Incidence and Risk Factors for Immune Reconstitution Inflammatory Syndrome in an Ethnically Diverse HIV Type 1-Infected Cohort

BACKGROUND: It is estimated that 10%-25% of patients who start highly active antiretroviral therapy (HAART) experience immune reconstitution inflammatory syndrome (IRIS). Our objective was to determine the incidence, clinical spectrum, and predictors of IRIS in an ethnically diverse cohort of patients initiating HAART. METHODS: A retrospective study of all patients starting HAART between 1 January 2000 and 31 August 2002 at a human immunodeficiency virus (HIV) clinic in London was performed. All laboratory measurements and data on antiretroviral therapies were obtained from the clinic database. Medical records were reviewed to identify clinical events consistent with IRIS during the 6 months after HAART was initiated. RESULTS: A total of 199 patients were included, of whom 50.8% were male, 59.3% were black African, 29.1% were white, and 10.5% were black Caribbean. The median baseline CD4 cell count and HIV RNA load were 174x10(6) cells/L (interquartile range IQR, 82-285x10(6) cells/L) and 37,830 copies/mL (IQR, 4809-149,653 copies/mL), respectively. Forty-four patients (22.7%) experienced an IRIS event at a median of 12 weeks after HAART initiation (IQR, 4-24 weeks after initiation); 22 events (50%) involved genital herpes, 10 (23%) involved genital warts, 4 (9.0%) involved molluscum contagiosum, and 4 (9.0%) involved varicella zoster virus infection. Five patients had mycobacterial infections, 4 had hepatitis B, 1 had Pneumocystis jirovecci infection, and 1 had Kaposi sarcoma. The strongest independent predictors of IRIS were younger age at initiation of HAART (P=.003), baseline CD4 cell percentage of 15%, and ratio of CD4 cell percentage to CD8 cell percentage of 0.3. CONCLUSIONS: Approximately one-quarter of patients who start HAART experience an IRIS event. The majority are dermatological, in particular genital herpes and warts. Patients with advanced immunodeficiency at HAART initiation are at greatest risk of developing IRIS and should be appropriately screened and monitored.