Age-related prevalence of platelet-associated immunoglobulins G in nonthrombocytopenic patients with autoimmune thyroid disease and autoimmune polyglandular syndrome.

Objective: The prevalence of platelet-associated IgG (paIgG) in nonthrombocytopenic patients with autoimmune thyroid disease (AITD) alone or associated with autoimmune polyglandular syndrome (APS) has been studied.

Subjects: A total of 164 individuals were enrolled in this study: 81 patients with AITD alone, 33 patients with APS, and 50 healthy controls.

Results: The presence of paIgG was recorded in 41 of 81 patients with AITD (51%) as compared with 2 of 50 control subjects (4%, p < 0.0001). The prevalence of paIgG in patients with APS was higher even when compared with patients with AITD alone (25/33, 76%; p = 0.02). The presence of paIgG was not related to the functional thyroid parameters. The prevalence of paIgG was higher in the older than in the younger patients (75 vs. 47%, p = 0.0037).

Conclusions: The results indicate that the prevalence of paIgG in patients with AITD is higher than previously thought, namely in elderly patients and in patients with APS, and not related to the thyroid function.