[Effect of phagocytosis in vitro on Paracoccidioides brasiliensis]

Peripheral leukocytes from 17 patients with paracoccidioidomycosis were mixed with yeast cells from Paracoccidioides brasiliensis and Rhodotorula sp. to ascertain their phagocytic and lytic capacities. The role of circulating antibodies in the process was also investigated by the use of autologous serum. The phagocytic capacity of the leukocytes was found to be normal for both types of yeasts. However, in the presence of the patient's serum, the percentage of P. brasiliensis cells ingested was increased (P smaller than or equql to 0.02). Furthermore, in 70-5% of the cases the lytic process was increased and more P. brasiliensis cells were killed when such a serum was employed (P smaller than or equal to 0.0013). This increased effect was not recorded for Rhodotorula sp. cells, thus indicating specificity. The peripheral leukocytes from patients with paracoccidioidomycosis are not defective. However, the success of the phagocytic process is aided by the opsonic action of the specific antibodies in the patient's serum.