To investigate the effect of Mycobacterium tuberculosis infection on regulatory immune cells in patients with non-small cell lung cancer (NSCLC).

The NSCLC patients in Wenzhou Central Hospital between March 2014 and March 2018 were selected as the infection group (n = 10) and cancer group (n = 10) according to whether suffering from Mycobacterium tuberculosis infection. Ten healthy subjects were enrolled as the control group at the same time. The proliferation level of Ki-67 was detected by immunohistochemistry. The flow cytometry was used to detect CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells and CD19⁺IL-10⁺ regulatory B (Breg) cells.

The proportion of Ki-67 was (35 ± 4)% in the cancer group and (66 ± 6)% in the infection group; it was much higher in the infection group than in the cancer group (t = 4.068, P < 0.001). The proportion of CD4⁺CD25⁺Foxp3⁺Treg cells and CD19⁺IL-10⁺Breg cells among three groups all showed significant differences (F = 69.400, P < 0.001; F = 16.090, P < 0.001). Compared with the cancer group, the proportion of CD4⁺CD25⁺Foxp3⁺Treg cells [(0.41 ± 0.03)%, (0.21 ± 0.03)%, (1.03 ± 0.08)%] and CD19⁺IL-10⁺Breg cells[(0.429 ± 0.021)%, (0.268 ± 0.013)%, (0.783 ± 0.111)%] decreased markedly in the control group, and increased obviously in the infection group (all P < 0.05).

The proportion of Treg and Breg cells in peripheral blood of NSCLC patients with tuberculosis infection is significantly higher.