Functions of salivary polymorphonuclear leukocytes (SPMNs) and peripheral blood polymorphonuclear leukocytes (PPMNs) were synchronously examined in 20 healthy individuals and 13 patients with oral squamous cell carcinoma. In healthy controls, PPMNs generated superoxide (O2-) of 105.2 +/- 19.4 and 105.1 +/- 22.0 pmol/min/10(4) cells under PMA and FMLP stimulation, respectively; SPMNs generated O2- of 50.3 +/- 10.5 pmol with PMA and 88.4 +/- 15.4 pmol with FMLP. Chemiluminescence intensity in SPMNs was 81.3 +/- 14.9 mV with PMA and 62.4 +/- 12.9 mV with FMLP, and chemiluminescence in PPMNs was 229.1 +/- 37.2 and 120.1 +/- 18.4 mV with PMA and FMLP, respectively. Corresponding to the productivity of reactive oxygens, candida killing, and phagocytic activity of SPMNs (24.9 +/- 3.1 and 49.8 +/- 3.6%, respectively) were inferior to those of PPMNs (37.8 +/- 3.8 and 57.5 +/- 3.3%, respectively). Compared with healthy controls, most PPMN and SPMN functions, except for phagocytosis and FMLP-stimulated chemiluminescence, were suppressed in the oral cancer patients. Before treatment, PMA-stimulated O2- generation levels and candidacidal activity were about 70-80% of those in healthy controls. A significant decrease of O2- generation in both PPMNs and SPMNs, as well as a decrease in the candida killing and phagocytic activity of SPMNs were observed following cancer treatment. These results indicate that, while inferior to PPMNs, SPMNs possess adequate candidacidal activity and produce active oxygens. However, both PPMN and SPMN functions are suppressed by the tumor burden, and tumor treatment brings additive neutrophil suppression which may allow fungal infections to develop.