Immunological phenotype of lymphomas induced by avian leukosis viruses

1983 ◽  
Vol 3 (6) ◽  
pp. 1077-1085
Author(s):  
L C Chen ◽  
S A Courtneidge ◽  
J M Bishop
Keyword(s):  
B Lymphocytes ◽  
Cell Lines ◽  
Light Chain ◽  
Avian Leukosis Virus ◽  
Immunoglobulin M ◽  
Light Chains ◽  
Free Light Chains ◽  
Viral Antigens ◽  
Immunological Phenotype ◽  
Avian Leukosis Viruses

The production of immunoglobulin by six cell lines derived from bursal tumors induced by avian leukosis virus follows two general patterns: (i) three cell lines that have been extensively passaged in culture synthesize and secrete light chains only; (ii) three cell lines that are recently isolated produce and secrete monomeric immunoglobulin M in addition to free light chains. All six cell lines synthesize and secrete both glycosylated and unglycosylated forms of light chain. We conclude that the cell lines established from lymphomas induced by avian leukosis virus represent relatively mature, but possibly abnormal, stages in the development of chicken B-lymphocytes. The immunoglobulin M produced by the cell lines failed to form detectable immune complexes with avian leukosis virus. It therefore appears that the immunoglobulin M is not directed against viral antigens and that autogenous antigenic stimulus cannot account for the sustained growth of the neoplastic B-lymphocytes.

scholarly journals Immunological phenotype of lymphomas induced by avian leukosis viruses.

1983 ◽  
Vol 3 (6) ◽  
pp. 1077-1085 ◽  
Author(s):  
L C Chen ◽  
S A Courtneidge ◽  
J M Bishop
Keyword(s):  
B Lymphocytes ◽  
Cell Lines ◽  
Light Chain ◽  
Avian Leukosis Virus ◽  
Immunoglobulin M ◽  
Light Chains ◽  
Free Light Chains ◽  
Viral Antigens ◽  
Immunological Phenotype ◽  
Avian Leukosis Viruses

The production of immunoglobulin by six cell lines derived from bursal tumors induced by avian leukosis virus follows two general patterns: (i) three cell lines that have been extensively passaged in culture synthesize and secrete light chains only; (ii) three cell lines that are recently isolated produce and secrete monomeric immunoglobulin M in addition to free light chains. All six cell lines synthesize and secrete both glycosylated and unglycosylated forms of light chain. We conclude that the cell lines established from lymphomas induced by avian leukosis virus represent relatively mature, but possibly abnormal, stages in the development of chicken B-lymphocytes. The immunoglobulin M produced by the cell lines failed to form detectable immune complexes with avian leukosis virus. It therefore appears that the immunoglobulin M is not directed against viral antigens and that autogenous antigenic stimulus cannot account for the sustained growth of the neoplastic B-lymphocytes.

scholarly journals Monoclonal anti-light chain idiotype as a tumor-specific probe for human neoplastic B lymphocytes

Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 919-923 ◽  
Author(s):  
M Wrightham ◽  
AL Tutt ◽  
MJ Glennie ◽  
TJ Hamblin ◽  
GT Stevenson ◽  
...  
Keyword(s):  
B Cell ◽  
Tumor Cells ◽  
B Lymphocytes ◽  
Light Chain ◽  
Normal Serum ◽  
Lymphocytic Leukemia ◽  
Light Chains ◽  
Specific Probe ◽  
Tonsillar Cells ◽  
Binding Curves

Abstract Tumor cells from patients with B cell neoplasms often secrete small amounts of free monoclonal light chains that can be found in the urine. Such tumor-derived light chains of the lambda type from a patient with typical chronic lymphocytic leukemia have been used to raise mouse monoclonal antibodies (MoAbs). A hybridoma-secreting antibody that recognized the idiotypic lambda chain but not normal lambda chains by a preliminary screen but which also reacted with idiotypic IgM from the patient's tumor cells was selected. This MoAb in fact recognized 1 in 20 X 10(3) molecules of pooled normal lambda chains, thus establishing its specificity for a private idiotypic determinant. It failed to give a detectable reaction with normal IgM, normal serum, or a panel of IgM paraproteins. The antibody bound to the patient's neoplastic B cells but not to normal tonsillar cells. The site of binding of the antibody to idiotypic IgM is clearly separate from that of another MoAb specific for idiotypic determinants on heavy plus light chains, since the two showed additive binding curves. The determinant also appeared to be less available in dimeric lambda chains than in monomeric lambda chains or in idiotypic IgM. Antibodies to idiotypic determinants on light chains show some technical advantages and should be useful for monitoring and possibly treating B cell tumors, either alone or together with the more conventional anti-idiotypic antibodies that usually recognize the heavy and light chain combination.

