Modulation of the Fcγ receptors induced by anti-Ro and anti-La autoantibodies:: observations in salivary gland cells

Only few reports have shown protein expression of the Fc gamma receptors (Fc gamma Rs) molecules on human salivary gland cells. In this study we investigate a possible upregulation of Fc gamma Rs following anti-Ro and anti-La autoantibodies treatment. Anti-Ro and anti-La autoantibodies were purified from IgG fractions obtained from 14 patients with primary Sjogren's syndrome (SS), using Sepharose 4B-Ro and Sepharose 4B-La affinity columns. Flow cytometry and RT-PCR were used to study the FC gamma RI, FC gamma RII and FC gamma RIII receptors expression and upregulation by anti-Ro and anti-La on a salivary gland cell line. The present data document that the anti-Ro and anti-La autoantibodies determine an increase of the Fc gamma Rs expression on salivary gland cells, and provide evidence that both the high affinity Fc gamma RI and the low affinity Fc gamma RII and Fc gamma RIII are overexpressed. Treatment with IgG isolated from healthy donors had no effect on the basal FC gamma Rs expression.