Plasma Cell Subtype Research Articles

1q amplification and PHF19 expressing high-risk cells are associated with relapsed/refractory multiple myeloma

Multiple Myeloma is an incurable plasma cell malignancy with a poor survival rate that is usually treated with immunomodulatory drugs (iMiDs) and proteosome inhibitors (PIs). The malignant plasma cells quickly become resistant to these agents causing relapse and uncontrolled growth of resistant clones. From whole genome sequencing (WGS) and RNA sequencing (RNA-seq) studies, different high-risk translocation, copy number, mutational, and transcriptional markers can be identified. One of these markers, PHF19, epigenetically regulates cell cycle and other processes and is already studied using RNA-seq. In this study, we generate a large (325,025 cells and 49 patients) single cell multi-omic dataset and jointly quantify ATAC- and RNA-seq for each cell and matched genomic profiles for each patient. We identify an association between one plasma cell subtype with myeloma progression that we call relapsed/refractory plasma cells (RRPCs). These cells are associated with chromosome 1q alterations, TP53 mutations, and higher expression of PHF19. We also identify downstream regulation of cell cycle inhibitors in these cells, possible regulation by the transcription factor (TF) PBX1 on chromosome 1q, and determine that PHF19 may be acting primarily through this subset of cells.

Multicentric Hyaline-Vascular Castleman Disease: The Missing Link?

Introduction: Castleman disease (CD) is a rare lymphoproliferative disorder that encompasses distinct clinicopathological entities. Unicentric form of the disease (UCD) usually involves a single lymph node station, exhibits hyaline vascular (HV) pathological changes with follicular dendritic cell expansion, and may associate with specific and life-threatening complications including paraneoplastic pemphigus (PNP) and follicular dendritic cell sarcoma (FDCS). Plasma cell interfollicular infiltration is absent in the HV subtype as opposed to the Plasma-Cell (PC) or Mixed subtypes. PC subtype has been associated with inflammatory symptoms thought to be secondary to plasma cell infiltration and represents the majority of HHV8-negative “idiopathic” multicentric forms of the disease. Interestingly, patients with PC-UCD behave as PC-MCD, suggesting a stronger role of histology rather than Unicentric vs Multicentric phenotype in disease expression. We here studied the phenotype of HV-MCD, a rare subtype of CD characterized by hyaline-vascular pathological changes involving 2 or more lymph node stations. Methods: Patients were screened through the French national reference center for CD between January 1994 and June 2023. Cases were followed from first symptoms to last follow-up visit. Comparators consisted of patients with HV-UCD and patients with PC/Mixed iMCD (P/M-iMCD). All cases and biopsies were reviewed by three expert clinicians and one expert pathologist. Results: Sixteen patients with a diagnosis of HHV8-negative HV-MCD were identified. All patients had supra- and infradiaphragmatic involvement. Four were excluded because of a subsequent diagnosis of POEMS, systemic lupus erythematosus, tuberculosis, or inborn error of immunity. The 12 remaining patients were considered as having HV-iMCD and compared to 101 patients with P/M-iMCD and 139 patients with HV-UCD. Characteristics and comparison between the 3 groups are depicted in Table 1. When compared to HV-UCD, HV-iMCD displayed frequent systemic involvement with significantly higher ECOG, higher frequency of fever and splenomegaly, and higher levels of C-reactive protein, gammaglobulins, leukocytes and ferritinemia ( Figure 1). Age at diagnosis was not different between HV-UCD and HV-iMCD. No cases of TAFRO syndrome were observed in HV-UCD whereas 4 cases were observed in HV-iMCD. All cases of PNP (n=12) and FDCS (n=3) were observed in the HV-UCD group. We observed a younger age at diagnosis in HV-iMCD compared to P/M-iMCD (median 24 [range 13-70] vs median 50 [range 11-88] years respectively, p = 0.01). We also noted a trend towards lower levels of C reactive protein and gammaglobulins as well a higher albumin level in HV-iMCD vs P/M-iMCD but these differences were not significant ( Figure 1 and Table 1). Treatments were similar between HV-iMCD and P/M-iMCD with prescription of steroids or anti-IL6R as first line therapy in 8/12 (67%) and 61/101 (60%) respectively. As expected, surgery was the first line therapy in 98/139 (72%) of HV-UCD patients. One patient with HV-iMCD and two with HV-UCD died (logrank p = 0.10), whereas 13 died in the P/M-iMCD group (logrank p = 0.8). Conclusions: These data altogether indicate that HV-iMCD appears to be a distinct entity in CD landscape, sharing pathological aspects of HV-UCD and clinical/biological features of P/M iMCD. In line with this view, there seems to be no overlap between HV-UCD and HV-iMCD-related complications. The findings also suggest that nodal PC infiltration is not sufficient to explain the inflammatory pattern of iMCD.

