The immaturity of the immune system increases the susceptibility of young infants to infectious diseases and prevents the induction of protective immune responses by vaccines. We previously reported that Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccination induces a potent Th1 response to mycobacterial Ags in newborns. In this study, we evaluated the influence of BCG on the response to unrelated vaccines given in early life. Newborns were randomly allocated to one of three study groups receiving BCG at birth, when infants received their first dose of hepatitis B and oral polio vaccines; at 2 mo of age, when infants received their first dose of diphtheria and tetanus vaccines; or at 4.5 mo of age, when immune responses to vaccines were measured. Administration of BCG at the time of priming markedly increased the cellular and Ab responses to the hepatitis B vaccine, but had only a limited influence on the cytokine response to tetanus toxoid and no effect on the Ab responses to tetanus and diphtheria toxoids. Although BCG induced a potent Th1-type response to mycobacterial Ags, it promoted the production of both Th1- and Th2-type cytokines in response to unrelated vaccines. The effect of BCG was apparent at the systemic level, as it increased the Ab response to oral polio vaccine. These results demonstrate that BCG influences the immune response to unrelated Ags in early life, likely through its influence on the maturation of dendritic cells.

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Polymorphonuclear leukocytes (PMN) are the predominant inflammatory cells recruited in acute lung injury. This study compares the concentration of interleukin-8 (IL-8) to those of GRO alpha, both of which are CXC chemokines, in bronchoalveolar lavage fluid (BALF) in three acute pathologic states: bacterial pneumonia (BPN); adult respiratory distress syndrome (ARDS); and Pneumocystis carinii pneumonia (PCP). Levels of both IL-8 and GRO alpha were below 5 pg/ml in 16 nonsmoking volunteers 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 BPN 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 ARDS patients. In the PCP group (n = 48, 45 human immunodeficiency virus [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 pathologic 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 absolute 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.(ABSTRACT TRUNCATED AT 250 WORDS)

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