CCR6 and respiratory tract infectious disorder: Our results have shown that ongoing respiratory infections in nursing infants promoted an increase in the concentrations of milk chemokines (CCL20 and CXCL10), probably induced by the release of cytokines (IL-6 and IL-8) into the breast, as shown by the positive correlation indices, resulting in increased numbers of T and B cells expressing the corresponding chemokine receptors (CCR6 and CXCR3, respectively) in milk.