[The possible curative therapy for rheumatoid arthritis--EBV infection control gene SAP and its application].

Epstein-Barr virus (EBV) belong to herpes virus group. This virus is transmitted by human contact and cause primary infection and may exist even for years in a latent state in healthy individuals. This virus may be reactivated by the dysregulation of the host immune system or possibly by virus mutation. Here we have firstly demonstrated the host defense of EBV infection and association of EBV with rheumatoid synovitis, and then discussed our own ideas of the possible treatment in near future. The key points of this new therapy are SAP (signaling lymphocytic-activation molecule associated protein) or SH2D1A (Src homology 2 domain-containing protein). SAP (or SH2D1A), an adaptor-like molecule expressed in immune cells, is composed almost exclusively of a Src homology 2 (SH2) domain. In humans, SAP is mutated and either absent or non-functional in X-linked lymphoproliferative (XLP) syndrome (Duncan disease), a disease characterized by an inappropriate response to EBV infection. SAP is essential for late B cell help and the development of long-term humoral immunity. New approach to the therapeutic method for EBV might be opened by the regulation of this molecule (SAP).