Increased Levels of Nitrite in the Sera of Children Infected with Human Immunodeficiency Virus Type 1

Nitric oxide (NO) is a newly discovered gas that plays an important role in cell communication and host resistance to infection. The production of NO was examined in the sera of seven children infected with human immunodeficiency virus type 1 (HIV-1) and in the sera of 14 children who became seronegative for HIV-1 during the first year of life. In addition, we determined serum levels of various cytokines, such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and gamma interferon (IFN-γ), inasmuch as these cytokines are potent inducers of NO production. Production of NO, detected as circulating serum levels of nitrite, was measured with use of the Griess reagent. Serum levels of cytokines were determined by enzyme immunoassay. Increased serum levels of nitrite were observed in children with HIV-1 infection (0.4 ± 0.2 µmol/L; P = .013), and in those who became seronegative for HIV-1 during the first year of life (0.5 ± 0.3 µmol/L; P = .04). Furthermore, serum levels of IL-1β and TNF-α were significantly elevated in children with HIV-1 infection (37.5 ± 23.6 pg/mL and 91.2 ± 45.1 pg/mL, respectively). Prophylactic administration of intravenous immune globulin provoked a significant decrease of circulating levels of nitrite in children with HIV-1 infection. In conclusion, NO may playa role as a cytostatic or cytotoxic factor for invading microorganisms, and thus it is probably involved in limiting and/or eradicating infection.