Plasma cell subtypes analyzed using artificial intelligence algorithm for predicting biochemical recurrence, immune escape potential, and immunotherapy response of prostate cancer.

Plasma cells as an important component of immune microenvironment plays a crucial role in immune escape and are closely related to immune therapy response. However, its role for prostate cancer is rarely understood. In this study, we intend to investigate the value of a new plasma cell molecular subtype for predicting the biochemical recurrence, immune escape and immunotherapy response in prostate cancer. Gene expression and clinicopathological data were collected from 481 prostate cancer patients in the Cancer Genome Atlas. Then, the immune characteristics of the patients were analyzed based on plasma cell infiltration fractions. The unsupervised clustering based machine learning algorithm was used to identify the molecular subtypes of the plasma cell. And the characteristic genes of plasma cell subtypes were screened out by three types of machine learning models to establish an artificial neural network for predicting plasma cell subtypes. Finally, the prediction artificial neural network of plasma cell infiltration subtypes was validated in an independent cohort of 449 prostate cancer patients from the Gene Expression Omnibus. The plasma cell fraction in prostate cancer was significantly decreased in tumors with high T stage, high Gleason score and lymph node metastasis. In addition, low plasma cell fraction patients had a higher risk of biochemical recurrence. Based on the differential genes of plasma cells, plasma cell infiltration status of PCa patients were divided into two independent molecular subtypes(subtype 1 and subtype 2). Subtype 1 tends to be immunosuppressive plasma cells infiltrating to the PCa region, with a higher likelihood of biochemical recurrence, more active immune microenvironment, and stronger immune escape potential, leading to a poor response to immunotherapy. Subsequently, 10 characteristic genes of plasma cell subtype were screened out by three machine learning algorithms. Finally, an artificial neural network was constructed by those 10 genes to predict the plasma cell subtype of new patients. This artificial neural network was validated in an independent validation set, and the similar results were gained. Plasma cell infiltration subtypes could provide a potent prognostic predictor for prostate cancer and be an option for potential responders to prostate cancer immunotherapy.

High-throughput sequencing unravels the cell heterogeneity of cerebrospinal fluid in the bacterial meningitis of children

Bacterial meningitis (BM) is a common life-threatening infection in children that occurs in the central nervous system (CNS). The cytologic examination of cerebrospinal fluid (CSF) is a key parameter in the diagnosis of BM, but the heterogeneity of cells in the CSF has not been elucidated, which limits the current understanding of BM neuroinflammation. In this study, CSF samples were collected from a number of BM patients who were in different stages of disease progression. Single-cell RNA-sequencing (scRNA-seq), with additional bulk transcriptome sequencing, was conducted to decipher the characteristics of CSF cells in BM progression. A total of 18 immune cell clusters in CSF were identified, including two neutrophils, two monocytes, one macrophage, four myeloid dendritic cells, five T cells, one natural killer cell, one B cell, one plasmacytoid dendritic cell, and one plasma cell subtype. Their population profiles and dynamics in the initial onset, remission, and recovery stages during BM progression were also characterized, which showed decreased proportions of myeloid cells and increased proportions of lymphoid cells with disease progression. One novel neutrophil subtype, FFAR2+TNFAIP6+ neutrophils, and one novel monocyte subtype, THBS1+IL1B+ monocytes, were discovered, and their quantity changes positively correlated with the intensity of the inflammatory response in the CSF during BM. In addition, the CSF of BM patients with unsatisfactory therapeutic responses presented with different cell heterogeneity compared to the CSF of BM patients with satisfactory therapeutic responses, and their CSF featured altered intercellular communications and increased proportions of type II myeloid dendritic cells and plasmacytoid dendritic cells. Moreover, the bulk transcriptome profiles of autologous CSF cells and peripheral blood leukocytes of BM patients showed that the immune cells in these two physiological compartments exhibited distinct immune responses under different onset conditions. In particular, the CSF cells showed a high expression of macrophage characteristic genes and a low expression of platelet characteristic genes compared with peripheral blood leukocytes. Our study conducted an in-depth exploration of the characteristics of CSF cells in BM progression, which provided novel insights into immune cell engagement in acute CNS infection.

A 41-Year-Old Man With an Abdominal Mass and Hepatomegaly

A 41-Year-Old Man With an Abdominal Mass and Hepatomegaly

18F-FDG PET/CT and contrast-enhanced CT in the diagnosis of Castleman disease.

