Background: To study the histological structure and immunohistochemical (IHC) parameters of the plasmacytoma tumour substrate in patients with multiple myeloma (MM). Methods: The study included 21 patients (10 men/11 women) aged 23 to 73 years old with newly diagnosed MM complicated by plasmacytoma. Bone plasmacytoma was diagnosed in 14 patients, and extramedullary plasmacytoma was diagnosed in 7 patients. Plasmacytoma tissue specimens were examined using a LEICA DM4000B microscope. Anti-CD56, anti-CD166, anti-CXCR4, anti-Ki-67, and anti-c-MYC antibodies were used for IHC study of plasmacytoma biopsies. Results: When comparing the morphology of bone and extramedullary plasmacytoma, no significant differences were revealed; however, the substrate of extramedullary plasmacytoma was more often represented by tumour cells with an immature morphology than was the bone plasmacytoma substrate (57.1% vs. 28.6%, respectively). We revealed a significant difference in the expression of CD166 between bone and extramedullary plasmacytoma. The mean values of CD166 expression in bone plasmacytoma cells were significantly higher (36.29 ± 7.61% versus 9.57 ± 8.46%, respectively; p = 0.033) than those in extramedullary plasmacytoma cells. We noticed that in extramedullary plasmacytoma cells, there were higher values for the Ki-67 index than in bone plasmacytoma cells, and this result was independent of cell morphology. Conclusion: The mechanisms involved in the dissemination of tumour plasma cells are currently unexplored. Even in such a small sample, some differences in expression could be identified, which may indicate that different mechanisms lead to the formation of bone and extramedullary plasmacytomas. Specifically, the expression of CD166 in extramedullary plasmacytoma cells was almost 4 times lower than that in bone plasmacytoma cells, which may indicate the involvement of CD166 in the mechanisms of bone destruction. The proliferative activity of extramedullary plasmacytoma cells was shown to be higher than that of bone plasmacytoma cells.

Background: Myelodysplastic syndromes (MDS) can present a challenge for clinicians. Multicolor flow cytometry (MFC) can aid in establishing a diagnosis. The aim of this study was to determine the optimal MFC approach for MDS. Methods:The study included 102 MDS (39 low-grade MDS), 83 cytopenic patients without myeloid neoplastic disorders (control group), and 35 healthy donors. Bone marrow was analyzed using a six-color MFC. Analysis was conducted according to the "Ogata score," "Wells score," and the integrated flow cytometry (iFC) score. Results:The respective sensitivity and specificity values were 77.5% and 90.4% for the Ogata score, 79.4% and 81.9% for the Wells score, and 87.3% and 87.6% for the iFC score. Specificity was not 100% due to deviations of MFC parameters in the control group. Patients with paroxysmal nocturnal hemoglobinuria (PNH) had higher levels of CD34 + CD7 + myeloid cells than donors. Aplastic anemia and PNH were characterized by a high proportion of CD56 + cells among CD34 + precursors and neutrophils. The proportion of MDS-related features increased with the progression of MDS. The highest number of CD34 + blasts was found in MDS with excess blasts.MDS with isolated del(5q) was characterized by a high proportion of CD34 + CD7 + cells and low granularity of neutrophils. In 39 low-grade MDS, the sensitivities were 53.8%, 61.5%, and 71.8% for Ogata score, Wells score, and iFC, respectively. Conclusion:The results support iFC as a useful diagnostic tool in MDS.

