IgE multiple myeloma: detection and follow-up

Objectives We report a new case of immunoglobulin E multiple myeloma (IgE), a very rare isotype that accounts for <0.1% of cases of this monoclonal gammopathy. To ensure the adequate detection, quantification and identification of the monoclonal component, it is crucial that protein assays are performed. We provide some clues related to clinical laboratory results, which will facilitate an adequate management of the disease. Case presentation A 45-year-old patient with a five-week history of pain at the level of the elbow, who was diagnosed with IgE-Kappa multiple myeloma based on laboratory, radiological, and bone marrow findings. The patient received induction chemotherapy prior to hematopoietic stem-cell transplantation and is currently on follow-up. Conclusions Protein assays performed in the clinical laboratory, including protein electrophoresis and immunofixation, allowed for the detection of an IgE-Kappa monoclonal component prior to the appearance of the typical CRAB symptoms (hypercalcemia, renal involvement, anemia, and bone pain) of multiple myeloma (MM). The detection of IgE-Kappa facilitated early diagnosis and management.

MGUS and Chip: Two Faces, but Not of the Same Medal

Clonal, pre-clinical expansions of hematopoietic cells are increasingly recognized. Clonal hematopoiesis of indeterminate potential (CHIP) has been recently described. It is characterized by the presence of mutations usually involved in myeloid neoplasia in people without any sign of hematological malignancy. Well before CHIP, another pre-clinical clonal expansion has been described for plasma cells (PC) based on the presence of a serum monoclonal protein, namely monoclonal gammopathy of undetermined significance (MGUS). Despite both being frequent, the association between these two bone marrow (BM) clonal entities has not been determined yet. Since the incidence of MGUS and CHIP rises with age reaching &gt;10% of people &gt;70y, we analyzed a unique oldest-old population dataset to define a possible association between these two different BM clonal disorders. We analyzed a cohort of 777 patients with a median age of 91 years (range, 81 - 104), significantly higher than previous studies on MGUS. 579 (74.5%) were females and 198 (25.5%) males. CHIP was assessed in all but 45 through sequencing of a myeloid specific gene panel. Serum protein electrophoresis was available in all of them to assess the prevalence of MGUS. The prevalence of CHIP and MGUS were 17.5% (128/732) and 9.5% (74/777), respectively. Importantly, CHIP and MGUS did not associate in our cohort but rather showed a non-significant trend towards anti-correlation (Fisher's Exact test, p-val = 0.09). We then tested associations with different clinical and laboratory features, finding that, as expected, MGUS associated with higher concentration of gamma-globulins (Wilcoxon test, p-val = 0.01414), but also with absolute lower levels of albumin (Wilcoxon test, p-val = 0.01398). No significant association was found with the mean corpuscular value (MCV), hemoglobin levels or age. These results were confirmed by a logistic univariate model, in which also the male gender resulted associated with the presence of a monoclonal component with borderline significance. Then, to further corroborate our results we performed univariate linear regression analyses. Given that CHIP and MGUS are mainly considered two aging conditions, we investigated in linear regression models the impact of age, as a continuous variable, on other clinical features. In particular, we observed that the increase of age was significantly correlated with lower albumin levels (F-stat: 1.921e+04, Adj R-squared: 0.9288, p-val: &lt; 2.2e-16), decreasing hemoglobin concentration (F-stat: 1.434e+05, Adj R-squared: 0.9898, p-val &lt; 2.2e-16), increasing levels of gamma-globulins (F-stat: 9.21e+04, Adj R-squared: 0.9843, p-val &lt; 2.2e-16) and higher MCV (F-stat: 18.04, Adj R-squared: 0.01144, p-val 2.3e-05). Then, a significant anti-correlation between gamma-globulin and serum albumin levels was also confirmed (F-stat: 2.807e+04, Adj R-squared: 0.9501, p-val &lt; 2.2e-16). Finally, we implemented two different multivariate logistic models using as independent variables the presence or absence of MGUS or CHIP, respectively. In these models, the presence of a monoclonal component was only positively associated with a higher level of gamma-globulins (Est: 0.16238, p-val = 0.00079) and not with increasing age (Est: 0.02680, p-val = 0.31819). Interestingly, the presence of an MGUS confirmed a tendency to an anti-correlation with the presence of CHIP (Est: -0.78959, p-val = 0.06468). On the contrary, CHIP as independent variable resulted significantly correlated with increasing age (Est: 0.07396, p-val = 0.00021). The spectrum of mutations in CHIP cases with or without MGUS was not significantly different, with DNMT3A and TET2 being the most frequently mutated genes. Our study shows that, in a large cohort of oldest-old patients, CHIP and MGUS are not correlated but follow two seemingly independent patterns, showing a tendency to a mutual exclusivity and associating with different clinical and laboratory values. One limitation of our study is the skewing towards female sex, where MGUS is less prevalent, but this is explained by the cohort's median age knowing that females have a longer expected life. Based on this, our findings that CHIP but not MGUS increased with age in our cohort suggest different selective pressures in this extreme age range. These results warrant further investigation as to whether there could be age-specific drivers for MGUS, and their clinical relevance. Disclosures Bolli: Amgen: Honoraria; Takeda: Honoraria; Janssen: Consultancy, Honoraria; Celgene/BMS: Consultancy, Honoraria.

