Serum and cerebrospinal fluid immunoglobulins M, A, and G in Japanese encephalitis.

A comparison was made of virus-specific immunoglobulin M (IgM), IgA, and IgG detected by capture or indirect enzyme immunoassay in serum and cerebrospinal fluid of patients with Japanese encephalitis. The IgM capture enzyme immunoassay was more sensitive than assays for other isotypes of viral antibody; IgM was detected in 75% of specimens collected less than or equal to 4 days after the onset of illness. Specific IgA was detected in both serum and cerebrospinal fluid; however, IgA levels were significantly lower than IgM levels.