Accumulation of common T cell clonotypes in the salivary glands of patients with human T lymphotropic virus type I-associated and idiopathic Sjogren's syndrome

To clarify the pathogenesis of human T lymphotropic virus type I (HTLV-I)-a ssociated Sjogren's syndrome (SS), the TCR V beta gene usage by the infiltr ating lymphocytes in the target organ was examined. The V beta families pre dominantly used in the labial salivary gland (LSG) from the HTLV-I-seroposi tive (HTLV-I+) SS patients were more restricted than those from the HTLV-I- seronegative (idiopathic) SS patients, and were commonly V beta 5.2, V beta 6, and V beta 7. The single-strand conformation polymorphism analysis reve aled that T cell clonotypes with V beta 5.2, V beta 6, and V beta 7 accumul ate in the LSG from the HTLV-I+ and idiopathic SS patients, Among junctiona l sequences of the most dominant V beta 7 transcripts, the conserved amino acid motif (QDXG:X is any amino acid) was found in six of the five HTLV-ISS patients and was also detected in two of the five idiopathic SS patients . Using the probes specific to the motif, the V beta 7 transcripts with the motif were detected in the LSG from all of the seven HTLV-I+ and five of t he six idiopathic SS patients, but not from eight healthy subjects. The V b eta 7 transcripts with this motif were also detected in the HTLV-I-infected T cell lines obtained from the LSG of an HTLV-I+ SS patient. The accumulat ion of HTLV-I-infected T cells expressing TCR with the conserved motif was thus indicated. These T cells were commonly present in patients with idiopa thic SS and are strongly suggested to most likely be involved In the pathog enesis of both HTLV-I-associated and idiopathic SS.