We hypothesized that the decrease in sOX40 levels in patients with MG may be related to a decrease in mOX40 shedding and that the reduced sOX40 levels may result in reduced binding of sOX40 to membranous and soluble OX40L, thereby increasing the opportunity for OX40L to bind to membranous OX40, leading to a relative increase in positive signaling to CD4+ T cells and relative immune hyperfunction. The gene discussed is CD4; the disease is myasthenia gravis.