Methotrexate-associated EBV-positive vasculitis in the skin: a report of two cases simulating rheumatoid vasculitis.

Rheumatoid vasculitis (RV) is one of the most serious extra-articular complications of rheumatoid arthritis (RA), generally treated with a high dose of immunosuppressive drugs. Recently, we encountered two cases of ulcerative vasculitis in methotrexate (MTX)-prescribed RA patients, which simulated RV; however, Epstein-Barr virus (EBV)-encoded RNA in situ hybridization on their skin biopsies revealed many EBV-positive lymphocytes (over 50 cells/high-power field) within the vessel walls and perivascular stroma, which led us to the diagnosis of EBV-related vasculitis instead of RV. Subsequently, both ulcers regressed after the discontinuation of MTX and no recurrence was noted during the follow-up period. To prevent unnecessary treatment, EBV-positive vasculitis should be added in the differential diagnosis of lymphocytic vasculitis observed in MTX-administered RA patients.

NKp46 regulates the production of serine proteases and IL-22 in human mast cells in urticaria pigmentosa.

NKp46 (natural cytotoxic receptor 1/CD335) is expressed on natural killer cells and Th2-type innate lymphocytes. However, NKp46 expression in human mast cells has not yet been reported. Here, we explored the expression of, and possible role played by, NKp46 in such cells. NKp46 protein was expressed in human mast cells in urticaria pigmentosa principally of the tryptase-positive/chymase-negative type (MCT), but not in human non-neoplastic skin mast cells of the tryptase-positive/chymase-positive (MCTC) type. NKp46 expression was also evident in the human neoplastic mast cell line HMC1.2. NKp46 knockdown changed the phenotype of this cell line from MCT to MCTC and downregulated GrB production, but did not influence IL-22 production. An agonistic anti-NKp46 antibody upregulated production of GrB and IL-22, but did not change the MCT-like phenotype of HMC1.2 cells. NKp46 was thus involved in the production of serine proteases and IL-22 in human mast cells.

Serum granulysin as a possible key marker of the activity of alopecia areata.

BACKGROUND: Alopecia areata (AA) is an organ-restricted autoimmune condition of the hair follicles (HFs) that presents as nonscarring hair loss. A collapse of immunoprivilege for cell-mediated cytotoxicity and following attacks by cytotoxic T cells to anagen HFs are considered to play a major role in the pathogenesis of AA. However, there has been no useful marker for the activity of AA to date. OBJECTIVE: The aim of this study is to examine whether granulysin, which is known to reflect the activity of cytotoxic immune responses, is related to the disease activity of AA. METHODS: We evaluated serum granulysin levels in acute and chronic AA patients compared to healthy controls in the perspective of bald skin areas, prognosis, and co-existence of other allergic diseases. In addition, immunohistochemical analysis for granulysin-, CD4-, CD8-, and CD56-positive cells in the lesional skin of acute and chronic AA patients was performed. RESULTS: Serum granulysin levels were significantly elevated in both acute and chronic AA patients (p=0.00081 and p=0.0012, respectively). Intriguingly, serum granulysin levels were significantly associated with the broader bald skin areas (Spearman's r=0.59, p=0.017), and poorer prognosis in acute AA patients (p=0.0080). They were also associated with co-existence of allergic disorders in AA patients (p=0.026). Immunohistochemical staining demonstrated that perifollicular granulysin-bearing cells were mainly detected in acute AA lesions with dense lymphocytic infiltration, and that these granulysin-bearing cells were consistent with CD8(+) T cells. CONCLUSION: The serum granulysin level may be a useful and novel marker for the disease activity in the acute phase of AA.

Stromal plasma cells expressing immunoglobulin G4 subclass in non-small cell lung cancer.

