Significance of multiple myeloma oncogene 1 immunohistochemistry in chronic endometritis detection in patients with recurrent pregnancy losses: an observational study.

The most reliable chronic endometritis diagnosis is based on immunohistochemistry plasma cell identification in endometrial samples. Our study aimed to compare multiple myeloma oncogene 1 (MUM1) and syndecan-1/CD138 immunohistochemistry staining for chronic endometritis diagnosis among patients with recurrent pregnancy loss. We evaluated the presence of endometrial stromal changes. Fifty-four patients with a history of at least two intrauterine pregnancy losses underwent diagnostic hysteroscopy in the follicular phase of the cycle with endometrial aspiration biopsy. In all 54 cases, three successive sections were cut from each paraffin-embedded tissue block for hematoxylin and eosin (H&E), CD138 and MUM1 staining. The goal was to evaluate the level of agreement between the MUM1 and CD138 results and plasma cell detection rate in assessing the endometrial stromal changes. The concordance analysis between CD138 and MUM1 immunohistochemistry staining showed consistent results in 43 of 54 (79.6%) cases. The level of agreement was moderate, based on a Kappa value of 0.60. MUM1 immunostaining was positive for CE in more cases than CD138 staining, and this difference was statistically significant, showing a higher sensitivity of MUM1 in plasma cell detection (p=0.01). Endometrial stromal changes were observed in the majority of cases - 49/54 (90%). Samples without stromal changes were consistently negative for plasma cells using both CD138 and MUM1 staining. We demonstrated that MUM1 staining, used in conjunction with assessing endometrial stromal changes, contributes to a more accurate and comprehensive diagnosis of chronic endometritis.

Structurally diverse diterpenoids from the roots of Euphorbia fischeriana Steud.

Four new diterpenoids (1-4), and 18 known ones were isolated from the roots of Euphorbia fischeriana Steud (Euphorbiaceae). These diterpenoids shared six skeleton types, including ent-atisane, kaurane, 3,4-secokaurane, lathyrane, 4,5-secoatisane and ingenane diterpenoids. The structures of the new diterpenoids were characterized by a combination of spectroscopic techniques and X-ray crystallography. Moreover, biological evaluation revealed that compounds (16S*)-atisan-3ß,16,17-triol (7), (16S*)-3ß,16,17,18-tetrahydroxykaurane (12) and (16S*)-3α-hydroxykauran-16,17-acetonide (15) showed inhibitory activity against the interferon regulatory factors (IRFs) involved pathway.

IRF8 is a Reliable Monoblast Marker for Acute Monocytic Leukemias.

Blast evaluation in patients with acute monocytic leukemias (AMoL) is notoriously difficult due to the lack of reliable surface markers and cytologic subtleties on the aspirate smears. While blasts of most nonmonocytic acute leukemias express CD34, available immunohistochemical antibodies to monocytic blasts also mark normal background mature monocytes. We searched for a potential biomarker candidate by surveying specific gene expression profiles of monocyte progenitors. Our investigations led us to IRF8, which is a lineage-specific transcription factor critical for the production of monocytic and dendritic cell progenitors. In this study, we tested and validated a monoclonal antibody to IRF8 as a novel immunohistochemical stain for trephine core biopsies of human bone marrow. We assessed the expression of IRF8 in 90 cases of AMoL, including posttherapy staging bone marrows, 23 cases of chronic myelomonocytic leukemia, 26 cases of other acute myeloid leukemia subtypes, and 18 normal control marrows. In AMoL, there was high correlation of IRF8-positive cells to aspirate blast count (R=0.95). Comparison of IRF8 staining to aspirate blast percentage in chronic myelomonocytic leukemia also showed good correlation (R=0.86). In contrast, IRF8-positive cells did not correlate with blast count in other subtypes of acute myeloid leukemia (R=0.56) and staining was <5% in all normal control marrows, even those with reactive monocytosis. We found that IRF8 was also weakly reactive in B cells and hematogones, with the latter accounting for rare cases of discrepancies. When IRF8 was used to categorize cases as AMoL, positive for residual leukemia or negative, the sensitivity was 98%, specificity was 82%, positive predictive value was 86%, and negative predictive value was 98%. These results demonstrate that IRF8 may serve as a clinically useful immunostain to diagnose and track AMoLs on bone marrow core biopsies. This can be particularly impactful in the setting of poor aspiration and focal blast increase. In the era of new targeted therapies that have been reported to induce monocytic outgrowths of leukemia, a marker for malignant monoblasts may prove even more critical.

