No association of PTPN22 R620 W gene polymorphism with rheumatic heart disease and systemic lupus erythematosus

Rheumatic heart disease (RHD) or acute rheumatic fever (ARF) develops as a consequence of an exaggerated immune response to Group A beta haemolytic streptococci causing pharyngitis. The molecular mimicry appears between human cardiac myosin and M protein of group A streptococcal membranes. The polymorphism of the protein tyrosine phosphatase nonreceptor 22 (PTPN22) gene, which encodes an important negative regulator of T cell activation, has been reported to be associated with susceptibility to several autoimmune diseases such as SLE and RA. The objective of this study was to investigate whether PTPN22 R620W polymorphism confers susceptibility to RHD in Turkish population. PTPN 22 R620W (rs2476601, A/G) polymorphism was genotyped by PCR-RFLP in 121 patients with RHD who fulfilling the revised classification criteria of Jones, and 160 healthy control (HC), and also 137 SLE as a diseased-control. The frequency of GG and AG genotypes were found to be 94% (114), 6% (7) in RHD, respectively and 96% (153) and 4% (7) in HC, respectively. The homozygous AA genotype was not present in RHD and HC. There was no statistically significant difference between RHD and HC according to the frequency of AG heterozygote genotype (P = 0.831; OR = 1.13; 95% CI 0.37-3.46). The frequency of the rare allele A was also very similar in RHD patients and HC (3, 2% respectively). A similar result was also found between SLE and HC. Our results demonstrated that the PTPN22 R620W polymorphism is not associated with RHD nor with SLE in Turkish population.