Interleukin-4RA gene polymorphism is associated with oral mucous membrane pemphigoid.

OBJECTIVE: The aim of this study was to analyse whether the polymorphisms of several pro- and anti-inflammatory cytokines may influence the susceptibility to predominantly oral Mucous membrane pemphigoid (MMP) in a Northern Italian population. MATERIAL AND METHODS: DNA was obtained from 41 MMP patients (29 with exclusively oral pemphigoid [OP]) and 140 unrelated bone marrow donors. Thirteen cytokine genes with 22 single-nucleotide polymorphisms (SNP) were studied by a sequence-specific PCR assay. RESULTS: There was no significant difference between the patients taken together and healthy controls for any cytokine gene polymorphism studied. However, the allele A of the IL-4 receptor A (IL-4RA) was significantly more frequent in OP than controls (P < 0.05), causing an increased frequency of genotype A/A in OP patients (89.7 vs 67.9, odds ratio: 4.11, 95% confidence intervals 1.18-14.28, P = 0.023, Pc = 0.046). CONCLUSION: IL-4RA-1902 A/A genotype has been associated with a reduced response to IL-4 and has been found in 90% OP patient. Giving the supposed importance of IL-4 in MMP fibrotic process, our results can partially explain the low likelihood of scarring in OP patients.