Downregulated IRF8 in Monocytes and Macrophages of Patients with Systemic Sclerosis May Aggravate the Fibrotic Phenotype.

Monocytes and macrophages may be involved in the pathogenesis of systemic sclerosis (SSc); however, the etiology and regulation of monocyte and macrophage function in SSc remain unknown. IRF8 is a transcriptional regulator that is essential for the differentiation and function of monocytes and macrophages and thus may be involved in the regulation of macrophage phenotypes in SSc fibrosis. In this study, we measured IRF8 levels in circulating monocytes of 26 patients with SSc (diffuse cutaneous SSc, n = 11; limited cutaneous SSc, n = 15) and 14 healthy controls. IRF8 levels were significantly suppressed in monocytes of patients with diffuse cutaneous SSc and correlated negatively with the modified Rodnan total skin thickness score. Next, we assessed expression levels of cell surface markers, cytokine profiles, and components of extracellular matrix in IRF8-silenced monocyte-derived macrophages. IRF8-silenced monocyte-derived macrophages displayed an M2 phenotype and significantly upregulated mRNA and protein levels of profibrotic factors and extracellular matrix components. Finally, we assessed skin fibrosis in myeloid cell-specific IRF8 conditional knockout (Irf8flox/flox; Lyz2Cre/+) mice and found upregulated mRNA levels of extracellular matrix components and increased bleomycin-induced skin fibrosis. In conclusion, altered IRF8 regulation in monocytes and macrophages may be involved in SSc pathogenesis.

Objective Visual Analog Scale for Biopsy Diagnosis of Helicobacter pylori Infection in Clinical Practice.

Historic and current pathology society guidelines recommend using visual gestalt to identify substantial inflammatory cell infiltrate in Helicobacter pylori gastritis, but these scales were subjectively designed. This study aims to objectively investigate the density of inflammation that justifies additional workup for H. pylori infection. We retrospectively identified 2 patient cohorts who had undergone endoscopy with gastric biopsies; 1 with H. pylori infection (n=66), confirmed with a positive stool antigen test and/or Campylobacter-like organism test, and 1 without infection (n=81). Antral and body biopsies were selected from each case, if available, and stained with MUM-1 to highlight mucosal plasma cells. Digital analysis was performed to calculate the number of plasma cells/mm2, termed the "inflammatory score" (IS). Patients with H. pylori infection had an average of 1289 plasma cells/mm2 in the antrum and 835 plasma cells/mm2 in the body, compared with 346 plasma cells/mm2 in the antrum and 178 plasma cells/mm2 in the body in patients without infection. IS cut-off values for a positive infection were 714 plasma cells/mm2 in the antrum and 316 plasma cells/mm2 in the body, with high sensitivities and specificities in both the antrum (92%, 92%) and body (85%, 84%), respectively. A visual analog scale was created to provide a histologic correlate of the observed IS ranges and cut-offs. This practical and objective scale is associated with a high sensitivity and specificity for diagnosing H. pylori infection and justifies moving away from upfront universal H. pylori testing in routine clinical practice.

Virus-infected peripheral blood plasmablasts in a patient with severe fever with thrombocytopenia syndrome.

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne viral hemorrhagic disease with a high fatality rate. It is caused by the SFTS virus and is endemic in East Asian countries such as China, South Korea, and Japan. Previous studies have shown that plasmablasts appear transiently in peripheral blood during the acute phase of SFTS, but do not specify the characteristics of these plasmablasts. In this report, we describe the features of peripheral blood plasmablasts in a patient with SFTS. Immunohistochemical and immunofluorescence staining detected a small number of atypical lymphocytes expressing the SFTS virus antigen among peripheral leukocytes in a blood sample. The phenotype of the virus-infected cells was CD27+, CD38+, MUM1+, and CD138+, which is consistent with that of plasmablasts. This novel study demonstrates that plasmablasts in the peripheral blood of patients with SFTS are targets of the SFTS virus.

