Type 2 diabetes mellitus is associated with altered CD8 + T and natural killer cell function in pulmonary tuberculosis.

Kumar, N.P.; Sridhar, R.; Dina, N.; Banurekha, V.V.; Nutman, T.B.; Babu, S .

Immunology; 2015; 144; 677-686.

Summary: Type 2 diabetes mellitus (DM) is associated with expanded frequencies of mycobacterial antigen-specific CD4 + T helper type 1 (Th1) and Th17 cells in individuals with active pulmonary tuberculosis (TB). No data are available on the role of CD8 + T and natural killer (NK) cells in TB with coincident DM. To identify the role of CD8 + T and NK cells in pulmonary TB with diabetes, we examined mycobacteria-specific immune responses in the whole blood of individuals with TB and DM (TB-DM) and compared them with those without DM (TB-NDM). We found that TB-DM is characterized by elevated frequencies of mycobacterial antigen-stimulated CD8 + T cells expressing type 1 [interferon- g and interleukin-2 (IL-2)] and type 17 (IL-17F) cytokines. We also found that TB-DM is characterized by expanded frequencies of TB antigen-stimulated NK cells expressing type 1 (tumour necrosis factor- a ) and type 17 (IL-17A and IL-17F) cytokines. In contrast, CD8 + T cells were associated with significantly diminished expression of the cytotoxic markers perforin, granzyme B and CD107a both at baseline and following antigen or anti-CD3 stimulation, while NK cells were associated with significantly decreased antigen-stimulated expression of CD107a only. This was not associated with alterations in CD8 + T-cell or NK cell numbers or subset distribution. Therefore, our data suggest that pulmonary TB complicated with type 2 DM is associated with an altered repertoire of cytokine-producing and cytotoxic molecule-expressing CD8 + T and NK cells, possibly contributing to increased pathology.

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