This discrepancy may reflect an RA-specific immune response impairment, consistent with the immune dysfunction associated with RA, which may be impede the differentiation of anti-inflammatory T-regulatory cells; Neutralization of the cytokine IL-4 has been shown to restrict the cell differentiation of the intestinal epithelium and impair regenerative capacity of the intestinal mucosal barrier (33, 34). This evidence concerns the gene IL4 and immune system disorder.