[Clinicopathological features of follicular lymphoma in children].

Objective: To investigate the clinicopathologic features of follicular lymphoma (FL) in children. Methods: One female and one male patients with FL diagnosed in the First College of Clinical Medical Science, China Three Gorges University and Beijing Friendship Hospital of the Capital University of Medical Science in February 2016 and June 2015 were studied by HE immunohistochemistry, EBER in situ hybridization, IgH and IgK gene rearrangement analysis and IRF4 fusion gene detection. Results: The two patients' age were 6.3 and 12 years, respectively. The lesions involved head and neck lymph nodes with duration of more than 2 months. Histopathologically, the lesions consisted of nodular proliferation of lymphoid follicles with diffuse distribution of large cells. Starry sky phenomenon was seen in one of the two cases. Immunohistochemistry showed that one case was positive for bcl-2 and MUM1, but negative for bcl-6 and CD10. Ki-67 index was>50% and oligoclonal IgK rearrangement was observed. The second case showed positivity for bcl-6, and CD10 but negative for bcl-2. Ki-67 index was>50% and clonal IgH FR1-JH and IgH FR2-JH rearrangements were detected. Both cases showed no evidence of IRF4 gene fusion. Conclusions: Childhood FL is a rare B-cell lymphoma with characteristic features and high-grade histomorphology. However, its immunophenotype and molecular genetic characteristics are divergent.

Multiple Myeloma 1 Transcription Factor Is Superior to CD138 as a Marker of Plasma Cells in Endometrium.

Chronic endometritis is characterized by plasma cell (PC) infiltration of endometrial stroma. Identification of PCs can be challenging by routine hematoxylin and eosin (H&E) stain due to the low numbers of PCs or to their being obscured by other cells in the stroma. CD138 is widely used as an ancillary immunohistochemistry stain to identify PCs; however, it has a high background reaction. In this study, multiple myeloma 1 (MUM1) transcription factor is introduced as an alternative PC marker in endometrial tissues. In this study, 311 endometrial biopsies, submitted to rule out chronic endometritis, were selected. They were divided into Group I (n = 87) and Group II (n = 224). Both had MUM1 and H&E while Group I also had accompanying CD138 stains. In both groups combined, MUM1 detected plasma cells in 48% of the cases, while CD138 and H&E identified the cells in 23% and 15% of the biopsies, respectively. In addition to having a clean background, MUM1 is a more sensitive stain than CD138 for detection of PCs in endometrium.

IRF5 is increased in labouring myometrium and regulates pro-labour mediators.

Preterm birth continues to be the leading cause of neonatal mortality and morbidities that can extend into adult life. Few treatment options stem from our incomplete understanding of the mechanisms of human labour and delivery. Activation of the inflammatory response in gestational tissues by inflammation and/or infection leads to the production of pro-inflammatory and pro-labour mediators, thus preterm birth. Interferon regulatory factor 5 (IRF5) has recently emerged as an important pro-inflammatory transcription factor involved in acute and chronic inflammation. The aims of this study were to determine the expression of IRF5 in human myometrium from labouring and non-labouring women, and whether IRF5 is involved in the genesis of pro-inflammatory and pro-labour mediators induced by pro-inflammatory cytokines or toll-like receptor (TLR) ligands. IRF5 mRNA and protein expression was significantly higher in human myometrium after spontaneous term labour, compared to non-labouring tissues. IRF5 mRNA expression was also significantly higher in primary myometrial cells treated with the pro-inflammatory cytokines IL1B or TNF. In primary myometrial cells, IRF5 knockdown by siRNA (siIRF5) was associated with significantly decreased expression and or secretion of pro-inflammatory cytokines (IL1A, IL6), chemokines (CXCL8, CCL2), adhesion molecules (ICAM1, VCAM1) and contraction-associated proteins PTGS2, PGF2α and PTGFR when in the presence of IL1B, TNF, fsl-1 (TLR2/6 ligand) or flagellin (TLR5 ligand). siIRF5-transfected cells also displayed decreased NF-κB RELA transcriptional activity in the presence of these preterm birth mediators. Our study suggests a novel role for IRF5 in the regulation of the inflammatory response in human myometrium.