Castleman disease (CD) is a rare group of lymphoproliferative disorders, which is easily confused with lymphoma or other solid tumors. Hence, this study aimed to investigate the diagnostic role of 18F-FDG PET/CT and contrast-enhanced CT (CECT) in patients with CD. Clinicopathological characteristics, and 18F-FDG PET/CT and CECT findings and parameters were retrospectively reviewed in 32 patients with CD. These 32 patients (12 males, 20 females; median age, 41years) consisted of 17 unicentric CD (UCD) patients and 15 multicentric CD (MCD) patients. Compared with MCD, UCD had a higher prevalence in female (82.4% vs. 40.0%) and hyaline vascular subtype (94.1% vs. 40.0%) (P < 0.05). FDG uptake was avid in all cases, including moderate uptake in 7 cases and intense uptake in 25 cases. The median SUVmax, SUVmean, MLV, and TLG of all cases were 4.4 (range, 1.4-23.6), 2.7 (range, 1.1-15.2), 26.6 (range, 4.8-393.0), and 78.8 (range, 9.4-1545.6), respectively. The lesions of 29 cases showed homogeneous enhancement, and marked enhancement was observed in 27 cases. 18F-FDG PET/CT corrected 6.3% CECT diagnoses, while CECT corrected 37.5% PET/CT diagnosis. The accuracy of combined PET/CT and CECT was superior to PET/CT or CECT alone (78.1%, 31.3%, and 62.5%). Besides, higher SUVmax and SUVmean were found in male subjects, MCD, and plasma cell subtype (P < 0.05), while higher MLV and TLG were observed in larger lesion size and volume (P < 0.05). Castleman disease most commonly appears as marked and homogeneous enhancement meanwhile with moderate or intense FDG uptake. 18F-FDG PET/CT combined with CECT was the effectively diagnostic modality for CD. The glucose metabolism of CD was associated with gender, clinical classification, histopathological classification, and lesion size and volume.

Integrative medicine and plasma cell disorders.

e20044 Background: Recent advancements in the treatment of plasma cell disorders (PCD) have led to a revolution in treatment options. Despite improved outcomes, patients have unmet symptom management needs. Integrative medicine (IM) is a method for addressing symptoms in cancer, but its use and efficacy is poorly defined in PCD patients. This analysis describes the utilization of IM among myeloma patients and explores associations with symptom burden. Methods: For 3 months, a 70-question online survey was hosted on HealthTree.org, an online resource for myeloma patients and researchers created by the HealthTree Foundation. The survey included questions about demographics, PCD type, disease stage, complementary practice use, PHQ-2 score (depression screen), and quality of life (sum of 6 interference items; possible score range 0-6). Mean outcome values were compared between IM users and non-users using two-sample t-tests. Proportions of supplement users and IM users were compared between patients currently on myeloma-specific treatment and patients not currently on treatment using chi-square tests. Results: Of 195 total respondents, 17 were excluded for not completing the survey section on IM practices. Median age range was 60-69 years old, 61% were female, 91% were non-Hispanic white, and 57% were overweight or obese. Plasma cell subtypes were active myeloma (81%), smoldering myeloma (12%), MGUS (3%), amyloidosis (2%), and plasmacytoma (1%), and 72% of patients were currently on cancer-specific treatment. On a scale of 1-10 (1=very uncomfortable; 10=very comfortable), patients reported a mean score of 3.7 when discussing IM therapies with their oncologist. The top 10 IM modalities reported were aerobic exercise (83%), nutrition (67%), natural products (60%), strength exercise (52%), support groups (48%), breathing exercises (44%), meditation (42%), yoga (40%), mindfulness-based stress reduction (38%), and massage (38%). Those who participated in meditation had significantly higher PHQ-2 scores (worse depression) than non-participants (1.1 vs. 0.8; p=0.05). Users of support groups (3.4 vs. 2.7; p=0.04), medicinal marijuana (4.0 vs. 2.9; p=0.03), or vitamin C (3.6 vs. 2.7; p=0.01) reported higher mean interference (worse quality of life) than non-users. Compared to patients currently on cancer treatment for PCD, untreated patients were significantly more likely to use curcumin (58% vs. 41%; p=0.04) or green tea (44% vs. 17%; p&lt;0.001), were less likely to use medicinal marijuana (6% vs. 18%; p=0.05), and reported significantly lower fatigue (p=0.02). Conclusions: This international survey-based analysis reveals that most patients participated in IM modalities, though felt uncomfortable discussing them with their oncologist. It is unclear if the use of some IM modalities were due to symptom burden or lead to higher symptom burden. This study provides a foundation in the understanding of IM use in PCD, but more research is needed to evaluate its efficacy.

A bendamustine resistance gene signature in diffuse large B-cell lymphoma and multiple myeloma.

