Importance of CD23 for collagen-induced arthritis: Delayed onset and reduced severity in CD23-deficient mice

Increased expression of the low affinity receptor for IgE, Fc epsilon RII/C D23 has been observed in rheumatoid arthritis. In view of this, we have inv estigated the expression and influence of CD23 in collagen-induced arthriti s (CIA), an animal model for rheumatoid arthritis. CD23(+) cells were analy zed in lymph nodes of DBA/1 mice immunized with bovine collagen type II (BC II) in CFA or with CFA only. The percentage of CD23(+) lymph node cells was increased in both BCII/CFA- and CFA-immunized mice at 1, 3, and 7 wk after immunization compared with unimmunized mice, indicating a role for the adj uvant to trigger general inflammation and CD23 expression, To investigate t he functional role of CD23 in CIA, CD23-deficient mice on the DBA/1 genetic background were studied. After immunization with BCII/CFA, these mice deve loped CIA. with delayed onset and reduced severity compared with wild-type mice. These findings suggest that an increased number of CD23(+) cells is p art of an inflammatory response and that CD23 expression is of pathogenic i mportance in the arthritic process.