Analysis of IL-1ß, TGF-ß, IL-5, ACE, PTPN22 gene polymorphisms, and gene expression levels in Turkish children with IgA vasculitis.

ABSTRACT

OBJECTIVE: Immunoglobulin-A vasculitis (IgAV) is an inflammatory disease that affects small blood vessels. This study was performed to identify an association between protein tyrosine phosphatase non-receptor type 22 (PTPN22) + 788G > A (rs33996649), transforming growth factor-beta (TGF-ß) -509C > T (rs18004069), interleukin 1-beta (IL-1ß) -511C > T (rs16944), interleukin 5 (IL-5) -746C/T (rs2069812), and angiotensin-converting enzyme (ACE) I/D (rs4646994) gene polymorphisms, susceptibility to IgAV, as well as the mRNA levels of IL-1ß, IL-1ß, and TGF-ß. METHOD: A total of 53 patients with IgAV and 50 healthy controls were enrolled. PTPN22, TGF-ß, IL-1ß, ACE gene polymorphisms, ACE gene I/D polymorphisms, and mRNA expression levels were analyzed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, allele-specific PCR, and real-time PCR with TaqMan kits, respectively. RESULTS: PTPN22, TGF-ß, IL-1ß, IL-5, and ACE variants showed no genotype or allele differences between patients with IgAV and controls. Increased levels of IL-1ß and TGF-ß mRNA expressions were observed in patients with IgAV (p < 0.001). Patients with the IL-1ß AG genotype showed significantly increased amounts of arthritis than patients with non-AG (p = 0.004). Age at disease onset was found to be significantly different in patients with IgAV according to the presence of TGF-ß TT genotype (p = 0.047). CONCLUSION: Polymorphisms in PTPN22, TGF-ß, IL-5, IL-1ß, and ACE genes are unlikely to confer susceptibility to IgAV. However, the presence of the AG genotype of IL-1ß is associated with susceptibility to IgAV-related arthritis. This is the first study to report a significant increase in serum mRNA levels of IL-1ß and TGF-ß in IgAV patients, supporting a susceptibility to IgAV in childhood.