Differentiation of primary from nonprimary genital herpesvirus infections by detection of polymeric immunoglobulin A activity.

We analyzed antibody responses to herpes simplex virus (HSV) in 18 patients by using sucrose gradient centrifugation and an enzyme-linked immunosorbent assay for antibody determination. We found that the HSV-specific immunoglobulin A (IgA) antibody in early-convalescent-phase serum specimens from all of 8 primary cases consisted solely of polymeric forms, whereas in all 10 nonprimary cases, the major component was monomeric. These results indicate that the ratio of polymeric IgA to monomeric IgA antibody activity may be useful for differentiating primary from nonprimary HSV infections.