Differential diagnosis between bone relapse of breast cancer and lambda light chain multiple myeloma: role of the clinical biochemist

Purpose: The integration of expertise between oncologist and clinical biochemist for the monitoring and diagnosis of plasma cell dyscrasia is crucial. In some cases, medical laboratory scientists can provide an original contribution using the appropriate techniques to arrive at a diagnosis. Methods: We report a case of 67-year-old woman who was admitted to our hospital for bone pain. Imaging studies showed multiple diffuse bone lytic lesions, and a laboratory screen revealed anemia and altered creatinemia; serum capillary zone electrophoresis confirmed a monoclonal peak in the γ-zone that had been known since 2011, typed as immunoglobulin G kappa by immunosubtraction electrophoresis. The patient had undergone surgery for breast cancer in 2013, and based on her clinical history, the oncologist suspected the presence of bone metastases from the breast cancer and opted for relative therapy. Immunosubtraction, however, showed a very small reduction in lambda free light chains in the beta zone, but it was difficult to establish if was a monoclonal component, and consequently additional tests were performed. Discussion: A monoclonal component composed of only lambda free light chains was evidenced. This result in association with multiple diffuse bone lytic lesions observed led us to suspect multiple myeloma and not bone metastases from the breast cancer. Based on these observations, we encouraged the oncologist to conduct an osteomedullary biopsy, allowing us to make a diagnosis of low-grade stage II lambda light chain multiple myeloma. Conclusion: In this report, we show how the expertise of the clinical biochemist was instrumental in solving this case.

Suspected Pericardial Tuberculosis Revealed as an Amyloid Pericardial Mass

Primary systemic amyloidosis is not easily diagnosed. The immunoglobulin deposits are usually localized in the kidney, heart, and liver. We describe an unusual case of a patient suffering from a pericardial amyloidoma with internal calcifications and air bubbles that compressed the right ventricle and shifted the heart to the left. Since the patient was in shock, urgent pericardiotomy was performed. This site showed PET uptake. A monoclonal component was present. On these findings, differential diagnoses included multiple myeloma and atypical pericardial tuberculosis, whereas a periumbilical fat tissue biopsy demonstrated amyloidosis. A previous Salmonella species infection had most likely stimulated the production of amyloid. The patient received bortezomib/dexamethasone treatment and achieved a good response.

