Correspondence B Lymphocytes from Patients with Tuberculosis Exhibit Hampered Antigen-Specific Responses with Concomitant

To the Editor—Tuberculosis due to My-cobacterium tuberculosis is 1 of the 3 major killers among infectious diseases. Deci-phering the interactions between M. tu-berculosis and the innate and adaptive im-mune compartments of the host is critical for understanding the pathogenesis of tu-berculosis and for designing effective im-munotherapeutic interventions. By use of a juvenile rhesus monkey model, Qiu et al recently demonstrated that severe tu-berculosis induces unbalanced up-regu-lation of the immune gene networks of inflammatory cytokines, chemokines, and their receptors, but low levels of T cell responses specific to purified protein de-rivative [1]. The authors conclude that the overexpression of immune genes after tu-berculosis infection favors inflammation and suppression of antigen-specific T cells. B lymphocytes, along with T cells, con-stitute the adaptive immune compart-ment. In addition to producing antibod-ies, B cells act as antigen presenting cells and can produce various inflammato-ry and immunoregulatory cytokines and chemokines [2]. Thus, B cells have a pleth-ora of functions that regulate the course of immune response and inflammation. B cells have been shown to be present at the site of granulomatous reactions dur-ing tuberculosis infection in both mice and humans [3]. Therefore, in view of the latest report on decreased tubercu-losis antigen–specific T cell responses af-ter severe tuberculosis, we aimed to de-cipher antigen-specific B cell responses and their inflammatory cytokine profiles in patients with tuberculosis. Peripheral blood mononuclear cells were isolated from heparinized blood samples obtained from healthy donors and patients with pulmonary tuberculosis. These patients had clinical symptoms of tuberculosis and positive tuberculin skin test results, and the presence of acid-fast bacilli was verified in sputum samples. Blood samples were collected after obtain-ing written informed consent, using pro-tocols approved by our institutional ethics committee. B lymphocytes were isolated from peripheral blood mononuclear cells by using CD19 beads (Miltenyi Biotech). Purified B cells were stimulated with either the total membrane fraction of M. tuber