Round-robin test for the cell-of-origin classification of diffuse large B-cell lymphoma-a feasibility study using full slide staining.

Diffuse large B-cell lymphoma (DLBCL) is subdivided by gene expression analysis (GEP) into two molecular subtypes named germinal center B-cell-like (GCB) and activated B-cell-like (ABC) after their putative cell-of-origin (COO). Determination of the COO is considered mandatory in any new-diagnosed DLBCL, not otherwise specified according to the updated WHO classification. Despite the fact that pathologists are free to choose the method for COO classification, immunohistochemical (IHC) assays are most widely used. However, to the best of our knowledge, no round-robin test to evaluate the interlaboratory variability has been published so far. Eight hematopathology laboratories participated in an interlaboratory test for COO classification of 10 DLBCL tumors using the IHC classifier comprising the expression of CD10, BCL6, and MUM1 (so-called Hans classifier). The results were compared with GEP for COO signature and, in a subset, with results obtained by image analysis. In 7/10 cases (70%), at least seven laboratories assigned a given case to the same COO subtype (one center assessed one sample as not analyzable), which was in agreement with the COO subtype determined by GEP. The results in 3/10 cases (30%) revealed discrepancies between centers and/or between IHC and GEP subtype. Whereas the CD10 staining results were highly reproducible, staining for MUM1 was inconsistent in 50% and for BCL6 in 40% of cases. Image analysis of 16 slides stained for BCL6 (N = 8) and MUM1 (N = 8) of the two cases with the highest disagreement in COO classification were in line with the score of the pathologists in 14/16 stainings analyzed (87.5%). This study describes the first round-robin test for COO subtyping in DLBCL using IHC and demonstrates that COO classification using the Hans classifier yields consistent results among experienced hematopathologists, even when variable staining protocols are used. Data from this small feasibility study need to be validated in larger cohorts.

Enhancement of Th1/Th17 inflammation by TRIM21 in Behçet's disease.

The etiology of Behçet's disease (BD), a chronic, multisystemic autoinflammatory and autoimmune disease, remains unknown; however, researchers have postulated that infectious agents, such as herpes simplex virus, are significant triggering factors of BD. Tripartite motif-containing (TRIM) proteins exhibit antiviral properties, mediating antiviral defense mechanisms. The purpose of this study was to investigate TRIM21 protein expression in the monocytes of BD patients and to identify the role of TRIM21 in immune dysregulation in BD. In this study, the expression of TRIM21 and related molecules, including interferon regulatory factor 8 (IRF8), was analyzed in monocytes from BD patients. Functional analyses using small interfering RNA and co-culture with responder T cells were performed to examine the pathological role of TRIM21 in BD. Peripheral blood monocytes from BD patients showed increased TRIM21 expression and decreased IRF8 expression compared with that in monocytes from healthy controls. TRIM21 was found to decrease IRF8 expression. BD monocytes facilitated Th1 and Th17 differentiation of co-cultured T cells, and knock-down of TRIM21 expression by small interfering RNA inhibited this differentiation. In conclusion, TRIM21 played a pivotal role in regulating the secretion of proinflammatory cytokines in monocytes of BD patients.

Prognostic significance of interferon regulating factor 4 (IRF4) in node-negative breast cancer.