Aim: Bendamustine is primarily used for treatment of indolent lymphomas but has shown efficacy in some patients with diffuse large B-cell lymphoma (DLBCL) and multiple myeloma (MM). Molecular-based patient stratification for identification of resistant patients, who will benefit from alternative treatments, is important. The aim of this study was to develop a resistance gene signature (REGS) from bendamustine dose-response assays in cultures of DLBCL and MM cell lines, enabling prediction of bendamustine response in DLBCL and MM patients.Methods: Bendamustine response was determined in 14 DLBCL and 11 MM cell lines. Using baseline gene expression profiles and degree of growth inhibition after bendamustine exposure, a bendamustine REGS was developed and examined for the risk stratification potential in DLBCL (n = 971) and MM (n = 1,126) patients divided into prognostic subtypes.Results: Bendamustine resistance significantly correlated with resistance to cyclophosphamide in DLBCL and melphalan in MM cell lines. The bendamustine REGS showed significantly lower bendamustine resistance probabilities in DLBCL patients with GCB subtype tumors and in tumors of the differentiation dependent centrocyte and plasmablast subtypes. In MM patients, pre-BII classified tumors displayed high bendamustine resistance probabilities and the plasma cell subtype had lower bendamustine resistance probability than memory cells. Furthermore, tumors belonging to the 4p14, MAF, and D2 TC subclasses consistently displayed high bendamustine resistance probabilities.Conclusion: Significant differences in predicted response to bendamustine were found in molecular subtypes of DLBCL and MM, encouraging validation in prospective bendamustine-treated cohorts with available gene expression profiles and follow-up data.

Subtype assignment of CLL based on B-cell subset associated gene signatures from normal bone marrow - A proof of concept study.

Diagnostic and prognostic evaluation of chronic lymphocytic leukemia (CLL) involves blood cell counts, immunophenotyping, IgVH mutation status, and cytogenetic analyses. We generated B-cell associated gene-signatures (BAGS) based on six naturally occurring B-cell subsets within normal bone marrow. Our hypothesis is that by segregating CLL according to BAGS, we can identify subtypes with prognostic implications in support of pathogenetic value of BAGS. Microarray-based gene-expression samples from eight independent CLL cohorts (1,024 untreated patients) were BAGS-stratified into pre-BI, pre-BII, immature, naïve, memory, or plasma cell subtypes; the majority falling within the memory (24.5–45.8%) or naïve (14.5–32.3%) categories. For a subset of CLL patients (n = 296), time to treatment (TTT) was shorter amongst early differentiation subtypes (pre-BI/pre-BII/immature) compared to late subtypes (memory/plasma cell, HR: 0.53 [0.35–0.78]). Particularly, pre-BII subtype patients had the shortest TTT among all subtypes. Correlates derived for BAGS subtype and IgVH mutation (n = 405) revealed an elevated mutation frequency in late vs. early subtypes (71% vs. 45%, P < .001). Predictions for BAGS subtype resistance towards rituximab and cyclophosphamide varied for rituximab, whereas all subtypes were sensitive to cyclophosphamide. This study supports our hypothesis that BAGS-subtyping may be of tangible prognostic and pathogenetic value for CLL patients.

Abstract 4036: Prognostic value of infiltrating immune cell profiling in lung adenocarcinoma

Abstract Neoplastic cancer cells and cancer stroma (including infiltrating immune cells) determine the biology and prognosis of cancer. Various types of adaptive and innate immune cells are known to infiltrate the cancer stroma. However, the patterns and spatial distribution of immune cell infiltration as well as their association with tumor histology remain poorly understood. To address these issues, we comprehensively analyzed the infiltrating immune cells present in lung adenocarcinoma. The principal types of both adaptive and innate infiltrating immune cells were immunohistochemically evaluated in the predominant histological components of 111 lung adenocarcinomas. The same analysis was also carried out on 143 samples of histological subtypes making up more than 20% of tumors. As a result, plasma cells and B cells with interfollicular distribution were almost exclusively observed in invasive histological subtypes, while increased number of mast cells were observed in noninvasive histological subtypes. Cluster analysis revealed four distinct immunosubtypes: those characterized by high CD8/CD3 ratios with low stromal cellularity (CD8 subtype), those with increased mast cell numbers (mast cell subtype), those with increased macrophage/DC infiltration with variable amounts of T cell infiltration (mϕ/DC subtype), and those with increased plasma cell infiltration in addition to increased macrophage/DC infiltration and variable increases in other infiltrating immune cells (T cells, Tregs, pDCs, and neutrophils) (plasma cell subtype). These immunosubtypes correlated with histological subtypes. Univariate and multivariate analyses identified the plasma cell subtype as an independent negative prognostic factor. Furthermore, we found that these plasma cells may be one of the major producers of immunosuppressive cytokine IL-35 in cancer stroma. Consequently, comprehensive immunohistochemistry-based profiling of infiltrating immune cells has potential as a powerful method for analyzing the cancer stroma of various cancer tissues. Citation Format: Yutaka Kurebayashi, Katsura Emoto, Yuichiro Hayashi, Ikuo Kamiyama, Takashi Ohtsuka, Hisao Asamura, Michiie Sakamoto. Prognostic value of infiltrating immune cell profiling in lung adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4036.

