The serum immunoglobulins at the time of infection with WNV were IgG 492 mg/dL (normal level [nl]) 700–1,500 mg/dL), IgA 86 mg/dL (nl 65–450 mg/dL), and IgM 80 mg/dL (nl 45–230 mg/dL). The gene discussed is CD40LG; the disease is infection.