PURPOSE: The transcription factor IRF4 regulates immunoglobulin class switch recombination as well as plasma cell differentiation. We examined the prognostic significance of IRF4 expression in node-negative breast cancer (BC). METHODS: IRF4 expression was evaluated by immunostaining in a cohort of 197 node-negative BC patients not treated in adjuvant setting, referred to as Mainz cohort. The prognostic significance of immunohistochemically determined IRF4 expression for metastasis-free survival (MFS) was examined by Kaplan-Meier survival analysis as well as univariate and multivariate Cox analysis adjusted for age, pT stage, histological grade, ER, and HER2 status. For verification of immunohistochemical results, IRF4 mRNA expression was evaluated using microarray-based gene expression profiling in four previously published cohorts (Mainz, Rotterdam, Transbig, Yu) consisting of 824 node-negative breast cancer patients in total, who were not treated with adjuvant therapy. The prognostic significance of IRF4 mRNA expression on metastasis-free survival (MFS) was examined by univariate and multivariate Cox analysis in the Mainz cohort and by a meta-analysis of all node-negative BC patients and different molecular subtypes. IRF4 mRNA levels were compared to immunohistochemically determined IRF4 expression in 140 patients of the Mainz cohort using Spearman correlation. RESULTS: Immunohistochemically determined high IRF4 expression was associated with higher MFS in univariate Cox regression (HR 0.178, 95% CI 0.070-0.453, p < 0.001). IRF4 maintained its significance independently of established clinical factors for MFS (HR 0.088, 95% CI 0.033-0.232, p < 0.001). Immunohistochemically, determined IRF4 correlated moderately with IRF4 mRNA expression (ρ = 0.589). Higher expression of IRF4 was associated with better MFS in a meta-analysis of the total cohort (HR 0.438, 95% CI 0.307-0.623, p < 0.001). Prognostic significance was more pronounced in the HER2+ molecular subtype (HR 0.215, 95% CI 0.090-0.515, p = 0.001) as compared to the luminal A (HR 0.549, 95% CI 0.248-1.215, p = 0.139), luminal B (HR 0.444, 95% CI 0.215-0.916, p = 0.028), and basal-like subtypes (HR 0.487, 95% CI 0.269-0.883, p = 0.018). Further, IRF4 expression showed independent prognostic significance in a multivariate analysis of the Mainz cohort (HR 0.236, 95% CI 0.105-0.527, p < 0.001). CONCLUSIONS: IRF4 had independent prognostic significance in node-negative BC. Higher expression of IRF4 was associated with improved outcome. The prognostic impact differed between diverse molecular subtypes and was most pronounced in HER2+ breast cancer.

miRNA-451a Targets IFN Regulatory Factor 8 for the Progression of Systemic Lupus Erythematosus.

Increasing evidence has shown that miRNA-451a (miR-451a) is associated with the development of systemic lupus erythematosus (SLE); however, the mechanism of this association is not fully known. The present study found an increased expression of miR-451a in the spleen and thymus of an SLE mice model. A decrease in miR-451a expression partly relieved the enlargement of the spleen and decreased the proteinuria content and immune complex deposits. The deficiency in miR-451a also decreased numbers of CD4+CD69+ and CD4+/CD8+ T cells and the levels of the serum cytokines IL-17a and IL-4. The IFN regulatory factor (IRF) 8 was highly expressed in the immune organs of wild-type mice but was suppressed in SLE-like mice. A dual-luciferase reporter assay was carried out in combination with gene silencing and overexpression to verify that IRF8 was a target of miR-451a in vitro and in vivo. The data indicate the function and a target of miR-451a in SLE, providing a new target for SLE therapy.

FOXO3, IRF4, and xIAP Are Correlated with Immune Activation in HIV-1-Infected Men Who Have Sex with Men During Early HIV Infection.

Forkhead box O (FOXO)1, FOXO3, interferon regulatory factor (IRF)4, X-linked inhibitor of apoptosis protein (xIAP), and E74-like factor (ELF)4 have been described as important regulators of T cell functions and differentiation. However, whether these molecules are associated with HIV-1 disease progression is still unknown. In this study, we showed that the levels of FOXO3, IRF4, and xIAP mRNA in rapid progressors (RPs) were significantly higher than in HIV-negative healthy controls (HCs). Moreover, FOXO3 expression was positively correlated with HIV-1 viral load and CD4+ T cell activation. Remarkably, increased CD4+ and CD8+ T cell activation was apparent in RPs compared with typical progressors and HCs. In addition, a profile of higher apoptosis, more CD8+ TEM cells, and fewer CD4+ and CD8+ Naive T cells were observed in early HIV infection patients with low CD4+ T cell counts. Furthermore, in vitro, IRF4 and xIAP expression was enhanced in peripheral blood mononuclear cells from healthy people following T cell receptor stimulation. T cell activation was decreased by treatment with siRNA inhibiting FOXO3, IRF4, and xIAP. Our results show that significantly increased levels of FOXO3, IRF4, and xIAP mRNA in Chinese HIV-1-infected patients were related to T cell immune activation, implicating them as potential targets for developing new therapeutic avenues to slow down HIV-1 disease progression.

