Ro/SS-A- and La/SS-B-reactive B lymphocytes in peripheral blood of patients with Sjogren's syndrome

The aim of this study was to investigate the production of anti-Ro/SS-A and anti-La/SS-B antibodies in peripheral blood (PB) of patients with Sjogren' s syndrome (SS). The ELISPOT method was performed to quantify the frequency of PB lymphocytes spontaneously secreting anti-Ro/SS-A and/or anti-La/SS-B antibodies. The total number of IgG-, IgA- and IgM-producing cells was als o quantified. The recombinant Ro 52-kD, Ro 60-kD and La 48-kD proteins were used as target antigens. Three of 18 SS patients had PB lymphocytes secret ing IgG antibodies against the recombinant Ro 52-kD protein. The same three patients had high serum titres of anti-Ro 52-kD antibodies. In addition, t hese patients were classified as having severe disease, and all three had f ocus scores of greater than or equal to 8 in biopsies of the labial salivar y glands (LSG). The correlation between the number of PB cells producing Ig G antibodies against the recombinant Ro 52-kD protein and the focus score w as significant (P < 0.01). The results indicate that only SS patients with severe disease and high degree of local inflammation in LSG have PB cells p roducing anti-Ro/SS-A antibodies in PB. Thus, most of the spontaneous autoa ntibody production must take place in other body compartments, e.g. in exoc rineglands and probably also in the lymphoid organs and/or other mucosal si tes.