[The structure of the determinants of streptococcal group A polysaccharide common to epidermal antigens to which antibodies are formed at different stages of the rheumatic process].

Several epidermal antigens containing carbohydrate determinants (DT), common with those of group A streptococcal polysaccharide (A-PS), were identified: basal-cell antigen (1), antigens of the cytoplasm (2) and perinuclear zone (3) of the cells of the differentiated epidermal layers, as well as antigen characteristic of all layers of skin epithelium (4). As shown for the first time, in addition to N-acetyl-D-glucosamine, cross-reacting DT of A-PS, antibodies to which were detected in rheumatism, also contained the remnants of rhamnose joined by bonds 1=> 2 and/or 1=>3. At the same time DT, common for A-PS and antigen 1, was found to contain N-acetylflucosamine and residues of rhamnose, joined by bond 1 reversible 2. N-acetylglucosamine was also contained in DT of A-PS, common with antigen 3. In addition, the epitopes of antigens 2 and 4, cross-reacting with A-PS, seemed to contain no N-acetylglucosamine and were characterized by some specific features of rhamnosides which they contained. It was at interest that at different stages of the rheumatism, simultaneously with autoantibodies having the same specificity, autoantibodies to different epidermal antigens were detected in the blood of patients. The determination of the spectrum of autoantibodies to epidermal antigens may be used both for diagnostic purposes and for the prognostication of the course of the rheumatism.