Immunologic & pulmonary function abnormalities in tropical pulmonary eosinophilia

Twenty six patients (24 males and 2 females) with tropical pulmonary eosinophilia (TPE) were studied. Arterial blood gas analysis, pulmonary functions, peripheral blood examination and bronchoalveolar lavage (BAL) were performed. Peripheral blood and BAL fluid analyses were performed in healthy volunteers. Pulmonary functions revealed a mild restrictive ventilatory defect with airways obstruction. Mild hypoxaemia was observed on arterial blood gas analysis. Serum immunoglobulins IgG (P < 0.01), IgA (P < 0.001) and IgM (P < 0.001) were significantly raised as compared to normal controls. Serum complement (C3) level was higher, however, it was not significantly different as compared to normal controls. Serum haemolytic component of the complement (CH50) was significantly higher (P < 0.001) in patients with TPE compared to normal control subjects. The immunoglobulins IgG, IgA and IgM in the BAL fluid were significantly (P < 0.001) increased as compared to normal controls. The fibronectin (FN) level was also significantly increased (P < 0.001) in the BAL fluid. It is concluded that patients with TPE have mild restrictive ventilatory defect with airways obstruction and mild hypoxaemia. They have eosinophilic alveolitis with increased levels of immunoglobulins in the peripheral blood and BAL fluid. The significance of elevated FN in the BAL fluid is not clear and serial estimations may have to be done in order to clarify its role in the pathogenesis of fibrosis in chronic TPE.