Serologic association of human herpesvirus eight with posttransplant Kaposi's sarcoma in Saudi Arabia

Abstract

Background: This study investigates the association between human herpesvirus eight (HHV8) and Kaposi's sarcoma (KS), the most common cancer occurring in renal transplant recipients in Saudi Arabia.

Methods: A cross-sectional study of seroreactivity to HHV8 antigens in posttransplant KS patients from a tertiary care hospital in Riyadh, Saudi Arabia, and in control subjects without KS was conducted. Seroreactivity rates were determined using immunoblotting assays to detect antibodies to two lytic cycle HHV8 antigens: p40, an antigen found in infected cells, and sVCA, an HHV8-encoded small viral capsid antigen expressed in Escherichia coli.

Results: Antibodies to HHV8 p40 and sVCA were present in a significantly higher proportion of renal transplant patients with KS (13 of 14 patients) compared to renal transplant patients without KS (5 of 18; P<0.001) and compared to other control individuals (6 of 44; P<0.001). HHV8 seroreactivity was more common among patients with renal failure (28%) than among other control groups (7%).

Conclusions: The serologic results provide evidence of a strong association between HHV8 and posttransplant KS in Saudi Arabia.

PIP: In Saudi Arabia, Kaposi's sarcoma occurs in 4.1% of renal transplant recipients and accounts for 70% of malignancies in this group. Human herpes virus 8 (HHV8) has been identified in the DNA of many of these patients. The association between HHV8 and Kaposi's sarcoma was investigated further in post-renal transplant Kaposi's sarcoma patients from a tertiary care hospital (King Faisal Specialist Hospital and Research Center) in Riyadh, Saudi Arabia (n = 14), and non-Kaposi's sarcoma controls with renal transplant (n = 18), chronic renal failure (n = 14), other cancers that did not affect renal function (n = 15), and healthy volunteers (n = 15). The median time from transplant to Kaposi's sarcoma was 13 months. A serum sample was assumed to have antibodies to HHV8 if antibody to either p40 or sVCA was detected. The prevalence of HHV8 seroreactivity was 13/14 (93%) in cases, 5/18 (28%) in renal transplants without Kaposi's sarcoma, and 11/62 (18%) in the aggregate control group. HHV8 seroreactivity was significantly more common (p 0.001) among transplant patients with Kaposi's sarcoma than those without this cancer (odds ratio, 33.80; 95% confidence interval, 2.96-904). These findings suggest an etiologic link between HHV8 and Kaposi's sarcoma presumably due to immunologic or cellular factors that influence host-virus interactions.