Antibodies against serotonin have no diagnostic relevance in patients withfibromyalgia syndrome

Objective. To determine the prevalence and potential diagnostic relevance o f autoantibodies against serotonin, thromboplastin, and ganglioside Gm1 in patients with fibromyalgia syndrome (FM). Methods. Sera from 203 patients with FM and 64 pain-free control subjects w ere analyzed with enzyme immunoassays. Clinical and psychometric data of th e patients were analyzed for the presence or absence of autoantibodies. Results. Compared with control subjects patients with FM had a significantl y higher prevalence of autoantibodies against serotonin (20% vs 5%; p = 0.0 03) and thromboplastin (43% vs 9%; p < 0.001), bur not against ganglioside Gm1 (15% vs 9%; p =0.301). Differences in autoantibody prevalence between c ontrols and FM patients were not related to age or sex. No association was found between autoantibody pattern and clinical or psychometric data, e.g., pain, depression, pain related anxiety, and activities of daily living. Conclusion. There is an elevated prevalence of antibodies against serotonin and thromboplastin in patients with FM. The pathophysiological significanc e of this finding is unknown. Calculation of positive predictive values of antiserotonin antibodies shows that measurement of these antibodies has no diagnostic relevance.