Background Kaposi sarcoma-associated herpesvirus (KSHV) is the causal agent for Kaposi sarcoma (KS) and multicentric Castleman disease (MCD) in HIV-infected patients. Patients with KSHV-MCD develop fevers, wasting, hypoalbuminemia, cytopenias, and hyponatremia that are related to overproduction of KSHV-encoded vial interleukin (IL)-6 (vIL-6) and human IL-6. Methods We identified 6 HIV-infected patients with KS or serological evidence of KSHV infection who had severe inflammatory MCD-like symptoms but in whom we could not diagnose MCD, and hypothesized that these symptoms resulted from vIL-6 overproduction. Serum vIL-6 levels were assessed in these 6 patients and compared to 8 control patients with symptomatic KSHV-MCD and 32 control patients with KS. KSHV viral load, serum human IL-6 (hIL-6), and human IL-10 were also evaluated. Results Patients with inflammatory MCD-like symptoms but without MCD had elevated vIL-6 levels comparable to patients with symptomatic KSHV-MCD and significantly greater than control patients with KS (P = 0.0026). Elevated hIL-6, IL-10, and KSHV viral loads were also comparable to patients with symptomatic KSHV-MCD and significantly greater than those with KS. Conclusions A subset of patients with HIV and KSHV co-infection, but without MCD, can develop severe systemic inflammatory symptoms associated with elevated levels of KSHV vIL-6, IL-6, and KSHV viral loads. Excess lytic activation of KSHV, production of the lytic gene product vIL6, and associated immunologic dysregulation may underlie the pathophysiology of these symptoms. This IL-6-related inflammatory syndrome is important to consider in critically ill patients with HIV and KSHV co-infection.

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Key Points Human IL-6 and a viral IL-6 homolog encoded by KSHV/HHV8 can independently or together lead to flares of KSHV-associated MCD. KSHV-MCD disease flares were more severe where both human and viral IL-6 were elevated, suggesting they jointly contribute to severity.

These data demonstrate that KSHV microRNA genes are under tight selection in vivo and suggest that they contribute to the biological activity and possibly the pathogenesis of KSHV-associated malignancies.

Kaposi sarcoma herpesvirus (KSHV)-associated multicentric Castleman disease (MCD) is a lymphoproliferative disorder most commonly observed in HIVinfected patients. It is characterized by KSHV-infected plasmablasts that frequently express lytic genes. Patients manifest inflammatory symptoms attributed to overproduction of KSHV viral IL-6, human IL-6, and human IL-6. There is no standard therapy and no established response criteria. We investigated an approach targeting 2 KSHV lytic genes, ORF36 and ORF21, the protein of which, respectively, phosphorylate ganciclovir and zidovudine to toxic moieties. In a pilot study, 14 HIV-infected patients with symptomatic KSHV-MCD received highdose zidovudine (600 mg orally every 6 hours) and the oral prodrug, valganciclovir (900 mg orally every 12 hours). Responses were evaluated using new response criteria. A total of 86% of patients attained major clinical responses and 50% attained major biochemical responses.

Primary effusion lymphoma (PEL) is an aggressive HIV-associated lymphoma with a relatively poor prognosis in the era of effective HIV therapy. Kaposi sarcoma herpesvirus (KSHV) is the etiologic agent, and ∼80% of tumors are coinfected with Epstein-Barr virus (EBV). A better understanding of how KSHV-related immune dysregulation contributes to the natural history of PEL will improve outcomes. Twenty patients with PEL diagnosed between 2000 and 2013, including 19 treated with modified infusional etoposide, vincristine, and doxorubicin with cyclophosphamide and prednisone (EPOCH), were identified. We compared their clinical, virologic, and immunologic features vs 20 patients with HIV-associated diffuse large B-cell lymphoma and 19 patients with symptomatic interleukin (IL)-6 related KSHV-associated multicentric Castleman disease. Survival analyses of treated patients with PEL were then performed to identify prognostic factors and cancer-specific mortality. Compared with HIV-associated diffuse large B-cell lymphoma, PEL was associated with significant hypoalbuminemia (P < .0027), thrombocytopenia (P = .0045), and elevated IL-10 levels (P < .0001). There were no significant differences in these parameters between PEL and KSHV-associated multicentric Castleman disease. Median overall survival in treated patients with PEL was 22 months, with a plateau in survival noted after 2 years. Three-year cancer-specific survival was 47%. EBV-positive tumor status was associated with improved survival (hazard ratio, 0.27; P = .038), and elevated IL-6 level was associated with inferior survival (hazard ratio, 6.1; P = .024). Our analysis shows that IL-6 and IL-10 levels contribute to the natural history of PEL. Inflammatory cytokines and tumor EBV status are the strongest prognostic factors. Pathogenesis-directed first-line regimens are needed to improve overall survival in PEL.

Key Points Rituximab plus liposomal doxorubicin is active and tolerated in patients with symptomatic KSHV-associated multicentric Castleman disease. This is a safe and effective initial regimen for concurrent symptomatic KSHV-associated multicentric Castleman disease and Kaposi sarcoma.

Purpose Alternatives to cytotoxic agents are desirable for patients with HIV-associated Kaposi's sarcoma (KS). Vascular endothelial growth factor-A (VEGF-A) contributes to KS pathogenesis. We evaluated the humanized anti–VEGF-A monoclonal antibody, bevacizumab, in patients with HIV-KS. Patients and Methods Patients with HIV-KS who either experienced progression while receiving highly active antiretroviral therapy (HAART) for at least 1 month or did not regress despite HAART for at least 4 months were administered bevacizumab 15 mg/kg intravenously on days 1 and 8 and then every 3 weeks. The primary objective was assessment of antitumor activity using modified AIDS Clinical Trial Group (ACTG) criteria for HIV-KS. HIV-uninfected patients were also eligible and observed separately. Results Seventeen HIV-infected patients were enrolled. Fourteen patients had been receiving effective HAART for at least 6 months (median, 1 year). Thirteen patients had advanced disease (ACTG T1), 13 patients had received prior chemotherapy for KS, and seven patients had CD4 count less than 200 cells/μL. Median number of cycles was 10 (range, 1 to 37 cycles); median follow-up was 8.3 months (range, 3 to 36 months). Of 16 assessable patients, best tumor responses observed were complete response (CR) in three patients (19%), partial response (PR) in two patients (12%), stable disease in nine patients (56%), and progressive disease in two patients (12%). Overall response rate (CR + PR) was 31% (95% CI, 11% to 58.7%). Four of five responders had received prior chemotherapy for KS. Over 202 cycles, grade 3 to 4 adverse events at least possibly attributed to therapy included hypertension (n = 7), neutropenia (n = 5), cellulitis (n = 3), and headache (n = 2). Conclusion Bevacizumab is tolerated in patients with HIV-KS and has activity in a subset of patients.