Lack of association of a functional single nucleotide polymorphism of PTPN22, encoding lymphoid protein phosphatase, with susceptibility to Henoch-Schdnlein purpura

Objective. To assess the possible association between the PTPN22 gene 1858C -> T polymorphism and the susceptibility to Henoch-Schonlein purpura (HSP) and determine if this polymorphism is implicated in the severity of this systemic vasculitis. Patients and methods. Fifty-seven unselected patients from Northwest Spain with primary systemic vasculitis, classified as HSP according to previously proposed criteria, with a follow-up of at least 2 years and 229 healthy controls, were included in this study. 411 the individuals were of Spanish Caucasian origin. Genotyping of the PTPN22 gene 1858C -> T polymorphism was performed by real time PCR technology, using TaqMan 5' allelic discrimination assay.. Results. No significant differences in allele or genotype distribution frequencies for the PTPN22 gene polymorphism were observed between HSP patients and controls. It was also the case when HSP patients were stratified for the presence of severe gastrointestinal complications (n = 46), nephritis (n= 37) or permanent renal involvement (renal sequelae) (n = 12). Conclusions. Our results do not support a potential implication of the PTPN22 gene polymorphism in the susceptibility to and clinical expression of HSP.