Monoclonal Immunoglobulin Heavy Chain Research Articles

Primary adrenal insufficiency developed 22 years after the diagnosis of light and heavy chain deposition disease: a case report.

Monoclonal immunoglobulin deposition diseases (MIDDs), including light and heavy chain deposition disease (LHCDD), are rare and heterogeneous disorders associated with underlying B-cell clonal disorders. Adrenal involvement is a potential extrarenal manifestation of MIDDs; however, limited data are available regarding its prevalence and clinical presentation. Herein, the present report describes, for the first time, a case of primary adrenal insufficiency that developed twenty-two years after a diagnosis of LHCDD had been made. A 69year-old woman with a 10year history of hemodialysis suddenly became bedridden after falling down stairs in the absence of focal neurological deficits. Subsequently, she experienced appetite loss, nausea, vomiting, a fever of unknown origin, and unexplained hypotension. Several months later, primary adrenal insufficiency and normal pressure hydrocephalus were diagnosed and successfully managed. The long-term clinical prognosis of MIDDs has not been fully elucidated despite recent advances in the management of the disorders. This report may contribute to improving our understanding of the disease course.

One Case of Heavy Chain Deposition Disease Treated with Dara+KD Regimen and Literature Review

Background: Heavy chain deposition disease (HCDD) is a systemic disease caused by the deposition of monoclonal immunoglobulin heavy chains in tissues.It is a rare monoclonal immunoglobulin deposition disease. The mechanism of HCDD is still unclear, which may be related to the deletion of heavy chain constant region 1 and the activation of the Complement system by monoclonal heavy chains. Renal biopsy remains the gold standard for diagnosing HCDD at present. There are significant individual differences in the formation of abnormal heavy chains in HCDD patients, and FLC, M protein, and complement detection have certain reference significance for the evaluation of diagnosis and treatment processes. The chemotherapy scheme represented by Bortezomib has a certain effect. HDM/ASCT and kidney transplantation can be used as second-line treatment for some patients. At present, there is no report on the use of CD38 monoclonal antibody combined with KD regimen. Objective: To explore the efficacy and toxicity of CD38 monoclonal antibody combined with KD regimen in the treatment of heavy chain deposition disease. Methods: The diagnosis, treatment and efficacy of HCDD who hospitalized in the Hematology Department of the First Affiliated Hospital of Sun Yat-sen University was analyzed, and the value of CD38 monoclonal antibody combined with KD regimen in the treatment of HCDD was discussed. The patient was male, 44 years old, due to “depressed edema of both lower limbs and eyelid edema for more than two months”. Results: Heavy chain deposition disease is a rare malignant Plasma cell disease. CD38 monoclonal antibody combined with KD regimen can rapidly alleviate the disease,.This patient got CR and obvious improvement of clinical symptoms after 1 cycle chemotherapy, and has no obvious side effects.We be expected to do 4 cycle chemothetaphy and would do ASCT.until now,this patient has got 3 cycles. Conclusion: Heavy chain deposition disease is a rare malignant Plasma cell disease. CD38 monoclonal antibody combined with KD regimen can rapidly alleviate the disease, with fast onset time, high CR rate, obvious improvement of clinical symptoms, and no obvious side effects.

Gastric Mucosa-associated Lymphoid Tissue Lymphoma Mimicking Signet Ring Cell Carcinoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the most common type of extranodal non-Hodgkin lymphoma. Endoscopic findings are nonspecific and variable; therefore, differentiation of this malignancy from early gastric cancer is challenging during endoscopy. Although an endoscopic biopsy is the gold standard for diagnosis, a biopsy may not conclusively establish the diagnosis in all cases. Diagnostic confirmation requires interpretation of the biopsy specimen findings by an experienced histopathologist, and an additional immunoglobulin heavy chain (IgH) rearrangement test may aid with accurate diagnosis. We present a case of gastric MALT lymphoma that histopathologically mimicked signet ring cell carcinoma (SRCC) on evaluation of repeat endoscopic biopsies. Following endoscopic submucosal dissection (ESD), we confirmed the final diagnosis of gastric MALT lymphoma based on histopathological findings of prominent lymphoid infiltrates accompanied by lymphoepithelial lesions and results of the monoclonal IgH rearrangement test. Notably, a few carcinoma-like signet ring cells (SRCs) in the specimen were attributed to a reactive change. Clinicians should be mindful of possible SRCs in gastric MALT lymphoma specimens to avoid misdiagnosis of SRCC in patients with gastric MALT lymphoma. Confirmatory ESD may be useful for accurate diagnosis and appropriate management of such lesions.

