The polymerase chain reaction detects B cell clonalities in patients with Sjogren's syndrome and suspected malignant lymphoma

Objective. To investigate the usefulness of the polymerase chain reaction (PCR) to detect B cell clonal expansions in tissues where lymphoproliferative disease was suspected in the course of Sjogren's syndrome (SS). Methods. Tissue samples from 7 patients with definite (5 cases) or probable (2 cases) SS were subjected to routine histopathologic studies, immunophenotyping, and genotypic analysis, including Southern blotting and PCR amplification of immunoglobulin heavy chain (IgH) variable-diversity-joining (VDJ) region gene rearrangements. Results. Malignant lymphoma was detected in 3 cases, and myoepithelial sialadenitis in the remaining 4. B cell clonal expansion was detected in 7/7 cases by PCR, 5/7 by Southern blotting, and in no case of myoepithelial sialadenitis by kappa/lambda light chain immunophenotyping. Conclusion. PCR may represent a quick and powerful tool to detect B cell clonalities in SS. Such information may provide new insights into the pathogenesis of the disease and may improve the clinical approach to the patients.