Comparison of viral antibodies in 2 groups of patients with fibromyalgia

Objective, The etiologies of fibromyalgia (FM) are unknown. In some cases a n acute onset following a flu-like episode is described; in other cases pat ients report slowly developing disease. We previously found increased preva lence of enterovirus IgM antibodies in patients with acute onset of FM comp ared to healthy controls. We looked for differences in antimicrobial IgM an tibodies in acute versus nonacute onset FM. Methods. Two well defined, comparable groups of patients with FM (acute 19, nonacute 20) were studied for antibodies in serum to an array of viruses i ncluding IgM antibodies. Results. In most viruses no IgM antibodies were found. However, about 50% o f the patients with acute FM onset had IgM antibodies against enterovirus c ompared to only 15% of the slow onset patients. Conclusion. The higher prevalence of IgM antibodies against enterovirus in patients with acute onset of FM may indicate a difference in the etiology o r the immune response in these patients.