Accumulation of common clonal T cells in multiple lesions of sarcoidosis

Background: T cells recognizing as yet unknown antigens (Ags) are considere d to play an important role in the development and perpetuation of the dise ase process of sarcoidosis. Several studies have shown that T cells that be ar a limited T-cell receptor (TCR) repertoire may play an important, role i n this disorder. However, regarding variable (V) gene repertoire usage, the results differ among various reports. One reason For such inconsistency ma y be due to the materials used in these studies. Most studies analyzed the T-cell repertoire in the sarcoid lung. However, clonal expansion of pulmona ry T cells, probably due to the activation by inhaled exogenous Ags, was ob served and such expansion may seriously influence the repertoire analysis. Materials and Methods:Reverse transcriptase-polymerase chain reaction and s ubsequent single-strand conformation polymorphism analysis were used for th e analysis of TCR repertoire. To exclude unrelated T-cell clones, we used i ntramuscular sarcoid nodules and/or lymph node (LN) sarcoid lesions as our materials. We also analyzed sarcoid lesions from different organs and then compared the results. Results: T cells of the same clonality were found to exist in widely separa ted sites in intramuscular and LN sarcoid lesions in almost all V beta subf amilies. Identical T-cell clones were present in the sarcoid lesions from d ifferent organs in several V beta subfamilies. Conclusions: Some of the common T-cell clones in separated sites in intramu scular and LN sarcoid lesions and in sarcoid samples from different organs may recognize Ags that are related to the pathogenesis of sarcoidosis.