Unmasking the Invisible Fire: Kaposi Sarcoma-Associated Inflammatory Cytokine Syndrome in a Kidney Transplant Recipient with HIV

Introduction: Kaposi sarcoma-associated herpesvirus (KSHV) is a human herpesvirus that causes various malignancies and inflammatory conditions, including Kaposi sarcoma (KS) and KSHV-associated inflammatory cytokine syndrome (KICS). Case Description: We present a case of a 56-year-old Hispanic male with a history of undetectable HIV, renal transplant, and pulmonary KS who developed KICS. The patient presented with chronic cough, shortness of breath, fatigue, and edema. Bronchoscopy and biopsy confirmed pulmonary KS. Laboratory findings revealed elevated levels of IL-6, IL-10, HHV-8 PCR, CRP, and IL-2, suggesting KICS. Treatment with rituximab, tocilizumab, and doxorubicin resulted in significant clinical improvement and reduction in inflammatory markers. Discussion: KICS is a recently described entity in HIV patients co-infected with HHV-8, characterized by fever, fatigue, respiratory symptoms, gastrointestinal symptoms, edema, effusions, and adenopathy. The pathogenesis involves viral IL-6 (vIL-6) and human IL-6 (hIL-6) production from infected cells. Diagnosis requires the presence of clinical features, laboratory findings, and radiological findings, with the exclusion of histopathological findings for multicentric Castleman disease (MCD). Although there are no standard therapeutic regimens for KICS, a combination of rituximab and doxorubicin has shown success in clinical response. Clinicians should be aware of the possibility of KICS in HIV and transplant-related KS patients with unexplained respiratory symptoms. Also, prior to transplantation, HHV-8 screening should be done routinely in HIV positive transplant recipients. while further studies are needed to standardize diagnostic and therapeutic approaches for KICS, clinicians should be aware of this rare possibility of unexplained inflammatory symptoms in HIV positive transplant recipients.