RÉSUMÉ
OBJECTIVE: To compare the frequencies of variants of TCRBV20S1 and TCRBV3S1 gene segments in patients with systemic sclerosis (SSc) and in controls. The null allele (allele 2) of TCRBV20S1 is associated with reduced levels of Vbeta20+ T-cells in the peripheral blood, while allele 1 of TCRBV3S1 is related to a low frequency of Vbeta3.1+ T-cells. METHODS: One hundred thirty patients with SSc and 118 healthy volunteer controls were genotyped for TCRBV20S1, and 117 patients and 85 controls were genotyped for TCRBV3S1 variants by PCR-RFLP. Patients underwent clinical evaluation, serology, pulmonary function tests, high resolution computed tomography, and Doppler echocardiography. RESULTS: The genotypic frequencies of TCRBV20S1 were 0.46 (allele 1/allele 1), 0.43 (allele 1/allele 2), and 0.11 (allele 2/allele 2) in SSc patients; in controls the frequencies were 0.70, 0.26, and 0.04, respectively (p < 0.001). The Mantel-Haenszel odds ratio (stratified by race and sex) of the allele 2 carrier state was 3.88 (95% CI 1.94 to 7.75). The allelic and genotypic frequencies of the TCRBV3S1 gene segment did not differ significantly in patients and controls. However, among patients, allele 1 (TCRBV3S1) carriers had a higher prevalence of interstitial lung disease (adjusted p = 0.032). CONCLUSION: The null allele of the TCRBV20S1 and the allele 1 of TCRBV3S1 gene segments may be considered risk factors for the development of SSc and interstitial lung disease, respectively, suggesting a protective role of Vbeta20+ and Vbeta3.1+ cells in the pathogenic immune responses in SSc.