scholarly journals Monoclonal anti-light chain idiotype as a tumor-specific probe for human neoplastic B lymphocytes

Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 919-923
Author(s):  
M Wrightham ◽  
AL Tutt ◽  
MJ Glennie ◽  
TJ Hamblin ◽  
GT Stevenson ◽  
...  
Keyword(s):  
B Cell ◽  
Tumor Cells ◽  
B Lymphocytes ◽  
Light Chain ◽  
Normal Serum ◽  
Lymphocytic Leukemia ◽  
Light Chains ◽  
Specific Probe ◽  
Tonsillar Cells ◽  
Binding Curves

Tumor cells from patients with B cell neoplasms often secrete small amounts of free monoclonal light chains that can be found in the urine. Such tumor-derived light chains of the lambda type from a patient with typical chronic lymphocytic leukemia have been used to raise mouse monoclonal antibodies (MoAbs). A hybridoma-secreting antibody that recognized the idiotypic lambda chain but not normal lambda chains by a preliminary screen but which also reacted with idiotypic IgM from the patient's tumor cells was selected. This MoAb in fact recognized 1 in 20 X 10(3) molecules of pooled normal lambda chains, thus establishing its specificity for a private idiotypic determinant. It failed to give a detectable reaction with normal IgM, normal serum, or a panel of IgM paraproteins. The antibody bound to the patient's neoplastic B cells but not to normal tonsillar cells. The site of binding of the antibody to idiotypic IgM is clearly separate from that of another MoAb specific for idiotypic determinants on heavy plus light chains, since the two showed additive binding curves. The determinant also appeared to be less available in dimeric lambda chains than in monomeric lambda chains or in idiotypic IgM. Antibodies to idiotypic determinants on light chains show some technical advantages and should be useful for monitoring and possibly treating B cell tumors, either alone or together with the more conventional anti-idiotypic antibodies that usually recognize the heavy and light chain combination.

scholarly journals Quantitative Immunoprecipitation Free Light Chain Mass Spectrometry (QIP-FLC-MS) Simplifies Monoclonal Protein Assessment and Provides Added Clinical Value in Systemic AL Amyloidosis

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4375-4375 ◽  
Author(s):  
Faye Amelia Sharpley ◽  
Hannah Victoria Giles ◽  
Richa Manwani ◽  
Shameem Mahmood ◽  
Sajitha Sachchithanantham ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Light Chain ◽  
Residual Disease ◽  
Renal Involvement ◽  
Light Chains ◽  
Al Amyloidosis ◽  
Free Light Chains ◽  
Accurate Identification ◽  
Monoclonal Protein ◽  
Serum And Urine

