JC Virus and APOL1 Risk Alleles in Black South Africans With Hypertension-Attributed CKD

Abstract

IntroductionThe polyomaviruses, John Cunningham (JC) and BK, infect humans, with primary infection occurring in childhood. First-degree relatives of African American individuals with nondiabetic chronic kidney disease (CKD) who had 2 apolipoprotein L1 (APOL1) risk variants had a lower prevalence of kidney disease in the presence of JC viruria. This study determined the prevalence of polyomavirus infections and their effects, in the presence APOL1 risk alleles, on CKD.MethodsSixty-four black South African individuals with hypertension-attributed CKD with an estimated glomerular filtration rate (eGFR) ≤60 ml/min per 1.73 m2, 44 first-degree relatives, and 56 unrelated controls were included. Viral DNA was extracted from urine and genomic DNA from blood using the Maxwell automated platform. Viral-load quantification was determined using Genesig polyomavirus kits. Genotyping of the APOL1 G1 and G2 variants was by polymerase chain reaction–restriction fragment length polymorphism.ResultsThe prevalence of JC viruria was significantly higher in controls (36%) and first-degree relatives (20%) than in patients with CKD (3%, P < 0.001). Although patients with CKD and their first-degree relatives had similar socioeconomic status scores, we found a lower prevalence of JC viruria in patients with CKD compared with their first-degree relatives, who had normal kidney function. The absence of John Cunningham virus (JCV), DNA was a strong predictor of CKD (odds ratio [OR] 43.43; 95% confidence interval [CI] 7.39–255.20; P < 0.001).ConclusionThere was a strong association between the absence of JC viruria and CKD. Studies with a larger sample are essential to determine the renoprotective effects of JCV and its interactions with APOL1.