Identification of differentially expressed genes in T-lymphocyte subsets of discordant monozygotic rheumatoid arthritis twins

To perform an objective analysis of gene expression in rheumatoid arthritis (RA) patients we used differential display (DD) technique to screen messen ger RNAs that are expressed by CD4(+) and CD8(+) peripheral blood lymphocyt es, In order to exclude false positives due to polymorphisms and randomly e xpressed genes only monozygotic twins were included in the study and DDRT-P CR analysis was repeatedly performed with highly specific cellular material collected at two different times. Herein we report the results of the pilo t study including 2 pairs of RA-discordant monozygotic twins. Till now DDRT -PCR analysis revealed 7 differences in gene expression between the compare d groups, Differentially expressed DDRT-PCR fragments were subjected to seq uence analysis and the obtained sequences were compared with the existing d atabases. In 5 cases no comparable sequences were found in databases, One o f the cDNAs detectable only by the healthy persons is 100% homologous to th e available sequence with accession no. aa833746 (EMBL-GDB). The other cDNA present only by the RA patient encodes a protein (EMBL-GDB accession no. a a970280) highly homologous to human 60S ribosomal protein L19. Our data dem onstrate that DDRT-PCR technique may be successfully used for objective ana lysis of differences in gene expression between patient groups and provide further evidence for complexity of the aetiological and pathogenetic mechan isms of RA.