CD4 and viral infectious disease: Virus infection also upregulated CXCR3 expression in CD4+ T-cells in MLN, as shown by the expansion of CXCR3+ (Student’s t-test, p = 0.002), CXCR3+CCR4+ (Student’s t-test, p = 0.007) and CXCR3+CCR5+CCR4+ CD4+ T-cell subsets (Student’s t-test, p = 0.001).