Introduction Early diagnosis, effective therapy and precise monitoring are central for improving clinical outcomes in systemic light chain (AL) amyloidosis. Diagnosis and disease response assessment is primarily based on the presence of monoclonal immunoglobulins and free light chains (FLC). The ideal goal of therapy associated with best outcomes is a complete responses (CR), defined by the absence of serological clonal markers. In both instances, detection of the monoclonal component (M-component) is based on serum FLC assessment together with traditional serum and urine electrophoretic approaches, which present inherent limitations and lack sensitivity particularly in AL where the levels are typically low. Novel mass spectrometry methods provide sensitive, accurate identification of the M-component and may prove instrumental in the timely management of patients with low-level amyloidogenic light chain production. Here we assess the performance of quantitative immunoprecipitation FLC mass spectrometry (QIP-FLC-MS) at diagnosis and during monitoring of AL amyloidosis patients treated with bortezomib-based regimens. Methods We included 46 serial patients with systemic AL amyloidosis diagnosed and treated at the UK National Amyloidosis Centre (UK-NAC). All patients had detailed baseline assessments of organ function and serum FLC measurements. Baseline, +6- and +12-month serum samples were retrospectively analysed by QIP-FLC-MS. Briefly, magnetic microparticles were covalently coated with modified polyclonal sheep antibodies monospecific for free kappa light chains (anti-free κ) and free lambda light chains (anti-free λ). The microparticles were incubated with patient sera, washed and treated with acetic acid (5% v/v) containing TCEP (20 mM) in order to elute FLC in monomeric form. Mass spectra were acquired on a MALDI-TOF-MS system (Bruker, GmbH). Results were compared to serum FLC measurements (Freelite®, The Binding Site Group Ltd), as well as electrophoretic assessment of serum and urine proteins (SPE, sIFE, UPE and uIFE). Results Cardiac (37(80%) patients) and renal (31(67%) patients) involvement were most common; 25(54%) patients presented with both. Other organs involved included liver (n=12), soft tissue (n=4), gastrointestinal tract (n=3) and peripheral nervous system (n=2). Baseline Freelite, SPE, sIFE and uIFE measurements identified a monoclonal protein in 42(91%), 22(48%), 34(74%) and 21(46%) patients, respectively. A panel consisting of Freelite + sIFE identified the M-component in 100% of the samples. QIP-FLC-MS alone also identified an M-component in 100% of the samples and was 100% concordant with Freelite for typing the monoclonal FLC (8 kappa, 34 lambda). In 4 patients, QIP-FLC-MS identified an additional M-protein that was not detected by the other techniques. In addition, 4/8(50%) kappa and 4/38(11%) lambda patients showed a glycosylation pattern of monoclonal FLCs at baseline by mass spectrometry. Interestingly, the frequency of renal involvement was significantly lower for patients with non-glycosylated forms (25% vs 76%, p=0.01), while no similar relationship was found for any other organs. During the 1-year follow-up period, 17 patients achieved a CR; QIP-FLC-MS identified serum residual disease in 13(76%) of these patients. Conclusion In our series, QIP-FLC-MS was concordant with current serum methods for identifying the amyloidogenic light chain type and provided, against all other individual tests, improved sensitivity for the detection of the monoclonal protein at diagnosis and during monitoring. The ability to measure the unique molecular mass of each monoclonal protein offers clone-specific tracking over time. Glycosylation of free light chains is over-represented in AL patients which may allow earlier diagnosis and better risk-assessment of organ involvement. Persistence of QIP-FLC-MS positive M component in patients otherwise in CR may allow targeted therapy. Overall, QIP-FLC-MS demonstrates potential to be exploited as a single serum test for precise serial assessment of monoclonal proteins in patients with AL amyloidosis. Disclosures Wechalekar: GSK: Honoraria; Janssen-Cilag: Honoraria; Amgen: Research Funding; Takeda: Honoraria; Celgene: Honoraria.

Lambda monoclonal free light chain abnormalities detected by a serum immunofixation electrophoresis assay are underrepresented by quantitative serum free light chain results

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S13-S14
Author(s):  
Rebecca Treger ◽  
Kathleen Hutchinson ◽  
Andrew Bryan ◽  
Chihiro Morishima
Keyword(s):  
Light Chain ◽  
Free Light Chain ◽  
Light Chains ◽  
Sample Population ◽  
Free Light Chains ◽  
Serum Free ◽  
Serum Free Light Chain ◽  
Immunofixation Electrophoresis ◽  
High Concordance ◽  
Polyclonal Antisera