Inflammatory cell infiltration in tumor stroma may represent the interaction between the tumor and the immune system. The significance of immunoglobulin (Ig) G4+ plasmacytic infiltration, however, is poorly understood. Here, we analyzed the number of stromal IgG4+ plasma cells and the IgG4/IgG ratio of plasma cells in 294 primary non-small cell lung cancers (NSCLCs) using tissue microarray (TMA) and conventional surgical specimens. In TMA, 35 (12%) cases of NSCLC revealed more than 20 IgG4+ plasma cells per high-power field. In surgical specimens, most (97%) of those IgG4+ plasma cell-enriched cases showed obliterative phlebitis or arteritis, one of the key morphologic features of IgG4-related disease, within or at the periphery of the tumor. Clinically, none of the patients showed symptoms associated with IgG4-related systemic diseases. In patients with stage I squamous cell carcinoma, IgG4-enriched stroma was significantly associated with a favorable prognosis (P = .04). In conclusion, considerable IgG4+ plasma cell infiltration can be seen in a minority of cases of NSCLC and might contribute to prognostic modulation of NSCLC.

PD-1 regulates the growth of human mastocytosis cells.

BACKGROUND: Programmed death-1 (PD-1) is a marker for human neoplastic T cells. Here, we evaluated whether or not PD-1 was also a marker for human mastocytosis, and explored the role of PD-1 in human mastocytosis cells. METHODS: Immunohistochemical analysis was used to evaluate the expression of PD-1 in clinical samples of human cutaneous mastocytosis. The expression of PD-1 in human mastocytosis cell lines was checked by RT-PCR, western blotting and flow cytometry. We stimulated human mastocytosis cell lines (LAD2 and HMC1.2) with recombinant ligand for PD-1, PD-L1 (rPD-L1), and tested the proliferative activity and the status of signal molecules by Cell Counting Kit-8 and ELISA, respectively. RESULTS: Ten of 30 human cutaneous mastocytosis cases (33.3%) expressed PD-1 protein. We also found that a human mastocytosis line LAD2 cells expressed PD-1 protein on their surfaces. The administration with rPD-L1 suppressed the stem cell factor-dependent growth of the LAD2 cells. And, rPD-L1 activated SHP-1 and SHP-2 simultaneously, and decreased the phosphorylation of AKT, in LAD2 cells. In contrast, we could not detect the expression of PD-1, and the significant effect of rPD-L1 on the mutated KIT-driven growth of HMC1.2 cells. CONCLUSIONS: PD-1 could be a marker for human cutaneous mastocytosis and regulate the growth of human PD-1-positive mastocytosis cells.

Acute humoral rejection and C4d immunostaining in ABO blood type-incompatible liver transplantation.

Complement C4d deposition in graft capillaries has been reported to be associated with antibody-mediated rejection in kidney and other solid organ transplantation. The correlation of C4d deposits and humoral rejection in liver transplants, however, is not well understood. We investigated the C4d immunostaining pattern in 34 patients whose liver biopsy was taken within the first 3 postoperative weeks for suspected acute rejection after ABO blood type-incompatible liver transplantation. The staining pattern was classified as positive (portal stromal staining), indeterminate (endothelial staining only), and negative (no staining). Positive C4d immunostaining was seen in 17 (50%) patients and was significantly associated with high (x64 or more) postoperative antidonor A/B antibody (immunoglobulin M (IgM)) titers (88 vs. 35%, P = 0.002) and poorer overall survival rate (41 vs. 88%, P = 0.007). Ten of 11 (91%) cases with histological acute humoral rejection (periportal edema and necrosis (PEN) or portal hemorrhagic edema) were positive for C4d, all of which showed high postoperative antibody titers. The other histologies associated with C4d positivity was purulent cholangitis (n = 4), coagulative hepatocyte necrosis (n = 1), acute cellular rejection (n = 1), and hepatocanalicular cholestasis (n = 1). Full clinical recovery was observed in only 6 of 17 (35%) C4d-positive patients, and tended to be associated with a lower rejection activity index (RAI). In conclusion, our study indicates that C4d deposits in the portal stroma can be a hallmark of acute humoral rejection in ABO-incompatible liver transplantation, and allograft damage can be reversible in a minority of cases.