Alpha Heavy Chain Disease Post-Diffuse Large B-cell Lymphoma Remission: A Series of Two Cases

Abstract Introduction/Objective Heavy chain disease is the production of abnormal monoclonal immunoglobulin heavy chains. Alpha heavy chain disease is typically identified in mucosa-associated lymphoid tissue lymphomas and is secreted due to chronic infection. The alpha heavy chain can manifest as hypogammaglobulinemia or a normal serum protein electrophoresis (SPEP). Broadband may appear in the alpha-2 or beta mobility regions. Methods/Case Report We describe two cases in which a monoclonal alpha heavy chain was detected in a 60-year-old female with diffuse large B-cell lymphoma (DLBCL) of the thoracic spine and a 71-year-old female with mediastinal DLBCL. Both patients achieved clinical and radiological remission. Results (if a Case Study enter NA) A distinct IgA band without an associated light chain was detected on the first patient's serum immunofixation essay (SIFE) one year later. For the second case, there was a distortion of the beta-2 region, elevated kappa free light chain (230.6 mg/dL), and a kappa to lambda free light chain ratio of 14.23, suggesting alpha heavy chain disease and a possible monoclonal gammopathy of unknown significance. Interestingly, even with a monoclonal IgA, the patients remained symptom-free, without any gastrointestinal manifestations, and concurrent PET scans show no recurrence. Conclusion To the best of our knowledge, these are the first two cases describing the presence of alpha heavy chain disease in association with DLBCL. The significance of alpha heavy chain secretion in patients with a history of DLBCL needs to be further assessed and we need to identify the possible presence of a non-clonally related paraprotein post-treatment for DLBCL.

Classification of Plasma Cell Disorders by 21 Tesla Fourier Transform Ion Cyclotron Resonance Top-Down and Middle-Down MS/MS Analysis of Monoclonal Immunoglobulin Light Chains in Human Serum.

The current five-year survival rate for systemic AL amyloidosis or multiple myeloma is ∼51%, indicating the urgent need for better diagnosis methods and treatment plans. Here, we describe highly specific and sensitive top-down and middle-down MS/MS methods owning the advantages of fast sample preparation, ultrahigh mass accuracy, and extensive residue cleavages with 21 telsa FT-ICR MS/MS. Unlike genomic testing, which requires bone marrow aspiration and may fail to identify all monoclonal immunoglobulins produced by the body, the present method requires only a blood draw. In addition, circulating monoclonal immunoglobulins spanning the entire population are analyzed and reflect the selection of germline sequence by B cells. The monoclonal immunoglobulin light chain FR2-CDR2-FR3 was sequenced by database-aided de novo MS/MS and 100% matched the gene sequencing result, except for two amino acids with isomeric counterparts, enabling accurate germline sequence classification. The monoclonal immunoglobulin heavy chains were also classified into specific germline sequences based on the present method. This work represents the first application of top/middle-down MS/MS sequencing of endogenous human monoclonal immunoglobulins with polyclonal immunoglobulins background.

Diagnostic Accuracy of Immunoglobulin Heavy Chain Rearrangement, FDG-PET/CT and Unilateral Bone Marrow Trephination for Detecting Bone Marrow Involvement in Diffuse Large B Cell Lymphoma