BACKGROUND: Follicular lymphoma (FL) is one of the most frequent types of B-cell lymphomas and accounts for about 22% of all non-Hodgkin lymphomas in Russia. The disease is usually a long-term condition with frequent relapse. At the same time 15-20% of pts have fast-tumor progression. Patients (pts) of this group die within the first 1.5-2 years from the time of diagnosis. High-dose chemotherapy (HDT) followed by ASCT in the presence of nonfavorable characteristics of FL (fast growth of tumor volume, B-symptoms, third citological grade of tumor, large tumor size, absence of anti-tumor response to R-CHOP courses in the first remission) increases the overall survival and progression-free survival of pts. AIM: To estimate HDT with ASCT efficiency among pts with FL in front-line therapy who received treatment in the National Research Center for Hematology during 2000-2013. PATIENTS AND METHODS: The results of ASCT among 12 pts with FL have been analyzed: 8 male and 4 female aged from 31 to 50 with median age 43. Patients in the main group (11/12) were on the IVth stage of tumor growth. In 6/12 cases the tumor size was more than 6 sm. Among 7/12 pts, besides lesions of lymphatic nodes, extra nodal lesions were found: infiltration in psoas (1/12), kidney (1/12), stomach (1/12), lungs (1/12), thyroid (1/12), pancreas (1/12). In 2/12 cases leukaemization was observed. Based on FLIPI criteria all the pts were divided into three groups: in the first risk group - 5/12 pts, in the second - 3/12, in the third - 4/12. B-symptoms were in the majority of cases (9/12). 9/12 pts were diagnosed with I-II cytological grade of FL, among 3/12 - III A/B. Based on the character of tumor growth the dispersion was the following: nodular tumor growth - 5/12, nodular-diffuse tumor growth-6/12, diffuse tumor growth - 1/12. Immuno-chemical investigation of protein serum and urine was performed in 9/12 cases, and among them rising serum β2-microglobulin above the norm was observed in 4/9 pts. A rise in lactate dehydrogenase concentration above the norm was observed among 4/12 pts. Lesion of bone marrow at the beginning of the disease was identified among half of the pts (6/12). Induction courses were performed on the R-CHOP programs, with intensive therapy - on protocol mNHL-BFM-90. RESULTS: Anthracycline courses were prescribed for nearly all of the pts as an inductive therapy: R-CHOP (11/12). mNHL-BFM-90 protocol was chosen as an inductive regime because of the fast growth of tumor size, IIIB grade of FL in 1/12 case. This tumor growth behaved like diffuse large B-cell lymphoma. In three cases medical-diagnostic splenectomy was undertaken before chemotherapy. After the inductive regimes the pts were given HDT based on the following scheme: two courses R-DHAP, course with rituximab and high-doses cyclophosphamide, a course with rituximab and high doses of etoposide, R-BEAM. All 12 pts, who were given ASCT are in full remission on the main disease. The period of observation is from 13 to 164 months. CONCLUSION: This first experience of intensive therapy in FL in Russia demonstrates that ASCT as a front-line therapy leads to complete remission of FL among pts who have nonfavorable prognosis factors. Disclosures No relevant conflicts of interest to declare.

Background: Primary bone lymphoma (PBL) accounts for about 5% of extranodal lymphomas, the most common type are Diffuse Large B-cell Lymphoma (PBL-DLBCL). R-CHOP chemotherapy combined with or no radiation therapy can induce 5-year overall and progression free survival about 63% and 60% for localized-stage and only 41% and 35% for advanced stage and with adverse factors (AF). Due to the rarity of the disease the optimal treatment strategy still remains unknown. Further research is thus needed to increase treatment efficacy for patients with advanced stage PBL-DLBCL and with AF. Aims: To evaluate the efficacy of mNHL-BFM-90 program in adult patients with advanced stage PBL-DLBCL and with AF. Methods: Twenty three previously untreated pts with PBL-DLBCL underwent mNHL-BFM-90 treatment between May 2007 and July 2014; mean age 41 years (range 17-65); age ≥60 years 3 pts (13,6%); M\F=14\9. Tumor stage according to the Ann-Arbor classification: stage I (involvement of 1 bone) - 7 pts (30,4%), II (involvement of regional lymph nodes) - 3 pts (13%), IV (multiple bone involvement) - 13 pts (56,6%); stage >I 16 pts (69,5%). All pts with stage I had large-size tumors (>6sm) with soft tissue contact invasion. LDH elevation was observed in 10 pts (43,5%), B-symptoms in 15 pts (65%), large-size tumors - 20 pts (87%). The most common tumor sites were the skull bones, vertebrae, and femur. All patients received treatment according to the mNHL-BFM-90 intensive program This program was modified in the following way: adriamycin was administered on the 3rd day of course AA at a dose 50 mg/m2; methotrexate was administered on the 1st day of course C at a dose 1.0 g/m2 for 12 hours. All patients underwent from 4 to 6 courses. Twelve (52%) pts received rituximab on day 0 prior to each course of therapy. Five pts received radiotherapy, all pts received intrathecal prophylaxis of central nervous system (CNS) involvement. Results. Complete remissions were achieved in 23 pts (100%). Relapses were observed in three patients in 6, 9 and 40 months after completion of treatment. From 2 pts with early relapse, one was diagnosed as «double-expression lymphoma» (MYC expression >70%, BCL2 >60%), both pts proliferation index Ki-67 accounted 100%. All 3 pts received salvage therapy and died from progression of disease. With a median follow-up of 69 months (range 17-110) both progression-free and overall survival of 23 pts constituted 87%. Grades 3, 4 hematological toxicity was observed in all pts. No deaths related to mNHL-BFM-90 treatment occurred. No second malignancies were observed. Conclusion The mNHL-BFM-90 demonstrated high efficacy and acceptable toxicity in patients with advanced-stage PBL-DLBCL and with AF. Figure Figure. Disclosures No relevant conflicts of interest to declare.

