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). The gene discussed is IL4; the disease is rheumatoid arthritis.