Bone marrow involvement (BMI) has important clinical implication in diffuse large B cell lymphoma (DLBCL) as a component of staging and International Prognostic Index (IPI). However, there are some limitations of BMI assessment using iliac bony trephination, such as low sensitivity to patchy or focal lymphomatous involvement, inter-observers variability, inappropriately obtained specimens in terms of technical problem. This study investigated that whether the combined evaluation with 18F-FDG PET/CT and molecular analysis of monoclonal Immunoglobulin heavy chain (IgH) rearrangement could increase the diagnostic accuracy of BMI at the time of diagnosis in DLBCL.MethodsThis observational study conducted in 100 patients with newly diagnosed DLBCL from January 2017 to May 2018 from single institution. The specimens for IgH rearrangement polymerase chain reaction (PCR) to detect the clonality were obtained by fine-needle aspiration and unilateral trephination biopsy. In addition, 18F-FDG PET/CT assessment was performed at the time of diagnosis and classified into two patterns (focal vs diffuse) based on the type of bony FDG uptakes. The section specimens were reviewed by hematopathologists according to the World Health Organization (WHO) classification.Results53 patients were diagnosed with advanced stage and 9 patients (9%) were confirmed morphologic BMI (mBMI) by section biopsy. IgH monoclonality (IgH BMI) was detected in 17 patients (17%) and bony involvement on PET/CT assessment (PET BMI) was observed in 16 patients (16%), respectively. All nine patients with mBMI were linked together with either IgH BMI or PET BMI. Of 17 patients with IgH BMI, 6 patients (35.2%) were concordant with mBMI. Overall diagnostic accuracy of IgH BMI for detection of mBMI was 86%, and it's sensitivity and specificity was 66.7% and 87.9% with 96.4% of negative predictve value (NPV), respectively. In addition, among the patients with PET BMI, 11 patients were sub-classified into focal type (68.8%, 11/16) with median 7.9 of SUVmax compared to diffuse type with median 5.6 of SUVmax. 5 patients (31.3%, 5/16) were concordant with mBMI. Two of these five concordant cases were focal type. PET/CT assessment showed 85% of diagnostic accuracy with 55.6% of sensitivity, 87.9% of specificity and 95.2% of NPV, respectively. However, the combination of IgH rearrangement with PET/CT assessment resulted in 100% of sensitivity and 79.1% of specificity with 100% of NPV, respectively. Total 28 patients had positive results either IgH rearrangement or PET BMI. 11 patients showed only PET BMI, and another 12 showed only IgH BMI.ConclusionEach PET/CT assessment and PCR-technique for IgH rearrangement was associated with low sensitivity and high NPV for detecting mBMI. However, combined evaluation with IgH monoclonality and initial PET/CT could give more information to predict bone marrow involvement of DLBCL [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Spontaneous regression of primary cutaneous diffuse large B-cell lymphoma, leg type, with multiple lesions

The prognosis of primary cutaneous diffuse B-cell lymphoma, leg type (PCDLBCL-LT) is poor, especially in patients with multiple lesions, which usually requires systemic chemotherapy as treatment. Here, we report a case of PCDLBCL-LT with multiple lesions and spontaneous regression after biopsy. A 66-year-old man was referred to our clinic with a half-year history of multiple plaques on his back and flank. He had hypertension and had been treated with olmesartan, but he did not have a history of autoimmune diseases, such as rheumatoid arthritis, and no medical history of using immunosuppressive agents. On physical examination, multiple annular to arcuate plaques, up to 4-cm diameter, were found in his back and left flank. Superficial lymph nodes were not palpable. A skin biopsy specimen from the lower and upper back showed bottom heavy dense nodular infiltrates with large atypical cells and many small inflammatory cells. Atypical cells were positive for CD20, CD79a, and bcl-2; partially positive for bcl-6; but did not show staining for MUM-1 or CD10. Small lymphoid cells were positive for CD3, and cytotoxic molecules, such as TIA-1 and perforin, were also positive. Monoclonal immunoglobulin heavy chain rearrangement was detected using Southern blotting. Epstein-Barr virus-encoded sRNA was not detected in the tumour using in situ hybridization. Position emission tomography and enhanced computed tomography did not detect any nodal and visceral involvement. We diagnosed the patient as having PCDLBCL-LT (T2, N0, M0). Most of the lesions, including un-biopsied ones, disappeared after biopsy; however, the plaque on the left flank remained. We performed skin biopsy on the remaining lesion, and its pathology was almost similar to those of the previously biopsied lesions. However, this lesion still remained after biopsy; therefore, it was treated with radiation therapy. The patient remained free from recurrence or distant metastasis for a year.

