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

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.