Impaired Interleukin-8-Induced Degranulation of Polymorphonuclear Neutrophils from Human Immunodeficiency Virus Type 1-Infected Individuals

Degranulation of peripheral blood polymorphonuclear leukocytes (PMNLs) was monitored in human immunodeficiency virus (HIV) type 1 (HIV-1)-infected individuals with or without pulmonary tuberculosis (HIV/TB and HIV groups, respectively) by measuring the release of beta-glucuronidase induced by interleukin-8 (IL-8). This was increased in a dose-dependent manner in the control groups consisting of healthy blood donors and patients with pulmonary tuberculosis. In contrast, PMNLs from the HIV and HIV/TB groups responded reciprocally in the same assay; that is, higher IL-8 input concentrations resulted in the release of less enzyme than lower IL-8 input concentrations. The degranulation response of PMNLs from HIV-1-infected individuals was similarly altered for another agonist, N-formyl-methionyl-leucyl-phenylalanine, suggesting that impairment of the nonoxidative armature of PMNL was a more generalized phenomenon. However, impaired IL-8-induced degranulation was found to be associated with the reduced expression of both IL-8 receptors, A and B, on whole-blood PMNLs from HIV-1-infected patients compared with that on whole-blood PMNLs from healthy persons. The density of IL-8RA, in particular, was most reduced on the surfaces of PMNLs from those patients with the poorest degranulation in response to IL-8. Inefficient agonist-induced degranulation may contribute to the increased susceptibility of HIV-1-infected persons to secondary microbial infections, this being further exacerbated in HIV/TB patients who, in addition, display defects in phagocytosis and oxidative burst.