The Th1 chemokine receptor-5 is downregulated in BD, and serum levels of Interferon-γ (IFN-γ), a cytokine produced by Th1, are significantly reduced, and in vitro stimulation of lymphocytes also results in reduced IFN-γ release [19, 32], while Th2 levels elevated and its marker IL-4 is also upregulated in BD [33, 34]. Here, IL4 is linked to Behcet disease.