Abstract
Purpose::
Wegener's granulomatosis (WG) is a systemic vasculitis of unknown origin characterized by prominent involvement of upper and lower respiratory tract and kidney. Histological pattern consists of the triad of giant cell granuloma, necrosis, and vasculitis involving capillaries and small and middle size arterioles. Ocular involvement is present in WG patients, particularly in the form of necrotizing scleritis with peripheral ulcerative keratitis. PTPN22 (Tyrosine-protein phosphatase non-receptor type 22) protein is supposed to alter the signaling threshold of the T lymphocyte receptor via binding of diverse intracellular tyrosine kinases, and thereby PTPN22 may function as an inhibitor of T cell activation. Genetic analyses of PTPN22 have revealed that the R620W polymorphism is a predisposing factor for several autoimmune disorders. This same polymorphism has been shown to be associated to WG in a cohort of patients of German origin. However, this association has not been tested in another ethnic group. In this work, we analyzed the possible association of the R620W PTPN22 variant in Mexican patients with WG.
Methods::
We studied 2 subject groups. Group 1 included 78 patients with ANCA-associated vasculities who were classified according to the ARC and Chapel Hill criteria as having WG. The control group was composed of 80 healthy adult subjects. DNA was obtained from peripheral blood leukocytes and the PTPN22 gene fragment enclosing the polymorphic 620 codon was amplified by PCR. Genotyping was done by direct sequencing of PCR amplified products using the dye terminator method.
Results::
The PTPN22 R620W allele was present in heterozygous state in 7 of 78 WG patients. No instances of homozigosity for this variant were found. From the control group, any individual had the R620W polymorphism (p=.006)(OR:2.13)
Conclusions::
The PTPN22 R620W polymorphism is associated whit WG in Mexican population. Our results support a role for this variant in the etiology of WG. Additional studies in patients from different populations will establish the real contribution of this polymorphism to the disease.
Keywords: autoimmune disease • genetics • uvea