JAK2 (Janus kinase 2) V617F, CALR (Calreticulin) exon 9, and MPL (receptor for thrombopoietin) exon 10 mutations are associated with the vast majority of Ph-negative chronic myeloproliferative neoplasms (MPNs). These mutations affect sequential stages of proliferative signal transduction and therefore, after the emergence of one type of mutation, other types should not have any selective advantages for clonal expansion. However, simultaneous findings of these mutations have been reported by different investigators in up to 10% of MPN cases. Our study includes DNA samples from 1958 patients with clinical evidence of MPN, admitted to the National Research Center for Hematology for genetic analysis between 2016 and 2019. In 315 of 1402 cases (22.6%), CALR mutations were detected. In 23 of these 315 cases (7.3%), the JAK2 V617F mutation was found in addition to the CALR mutation. In 16 from 24 (69.6%) cases, with combined CALR and JAK2 mutations, V617F allele burden was lower than 1%. A combination of JAK2 V617F with MPL W515L/K was also observed in 1 out of 1348 cases, only. JAK2 allele burden in this case was also lower than 1%. Additional mutations may coexist over the low background of JAK2 V617F allele. Therefore, in cases of detecting MPNs with a low allelic load JAK2 V617F, it may be advisable to search for other molecular markers, primarily mutations in exon 9 of CALR. The load of the combined mutations measured at different time points may indicate that, at least in some cases, these mutations could be represented by different clones of malignant cells.

Background: Castleman' s disease (CD) is rare lymphoproliferative disorder with long asymptomatic current and high risk of transformation in malignant lymphoma. For last years, diagnostics of CD improved and uniform classification of an illness was accepted. Depending on morphological features allocate 3 variant of CD: hyaline-vascular (HVV), plasma cell (PCV) and mixed cell. Most cases of the ÑD involve a single or localized group of lymph nodes and can be asymptomatic. In these cases the histologic picture can be characterized as a HVV or mixed cell and PCV morphology. Less often the disease proceeds with multiple lymphoid regions (multicentric CD, MCD) and is usually accompanied by various systemic inflammatory symptoms (fever, weight loss and night sweats). In these cases histologic picture in the involved lymph nodes meet mix cell or PCV of CD. The role of a human herpes virus-8 (HHV-8) in pathogenesis of MCD is studied. It is known that HHV-8 codes in a genome of a cell of the person some regulatory proteins and cytokines, first of all a virus homolog interleukin-6 which stimulates development of human IL-6 and endothelial factor of growth that conducts to a neoangiogenesis in not tumoral lymph nodes. HHV-8-positive MCD allocate separately in due to its extremely aggressive course and a high risk of transformation into HHV-8-positive plasmablastic lymphoma. Aim: Explore the features of a clinical current and of therapeutic approaches at different variants CD. Patients and Methods: In Center for Hematology since 1996 to the present time observed clinical and morphological features of 76 pts with CD. Clinical data were obtained during the retrospective analysis of 17 outpatient clinical records and prospective supervision over 59 pts. The diagnosis was established from results of histological and immunohistochemical examinations of removed lymph nodes in all cases. Frequency analyses were performed using z-tests with SAS 9.1 software. Results: HVV with local lymph nodes involvement was diagnosed in 38 (50%) pts. The average age of pts was 40 years The PCV was also observed in 38 (50%) cases, among them in 17 (22%) pts were found to have local involvement and 21 (28%) had multicentric involvement. Five (24%) pts with MCD were established to be infected with human herpesvirus type 8. Male (37 pts) and female (39 pts) are suffering with an identical frequency. However, HVV is more often diagnosed for female, than at male (71% to 29% respectively), PCV