Monitoring immunoglobulin heavy chain and T‑cell receptor gene rearrangement in cfDNA as minimal residual disease detection for patients with acute myeloid leukemia

The present study aimed to examine whether monoclonal immunoglobulin heavy chain (IGH) or T-cell receptor (TCR) gene rearrangement in cell-free DNA (cfDNA) may be used for minimal residual disease (MRD) monitoring in patients with acute myeloid leukemia (AML). Monoclonal IGH and TCR rearrangement in cfDNA were monitored in patients with AML. A total of 94 (40%) patients had monoclonal IGH or TCR rearrangements in cfDNA at diagnosis; 84% of these patients (79 cases) achieved complete remission following 1–3 courses of induction chemotherapy. Among these cases, 89.9% were negative for monoclonal IGH or TCR rearrangement in cfDNA following consolidation chemotherapies. A total of 8 patients with consistently positive monoclonal IGH or TCR rearrangement in cfDNA relapsed within 6–10 months. During follow up, 39 patients demonstrated positive monoclonal IGH or TCR rearrangement in cfDNA and relapsed. Recurrence of monoclonal IGH or TCR rearrangement in cfDNA was observed 1–3 months earlier than bone marrow relapse and 11 patients with solitary extramedullary relapse demonstrated positive monoclonal IGH or TCR rearrangement recurrence in cfDNA. In conclusion, the detection of monoclonal IGH and TCR rearrangement in cfDNA may represent a useful tool for MRD monitoring in patients with AML.

Monoclonal immunoglobulin heavy chain gene rearrangement in Fuchs\u2019 uveitis

BackgroundFuchs’ uveitis (FU) is occasionarlly complicated with heavy vitreous opacity. We have performed vitrectomy procedures to remove vitreous opacity in affected patients as part of differential diagnosis for primary vitreoretinal lymphoma (PVRL).Case presentationWe retrospectively reviewed the clinical records of five patients who first visited the Uveitis Clinic of the University of Tokyo Hospital between 2009 and 2013, were diagnosed with FU and underwent a vitrectomy for removal of dense vitreous opacity. All were diagnosed as FU by ocular findings and elevation of Goldmann-Witmer coefficient (GWC) value for the rubella virus (RV) antibody. In examinations of the vitreous body, cytological diagnosis, elevation of IL-10/IL-6 ratio, and the kappa/lambda ratio in flow cytometry findings were negative in all cases, whereas monoclonal immunoglobulin heavy chain (IgH) gene rearrangement was positive in 4 cases and negative in 1 case.ConclusionsAlthough monoclonal IgH gene rearrangement is thought to be a reliable biomarker for PVRL, a high percentage of vitreous specimens from our FU patients showed pseudo-positive results. Ophthalmologists must take care regarding possible pseudo-positive findings when performing differential diagnosis between FU and PVRL. Combinations of results of cytological diagnosis, IL-10/IL-6 ratio, kappa/lambda ratio, and IgH gene rearrangement may be necessary for a definitive diagnosis of PVRL and differentiation from FU.

Comparison of Epstein–Barr virus‐positive mucocutaneous ulcer associated with treated lymphoma or methotrexate in Japan

The aim of the present study was to compare treated lymphoma-associated Epstein-Barr virus (EBV)-positive mucocutaneous ulcer (EBVMCU) and methotrexate (MTX)-associated EBVMCU. Of a series of 15 Japanese patients (11 women, four men; median age 74years, range 35-84years), seven received MTX for the treatment of autoimmune disease and eight developed EBVMCU after treatment of malignant lymphoma [diffuse large B-cell lymphoma (n=4) without EBV association, adult T-cell leukaemia/lymphoma (n=2), angioimmunoblastic T-cell lymphoma (n=1), and follicular lymphoma (n=1)]. Ulcers were observed in the oral cavity (n=11), gastrointestinal tract (n=2), and skin (n=2). All were histologically characterised by a mixture of EBV-positive large B-cell proliferation and Hodgkin/Reed-Sternberg-like cells on a polymorphous background. A total of 46% (6/13) had monoclonal immunoglobulin heavy chain gene rearrangement, but none had clonal T-cell receptor gene rearrangement. Spontaneous regression occurred in 13 of 15 cases (87%); the other two cases (13%) achieved complete remission after treatment. Of two patients in the treated lymphoma-associated subgroup, one developed multiple new ulcerative lesions on previously unaffected skin, and the other had a relapse of EBVMCU in the oral cavity. No significant clinicopathological differences were found between the subgroups. Notably, none of the patients died from EBVMCU. However, the treated lymphoma-associated subgroup had lower overall survival (P=0.004) and a shorter follow-up period (P=0.003) than the MTX-associated subgroup, owing to death from non-associated causes. Treated lymphoma-associated EBVMCU, which is an indolent and self-limited condition, must be recognised to avoid misdiagnosing it as a relapse of malignant lymphoma during treatment.