Comprehensive Immune Profiling of Lung Adenocarcinomas Reveals Four Immunosubtypes with Plasma Cell Subtype a Negative Indicator.

Neoplastic cancer cells and cancer stroma (including infiltrating immune cells) determine the biology and prognosis of cancer. Various types of adaptive and innate immune cells are known to infiltrate the cancer stroma. However, the patterns and spatial distribution of immune cell infiltration as well as its association with tumor histology remain poorly understood. To address these issues, we comprehensively analyzed the infiltrating immune cells present in lung adenocarcinoma. The principal types of both adaptive and innate infiltrating immune cells were immunohistochemically evaluated in the predominant histologic components of 111 lung adenocarcinomas. The same analysis was also carried out on 143 samples of histologic subtypes making up more than 20% of tumors. As a result, plasma cells and B cells with interfollicular distribution were almost exclusively observed in invasive histologic subtypes, while an increased number of mast cells were observed in noninvasive histologic subtypes. Cluster analysis revealed four distinct immunosubtypes (CD8, mast cell, macrophage/dendritic cell, and plasma cell subtypes) based on the infiltrating immune cell profiles. These immunosubtypes correlated with histologic subtypes, and univariate and multivariate analyses identified the plasma cell subtype as an independent negative prognostic factor. These plasma cells may be one of the major producers of the immunosuppressive cytokine IL35 in cancer stroma.

Human Immunodeficiency Virus-Negative Castleman's Disease: Clinicopathological and Laboratory Characteristics and Outcomes in Patients Treated in a Single Institution

Background Human Immunodeficiency Virus (HIV)-negative Castleman's Disease (HIVnegCD) is a group of rare heterogeneous polyclonal lymphoproliferative disorders of poorly understood etiopathogenesis. Several histological subtypes were previously described including hyaline-vascular, plasma-cell, mixed and plasmablastic. Unicentric Castleman's disease (UCD) is usually treated with complete surgical excision of involved lymph node(s). Multicentric Castleman's Disease (MCD) frequently manifests with generalized lymphadenopathy and systemic B-symptoms due to inflammatory hypercytokinemia. An important role of inflammatory cytokine IL-6 was previously established in MCD in experimental and clinical studies. Patients with MCD usually require systemic therapy. Objectives Primary purpose of this study was to collect and analyze clinicopathological and laboratory characteristics and outcomes of patients with HIVnegCD treated in a single institution. Methods Institutional review board (IRB)-approved, Health Insurance Portability and Accountability Act (HIPAA) compliant, retrospective study was conducted at Moffitt Cancer Center. Clinical and laboratory characteristics were extracted from electronic medical records and analyzed using SPSS version 22.0 statistical software. Results We identified a total of 28 patients (pts) between 1993 and 2015. 14 pts had UCD and 14 MCD. Median age was 49 (35-87) years (UCD) and 47 (31 -79) years (MCD). Male: female ratio was 1:2.5 (UCD) and 1:1.33 (MCD). A majority of patients had a PS 0-1 in both groups (13/13 and 9/10 respectively). Only 2/13 (15.4%) pts with UCD presented with fatigue and 2 (15.4%) had CNS symptoms. 9 of 14 (64%) pts with MCD reported fatigue and 8/14 (57.1%) presented with night sweats and anorexia. 5 of 14 pts (36%) with MCD were concurrently diagnosed with POEMS syndrome, 2 pts with MGUS and 1 pt with smoldering IgA kappa light chain restricted multiple myeloma. HIV-1/2 ELISA test was negative in all tested pts (18/18). In the remaining 10 pts the test was not available, but a longitudinal follow-up revealed no evidence of immunodeficiency or history of opportunistic infections. HHV-8 test was negative in 9 of 9 tested pts. 2 of 18 pts showed polyclonal hypergammaglobulinemia. 10 of 18 pts had soluble IL-6 tested and only 1 pt with MCD had an elevated level. C-reactive protein (CRP) was elevated in only 1 of 10 pts. Confirmatory histology slide review in our institution revealed a hyaline-vascular subtype in 4 pts with UCD and 6 pts with MCD. 10 pts had plasma-cell subtype (6 with UCD and 4 with MCD) and 2 had mixed subtype (1 each in UCD and MCD). In 6 pts, pathological diagnosis was based only on outside report due to the absence of the original histology slides or insufficient tissue for confirmatory studies. 11 of 13 pts with UCD underwent surgical excision, 1 received radiation therapy and 1 chemotherapy in the frontline settings resulting in complete response. 1 patient with UCD received anti-IL-6 monoclonal antibody for the second line therapy followed by rituximab monotherapy. This patient was the only pt with UCD demonstrating progressive disease. Management of MCD included various systemic regimens listed in Table #1. Chemotherapy regimens included chloramubucil, thalidomide, cyclophosphamide, melphalan, DT-PACE, R-CHOP and lenalidomide. Only 3 pts died and all 3 had progressive refractory MCD. 2 of the pts who died also had POEMS syndrome. Median survival was not reached, as 25 of 28 pts were alive at the time of data collection. Conclusions This retrospective study indicated that HIVnegCD is a heterogeneous disorder with very good prognosis in patients with resectable UCD. Systemic therapy is usually required in patients with MCD. The increased frequency of malignancies associated with CD such as POEMS syndrome, multiple myeloma, and follicular dendritic cell sarcoma can have adverse impact on prognosis. Table 1. Treatment of MCD MCD First Line Surgery 1 12 8.3% Steroids 6 12 50% Rituximab 1 12 8.3% IL-6 2 12 16.7% Chemo1 2 12 16.7% Second Line Surgery 1 8 12.5% Rituximab 2 8 25% Chemo2 1 8 12.5% Combo chemo3 2 8 25% Surgery +XRT 1 8 12.5% Auto BMT 1 8 12.5% Third Line XRT 1 5 20% IL-6 1 5 20% Chemo4 2 5 40% Combo chemo5 1 5 20% 1 Chlorambucil/Pred, Thalidomide/Dex 2 Melphalan/Pred 3 Etoposide/Ritux, Lenalidomide/Ritux 4 DT-PACE, Cyclophosphamide/Pred 5 R-CHOP Disclosures Sokol: Janssen Research &amp; Development, LLC: Consultancy.