Abstract Protein and immunofixation (IFIX) electrophoresis are used to diagnose and monitor monoclonal gammopathies. While IFIX detects clonal production of intact immunoglobulins and free light chains (FLC), the latter can also be quantified using a serum free light chain (SFLC) assay, in which polyclonal antisera detects epitopes specific for free kappa (KFLC) or lambda light chains (LFLC). An abnormal KFLC: LFLC ratio (KLR) serves as a surrogate for clonality. While the SFLC assay is highly sensitive, normal LFLC (<2.63mg/dL) and KLR results (>0.26 & <1.65) were found in samples with distinct lambda monoclonal free light chains visualized by IFIX (X-LMFLC). To investigate this discordance, contemporaneous SFLC or KLR values were evaluated for their ability to accurately classify monoclonal FLCs identified by IFIX. We performed a retrospective analysis of serum and urine IFIX (Sebia Hydrasys) and SFLC (Freelite®, Binding Site) results from our institution between July 2010 through December 2020, using R 4.0.2 and Tidyverse packages. From among 9,594 encounters in which a single monoclonal component was initially identified by IFIX, 157 X-LMFLC and 131 X-KMFLC samples were analyzed. Elevated LFLC with normal KFLC was identified in 105/157 X-LMFLC samples (67%), while both LFLC and KFLC were elevated in 42/157 samples (27%). Concordance between X-KMFLC and KFLC was markedly higher, where 122/131 samples (93%) displayed elevated kappa FLC (>1.94mg/dL) with normal LFLC, and only 7/131 X-KMFLC samples (5%) possessed both elevated KFLC and LFLC. The use of KLR to identify pathogenic monoclonal free light chains improved lambda concordance to 85%; however, 19/157 (12%) of X-LMFLC samples still exhibited normal KLR. High concordance of 98% was again observed for X-KMFLC with abnormal KLR. When samples were segregated according to normal or impaired renal function (eGFR > or ≤60mL/min/1.73m², respectively), this disparate identification of X-LMFLC and X-KMFLC by the SFLC assay persisted, suggesting that renal dysfunction (as measured by eGFR) does not underlie this phenomenon. Lastly, we corroborated the above findings in a larger sample population by examining patients with urine Bence Jones FLC identified by IFIX who had free or intact monoclonal components in serum (N=724), grouped by lambda or kappa light chain involvement. The cause(s) of the discrepant performance by the Freelite® SFLC assay, relative to the Sebia Hydrasys IFIX assay, for identifying lambda FLC components is currently unclear. Possible contributory factors include assay reference range cutoffs, other patient disease parameters, and differences in assay-specific polyclonal antisera. Future analyses of these factors will help to further characterize SFLC assay performance and elucidate how interpretation of composite serum FLC test results can be improved to better guide patient management.

scholarly journals In-house age-specific reference ranges for free light chains measured on the SPAPlus® analyser

2020 ◽  
Vol 57 (2) ◽  
pp. 138-143
Author(s):  
Lauren Campbell ◽  
Dawn Simpson ◽  
Adrian Shields ◽  
Berne Ferry ◽  
Karthik Ramasamy ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Light Chain ◽  
Filtration Rate ◽  
Estimated Glomerular Filtration Rate ◽  
Free Light Chain ◽  
Light Chains ◽  
Reference Ranges ◽  
Free Light Chains ◽  
Serum Free ◽  
Serum Free Light Chain

Background The measurement of monoclonal free light chains is being increasingly utilized since the introduction of serum-based assays. It is important for laboratories to determine their own reference ranges in order to reflect the local population. The aim of this study was to determine if age-adjusted reference ranges for serum free light chains would have implications for demand management of further laboratory investigations including immunofixation. Methods After certain exclusions, 4293 samples from individuals seen in primary care across Oxfordshire between 2014 and 2016 were identified for analysis of patient characteristics, serum free light chain results and estimated glomerular filtration rate. Results We found age to be an independent variable when considering serum free light chain concentrations, ratio and estimated glomerular filtration rate. The reference ranges derived from our data differ markedly from the original Binding Site ranges. When the age-specific ranges are retrospectively applied to our population, there is a 38% decrease in follow-up testing with no loss of specificity. Conclusion We feel confident implementing new age-specific serum free light chain reference ranges in our laboratory. We have developed a simple algorithm for evaluating serum free light chains based on age and estimated glomerular filtration rate. We encourage laboratories to establish their own local reference ranges using large cohorts and their chosen serum free light chain assay platform.

Quantification by Ultrafiltration and Immunofixation Electrophoresis Testing for Monoclonal Serum Free Light Chains

2020 ◽  
Vol 51 (6) ◽  
pp. 592-600 ◽  
Author(s):  
Gurmukh Singh ◽  
Roni Bollag
Keyword(s):  
Plasma Cell ◽  
Light Chain ◽  
Limit Of Detection ◽  
Light Chains ◽  
Total Serum ◽  
Reliable Estimate ◽  
Free Light Chains ◽  
Serum Free ◽  
Immunofixation Electrophoresis ◽  
Serum Free Light Chains

