Increased monomeric immunoglobulin A levels in tears from multiple sclerosis patients.

Mucosal immunity and the secretory antibody are known to be important defense mechanisms against many common viruses. Tears were selected as a representative mucosal fluid, and immunoglobulin A (IgA) was examined by enzyme-linked immunosorbent assay and immunoblot. Tears from 38 normal controls and patients with systemic or ocular diseases contained almost exclusively polymeric IgA. In contrast, almost 75% of 23 patients with multiple sclerosis had detectable monomeric IgA in addition to polymeric IgA. The functional importance of this alteration in the molecular form of secretory IgA remains to be determined.