IgA antibodies to gliadin and coeliac disease in psoriatic arthritis.

OBJECTIVES To find out whether patients with psoriatic arthritis (PsoA) have an increased prevalence of antibodies to gliadin (AGA) and of coeliac disease. METHODS One hundred and fourteen PsoA patients with skin disease of 20+/-13 yr and joint disease of 11+/-10 yr duration answered a questionnaire concerning their medical history and underwent clinical examination, including radiology. Serum IgA AGA and IgG AGA, IgA antibodies to endomysium and immunoglobulins, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) concentration were determined. RESULTS Five of the 114 patients (4.4%) had coeliac disease. After exclusion of these five patients, the mean IgA AGA concentration was significantly higher (P=0.0005) than that in a reference group. None of the patients had IgA antibodies to endomysium. The mean serum IgA concentration was significantly increased and IgM decreased. Patients with a high concentration of IgA AGA had significantly higher ESR and CRP and a longer duration of morning stiffness than those with a low AGA concentration. CONCLUSIONS Patients with PsoA have an increased prevalence of raised serum IgA AGA and of coeliac disease. Patients with raised IgA AGA seem to have more pronounced inflammation than those with a low IgA AGA concentration.