Abstract Objective Measurement of monoclonal immunoglobulins is a reliable estimate of the plasma cell tumor mass. About 15% of plasma cell myelomas secrete light chains only. The concentration of serum free light chains is insufficient evidence of the monoclonal light chain burden. A sensitive quantitative estimate of serum free monoclonal light chains could be useful for monitoring patients with light chain myeloma. We describe such an assay that does not require mass-spectrometry equipment or expertise. Methods Serum specimens from patients with known light chain myelomas and controls were subjected to ultrafiltration through a membrane with pore size of 50 kDa. The filtrate was concentrated and tested by immunofixation electrophoresis. The relative area under the monoclonal peak, compared to that of the total involved light chain composition, was estimated by densitometric scanning of immunofixation gels. The proportion of the area occupied by the monoclonal peak in representative densitometric scans was used to arrive at the total serum concentration of the monoclonal serum free light chains. Results Using an ultracentrifugation and concentration process, monoclonal serum free light chains were detectable, along with polyclonal light chains, in all 10 patients with active light chain myelomas. Monoclonal light chains were identified in serum specimens that did not reveal monoclonal light chains by conventional immunofixation electrophoresis. The limit of detection by this method was 1.0 mg/L of monoclonal serum free light chains. Conclusion The method described here is simple enough to be implemented in academic medical center clinical laboratories and does not require special reagents, equipment, or expertise. Even though urine examination is the preferred method for the diagnosis of light chain plasma cell myelomas, measurement of the concentration of serum free light chains provides a convenient, albeit inadequate, way to monitor the course of disease. The method described here allows effective electrophoretic differentiation of monoclonal serum free light chain from polyclonal serum free light chains and provides a quantitation of the monoclonal serum free light chains in monitoring light chain monoclonal gammopathies.

Free Light Chains, Monoclonal Proteins, and Chronic Lymphocytic Leukemia.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4697-4697 ◽  
Author(s):  
Rosa Ruchlemer ◽  
Constantine Reinus ◽  
Esther Paz ◽  
Ahuva Cohen ◽  
Natalia Melnikov ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Light Chain ◽  
Lymphocytic Leukemia ◽  
Light Chains ◽  
P Value ◽  
Advanced Stage ◽  
Free Light Chains ◽  
Monoclonal Protein ◽  
Low Levels ◽  
Monoclonal Proteins

Abstract Monoclonal proteins(MPs) can frequently be detected in the serum/urine of chronic lymphocytic leukemia(CLL) patients. Serum free light chains(FLC) assays can detect MPs in the absence of M bands on immunofixation(IMF).An abnormal FLC ratio indicates excess of one light chain type suggesting clonality.We evaluated fresh serum/urine samples from 34 CLL patients at various stages of disease by quantitative nephelometric assay,IMF and FLC assay.Median age was 66 yrs(43–87),M:F 1.9:1 and median time from diagnosis 41.5 mos(5–288). 45% had advanced stage and 39% prior treatment with 1–7 therapies.Only 2 patients had mild renal failure.Serum immunoglobulins were normal/low in 94% of patients:IgG (171–1580 mg/l, median 803 mg/l), IgA(<25–310 mg/l, median 88 mg/l),IgM(<18–290 mg/l, median 38 mg/l), irrespective of the presence of a monoclonal protein. 71% of patients had evidence of abnormal immunoglobulin synthesis: by IMF alone (8),IMF and FLC(10) or FLC alone(8).Abnormal FLC ratios were more frequently associated with advanced stage disease and increased κ chains(see table 1). Abnormal FLC ratios(< 0.26 or >1.65) were measured in 18(53%) patients, 8 of whom did not have MPs by IMF. Two advanced stage patients had abnormal FLC ratios due to very low levels of a single light chain, most probably reflecting secondary hypogammaglobulinemia due to CLL and/or chemotherapy.Abnormal FLC ratios reverted to normal after 1 course of chemotherapy(FC+/−R) in 3 patients despite persistence of minimal residual disease(MRD).FLC were of the same type as expressed on the surface of CLL cells, with discrepancies observed in 5 patients.BM biopsy staining for light chains revealed IgAκ MGUS in addition to λ chain restricted CLL in one patient, but was noncontributory in the other 4. Conclusions: Neither IMF nor the FLC assay alone could detect all MPs. Normal FLC ratios do not exclude the presence of MPs. The FLC ratio should be interpreted with caution in CLL patients with advanced disease and hypogammaglobulinemia. Monoclonal bands and abnormal FLC ratios can be detected despite normal or low levels of serum immunoglobulins in CLL patients. The significance of these monoclonal gammopathies in CLL is not clear and warrants further study in a larger group of patients. Discrepancies between surface immunoglobulins and serum/urine MPs might suggest the presence of an additional condition:ex. MGUS. FLC may not be a sensitive measure of MRD. Normal FLC ratio Abnormal FLC ratio P value *median No. patients 16(47%) 18(53%) M:F 1.3:1 3.5:1 NS Age* 62.5 yrs(49–73) 68 yrs(43–87) NS Time from CLL diagnosis* 25.3 mos(0–282) 59 mos(0–210) NS Adv stage(Rai III/IV-Binet C) 25% 66.7% 0.018 Untreated 62% 50% NS CLL:κ:λ restriction 7:8(0.88:1) 11:6(1.8:1) NS Monoclonal protein 8(50%) 10(56%) NS Increased freeκ no. 8 15 0.043 Freeκ level* 19.6(4.5–200) 39.2(2.9–386) 0.0064 Increased freeλ no 4 3 NS Free λ level* 19.3(12.4–146) 15.4(0.1–517) NS Serum β 2m* 3.1(1.8–6.7) 4.3(2.2–10.2) NS Zap70≥20 86% 36% 0.002 CD38≥30 44% 44% NS 17pdel/11qdel 40% 44% NS