Heavy-Chain Diseases and Myeloma-Associated Fanconi Syndrome: an Update.

The heavy chain diseases (HCDs) are rare B-cell malignancies characterized by the production of a monoclonal immunoglobulin heavy chain without an associated light chain. There are three types of HCD, defined by the class of immunoglobulin heavy chain produced: IgA (α-HCD), IgG (γ-HCD), and IgM (μ-HCD). Alpha-HCD is the most common and usually occurs as intestinal malabsorption in a young adult from a country of the Mediterranean area. Gamma- and μ-HCDs are rarer and associated with a B-cell non-Hodgkin lymphoma that produces an abnormal Ig heavy chain. These patients may occasionally be diagnosed with a monoclonal gammopathy of undetermined significance (MGUS). Fanconi syndrome, on the other hand, can be primary (inherited) or secondary (acquired). The only exception to this rule is the idiopathic form. Adult acquired Fanconi syndrome can be a rare complication of a monoclonal gammopathy. At diagnosis, most patients have an MGUS or smoldering multiple myeloma, with renal failure and evidence of osteomalacia. During follow-up, patients can develop an end-stage renal disease. Chemotherapy provides little benefit on renal function.

Spontaneous development of Epstein-Barr Virus associated human lymphomas in a prostate cancer xenograft program.

Prostate cancer research is hampered by the lack of in vivo preclinical models that accurately reflect patient tumour biology and the clinical heterogeneity of human prostate cancer. To overcome these limitations we propagated and characterised a new collection of patient-derived prostate cancer xenografts. Tumour fragments from 147 unsupervised, surgical prostate samples were implanted subcutaneously into immunodeficient Rag2-/-γC-/- mice within 24 hours of surgery. Histologic and molecular characterisation of xenografts was compared with patient characteristics, including androgen-deprivation therapy, and exome sequencing. Xenografts were established from 47 of 147 (32%) implanted primary prostate cancers. Only 14% passaged successfully resulting in 20 stable lines; derived from 20 independent patient samples. Surprisingly, only three of the 20 lines (15%) were confirmed as prostate cancer; one line comprised of mouse stroma, and 16 were verified as human donor-derived lymphoid neoplasms. PCR for Epstein-Barr Virus (EBV) nuclear antigen, together with exome sequencing revealed that the lymphomas were exclusively EBV-associated. Genomic analysis determined that 14 of the 16 EBV+ lines had unique monoclonal or oligoclonal immunoglobulin heavy chain gene rearrangements, confirming their B-cell origin. We conclude that the generation of xenografts from tumour fragments can commonly result in B-cell lymphoma from patients carrying latent EBV. We recommend routine screening, of primary outgrowths, for latent EBV to avoid this phenomenon.

Unravelling the immunopathological mechanisms of heavy chain deposition disease with implications for clinical management

