Immunoglobulin levels and specific viral antibodies in relation to smooth-muscle antibodies in cytomegalovirus infection.

Among 17 patients with cytomegalovirus (CMV) infection smooth-muscle antibodies (SMA) of the IgM class were detected in 9 (53%) and IgG-SMA in 6 (35%), while no IgA-SMA were found. IgM-SMA were present most often and in the highest titres (10-160) in the beginning of the disease, while IgG-SMA were found both early and late during the course of infection. SMA occurred most frequently in patients with specific CMV antibodies of the IgM class and in patients with elevated serum alanine aminotransferase values, but these relationships were not significant. Elevated levels of serum IgG, IgA and IgM were found in CMV infection, and a correlation between serum IgM values and IgM-SMA titres was demonstrated (alpha less than 0.01). A similar correlation between serum IgG and IgG-SMA could not be established. These findings are in support of the assumption that IgM-SMA account for a minor part of the elevated serum IgM levels in CMV infection, but not of the hypothesis that the stimulus for antibody production is the release of antigens from liver cells.