CD229 is expressed on the surface of plasma cells carrying an aberrant phenotype and chemotherapy-resistant precursor cells in multiple myeloma

Multiple Myeloma (MM) is a plasma cell (PC) malignancy, which despite significant therapeutic advances, is still considered incurable. This is due to the persistence of chemotherapy-resistant minimal residual disease in the patients' bone marrow (BM) after an effective induction therapy. Immunotherapies targeting surface molecules expressed on the bulk of tumor cells and the chemotherapy-resistant, myeloma-propagating cells could play a central role in this clinical setting. We recently described surface molecule CD229 as a potential therapeutic target for MM. In our current study we assessed the expression of CD229 on different PC subtypes and on cells with a myeloma-propagating phenotype in a total of 77 patients with PC dyscrasias independently at 2 different cancer centers. We found that CD229 was strongly and homogeneously overexpressed on the PC of patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering myeloma, MM, and PC leukemia. CD229 was particularly overexpressed on those PC showing an abnormal phenotype such as expression of CD56. Most importantly, CD229 was also highly expressed on those cells in the patients' BM displaying the phenotype of chemotherapy-resistant and myeloma-propagating cells. In conclusion, our combined findings suggest that immunotherapies targeting CD229 will not only be effective for the bulk of tumor cells but will also help to eradicate chemotherapy-resistant cells remaining in the patients' BM after induction treatment. Hopefully, the design of CD229-specific monoclonal antibodies or chimeric antigen receptor-transduced T cells will help to achieve prolonged remissions or even cures in MM patients.

Unicentric mixed variant Castleman disease associated with intrabronchial plasmacytoma

Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2872096831190851.Castleman disease (CD), described as a heterogeneous lymphoproliferative disorder, can be divided into different subtypes according to clinical appearance (unicentric and multicentric form) and histopathological features (hyaline vascular, plasma cell, mixed type, human herpesvirus 8–associated and multicentric not otherwise specified). Unicentric CD is known to be usually of the hyaline vascular variant, plasma cell and mixed type of this form are quite uncommon. Malignancies are mainly associated with the multicentric form. We report a rare case of unicentric mixed variant CD evolving into intrabronchial, extramedullary plasmacytoma.Intrabronchial mass with consequential obstruction of the left main bronchus, left lung atelectasis and mediastinal lymphadenomegaly was detected by chest CT in our patient suffering from cough and hemoptysis. Pulmonectomy was performed, histopathological and immunhistochemical analysis of lymph nodes revealed mixed type of CD with interfollicular monotypic plasma cell proliferation. The intrabronchial mass consisted of monotypic plasma cells confirming plasmacytoma. Systemic involvement was not confirmed by further tests.Although malignancies more often present in multicentric CD that usually belongs to the plasma cell subtype, this case confirms the neoplastic potential of the rarest, unicentric mixed variant of CD.