Impact of Normalized Free Light Chain Ratio for Assessment of Monoclonal Protein in Patients with Light Chain Only and Oligosecretory Myeloma

Background: Monitoring of serum free light chain (sFLC) ratio after treatment in multiple myeloma (MM) patients is valuable for assessing monoclonal component of free light chain (FLC). However, the recent International Myeloma Working Group guidelines did not recommend replacing 24-hour urine analysis with FLC analysis in diagnosis or response assessment of MM, and previous studies indicated discordance between urine analysis and sFLC levels in light chain-only MM (LCMM). This is clinically relevant because sFLC normalization was considered a surrogate for improved outcome in both LCMM and intact immunoglobulin MM (IIMM). The clinical impact of FLC ratio normalization on detection of monoclonal component may differ between LCMM or oligosecretory myeloma (OSMM) and IIMM. This study explored the utility of sFLC ratio as a surrogate for residual clonal monoclonal component compared with 24-hour urine immunofixation electrophoresis (uIFx) after treatment. We evaluated the impact of normalization of sFLC ratio in patients with LCMM/OSMM that obtained very good partial response (VGPR), complete response (CR), and immunophenotypic CR (iCR; sIFx/uIF negative plus ≤ 10-4 clonal PCs) determined by multicolor flow cytometry (MFC). Methods: We included 176 patients (51 with LCMM and OSMM, 125 with IIMM) treated between April 2006 and January 2016 at Kameda Medical Center, Japan. Immunoglobulin levels in serum and urine samples were examined by serum protein electrophoresis (SPEP), serum immunofixation electrophoresis (sIFx), urine protein electrophoresis (UPEP), uIFx, and sFLC for response assessment. Minimal residual disease (MRD) assessments after treatment were performed by 6-color MFC and the results were compared to other tests of monoclonal components, including SPEP, UPEP, sIFx, uIFx, and FLC. Agreement between sFLC normalization and MRD by MFC was assessed using kappa statistic. Disease response was evaluated using IMWG criteria. sFLC was measured by Fleelite® assay (The Binding Site Group Ltd.). Reference ranges for sFLC have been previously published. Statistical analyses were performed with EZR, which is a graphical user interface for R ver. 3.2.1. Ethical considerations: This study was approved by the local ethics committee and conducted in accordance with the Declaration of Helsinki and Good Clinical Practice Guidelines. Results: All of 51 LCMM/OSMM patients (100%) and 95 of the 125 IIMM patients (72%) had measurable and abnormal involved sFLC (≥ 100 mg/L) and positive uIFx at presentation. VGPR, CR, and iCR were obtained in 31 (61%), 25 (49%), and 14 (27%) patients with LCMM/OSMM, respectively, and normalization of sFLC ratio at VGPR, CR and iCR was seen in 1/31 (3%), 13/25 (48%), and 8/14 (57%) of these patients, respectively. Among the LCMM/OSMM patients with iCR, 4 patients obtained deeper iCR (≤ 10-5 clonal PCs) and all of them had normal sFLC ratio, while sFLC ratio remained abnormal in the rest of 10 iCR patients that did not achieve deeper iCR. In IIMM patients, VGPR, CR, and iCR were obtained in 78 (61%), 52 (42%), and 20 (16%) patients, respectively. In contrast to the LCMM/OSMM patients, normalization of the sFLC ratio at VGPR, CR, and iCR was seen in 52/78 (67%), 39/52 (75%), and 17/20 (85%) of IIMM patients, respectively. Thirteen of the 14 IIMM patients (93%) that obtained deeper iCR had normal sFLC ratio. Among the patients with IIMM, percentage of patients with normalized sFLC ratio did not differ between the response groups (p=0.11), while it was significantly different in LCMM/OSMM patients (p<0.001) (Figure 1). These observations indicated that the normalization of sFLC ratio is significantly associated with deeper response in LCMM/OSMM patients, but not in IIMM patients. Conclusions: Our observations indicated that sFLC test has greater sensitivity than urine immunofixation for detection of the monoclonal component of sFLC, especially in patients with LCMM/OSMM. In addition, we also showed that normalization of sFLC ratio is correlated with the depth of response assessed by MFC in patients with LCMM/OSMM, but not in IIMM patients. These findings suggest that FLC ratio provides greater sensitivity for residual disease monitoring than uPEP or uIFx in patients with LCMM and OSMM, and therefore could be considered as an alternative to urine analysis for monitoring of LCMM/OSMM patients. Disclosures No relevant conflicts of interest to declare.

