Immunological study in pleural effusion

Thirty patients of pleural effusion (25 tubercular, 5 malignant) were studied for enumeration of T and B cell percentage in pleural fluid (PF) and peripheral blood (PB) along with estimation of IgG, IgA and IgM. Ten healthy subjects were taken as controls. T cell percentage was significantly low and B cell percentage high in the PB of patients with effusion compared with controls. Comparing malignancy and tuberculosis patients it was seen that in both T cells in PF were higher and B cells lower compared with their respective values in PB. Significantly increased percentage of T cells in PF indicates either an active sequestration in PF or the presence of suppressor adherent cells in PB. However, T and B cell percentage in PB and PF were not significantly different in the two study groups. PB immunoglobulin (IgG, IgA, IgM) levels in patients were higher as compared to those in the controls, without significant difference in their levels in the two study groups. Ratio of PF/PB values for various immunoglobulins was less than unity but a cut-off point of 0.6 for IgG & IgA and 0.5 for IgM worked out as pointer for differentiating between malignant and tubercular effusions.