Randall-type heavy chain deposition disease (HCDD) is a rare disorder characterized by tissue deposition of a truncated monoclonal immunoglobulin heavy chain lacking the first constant domain. Pathophysiological mechanisms are unclear and management remains to be defined. Here we retrospectively studied 15 patients with biopsy-proven HCDD of whom 14 presented with stage 3 or higher chronic kidney disease, with nephrotic syndrome in 9. Renal lesions were characterized by nodular glomerulosclerosis, with linear peritubular and glomerular deposits of γ-heavy chain in 12 patients or α-heavy chain in 3 patients, without concurrent light chain staining. Only 2patients had symptomatic myeloma. By serum protein electrophoresis/immunofixation, 13 patients had detectable monoclonal gammopathy. However, none of these techniques allowed detection of the nephrotoxic truncated heavy chain, which was achieved by immunoblot and/or bone marrow heavy chain sequencing in 14 of 15patients. Serum-free kappa to lambda light chain ratiowasabnormal in 11 of 11 patients so examined. Immunofluorescence studies of bone marrow plasma cells showed coexpression of the pathogenic heavy chain with light chain matching the abnormal serum-free light chain in all 3 tested patients. Heavy chain sequencing showed first constant domain deletion in 11 of 11 patients, with high isoelectric point values of the variable domain in 10 of 11patients. All patients received chemotherapy, includingbortezomib in 10 cases. Renal parameters improved in 11patients who achieved a hematological response, as assessed by normalization of the free light chain ratio in8cases. Tissue deposition in HCDD relates to physicochemical peculiarities of both variable and constant heavy chain domains. Early diagnosis and treatment with bortezomib-based combinations appear important to preserve renal prognosis. Thus, monitoring of serum-free light chain is an indirect but useful method to evaluate the hematological response.

T cell receptor rearrangements in a patient with γ-heavy chain disease: A case report.

Heavy chain diseases (HCDs) are rare B cell lymphoplasma cell proliferative disorders that are characterized by the production of incomplete monoclonal immunoglobulin (Ig) heavy chains without the associated light chains. γ-HCD (IgG subtype) is a rare subtype, with ~150 cases reported in the literature to date; however, to the best of our knowledge, no reports of T cell receptor (TCR) gene rearrangement in γ-HCD exist in the literature. The present study reports the case of an 81-year-old man with γ-heavy chain disease associated with TCR gene rearrangement, identified in lymph node biopsy and bone marrow aspirate specimens. The present case revealed an alternative manifestation of γ-HCD, which may provide additional biological insights into this rare B cell disorder.

Serum Versus Urine Free Light Chains for Assessment of Monoclonal Gammopathies

IntroductionMonoclonal gammopathies comprise a spectrum of disorders including Monoclonal Gammopathy of Undetermined Significant (MGUS), Smoldering Multiple Myeloma (SMM), and Active Multiple Myeloma (MM) characterized by production of monoclonal immunoglobulin heavy and/or light chains. Prior to availability of the FREELITE™ (Binding Site Ltd; Birmingham, UK) assay for measurement of immunoglobulin free light chains (FLC), laboratory monitoring of these disorders used predominantly SPEP, quantitation of immunoglobulin heavy chains (quantitative immunoglobulins), and 24 urine collection for total protein and UPEP to extrapolate production of immunoglobulin light chains. The FREELITE™ assay has up to 3-log increased sensitivity (1.5-3.0 mg/L) for detection of free light chains over standard electrophoresis (500-2,000 mg/L) and immunofixation (150-500 mg/L), and since its introduction, has been an integral tool in diagnosis and monitoring of monoclonal gammopathies. This assay detects more plasma cell disorders than SPEP, UPEP and IFE combined due to its higher sensitivity and ability to derive the ratio of affected to unaffected light chain. Measurement of urine FLC using FREELITE™ has not been integrated into standard practice due to presumed variability in FLC concentration due to changes in glomerular filtration, variability in tubular reabsorption of light chains, and lack of data regarding this use. In our practice, we routinely use random urine samples instead of 24 hour urine collections which are cumbersome and suffer from poor patient compliance.Methods:The study was approved by the Stratton VA Medical Center Institutional Review Board. As it has been our practice to obtain both random urine along with serum for FLC, we retrospectively reviewed patients diagnosed with monoclonal gammopathies and compared random urine free light chains measured by FREELITE™ to serum FLC and serum quantitative immunoglobulins. Data was analyzed for correlation using Pearson product moment correlation. P values of >0.05 were considered significant.Results:We identified 23 individuals, all male (consistent with VA population). Mean (±SD) age was 68±10 years at diagnosis, creatinine 1.3±0.5 mg/dl, and 9±6 pairs of data points per patient. Five (5) had MGUS, 5 SM, and 13 MM (2 light chain only). Results are illustrated in the Table. Normalization of urine results using concurrent serum and urine creatinine did not change the statistical significance of any of the results.TableCorrelation (p<0.05) between affected serum immunoglobulin, urine FLC, and serum FLCSerum ImmunoglobulinUrine FLCSerum FLC#(%) of PatientsYESYESno2(10)YESnoYES6(29)YESYESYES5(24)Nonono7(33)YESYES11(48)DiscussionWhile serum FLC is adequate in the majority of patients for monitoring monoclonal gammopathies, urine FLC correlates as well as serum FLC in about ½ of the patients. In addition, in a small number of individuals, urine FLC correlates with serum total serum immunoglobulin better than serum FLC. We feel that random urine FLC is useful for monitoring monoclonal gammopathies, and in a minority of instances, provides more accurate assessment of disease activity than serum. DisclosuresNo relevant conflicts of interest to declare.