Overcoming the Interference of Daratumumab with Immunofixation Electrophoresis (IFE) Using an Industry-Developed Dira Test : Hydrashift 2/4 Daratumumab

Background : Detection and quantification of monoclonal component (M-spike) by serum protein electrophoresis (SPE) and immunofixation (IFE) are essential for response evaluation in multiple myeloma (MM) according to the International Myeloma Working Group (IMWG) criteria. Recent clinical trials on daratumumab, an IgG Kappa anti-CD38 monoclonal antibody, have shown impressive results with deep responses. However daratumumab may be detected on serum protein electrophoresis (SPE) and immunofixation (IFE) assays used for monitoring disease monoclonal immunoglobulins (M protein). This can lead to false positive SPE and IFE assay results for patients with IgG kappa myeloma protein impacting initial assessment of complete responses (CR) by International Myeloma Working Group (IMWG) criteria. Differentiating therapeutic monoclonal antibodies, such as daratumumab, from endogenous monoclonal protein can be challenging when both molecules co-migrate or migrate closely on electrophoresis. The availability of a specific, anti-daratumumab antibody has provided the opportunity to overcome this interference and to correctly assess biochemical response. Indeed, Mc Cudden and al. in collaboration with Janssen developed a technique, the Daratumumab Interference Reflex Assay (DIRA) test, which has been utilised in daratumumab clinical trials. Given the need for a commercially available automated and standardized test, we evaluated a new commercial DIRA kit test being developed by Sebia (Lisses, France): the Hydrashift 2/4 daratumumab. Objective: The aim of this study is to evaluate the Hydrashift 2/4 daratumumab in comparison with our laboratory developed DIRA test for the displacement of daratumumab on IFE. Design and methods: The Hydrashift 2/4 daratumumab assay was prepared by Sebia using the anti-daratumumab antibody produced by Janssen and modified to allow a migration of daratumumab/anti-daratumumab complexes toward the α-globulin fraction on IFE. IFE technical procedures, migration, and staining programs were performed according to the manufacturer instructions, and run on the standard Sebia, Hydrasys plateform, with the HYDRAGEL 4 IF kit. In addition to the regular procedure, an additional applicator to apply the anti-daratumumab antibody was used. Analytical performances including sensitivity, specificity and comparisons with the original DIRA test were assessed on 31 samples from ongoing daratumumab clinical trials. Results: Serum samples from 309/324 (95.4%) patients assessed demonstrated a positive IFE at diagnosis. In 119/309 (38,5%) of cases, the M-spike partially or totally co-migrated with daratumumab detected in serum. Of these, MM cases displayed an isotype other than IgG Kappa or Kappa light chains did not require a DIRA test during follow-up for response assessment as a standard IFE could clearly show if initial monoclonal component was still detectable or not. From our experience, an anti-daratumumab displacement assay was only required for IgG Kappa MM or Kappa Light Chain MM (LCMM) when standard IFE could not distinguish daratumumab from endogenous M-spike. This situation represented 66 cases (21,4 %, i.e. 66 on 309). The Hydrashift 2/4 daratumumab assay showed excellent concordance (100%) with the laboratory developed test on the 31 samples tested (i.e. 17 negative DIRA, 10 positive DIRA and 4 doubtful DIRA). Daratumumab/anti-daratumumab complexes were detected in the α-globulin fraction with a sensibility of 200 mg/L. Daratumumab/anti-daratumumab complex was difficult to visualize when daratumumab concentrations were less than 200 mg/L but daratumumab was shown to be completely removed from the gamma globulin fraction with no trace left for all tested patients. For 48 samples tested on diagnosis, the anti-daratumumab shifted specifically the daratumumab with no effect on the patients' M-spike (100% specificity). Conclusion: With the growing application of monoclonal antibodies such as daratumumab in the treatment of multiple myeloma, the development of validated, widely available assays to overcome antibody interference will become increasingly important. The Hydrashift 2/4 daratumumab test provides the opportunity to automate and standardize the displacement of daratumumab interference and help with the correct interpretation of IFE results for clinical outcome measures. Disclosures Simon: Janssen: Employment. Axel:Janssen Pharmaceuticals Research and Development: Employment. Sasser:Johnson & Johnson: Equity Ownership; Janssen Pharmaceuticals R&D: Employment. Scullion:Janssen: Employment. Ligneel:Sebia: Employment. Nouadje:Sebia: Employment. Moreau:Bristol-Myers Squibb: Honoraria; Amgen: Honoraria; Janssen: Honoraria, Speakers Bureau; Novartis: Honoraria; Takeda: Honoraria; Celgene: Honoraria.

