Introduction and Background
Controlling pulmonary Mycobacterium avium complex (MAC) disease is difficult because there is no way to know clinical stage accurately. There have been few attempts to use cell-mediated immune responses for diagnosing the stage of MAC.
Aims and objects
To characterize cytokine profiles of CD4+T and CD19+B cells that recognize various Mycobacterium avium (MA)-associated antigens in different clinical stages of MAC.
Methods
47 MAC patients at different stages based on clinical information (14 before-treatment, 16 on-treatment and 17 after-treatment) and 17 healthy controls were recruited. Peripheral blood mononuclear cells (PBMCs) were cultured with MA-associated antigens (named MAV0968, MAV1160, MAV1276, MAV4925), and the cytokine profiles (IFN-?, TNF-?, IL-2, IL-10, IL-13, IL-17) of CD4+/CD3+ and CD19+ cells in cultured PBMCs were analyzed by flow cytometry.
Results
The response of Th1 cytokines such as IFN-? and TNF-? against various antigens was significantly higher in both the on-treatment and after-treatment groups than in the before-treatment group and control (P < 0.01-0.0001, and P < 0.05-0.0001). Analysis of polyfunctional T cells suggested that IL-2 is closely related to the stage after the start of treatment (P = 0.0309-P < 0.0001) and is involved in memory function. Non-Th1 cytokines, such as IL-10 and IL-17, showed significantly higher responses in before-treatment (P < 0.0001 and P < 0.01-0.0001). These responses were not observed with PPD. CD19+B cells showed a response similar to that of CD4+T cells.

Conclusions
There is a characteristic cell-mediated immune response against specific antigen at each clinical stage of MAC.