Abatacept: A review of a new biologic agent for refractory rheumatoid arthritis for dermatologists

Abatacept is a newly approved treatment for rheumatoid arthritis refractory to other agents. Abatacept is a fusion protein of the cytotoxic T-lymphocyte antigen (CTLA) molecule and immunoglobulin (Ig) G1 that blocks CD28. Specifically, abatacept blocks the CD80 and CD86 ligands on the surface of antigen-presenting cells that must interface with the T-cell's CD28 receptor to activate T cells. Abatacept seems to be more immunosuppressive than tumor necrosis factor alpha blockers. The combination of abatacept and a tumor necrosis factor alpha blocking agent does not seem more effective than either agent alone. Because abatacept has the ability to suppress T-cell function, it has the potential to be a treatment for psoriasis and other autoimmune conditions involving pathologic processes driven by T cells.