ObjectiveTo evaluate the diagnostic and prognostic value of serum tumor necrosis factor-α (TNF-α) levels in HIV-1-infected children.DesignSerum levels of TNF-α were evaluated in 57 HIV-1-infected symptomatic children aged between 7 months and 8 years.MethodsTNF-α levels were determined by enzyme immunoassay. The sensitivity of the assay was 10pg/ml.ResultsTNF-α levels (mean ± s.d.) were significantly elevated in HIV-1-infected patients (285 ± 390 pg/ml), compared with HIV-1-uninfected age-matched controls (22.7 ± 4.9 pg/ml). Among HIV-1-infected children the highest levels of TNF-α were noted in those withMycobacterium avium intracellulare(MAI) infection and those with interstitial lymphoid pneumonitis (LIP). In contrast, patients withPneumocystis cariniipneumonia, progressive encephalopathy or cachexia did not have markedly elevated TNF-α levels.ConclusionsSerum TNF-α is increased in symptomatic HIV-1-infected children, with higher levels in children with LIP or MAI. Serum TNF-α levels are not diagnostic for cachexia or progressive encephalopathy.