目的 The function of B cells in the immune response against Mycobacterium tuberculosis (Mtb) is still regarded as secondary, although major findings in mouse models of tuberculosis (TB) support their participation as antigen presenting cells, cytokine and antibody producers. However, studies in TB patients have failed to clearly identify the differences of B cell subpopulations between tuberculosis pleural effusion (TPE) and peripheral blood (PB). Therefore, in the present study we aimed at identifying the B cell subpopulation alterations in TPE of HIV-negative tuberculosis pleurisy patients when compared to the corresponding PB.