In contrast, TB antigen stimulation did not induce a significantly increased expression of IL-21 and Ki-67 on CD4<sup>+</sup>CXCR5<sup>+</sup> T cells.
This review summarizes the contribution of IL-22, a potentially under-appreciated key player in natural resistance to TB, at the interface between the immune response to Mtb and the lung epithelium.
Increased age and HIV co-infection were associated with decreased cytokine induction, and especially IL-21 and IP-10 were less prevalent in HIV co-infected children with tuberculosis.
IFNγ-, IL17-, and IL22-producing γδ T cells, IL22-producing CD4<sup>+</sup> T cells and secreted pro-inflammatory cytokines (IFNγ, IL1β, and TNFα) were significantly lower in children with TB disease compared to healthy controls.
Analysis of corresponding serum samples showed significantly higher concentrations of IL-10 and IL-22 in tuberculosis-IRIS patients, compared with non-IRIS patients.
Therefore, ectopic lung B cell formation is important for containment of M. tuberculosis, and up-regulation of IL-17 and IL-22 responses may be an important mechanism underlying the protective role B cells in human tuberculosis.