Preclinical activity of CPI-0610, a novel small-molecule bromodomain and extra-terminal protein inhibitor in the therapy of multiple myeloma.

Inhibition of the bromodomain and extra-terminal (BET) proteins is a promising therapeutic strategy for various hematologic cancers. Previous studies suggest that BET inhibitors constrain tumor cell proliferation and survival mainly through the suppression of MYC transcription and activity. However, suppression of the transcription of additional genes also contributes to the antitumor activity of BET inhibitors but is less well understood. Here we examined the therapeutic potential of CPI-0610, a potent BET inhibitor currently undergoing phase I clinical testing, in multiple myeloma (MM). CPI-0610 displays potent cytotoxicity against MM cell lines and patient-derived MM cells through G1 cell cycle arrest and caspase-dependent apoptosis. CPI-0610-mediated BET inhibition overcomes the protective effects conferred by cytokines and bone marrow stromal cells. We also confirmed the in vivo efficacy of CPI-0610 in a MM xenograft mouse model. Our study found IKZF1 and IRF4 to be among the primary targets of CPI-0610, along with MYC. Given that immunomodulatory drugs (IMiDs) stabilize cereblon and facilitate Ikaros degradation in MM cells, we combined it with CPI-0610. Combination studies of CPI-0610 with IMiDs show in vitro synergism, in part due to concomitant suppression of IKZF1, IRF4 and MYC, providing a rationale for clinical testing of this drug combination in MM patients.

The importance of Myd88 L265P mutation, clinical and immunohistochemical prognostic factors for the survival of patients with diffuse large B-cell non-Hodgkin lymphoma treated by immunochemotherapy in southeast Serbia.

PURPOSE: Immunochemotherapy used in the treatment of non-Hodgkin diffuse large B-cell lymphoma (DLBCL) modifies the course of disease and has a positive effect on overall survival (OS). The purpose of this study was to verify the existence of the important Myd 88 mutation and other immunohistochemical factors on disease prognosis in patients with DLBCL in southeast Serbia. METHODS: Immunohistochemical expression of CD10, Bcl- 2, Bcl-6, Ki-67 and MUM 1 was performed using paraffin blocks of DLBCL. Molecular-genetic study of MyD88 L265P gene polymorphism was done by isolation of genomic DNA from paraffin embedded tissue by means of polymerase chain reaction (PCR). RESULTS: Immunochemotherapy (rituximab+CHOP/R-CHOP) significantly improved the overall survival (OS) of patients with DLBCL compared with patients treated with CHOP alone (p<0.0001). OS in the R-CHOP group was longest in patients with International Prognostic Index (IPI) 2 score (p=0.012) and IPI 4 score (p=0.024). Patients with Bcl-2 +, and MUM 1+ benefited from R-CHOP and their expression had no effect on OS. Analysis of restriction fragment length on the genomic DNA showed a homozygous normal TT genotype. CONCLUSION: Addition of rituximab to CHOP standard protocol improved the OS rate in patients with DLBCL and altered the character and significance of previously recognized prognostic factors. IPI score in the immunochemotherapy era could not reveal possible predictive factors of poor prognosis which would help identify a high-risk subgroup of newly diagnosed DLBCL. In the patient population from Southeast Serbia pathological signaling pathway achieved by Myd 88 L265 mutation was not responsible for the development of DLBCL.

The immunophenotypic spectrum of primary mediastinal large B-cell lymphoma reveals prognostic biomarkers associated with outcome.

