Neutrophil adherence and polymorphonuclear chemotaxis are altered in anergic patients, but the phagocytic and bactericidal capacities of their polymorphonuclear neutrophils are not known. Nineteen healthy control subjects, 6 reactive patients and 37 anergic patients were studied. Patients were classified as reactive, relatively anergic or anergic if they responded to two, one or none, respectively of five recall antigens injected intradermally. Polymorphonuclear chemotaxis (Boyden chamber assay, leading front method) was measured simultaneously with phagocytosis and killing capacity of Staphylococcus aureus 502A labelled with tritiated thymidine (suitably opsonized with 10% pooled normal serum) in a serum-free medium. Phagocytosis appeared increased in the nonreactive patients. There was a significant correlation between phagocytosed bacteria and depressed polymorphonuclear chemotaxis (r = 0.472, p less than 0.001). Although normal polymorphonuclear neutrophils had lower phagocytosis than those from anergic patients, their killing capacity was significantly (P less than 0.05) better at the first sampling (10 minutes). The polymorphonuclear neutrophils of anergic and reactive patients had similar bactericidal function after 10 minutes up to 160 minutes. The authors conclude that there exist subtle defects in bactericidal function of chemotactically inhibited polymorphonuclear neutrophils from anergic patients, manifested by (a) increased survival of S. aureus within polymorphonuclear neutrophils (increased "phagocytosis") and (b) decreased bactericidal capacity for the first 10 minutes of neutrophil-bacterial contact.