Kaposi sarcoma herpesvirus viral load in bronchoalveolar lavage as a diagnostic marker for pulmonary Kaposi sarcoma

Abstract

Objective: Kaposi sarcoma is a vascular tumor that affects the pulmonary system. However, the diagnosis of airway lesions suggestive of pulmonary Kaposi sarcoma (pKS) is reliant on bronchoscopic visualization. We evaluated the role of Kaposi sarcoma herpesvirus (KSHV) viral load in bronchoalveolar lavage (BAL) as a diagnostic biomarker in patients with bronchoscopic evidence of pKS and evaluated inflammatory cytokine profiles in BAL and blood samples. Design: In this retrospective study, we evaluated KSHV viral load and cytokine profiles within BAL and blood samples in patients who underwent bronchoscopy for suspected pKS between 2016 and 2021. Methods: KSHV viral load and cytokine profiles were obtained from both the circulation and BAL samples collected at the time of bronchoscopy to evaluate compartment-specific characteristics. BAL was centrifuged and stored as cell pellets and KSHV viral load was measured using primers for the KSHV K6 gene regions. Results: We evaluated 38 BAL samples from 32 patients (30 with HIV co-infection) of whom 23 had pKS. In patients with airway lesions suggestive of pKS, there was higher KSHV viral load (median 3188 vs. 0 copies/106 cell equivalent; P = 0.0047). A BAL KSHV viral load cutoff of 526 copies/106 cells had a sensitivity of 72% and specificity of 89% in determining lesions consistent with pKS. Those with pKS also had higher IL-1β and IL-8 levels in BAL. The 3-year survival rate for pKS patients was 55%. Conclusion: KSHV viral load in BAL shows potential for aiding in pKS diagnosis. Patients with pKS also have evidence of cytokine dysregulation in BAL.