Biclonal Multiple Myeloma with Monoclonal Free IgG3 Heavy Chain and kappa Free Light Chains.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4768-4768
Author(s):  
Alex G. Richter ◽  
Stephen Harding ◽  
Steve Rimmer ◽  
Guy Pratt ◽  
Aarnoud Huissoon ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Western Blot ◽  
Heavy Chain ◽  
Light Chain ◽  
Lymphoproliferative Disorder ◽  
Plasma Cells ◽  
Light Chains ◽  
Cell Transplant ◽  
Free Light Chains ◽  
Night Sweats

Abstract Background: Heavy chain disease (HCD) is a rare lymphoproliferative disorder characterized by a monoclonal heavy chain (HC) unattached to a light chain (LC). IgGHCD or γHCD typically presents as a lymphoproliferative disorder with lymphadenopathy and hepatosplenomegaly. Myeloma has been described associated with γHCD but only with a second intact Ig paraprotein. This report describes a unique presentation of multiple myeloma with monoclonal free γ3HC and kappa free light chains. Case: A 34 year old gentleman presented with mild persistent neutropenia following two episodes of pneumonia, 18 months previously. He admitted to persistent night sweats but no other significant history. Baseline investigations revealed a mild anaemia, neutropenia and a large IgG paraprotein with no associated light chain. Bone marrow aspirate and trephine confirmed myeloma. The patient was treated with cyclophosphamide, thalidomide and dexamethasone and has had a very good partial remission. He is awaiting a sibling allogeneic peripheral blood stem cell transplant. Investigations and results: Serum Electrophoresis confirmed a large IgG paraprotein (23g/l) with no associated light chain in the serum and identified as γ3 subclass by radial immunodiffusion. Western blot showed the γ3HC was truncated with a large deletion. Markedly elevated free kappa (κ) LC (503.58 mg/l [3.30–19.4]) were found in the serum with gross skewing of the kappa/lambda ratio. Urine electrophoresis revealed separate γHC and κ LC paraproteins. Western blot of the fractionated urine protein demonstrated different sized κLC aggregates. Flow cytometry of the marrow aspirate revealed an unusual staining pattern; CD5,19,38,45+ve and CD20,22,23,34,56,138 –ve plasma cells. Cytoplasmic staining revealed 2 distinct populations of plasma cells, the first producing γ3HC and the second only free κLC. Cytogenetics and FISH analysis for 14q, p53 and c-myc abnormalities were normal. Discussion: This is the first description of a Biclonal Myeloma with separate plasma cell populations producing γ3HC and κLC paraproteins. The biclonality confirms the free HC occurs as a result of abnormal synthesis not cleavage. The clinical and immunological findings are clearly different to typical findings in both γ3HCD and Myeloma. HCD has an appalling prognosis and this case is likely to have been ‘smouldering’ for 18 months, evidenced by the 2 pneumonias and persistent night sweats. There is no lymphadenopathy or organomegaly associated with γ3HCD. The immunophenotype of the malignant plasma cells is unique. Other atypical features include frank proteinuria, with a HC in the urine, but normal renal function and no radiological or biochemical evidence of bone involvement. We propose that this unique biclonal myeloma has distinct immunological and clinical features.

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