Increased circulating anti-6-integrin autoantibodies in psoriasis and psoriatic arthritis but not in rheumatoid arthritis

In psoriatic skin, laminin integrity is altered, which could lead to insufficient laminin integrin interactions, leaving the 6-integrin exposed and possibly accessible for autoantibody production. Therefore we investigated the presence of anti-6-integrin autoantibodies in the serum of patients with psoriasis vulgaris (Ps), psoriatic arthritis (PsA) and rheumatoid arthritis (RA) in comparison with healthy donors. The level of circulating anti-6-integrin antibodies was determined by enzyme-linked immunoassay using 6-integrin fragments. Antibodies against at least one recombinant fragment were found in approximately 30% of Ps and PsA patients. In contrast, in RA patients, the frequency of antibodies was similar to healthy controls. Our study shows the presence of anti-6-integrin antibodies in Ps and PsA but not in RA, which could indicate ongoing abnormal processes in the skin. Anti-6-integrin autoantibodies may contribute to the formation of micro-wounds in the skin and to the characteristic wound-healing phenotype in psoriasis.