Renal AH Amyloidosis Associated With a Truncated Immunoglobulin Heavy Chain Undetectable by Immunostaining

AH amyloidosis is a rare type of amyloidosis caused by deposition of monoclonal immunoglobulin heavy chain. The key diagnostic feature is positive immunostaining for a single class of immunoglobulin heavy chain. We report a case of AH amyloidosis with immunoglobulin G (IgG) λ monoclonal gammopathy that was diagnosed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after immunostaining of renal tissue for immunoglobulin heavy chain gave negative results. The molecular weight of the purified renal amyloid protein was ∼11kDa, which was determined by LC-MS/MS analysis to correspond to an amino acid sequence comprising the variable region and a truncated portion of the constant region of IgG heavy chain. The exact same truncated heavy chain was detected by LC-MS/MS of a protein isolated from the patient's serum, suggesting that the truncated serum protein was the precursor of the amyloid protein. Because antibodies to immunoglobulin heavy chain recognize the Fc portion, the large deletion in the constant region could explain the negative results upon immunostaining. Direct protein detection by LC-MS/MS is a powerful aid to diagnose renal AH amyloidosis, particularly when the findings of immunoglobulin staining are inconsistent with the background monoclonal gammopathy.

Rapid detection of immunoglobulin heavy chain gene rearrangement by PCR and melting curve analysis using combined FR2 and FR3 primers

BackgroundImmunoglobulin heavy chain (IgH) gene rearrangement test is a standard tool in diagnosing B-cell lymphoma. The BIOMED-2 multiplex PCR protocol has become the most commonly used laboratory method for detecting clonal IgH gene rearrangement. However, post-PCR procedure requires manual transfer of PCR product for analysis and is time-consuming. A novel strategy using LightCycler to continuously monitor fluorescence during melting curve analysis (MCA) can overcome these shortcomings. The previous studies published on this method were all restricted to FR3 primers of BIOMED-2.MethodsReal-time PCR and subsequent MCA were performed on 71 clinical DNA samples from formalin-fixed, paraffin-embedded tissues, including 40 with B-cell non-Hodgkin lymphomas and 31 with reactive lymphoid hyperplasia. We optimized the current method using FR3 primers and applied FR2 primers for the first time into MCA to detect IgH gene rearrangement. Polyacrylamide gel electrophoresis and capillary gel electrophoresis were also performed on all lymphoma samples with the identical FR2 primers.ResultsMCA of combined FR2 and FR3 primer sets yielded the sensitivity and the specificity equal to 70 % (28/40) and 100 % (31/31), respectively. Addition of FR2 primers increased the sensitivity by 12.5 % (5/40) comparing to FR3 primers alone. MCA was slightly more sensitive than polyacrylamide gel electrophoresis and comparable to capillary gel electrophoresis to detect clonal IgH gene rearrangement.ConclusionsCombined PCR and DNA melting curve analysis in a closed system can reduce cross-contamination risk. This method can test 96 samples simultaneously within 90 min and therefore, it is high-throughput and faster. PCR-MCA in the LightCycler system has potential for evaluating monoclonal IgH gene rearrangement in a clinical environment.

