Protein tyrosine phosphatase non-receptor type 22 (PTPN22) +1858 C>T gene polymorphism in Egyptian cases with rheumatoid arthritis

Abstract

Background: Rheumatoid arthritis (RA) is a common autoimmune disease with a complex genetic background. The gene encoding protein tyrosine phosphatase non-receptor type 22 (PTPN22) has been reported to be associated with RA in several populations.

Objectives: This work aimed at assessing the association of PTPN22 +1858 C>T gene polymorphism with the susceptibility, activity and severity of RA in Egyptian subjects.

Subjects and methods: This study included 112 unrelated RA patients who were compared to 122 healthy unrelated individuals taken from the same locality. For all subjects, DNA was genotyped for PTPN22 +1858 C>T (rs2476601) polymorphism using the PCR-RFLP technique. Antibodies to cyclic citrullinated peptides (anti-CCP) were measured by enzyme-linked immunosorbent assay (ELISA).

Results: Cases showed significantly higher PTPN22 +1858 T allele carriage rate (CT+TT genotypes) compared to controls (34.8% vs. 8.2%, OR=5.98, 95% CI=2.81-12.73, p<0.001). Also the frequency of the PTPN22 +1858 T allele was significantly higher among cases compared to controls (18.7% vs. 4.5%, OR=4.89; 95% CI=2.45-9.76, p<0.001). Cases positive to the PTPN22 T allele (CT+TT genotypes) showed no significant difference from those with the CC genotype regarding clinical and immune parameters. Nonetheless, they showed a more functional disability presented in their significantly higher health assessment questionnaire (HAQ) score (p=0.04).

Conclusions: This study is a confirmatory evidence of the association of the PTPN22 +1858 T allele with susceptibility and functional disability of RA in Egyptian subjects.

Keywords: Anti-CCP; Gene; PTPN22; Polymorphism; Rheumatoid arthritis.