Monocyte alterations in rheumatoid arthritis are dominated by preterm release from bone marrow and prominent triggering in the joint.

OBJECTIVE: Rheumatoid arthritis (RA) accompanies infiltration and activation of monocytes in inflamed joints. We investigated dominant alterations of RA monocytes in bone marrow (BM), blood and inflamed joints. METHODS: CD14+ cells from BM and peripheral blood (PB) of patients with RA and osteoarthritis (OA) were profiled with GeneChip microarrays. Detailed functional analysis was performed with reference transcriptomes of BM precursors, monocyte blood subsets, monocyte activation and mobilisation. Cytometric profiling determined monocyte subsets of CD14++CD16-, CD14++CD16+ and CD14+CD16+ cells in BM, PB and synovial fluid (SF) and ELISAs quantified the release of activation markers into SF and serum. RESULTS: Investigation of genes differentially expressed between RA and OA monocytes with reference transcriptomes revealed gene patterns of early myeloid precursors in RA-BM and late myeloid precursors along with reduced terminal differentiation to CD14+CD16+monocytes in RA-PB. Patterns associated with tumor necrosis factor/lipopolysaccharide (TNF/LPS) stimulation were weak and more pronounced in RA-PB than RA-BM. Cytometric phenotyping of cells in BM, blood and SF disclosed differences related to monocyte subsets and confirmed the reduced frequency of terminally differentiated CD14+CD16+monocytes in RA-PB. Monocyte activation in SF was characterised by the predominance of CD14++CD16++CD163+HLA-DR+ cells and elevated concentrations of sCD14, sCD163 and S100P. CONCLUSION: Patterns of less mature and less differentiated RA-BM and RA-PB monocytes suggest increased turnover with accelerated monocytopoiesis, BM egress and migration into inflamed joints. Predominant activation in the joint indicates the action of local and primary stimuli, which may also promote adaptive immune triggering through monocytes, potentially leading to new diagnostic and therapeutic strategies.

Complete Remission in Systemic Skin Interdigitating Dendritic Cell Sarcoma after ABVD Chemotherapy.

Interdigitating dendritic cell sarcoma (IDCS) is a rare and aggressive neoplasm that is thought to arise from dendritic cells. This disease usually involves the lymph nodes and, rarely, extra-nodal sites. We report a 62-year-old man presenting skin nodules in the head, body, and extremities, as well as bone marrow involvement. Morphologic analysis of a biopsied specimen from the skin lesion was consistent with IDCS. Immunohistochemical staining demonstrated that the tumor cells were positive for IDCS-associated antigens such as CD4, CD45, CD68 (KP-1), and S-100 protein. Complete remission was achieved by treatment with 6 cycles of ABVD (adriamycin, bleomycin, vinblastine, and dacarbazine) chemotherapy. Although the optimal treatment of IDSC remains unknown, the experience in the current case supports the notion that ABVD chemotherapy may be effective for IDCS, and further extends this idea to rare patients presenting multiple skin lesions.

FcgammaRIIB Ile232Thr transmembrane polymorphism associated with human systemic lupus erythematosus decreases affinity to lipid rafts and attenuates inhibitory effects on B cell receptor signaling.

The B cell inhibitory receptor FcgammaRIIB plays crucial roles in the maintenance of self-tolerance. We have identified a polymorphism FCGR2B c.695T>C that results in the non-conservative replacement of 232Ile at the transmembrane helix to Thr and demonstrated the association of the polymorphism with susceptibility to systemic lupus erythematosus (SLE) in Asians. In this study, we examined the impact of FCGR2B c.695T>C on the functional properties of FcgammaRIIB by expressing each allele product in a human B cell line ST486 lacking endogenous FcgammaRIIB. FcgammaRIIB 232Thr was found to be significantly less potent than wild-type 232Ile in inhibiting B cell receptor (BCR)-mediated phosphatidylinositol-3,4,5-trisphosphate accumulation, Akt and PLCgamma2 activation and calcium mobilization, and to display decreased levels of tyrosine phosphorylation and SH2-containing 5'-inositolphosphate phosphatase recruitment compared with 232Ile after IgG Fc-mediated coligation with BCR. Notably, a quantitative analysis of the subcellular distribution of FcgammaRIIB using 125I-labeled anti-FcgammaRIIB revealed that FcgammaRIIB 232Thr is less effectively distributed to detergent-insoluble lipid rafts than 232Ile, findings in accordance with the importance of the transmembrane amino acid residues, in particular large hydrophobic amino acids including Ile, in the association of membrane proteins with lipid rafts. Given the crucial roles of lipid rafts in integrating BCR signaling, decreased association of FcgammaRIIB 232Thr could contribute to its impaired inhibitory potential. Collectively, the present findings indicate that the Ile232Thr substitution affects the localization and function of FcgammaRIIB and that the molecular mechanism may link the polymorphism and susceptibility to SLE.

Genetic background of Japanese patients with antineutrophil cytoplasmic antibody-associated vasculitis: association of HLA-DRB1*0901 with microscopic polyangiitis.

OBJECTIVE: To examine association of 8 candidate genes with susceptibility to antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in Japanese patients. Little is known on the genetic background of AAV in Japanese patients mainly because of the difficulty in collecting a sufficient number of samples for the genetics study. METHODS: Sixty-nine patients, including 50 with microscopic polyangiitis (MPA), were recruited in a multicenter study. Among them, 64 patients were positive for myeloperoxidase (MPO)-ANCA. Associations of HLA-DRB1, tumor necrosis factor-alpha promoter (TNF), TNF receptor 2 (TNFR2), Fcgamma receptor IIa (FCGR2A), IIb (FCGR2B), IIIa (FCGR3A), IIIb (FCGR3B), and CTLA-4 (CTLA4) polymorphisms were examined in a case-control analysis. RESULTS: A significant association of HLA-DRB1*0901 with MPA (p = 0.0037, OR 2.44, 95% CI 1.33-4.46), as well as with MPO-ANCA positivity (p = 0.0014, OR 2.44, 95% CI 1.41-4.22), was detected. There was no difference in the TNF promoter haplotype frequencies between patients with MPA and controls, excluding the possibility that the association of DRB1*0901 was secondarily caused by linkage disequilibrium with TNF. No association was observed for TNFR2, FCGR, or CTLA4 with MPA, nor with the presence of MPO-ANCA, although the combined genotype FCGR2A-131H/H and 3A-176F/F was increased in patients with MPA (p = 0.025). CONCLUSION: There was an association of HLA-DRB1*0901 with MPA and MPO-ANCA positive vasculitis in Japanese patients.