A mouse model recapitulating human monoclonal heavy chain deposition disease evidences the relevance of proteasome inhibitor therapy

AbstractRandall-type heavy chain deposition disease (HCDD) is a rare disorder characterized by glomerular and peritubular amorphous deposits of a truncated monoclonal immunoglobulin heavy chain (HC) bearing a deletion of the first constant domain (CH1). We created a transgenic mouse model of HCDD using targeted insertion in the immunoglobulin κ locus of a human HC extracted from a HCDD patient. Our strategy allows the efficient expression of the human HC in mouse B and plasma cells, and conditional deletion of the CH1 domain reproduces the major event underlying HCDD. We show that the deletion of the CH1 domain dramatically reduced serum HC levels. Strikingly, even with very low serum level of truncated monoclonal HC, histologic studies revealed typical Randall-type renal lesions that were absent in mice expressing the complete human HC. Bortezomib-based treatment resulted in a strong decrease of renal deposits. We further demonstrated that this efficient response to proteasome inhibitors mostly relies on the presence of the isolated truncated HC that sensitizes plasma cells to bortezomib through an elevated unfolded protein response (UPR). This new transgenic model of HCDD efficiently recapitulates the pathophysiologic features of the disease and demonstrates that the renal damage in HCDD relies on the production of an isolated truncated HC, which, in the absence of a LC partner, displays a high propensity to aggregate even at very low concentration. It also brings new insights into the efficacy of proteasome inhibitor-based therapy in this pathology.

Concomitant angiosarcoma and lymphoproliferative disorder in solid organ transplant recipients.

An increased risk of posttransplant malignancy has been consistently reported following various solid organ transplants. The malignancies most commonly encountered are non-melanoma skin cancers, carcinomas of lung or breast and posttransplant lymphoproliferative disorders. Angiosarcoma, an uncommon vascular mesenchymal neoplasm, is rare in the posttransplant setting. This report describes two patients who developed high-grade angiosarcoma following a solid organ transplant. Notably, in both patients, the diagnosis of angiosarcoma was preceded by diagnosis of a lymphoproliferative disorder with monoclonal immunoglobulin heavy chain rearrangement.

PCR Analysis of IgH and TCR-γ Gene Rearrangements as a Confirmatory Diagnostic Tool for Lymphoproliferative Disorders.

This study investigates PCR analysis of immunoglobulin heavy chain (IgH) and T cell receptor (TCR) gene rearrangements on paraffin-embedded tissue sections and bone marrow aspirates of patients suspected to have lymphoproliferative disorders but with inconclusive diagnosis in histopathological examination. 130 samples of patients with inconclusive immunohistochemistry results were evaluated for clonal rearrangement of IgH and TCR genes. Based on histopathology examination, the patients were divided into three groups: the first group without any definite diagnosis of lymphoproliferative disorders (60 cases, 46.2%), the second group suspected to have a lymphoproliferative disorder but in favor of benign disorders (19 cases, 14.6%) and the third group suspect to lymphoproliferative disorders but relatively in favor of malignant disorders (51 cases, 39.2%). After DNA extraction and quality control, semi-nested PCR was performed using consensus primers for amplification of TCR-γ and CDR-3 regions of IgH genes. PCR products were analyzed after heteroduplex analysis using polyacrylamide gel electrophoresis, and were subject to silver staining. Totally, in over half of the cases (55.4%), a monoclonal pattern was found in IgH or TCR-γ genes rearrangements. Monoclonal IgH gene rearrangement was detected in 48.1% of patients, whereas monoclonal TCR-γ gene rearrangement was found in 33.6% of them, which was not statistically significant (P=0.008). Only in 32 patients (24.6%) were the results of TCR-γ and IgH gene rearrangements consistent with respect to the presence (2.3%) or absence (22.3%) of monoclonality. Finally, PCR analysis of TCR-γ and IgH gene rearrangements led to definite diagnosis in 105 patients (80.8%), and only 25 cases (19.2%) remained inconclusive. Our results emphasize the usefulness of gene rearrangement study in cases without a definite diagnosis in immunohistochemistry studies. Multiple PCR analysis results when combined with patient's clinical course and immunohistochemistry can lead to early diagnosis and subsequent therapy.