T-cell receptor BV gene segment polymorphisms in healthy elderly individuals from the south of Brazil

The ageing of the immune system (immunosenescence) is believed to be involved in both morbidity and mortality in elderly humans due to a higher incidence of infections, autoimmune diseases, cancers and other pathological situations. As any specific immune response involves recognition of antigens by T cells, the ability to develop a given immune response is also dependent on the T-cell repertoire available at a given time point. Different T-cell receptor beta variable segment (BV) (TCRBV) gene segment alleles have been associated with diseases in various human populations. In the present work we analysed the allelic frequencies of four biallelic polymorphisms in TCRBV gene segments (TCRBV3S1, TCRBV13S5, TCRBV13S6 and TCRBV18) in healthy elderly human subjects (80 years old or more) from the south of Brazil, where life expectancies reach similar levels to those observed in developed countries. Except for allele 2 of the TCRBV13S6 polymorphism, which was more frequent in elderly than in young individuals (P = 0.0105), there were no differences in allele or genotype frequencies between young and elderly individuals. The data suggest that there is no direct correlation between the TCRBV3S1, TCRBV13S5 and TCRBV18 polymorphisms analysed and healthy senescence in this particular group of elderly individuals. The higher frequency of TCRBV13S6 allele 2 in healthy elderly individuals should be confirmed in other samples to establish the significance of this finding.