GRO-ALPHA AND INTERLEUKIN-8 IN PNEUMOCYSTIS-CARINII OR BACTERIAL PNEUMONIA AND ADULT-RESPIRATORY-DISTRESS-SYNDROME

Polymorphonuclear leukocytes (PMN) are the predominant inflammatory ce lls recruited in acute lung injury. This study compares the concentrat ion of interleukin-8 (IL-8) to those of GRO alpha, both of which are C XC chemokines, in bronchoalveolar ravage fluid (BALF) in three acute p athologic states: bacterial pneumonia (BPN); adult respiratory distres s syndrome (ARDS); and Pneumocystis carinii pneumonia (PCP). Levels of both IL-8 and GRO alpha were below 5 pg/ml in 16 nonsmoking volunteer s who served as controls. Despite more than twice as many neutrophils in the BALF of the BPN group (n = 12) than in the group with ARDS (n = 13), both groups had similar levels of IL-8, of 569 +/- 120 pg/ml and 507 +/- 96 pg/ml, respectively. The GRO alpha concentrations in the B PN and ARDS patients were respectively 3.3 and 3.4 times those of IL-8 , reaching 1,870 +/- 314 pg/ml for the BPN and 1,699 +/- 377 for the A RDS patients. In the PCP group (n = 48, 45 human immunodeficiency viru s [HIV]-positive, 3 HIV-negative), GRO alpha levels (897 +/- 172 pg/ml ) were sevenfold higher than IL-8 levels (123 +/- 40 pg/ml). In all pa thologic states there was a good correlation between GRO alpha and IL- 8 (r = 0.53, p = 0.0001). GRO alpha or IL-8 both correlate with the ab solute neutrophil number/ml when all groups were studied together (r = 0.52, p = 0.0001). Only in the PCP and ARDS groups did IL-8 correlate with the PMN number. The elastase concentration in BALF correlated wi th either IL-8 or GRO alpha when all groups were studied together. The elastase levels correlated with IL-8 levels in the ARDS group and wit h GRO alpha levels in the PCP group. GRO alpha is shown to be biologic ally active, in that specific blocking antibodies against this chemoki ne significantly reduce neutrophil chemotactic activity. Overall, GRO alpha may be as important as IL-8 in acute lung inflammatory processes .