Where an underlying myeloid disease is suspected the cIg-FISH-negative cells can be scored separately. Two methods are provided in this chapter: the technique for cIg-FISH in fresh PCM BM samples and a procedure for use in fixed cytogenetics preparations.

Daratumumab Interferes with Flow Cytometric Evaluation of Multiple Myeloma

The diagnosis of multiple myeloma (MM) requires the demonstration of clonal plasma cells at ≥10% marrow cellularity or a biopsy-proven bony or extra-medullary plasmacytoma, plus one or more myeloma-defining events. Clinical laboratories use multi-parameter flow cytometry (MFC) evaluation of cytoplasmic light chain expression in CD38-bright, CD45-dim or CD138-positive, CD45dim cells to establish plasma cell clonality with a high-degree of sensitivity and specificity.Daratumumab, a humanized IgG1 kappa monoclonal antibody targeting CD38, has been shown to significantly improve outcomes in refractory MM, and daratumumab was granted breakthrough status in 2013. Daratumumab is currently approved for treatment of MM patients who have failed first-line therapies. It has been noted that daratumumab can interfere in blood bank assays for antibody screening, as well as serum protein electrophoresis (SPEP). We describe for the first time daratumumab interference in the assessment of plasma cell neoplasms by MFC; daratumumab interfered with both CD38- and CD138-based gating strategies in three MM patients.Patient A is a 68 year old man with a 10 year history of MM who had failed multiple therapies. He had then been treated with daratumumab for two months, stopping therapy 25 days prior to bone marrow assessment. Patient B is a 53 year old man with a 3 year history MM who had failed numerous treatments. He had been receiving daratumumab monotherapy for two months at the time of his bone marrow studies. On multiple marrow aspirates at times of relapse prior to receiving daratumumab, both patients had demonstrated CD38-bright positive CD45dim/negative plasma cells expressing aberrant CD56, as well as kappa light chain restriction; mature B cells were polyclonal in both. Patient C is a 65 year old man with a four-year history of MM status post autologous stem cell transplantation, who had been receiving carfilzomib and pomalidomide following relapse and continues to have rising lambda light chains and rib pain. He now has abnormal plasma cells in blood worrisome for plasma cell leukemia.Bone marrow aspirates from patients A and B, and blood from patient C demonstrated near absence of CD38-bright events as detected by MFC (Figure 1). Hypothesizing that these results were due to blocking of the CD38 antigen by daratumumab, gating on CD138-positive events was assessed; surprisingly, virtually no CD138-positive events were detected by MFC. All 3 samples demonstrated a CD56-positive CD45dim population; when light chain studies were employed using specific gating on the CD56-positive population, light chain restriction was demonstrated in all patients (Figure 1). Aspirate morphology confirmed numerous abnormal, nucleolated plasma cells (Figure 2A), thus excluding a sampling error. CD138 and CD38 expression was also tested on the marrow biopsy cores from both patients. In contrast to MFC, immunohistochemistry (IHC) showed positive labeling of plasma cells with both CD138 (Figure 2B) and CD38 (Figure 2C). The reason for the labeling discrepancy between MFC and IHC is unknown. The different antibodies in the assays may target different epitopes; alternatively, tissue fixation/decalcification may dissociate the anti-CD38 therapeutic monoclonal from its target.Detection of clonal plasma cell populations is important for assessing response to therapy. Laboratories relying primarily on MFC to assess marrow aspirates without a concomitant biopsy may falsely diagnose remission or significant disease amelioration in daratumumab-treated patients. MFC is generally highly sensitive for monitoring minimal residual disease (MRD) in MM, but daratumumab-treated patients should have their biopsy evaluated to confirm the MRD assessment by MFC. We were able to detect large numbers of plasma cells and also demonstrate clonality in our patients based on an alternative MFC marker, aberrant CD56 expression, an approach that may not be possible in all cases. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.