Primary mediastinal large B-cell lymphoma (PMBL) is a distinct subtype of diffuse large B-cell lymphoma (DLBCL) that shows overlap with classical Hodgkin lymphoma (CHL) and a favorable prognosis compared to mediastinal gray-zone lymphoma (MGZL). We performed immunohistochemistry on initial diagnostic specimens of 49 cases of uniformly treated PMBL to determine the frequency and clinical significance of expression of antigens commonly seen in CHL and MGZL, along with markers previously shown to be prognostic in DLBCL, not otherwise specified. The median age was 37 years with a female:male ratio of 2.3. After a median follow-up of 78 months, 24% of patients had relapsed or refractory disease and 22% had died; the 5-year PFS was 70%. Variable CD15 expression was seen in 31% of cases, but was not associated with adverse outcome. Hans cell-of-origin, proliferation index, and MYC/BCL2 coexpression were not associated with outcome, while low PDL1 (P = 0.011) and high MUM1 (P = 0.065) staining were each associated with shorter PFS. A biologic risk score (one point each for low PDL1 and high MUM1) stratified patients into three prognostic risk groups for PFS (P = 0.001) and OS (P = 0.032). On separate multivariate models, low PDL1 was independent of R-IPI risk group for PFS (HR 6.0, P = 0.023), as was a biologic risk score of 2 (HR 5.6, P = 0.011). Incorporation of the biologic risk score sub-stratified patients within R-IPI groups for both PFS (P < 0.001) and OS (P < 0.001). In summary, we characterize the immunophenotypic spectrum of PMBL and identify PDL1 and MUM1 as prognostic biomarkers for high-risk disease. Am. J. Hematol. 91:E436-E441, 2016. © 2016 Wiley Periodicals, Inc.

Impaired signaling through the Fms-like tyrosine kinase 3 receptor increases osteoclast formation and bone damage in arthritis.

Osteoclasts are bone-resorbing cells that accumulate in the joints of patients with rheumatoid arthritis causing severe bone damage. Fms-like tyrosine kinase 3 ligand is enriched in the synovial fluid of patients with rheumatoid arthritis, and local exposure to Fms-like tyrosine kinase 3 ligand aggravates arthritis in mice. Because Fms-like tyrosine kinase 3 ligand has been suggested to facilitate osteoclast differentiation, we asked whether Fms-like tyrosine kinase 3 ligand affects bone remodeling in arthritis. The effect of Fms-like tyrosine kinase 3 signaling on osteoclast development was studied by immunohistochemistry in methylated bovine serum albumin-induced arthritis using mice that lack the gene for Flt3l (Flt3L(-/-)) and by an in vitro assay. Bone and joint changes were studied morphologically and by microcomputer tomography. We found that Flt3L(-/-) mice had increased accumulations of osteoclasts in the periarticular area of the arthritic joint. This triggered bone destruction and trabecular bone loss. The increased number of osteoclasts in Flt3L(-/-) mice may be a consequence of insufficient expression of interferon regulatory factor 8. Treatment of Flt3L(-/-) mice with Fms-like tyrosine kinase 3 ligand increased expression of interferon regulatory factor 8, reduced the number of osteoclasts in arthritic mice, and promoted trabecular bone formation. Finally, the reduced number of regulatory T cells in the bone marrow of Flt3L(-/-) mice could further contribute to the increased osteoclastogenesis by reducing the ratio of regulatory T cells to T helper 17 cells. This study shows that Fms-like tyrosine kinase 3 ligand may serve as a negative regulator of osteoclast development by promoting transcription of interferon regulatory factor 8 and sustaining a balance between protective regulatory T cells and pathogenic T helper 17 cells in the pathogenesis of arthritis.

MUM-1 expression differentiates AITL with HRS-like cells from cHL.

MUM1 is a member of the interferon regulatory factor family of transcription factors. It is normally expressed in plasma cells, late B cells, and activated T cells, and has been described in several B-cell malignancies and some T-cell neoplasms. The aim of our study was to evaluate the role of MUM-1/IRF4 protein in differentiating angioimmunoblastic T cell lymphoma (AITL) with Hodgkin/Reed-Sternberg (HRS)-like cells from cHL. We identified 12 cases of AITL with HRS-like cells and 24 cases of cHL from March 2013 to November 2014. IHC for MUM-1/IRF4 protein was performed on the tissue of these cases and some relevant positive and negative controls. MUM-1 was expressed in HRS-like cells and some neoplastic T-cells in AITL with HRS-like cells (12/12, 100%) and formed the rosettes around the HRS-like cells (12/12, 100%), expressed in HRS cells in classic Hodgkin Lymphoma (cHL) (24/24, 100%) and just one case formed rosettes around the HRS cells (1/24, 4.2%). Based on the results, MUM-1 could be a useful marker for the differential diagnosis between AITL with HRS-like cells and cHL.