DETERMINATION OF TOTAL AND HERPES-SIMPLEX VIRUS-SPECIFIC MONOMERIC AND DIMERIC IGA IN SERUM AND CEREBROSPINAL-FLUID BY ULTRACENTRIFUGATION

An improved method is described for differentiating between monomeric and dimeric total and herpes simplex virus (HSV) specific IgA by ultra centrifugation in sucrose gradient, using recovery and quantitative an alysis of the fractions obtained. Calculation of monomeric and dimeric IgA was based on IgG as an internal standard. Intrathecally produced monomeric and dimeric IgA were judged by calculating IgA indices for e ach form. A new type of formula indicating relative over-production of dimeric compared with monomeric IgA (IgA dimeric-monomeric index) is suggested. The method was applied to serum and cerebrospinal fluid (CS F) from three patients with HSV encephalitis. The index for monomeric as well as dimeric IgA was high during the acute phase of the disease, indicating intrathecal synthesis of both molecular forms. One year af ter onset, there was no detectable HSV-specific IgA in CSF: both molec ular forms, however, remained in serum. The amount of dimeric compared with monomeric IgA was high during the acute phase, and subsequently decreased after successful treatment. A new finding was the detection of HSV-specific IgA heavier than dimeric IgA in serum one year after o nset of the disease. These components may be tetrameric IgA, or immune complexes containing IgA.