Soluble versus cell-bound CD4, CD8 from bronchoalveolar lavage: correlation with pulmonary diagnoses in human immunodeficiency virus-infected individuals.

Identification and assessment of cell populations in bronchoalveolar lavage (BAL) specimens may he used to follow the course of a disease state or response to specific therapy. Beyond cellular assessment, there are indications that the presence and quantity of soluble surface antigens released from activated cells may lead to improved understanding and facilitated diagnosis of a number of disease states. This study evaluated soluble markers (sCD4 and sCD8) in BAL and serum from HIV-infected individuals undergoing diagnostic bronchoscopy, and compared these values to flow cytometry-quantified BAL and peripheral blood cell CD4 and CD8. Patient pulmonary diagnosis (based on cytology and microbiology) was compared with patient blood and BAL-soluble and cell-bound CD4 and CD8 to determine the relationship of these markers to disease states in this population. Serum sCD8 in patients with fungal infections was significantly elevated above sCD8 in patients with Pneumocystis carinii or pulmonary bacterial infections, p = 0.0001. BAL sCD4/sCD8 ratio was also significantly different in patients with bacterial vs. fungal pulmonary infections, p = 0.01. These findings suggest that soluble markers, particularly elevated sCD8, may be an important indication of pulmonary disease progression in these HIV+ patients with fungal infections.