A case of cervical multicentric Castleman disease treated with intensity-modulated radiation therapy using helical tomotherapy

Castleman disease (CD) is a rare lymphoproliferative disorder. Two clinical entities are described: a unicentric form with disease confined to a single lymph node region and a multicentric form characterized by generalized lymphadenopathy and systemic symptoms. Although surgery is regarded as standard therapy for the unicentric form, no consensus has been reached concerning the standard treatment for multicentric CD. We report here a case of cervical multicentric CD treated with intensity-modulated radiation therapy (IMRT), using helical tomotherapy to minimize xerostomia in comparison with conventional radiotherapy. A 29-year-old woman complained of neck swelling. Computed tomography showed lymphadenopathy in both sides of the neck. The patient was diagnosed with the plasma cell subtype of CD on biopsy. After initial treatment with prednisone, IMRT was planned to avoid normal structures, for example the parotid gland. The cervical lymphadenopathy shrank gradually during IMRT with 44 Gy in 22 fractions. Four years and 3 months after IMRT, regrowth of cervical lymph nodes has not been detected. The parotid function improved dramatically on quantitative salivary scintigraphy between 3 and 12 months after IMRT. Radiotherapy could be an option for multicentric CD, and IMRT is an effective means of minimizing xerostomia in head and neck lesions.

Salivary glands of primary Sjögren's syndrome patients express factors vital for plasma cell survival

IntroductionThe presence of circulating Ro/SSA and La/SSB autoantibodies has become an important marker in the classification criteria for primary Sjögren's syndrome (pSS). Plasma cells producing these autoantibodies are mainly high affinity plasma cells originating from germinal centre reactions. When exposed to the right microenvironment these autoimmune plasma cells become long-lived and resistant to immunosuppressive treatment. Since autoimmune plasma cells have been detected in the salivary glands of SS patients, we wanted to investigate if the glandular microenvironment is suitable for plasma cell survival and if glandular residing plasma cells are the long-lived plasma cell subset.MethodsSingle, double and triple immunohistochemistry as well as immunofluorescence staining was performed on minor salivary gland tissue retrieved from pSS, chronically inflamed and normal subjects.ResultsWe detected significant numbers of CD138+, non-proliferating, Bcl-2 expressing plasma cells in the salivary glands of pSS patients with high focus score (FS). Furthermore, we demonstrated that CXCL12 and interleukin (IL)-6 survival factors were highly expressed in pSS salivary gland epithelium and by focal mononuclear infiltrating cells. Notably, adipocytes when present in the salivary gland tissue were an important source of CXCL12. We clearly demonstrate that plasma cells are localised in close proximity to CXCL12 and IL-6 expressing cells and thus that the environment of salivary glands with high FS provide factors vital for plasma cell survival.ConclusionsPlasma cells residing in the salivary glands of pSS patients with high FS showed phenotypic characteristics of the long-lived plasma cell subtype. Furthermore, the pSS salivary gland microenvironment provided niches rich in factors vital for plasma cell survival.

Prognostic Significance of Morphological Evaluation of Tumor Cells in Multiple Myeloma.

