Marked Disparity in Incidence of Bacterial Infections in Patients with the Acquired Immunodeficiency Syndrome Receiving Interleukin-2 or Interferon-γ

Abstract

Study Objective: To compare the infectious complications that occurred during trials of immunomodulatory agents in patients with the acquired immunodeficiency syndrome (AIDS).

Design: A survey of two cohorts of patients with AIDS who participated in nonrandomized, unblinded, non-placebo-controlled investigations of the toxicity and efficacy of interleukin-2 and interferon-γ.

Setting: Clinical research unit in a tertiary care center.

Patients: Consecutive samples of 52 patients given interleukin-2 and 22 patients given interferon-γ. Selection criteria for referred patients included a diagnosis of AIDS, hemoglobin level of greater than 100 g/L (2.0 mg/dL), creatinine level of less than 176.8 µmol/L , bilirubin level of less than 25.65 µmol/L (1.5 mg/dL), the absence of active infection, and the absence of other drug therapy for 2 weeks before entry. Four patients given interleukin-2 failed to complete the study.

Interventions: Intravenous infusion of natural-product or recombinant human interleukin-2, 250 to 10 000 000 U/day for 23. 4 ± 1.5 (SE) days, or recombinant human interferon-γ, 0.001 to 1.0 mg/m² . d for 17.7 ± 4.8 days.

Measurements and Main Results: Twenty nonopportunistic bacterial infections occurred in 17 of 52 patients given interleukin-2, whereas none occurred in 22 patients given interferon-γ (P < 0. 05). Bacteremia accounted for 12 of the infections. Staphylococcus aureus and gram-negative bacilli accounted for 16 of the isolates. Opportunistic infections occurred in 6 patients during interleukin-2 infusion and in 1 patient during interferon-γ infusion (P > 0.5). Clinical and immunologic variables and methods of management of intravenous catheters were similar in the two groups.

Conclusions: A marked disparity in infection with nonopportunistic bacteria, but not with opportunistic organisms, occurred in patients with AIDS who were treated with interleukin-2 as compared with those who were treated with interferon-γ. A high incidence of bacteremia and localized bacterial infection should be anticipated in patients with AIDS who receive interleukin-2.