Sjögren’s syndrome patients shares stereotypic B cell receptor clonotypes including homologous rheumatoid factor clonotypes present in more than a half of the patients

Autoantibodies play a key role in Sjögren's syndrome (SS) pathogenesis but its B cell receptor (BCR) repertoire has not been studied thoroughly. We analyzed peripheral blood BCR repertoire of twenty SS patients. It showed increased class switch recombination, elevated clonality, skewed usage of IGHV and IGHJ genes and its recombination pairing. Stereotypic BCR clonotypes were significantly more frequent, dominated by IgA2 isotype and showed increased somatic hypermutation. The most prevalent stereotypic clonotype specific to SS patients was shared by seven patients. And five very homologous clonotypes were present in seven other patients. All these clonotypes were proved to be rheumatoid factor.