Abstract 4889Multiple myeloma (MM) is the second most common hematological malignancy. It is caused by clonal proliferation of terminally differentiated cells of B-lineage. Morphology assessment including the determination of plasma cell percentage in the bone marrow remains one of the basic diagnostic procedures even in the era of genomics. The objective of this study was to evaluate the prognostic impact of the presence of different plasma cell morphological subtypes on overall treatment response and long-term survival. We also analyzed whether this parameter can be correlated to other conventional prognostic/predictive markers. Our cohort consisted of 139 newly diagnosed MM patients who subsequently underwent autologous transplantation (AT) within the 4W and CMG 2002 clinical trials in a single center. Percentage of plasma cell subtypes in the bone marrow was evaluated based on the progressive nucleolus analysis, assessment of nuclear chromatin, and the nucleus/cytoplasm (N/C) ratio. A combination of these elements permits differentiation of eight subtypes P000-P111 and four subclassifications. Mature plasma cells (P000, P001) were found in 42.4% of patients; type I proplasmocytes (P010, P011, P100) in 38.1% of patients; and type II proplasmocytes (P101, P110) in 19.4% of patients. For patients undergoing AT, there was a statistically significant association between the presence of P000 subtype and overall treatment response whereas group of patients with overall therapeutic response ORR has lower number of mature plasma cell (P000 subtype) than patients without treatment response (median 24.0% vs. 36.0%, p = 0.032). Patients with <10% bone marrow infiltration by mature plasmocytes (P000 subtype) had shorter overall survival compared with patients with P000 percentage of ≥37% (46.8 months vs. 77.8 months; p = 0.020). The presence of <3% proplasmocytes (P110 subtype) was associated with longer time to progression compared with P110 ≥31% infiltration (median: 54.6 months vs. 22.4 months; p=0.045). Patients in ISS stage 1 or 2 had lower percentage of P010 (type I) proplasmocytes than patients in stage 3 (11.5% vs. 23.0%; p=0.030). In contrast, higher infiltration of P100 (type I) proplasmocytes and P101 (type II) proplasmocytes was observed in patients in 1-2 ISS stage compared with stage 3 patients (12.0% vs. 6.5%; p=0.015 for P100 and 1.0% vs. 0.0%; p=0.046 for P101). Patients without deletion of 13q14 chromosome had higher bone marrow percentage of mature P000 plasmocytes than patients with deletion of 13q14 (35% vs. 13%; p=0.014). Deletion of 13q14 was also associated with lower number of type II P110 proplasmocytes (36.5% vs. 6.0%; p=0.012). Despite advances in high-tech genomic technologies, evaluation of plasmocyte infiltration of the bone marrow still belongs to basic diagnostic procedures in MM and further morphological subtyping of plasmocytes should provide important prognostic information for MM patients treated by autologous stem cell transplantation. Supported by grants MSM 0021622434, MŠMT LC06027, MZCR NR9225-3 and IGA NR9225-3. DisclosuresNo relevant conflicts of interest to declare.

Clinical data analysis on 43 cases of the giant lymph node hyperplasia

To summarize the clinical features, treatment and prognosis of giant lymph node hyperplasia (Castleman's disease, CD). The clinical data of 43 CD patients with the tumor located in neck (n = 10), chest (n = 20), abdomen (n = 9) and multi-centers (n = 4) were analyzed. All the patients underwent surgical resection of tumor or lymph and the patients of multicentric disease underwent adjuvant chemotherapy or radiotherapy. All the diagnoses of CD were confirmed by pathological examination. Among all the cases, 26 patients were hyaline vascular subtype (HV), 16 patients plasma cell subtype (PC) and 1 patient mixed subtype. All 39 patients of unicentric disease survived without disease evidence. 2 patients of multicentric disease died at 18 months and 54 months after surgery; 1 patient survived with disease; 1 patient survived with no evidence of disease. Giant lymph node hyperplasia is a rare disease. The diagnosis depends mainly on the pathological examination. Surgery is the best choice for unicentric disease with an excellent prognosis. Patients with multicentric disease may benefit from surgery, adjuvant chemotherapy or radiotherapy, but the prognosis remains grim.

Retroperitoneal Castleman’s disease with colon cancer. A rare association

Castleman's disease (CD) is a rare disorder of uncertain aetiology characterised by massive proliferation of lymphoid tissue usually localised as mediastinal masses, although abdominal involvement has been reported. Localised forms are usually associated with a good prognosis, but several more aggressive multifocal variants have been observed. Two different histologic subtypes have been described: the hyaline vascular type, more common in unicentric CD and usually asymptomatic, and the plasma cell form. Unicentric CD may be associated with an increased risk of lymphoma, but there was no reported increased risk of other malignancies. A patient with plasma cell subtype unicentric CD localised in retroperitoneum associated with an adenocarcinoma of ileocaecal valve and liver metastasis is reported.

Analysis of multiple sclerosis cerebrospinal fluid reveals a continuum of clonally related antibody-secreting cells that are predominantly plasma blasts

Fluorescence-activated cell sorting (FACS) analysis of B cell subtypes in 17 CSF samples from 15 patients with clinically-definite MS revealed that CD19+ B cells accounted for 2 to 11% (mean 5%) and CD138+ cells constituted 0 to 5% (mean 2%) of total CSF lymphocytes. Further stratification of CD138+ cells based on expression levels of CD19 showed that CD138+19+ plasma blasts constituted 89 ± 2% (mean ± SE) of the CD138+ cell population ( P < 0.00001), with more mature plasma cells (CD138+19−) constituting the remaining 11 ± 2%. Sequence analysis of immunoglobulin variable regions in single CD138+19+ and CD138+19− cells sorted from MS CSF identified many of the same clonal populations in both populations, indicating a continuum of clonally related plasma cell subtypes of which CD138+19+ plasma blasts are most abundant.