Two cases of ulcerative colitis that developed while using abatacept.

Abatacept (ABT) is a recombinant fusion protein consisting of the Fc domain fragment of human IgG1 and the extracellular domain of human cytotoxic T lymphocyte antigen-4 (CTLA-4). The function of ABT is similar to that of CTLA-4, which selectively regulates T-cell activation by inhibiting the co-stimulation of CD80/CD86 on antigen-presenting cells and CD28 on T lymphocytes. ABT is used for the treatment of rheumatoid arthritis (RA) and juvenile idiopathic arthritis. We report two cases of ulcerative colitis (UC) that developed while using ABT. Case 1 is of a 58-year-old man who developed diarrhea and hematochezia 2 months after starting ABT therapy for RA. Case 2 is of a 66-year-old man who experienced hematochezia 15 months after starting ABT therapy for RA. In both cases, no obvious gastrointestinal symptoms were observed before ABT therapy was initiated. Colonoscopy after disease onset showed UC findings in both cases. The patients' condition improved following ABT withdrawal and treatment for UC. Several cases of UC development during ABT therapy have been reported. The complication of UC should be considered when diarrhea and hematochezia are observed in patients with RA being treated with CTLA-4Ig agents.

Selective recruitment of CXCR3+ and CCR5+ CCR4+ T cells into synovial tissue in patients with rheumatoid arthritis.

The inflamed synovial tissue (ST) of rheumatoid arthritis (RA) is characterized by the selective accumulation of interferon gamma-producing Th1-type CD4+ T cells. In this study, we investigated whether the predominance of Th1-type CD4+ cells in the ST lesion is mediated by their selective recruitment through Th1 cell-associated chemokine receptors CXCR3 and CCR5. The lymphocyte aggregates in the ST of RA contained a large number of CD4+ T cells, which mostly expressed both CXCR3 and CCR5, but not CCR4. In contrast, the frequencies of CD4+ and CD8+ T cells expressing CXCR3 and CCR5 in the blood were significantly decreased in RA patients, compared with healthy controls (HC), although there was no difference in the frequencies of CCR4-expressing CD4+ and CD8+ T cells between RA and HC. CXCR3, CCR5, and CCR4 expression in blood CD4 + T cells and CXCR3 expression in CD8+ T cells were increased after interleukin-15 (IL-15) stimulation. Therefore, the distribution of Th1-type CD4+ T cells into the ST from the blood in RA may be associated with the local expression of chemokines, both CXCR3 and CCR5 ligands, and IL-15 may play a role in enhancing these chemokine receptors on CD4+ T cell infiltrates.