Nontuberculous Mycobacterial Immune Reconstitution Syndrome in HIV-Infected Patients: Spectrum of Disease and Long-Term Follow-Up

Abstract

The long-term outcome and spectrum of disease of nontuberculous mycobacterial immune reconstitution syndrome have not been described. We report the findings of an observational study. Among 51 patients (43 with Mycobacterium avium complex [MAC] infection, 2 with Mycobacterium genavense infection, and 6 whose samples were smear positive but culture negative) from 1993-2004, the median follow-up period was 29 months. The incidence of nontuberculous mycobacterial immune reconstitution syndrome was 3.5% among patients initiating highly active antiretroviral therapy (HAART) with a baseline CD4+ cell count of <100 cells/microL. Three main clinical presentations were peripheral lymphadenitis (in 17 patients), pulmonary-thoracic disease (in 15 patients), and intra-abdominal disease (in 13 patients). Six other patients had cases that involved joint, spine, prostate, skin, soft tissue, and spontaneously resolving MAC bacteremia. Disease was usually localized. Median CD4+ cell counts before initiation of HAART and at diagnosis were 20 and 120 cells/microL, respectively, and the median reduction in human immunodeficiency virus (HIV) RNA load was 2.5 log10 copies/mL. Intra-abdominal disease was frequently preceded by disseminated MAC infection (in 62% of cases, compared with 6%-33% of cases for other groups; P=.003) and accounted for 16 (43%) of 36 hospitalizations (compared with 5%-35% for other groups; P=.008). The relapse rate was not higher among 10 patients who received no MAC therapy or received MAC therapy for < or =2 weeks. Prednisone was associated with clinical responses in 8 (89%) of 9 patients with evaluable cases. In total, 7 patients (14%) had 13 subsequent culture-positive MAC events (6 of which were cases of immune reconstitution syndrome, and 7 of which were cases of disseminated MAC infection). Ten patients (20%) died (2 of disseminated MAC infection, 5 of other opportunistic infections, and 3 of HIV-unrelated causes). Nontuberculous mycobacterial immune reconstitution syndrome has a wide range of clinical presentations and severity. The long-term prognosis is favorable for HAART-adherent patients. Intra-abdominal disease is associated with greater morbidity than is peripheral lymphadenitis. The role of antimycobacterial therapy is uncertain, given the self-limited course of most nonabdominal cases.