equally often meets both at male, and at female (47% of male, 53% of female) and, at last, at MCD the share of male statistically significantly is more than share of female (86% against 14%, p=0,05) (Figure 1). The basic involvement areas in local HVV and PCV were peripheral (38%), mediastinal (29%), retroperitoneal (18%) abdominal (9%) and small pelvic (6%) lymph nodes (95% CI). Local HVV and PCV proceed benign and in 94.5% of cases are cured by surgical removal of lymph nodes involved in the pathological process, in 5.5% of cases with inoperable cases require followed by radiation therapy. MCD was significantly more common in male, occurs aggressively with severe constitutional symptoms, generalized lymphadenopathy, hepatosplenomegaly, hypergammaglobulinemia, autoimmune hemolysis, thrombocytopenia, and involvement of extranodal foci in the pathological process. MCD transformation to plasmoblastic lymphoma was observed in 4 of 5 HHV8-positive pts and followed by a poor outcome. The prognosis of untreated MCD was unfavorable. In a number of cases prednisolone monotherapy worsened and the MCD pts receiving timely R-CHOP or R-VD chemotherapy could achieve sustained remission (the 5-year OS was 55%). Conclusion: The prognosis of HVV and local PCV is favorable: the disease is surgically cured in 95% of cases. Chemotherapy according to the program of Non-Hodgkins Lymphomas indicated for the treatment of MCD: sustained remission can be achieved by the use of R-CHOP or R-VD programs. HHV8-positive MCD characterized by high risk disease transformation to incurable plasmablastic lymphoma. Overall, prognosis and therapy choice in HIV-negative pts with CD depend on the histological type of the disease, the extent of a tumor and HHV-8 infection. Figure 1. Gender distribution for three variants of CD; there is male-female imbalance in HVV and MCD groups (z-test, ð<0.05); analysis based on initial diagnosis data. Figure 1. Gender distribution for three variants of CD; there is male-female imbalance in HVV and MCD groups (z-test, ð<0.05); analysis based on initial diagnosis data. Disclosures No relevant conflicts of interest to declare.

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Objectives to describe a group ofpatients with IgG4-related systemic disease (IgG4-RSD), followed up in the Institute of Rheumatology, Moscow, Russia Methods Between 2008 and 2011 25 patients were diagnosed with IgG4-RSD. Of these, male - 12, female - 13, mean age - 43.6 years (22 - 71). The diagnosis was based on clinical features, evaluation of serum IgG4 level (>1,35 g/l), histological and immunomorphological examination of affected tissue specimens using IgG, IgG4, CD20, CD138 and κ/λ stainig. Results As part of the IgG4-RSD 32% (n=8) of patients were diagnosed with multifocal fibrosclerosis, IgG4-associated sclerosing orbit pseudotumor (sclerosing dacryoadenitis, solitary fibrotic mass, fibroplasia of extraocular muscles and orbit fat)–28% (n=7), retroperitoneal fibrosis (Ormond’s disease) with periaortic mass, often compressing ureter–16% (n=4), Miculicz’s disease–8% (n=2), Küttner’s tumor–4% (n=1), autoimmune pancreatitis (AIP) (type I), mediastinal fibrosclerosis and juvenile xanthogranuloma of the orbit–by 4% (n=1) respectively. Among affected areas were orbit (n=17), salivary (parotid and submandibular) glands (n=8), retroperitoneum (n=5), sinuses (n=3), mediastinum (n=2), pancreas (n=2), lymph nodes (n=1), biliary ducts (n=1). Serum IgG4 was elevated >1,35g/l in 65% of patients (1,5–16,5 g/l). IgG4-staining of plasma cells was diagnostic in 100% of cases with maximum IgG4/IgG ratio – 50%. All cells were polyclonal. Highest levels of IgG4 were detected in cases of Miculicz’s disease. Histology showed the absence of fibroplasia, MALT-tissue formation with no lymphoepithelial lesions and the abundance of IgG4-expressing plasma cells. Conclusions In Russian IgG4-RSD cohort multifocal forms prevail predominantly with orbital affection. Relatively few patients with AIP were found. Disclosure of Interest None Declared