The demonstration by Upham et al 1that human alveolar macrophages selectively inhibit proliferation of T cells by secretion of unidentified effector molecules raises the question as to whether pathological processes in the lung characterised by extensive macrophage recruitment or activation can have a systemic effect on T cell development.

It has been shown in several studies that patients with pulmonary tuberculosis who are not infected by HIV often show a lymphopenia principally affecting the CD4+ T cells.2 ,3 This appears to be a transient phenomenon as the …