Clinical Impact of Haemophagocytic Lymphohistiocytosis Among Patients With HIV / AIDS and Disseminated Histoplasmosis in a Hyperendemic Region of Northeastern Brazil

BACKGROUND: Haemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome that may occur in people living with HIV/AIDS (PLWHA), often triggered by opportunistic infections such as disseminated histoplasmosis (DH). The substantial overlap in clinical and laboratory features between HLH and DH complicates timely diagnosis. OBJECTIVES: To describe HLH among PLWHA with DH and compare clinical, laboratory and outcome characteristics between patients with and without HLH. PATIENTS/METHODS: A retrospective observational study was conducted at São José Hospital of Infectious Diseases, Fortaleza, Brazil, between March 2023 and June 2024. Hospitalised PLWHA with DH were evaluated for HLH based on the presence of ≥ 3 HLH-2004 criteria and an H-Score ≥ 169. Baseline clinical, laboratory and outcome parameters were compared between patients with and without HLH. RESULTS: Among 61 patients diagnosed with DH, 11 (18.0%) met the study criteria for HLH. Patients with HLH were more likely to present with hepatomegaly (p = 0.036), haemoptysis (p = 0.030) and lower platelet counts (p = 0.029). In-hospital mortality was significantly higher among patients with HLH (54.5% versus 18.0%; p = 0.019). These patients more frequently required renal replacement therapy (p = 0.028) and intensive care unit admission (p = 0.048). Kaplan-Meier analysis with log-rank testing demonstrated significantly reduced in-hospital survival among patients with HLH (p = 0.015). CONCLUSIONS: HLH represents a severe complication in PLWHA with DH and is associated with increased mortality and greater need for intensive care. Early recognition and use of adjunctive diagnostic tools may facilitate timely management and improve clinical outcomes.