Free Light Chain Escape in Multiple Myeloma : an Exceptional Phenomenon

Background : Free Light Chain (FLC) escape has been described for the first time in 1971 by Hobbs, who reported biochemical relapses of multiple myeloma (MM) with only Bence Jones proteinuria, in patients followed for an intact monoclonal immunoglobulin (Ig) MM. Indeed, FLC escape is defined as an increase of FLC without corresponding increase of the intact monoclonal Ig. In the era of novel-agent based therapy and autologous stem cell transplantation (ASCT), the patterns of disease progression may change, including a potential increased rate of FLC escape. Brioli and al (Blood 2014;123(22):3414-9) reported that 10% of the cases at relapse presented with FLC escape, and that FLC evaluation at relapse could represent an interesting marker of impact from intraclonal heterogeneity on myeloma outcome. We analysed the relapse patterns of patients treated according to the IFM 2009 clinical trial. Methods: Patients treated according to the IFM 2009 clinical trial (Lenalidomide bortezomib dexamethasone RVD + / - ASCT, Attal and al, ASH 2015) were analyzed. In patients presenting with an intact monoclonal Ig at diagnosis, serum and urine electrophoresis + FLC were compared in a central lab at the time of diagnosis and at the time of progression, in order to identify FLC escape. Results: 700 patients with symptomatic de novo MM were enrolled in the IFM DFCI 2009 clinical trial. Among them, 318 had a progressive disease, assessed with a centralized biochemistry analysis and 267 patients of them with an intact monoclonal Ig were included in this study. A vast majority (250 patients, 94%) showed an increase of the initial serum monoclonal component up to 5 g/L or up to 25% from the NADIR (IMWG criteria for progressive disease). 8 patients progressed with new bone lesions or plasmocytoma (3%) without any biological markers of progressive disease... Finally, 9 patients (3%) were identified as FLC escape as they did not exhibit an increased intact monoclonal Ig but they had an increased serum FLC and/or an increased Bence Jones proteinuria. Three of them had a serum and urinary measurable disease on diagnosis and they relapsed with both an increase of FLC and an increase of Bence Jones proteinuria. The six other patients presented at diagnosis only with an urinary measurable disease: 3 of them relapsed with an increase of FLC, without any Bence Jones proteinuria, the three others relapsed both on FLC and urines. Isotype of monoclonal component was IgG (6 patients), IgA (2) or IgD (1); light chain was Kappa for 6 patients and Lambda for the three others. Four patients were treated with RVD alone, and 5 patients with RVD + ASCT. The relapse occurred in a median of 2 years after diagnosis (5 months - 3.5 years). Conclusion: Based on a very large study of patients treated into a phase 3 clinical trial with centralized assessment of response and relapse, we are showing that FLC escape in a very rare phenomenom, observed in 3% of the cases. The low frequency of FLC escape does not lead to a systematic monitoring of intact Ig MM by FLC. Disclosures Attal: amgen: Consultancy, Research Funding; celgene: Consultancy, Research Funding; janssen: Consultancy, Research Funding; sanofi: Consultancy. Avet-Loiseau:sanofi: Consultancy; janssen: Consultancy; amgen: Consultancy; celgene: Consultancy. Moreau:Takeda: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Janssen: Honoraria, Speakers Bureau; Amgen: Honoraria; Bristol-Myers Squibb: Honoraria.