Molecular Detection and Glycoprotein B (UL55) Genotyping of Cytomegalovirus among Sudanese Renal Transplant Recipients

Abstract

Background Cytomegalovirus (CMV) is the most common opportunistic pathogen among solid organ transplant recipients’ especially renal transplants with significant morbidity and mortality. This study was designed to detect CMV DNA and to determine the frequency of different glycoprotein B (UL55) genotypes among Sudanese renal transplant recipients. Methods One hundred and four renal transplant recipients were included in this study. A blood specimen was collected from each recipient. DNA was extracted from plasma using QIAamp DNA mini kit. CMV amplification and quantification (estimation of viral load) was performed using CMV Real – RT Quant kits. Genotyping of Human CMV gB was carried out by nested PCR and sequencing of the highly diverse region of glycoprotein B. Results Cytomegalovirus (CMV) DNA (viremia) was detected in 40/104 (38.5%) of renal transplant recipients. The average of CMV DNA viral load was 358 x104 copies/ml (6.5 log10) ranged from 62 copies/ml (1.8 log 10) to 1.43x108 copies/ml (9 log10). CMV viremia was detected in (60%) of recipients of less than 1-12 months, (17%) of 13-24, (10%) of 25-36, (5%) of 37- 48 and (8%) in more than 48 months post-transplantation with no significant association (P. value = 0.296) between CMV viremia and post renal transplantation time. The association between the type of immunosuppressive drugs and high viral loads (more than 1000 copies /ml) showed a significant difference (P. value =0.05). The correlation between CMV loads of more than 1000 copies/ml and the presence of symptoms of CMV disease were highly significant (P.value =0.00). Fever 7(41%), fever and leucopenia 6(35%) and gastrointestinal disease 4(24%) were the most common presenting symptoms of CMV disease. CMV-genotyping revealed 8 cases (80%) for gB3, and 2 cases (20%) for gB4 genotypes. The most frequent genotype among Sudanese renal transplant recipients was gB3 and no mixed genotypes were observed. Conclusions The frequency of CMV DNA is high among Sudanese renal transplant recipients. CMV viremia viral loads were slightly lower in asymptomatic patients. CMV gB3 is the most predominant glycoprotein B genotype in Sudanese renal transplant recipients.