Serological Detection and Molecular Characterization of Cytomegalovirus and its Glycoprotein B (UL55) among Sudanese Renal Transplant Recipients

Abstract

This is analytical cross sectional study conducted at Kidney transplanted association hospital and Ahmed Gassim teaching hospital in Khartoum state in the period from 2013 to 2015, was aimed to detect CMV using ELISA and quantitative real-time PCR (qRT PCR), estimate viral loads and to determine the distribution of gB genotypes among Sudanese renal transplant recipients by DNA sequencing. One hundred and four renal transplant recipients were included in this study. Blood and serum samples were collected from them, their age ranged from 11 to 72 years with mean age of 37 years. Males were 72(69.2%), while females were 32(30.8%). In this study, 50(48%) of them received their organs in local hospitals, while 54(52%) received their organs in abroad. Most of the renal transplant recipients’ received organs from relative donors 79(76%) and only 25 (24%) received organs from non-relative donors. The mean post-transplantation duration was 54 months, ranged from < than month - 204 months. The majority of post-transplantation duration varies from < than month - 12 months which represents 53(51%), 13 to 24 months 18(17.3%), 25 to 36 months 9(8.8%), 37 to 48 months 8(7.7%), and more than 48 months was 16(15.4%). The majority of recipients under study 79(75.9%) received triple immunosuppressive drugs, 24(23.1%) received two drugs while only one (1%) received one drug. CMV IgM was detected using ELISA technique in 27(26%) of recipients, while 103(99%) recipients had CMV IgG in their serum. CMV DNA (viremia) was detected in 40/104 (38.5%) of renal transplant recipients using quantitative real time PCR with viral loads ranging from 62 copies /ml (1.8 log10) to 1.43x108 copies/ml ( 9 log10) and average of 358 x104 copies/ml (6.5 log10). Symptomatic recipients with CMV disease were 17/104 (16.3%) while asymptomatic with CMV infection were 23/104 (22.1%). CMV viremia showed no significant difference (P.value > 0.05) with sex and types of immunosuppressive therapy received by transplant recipients, while there is a significant difference (P.value = 0.05) between high viral loads and types of immunosuppressive therapy received by transplant recipients. At the same time the correlation between high viral loads (>1000 copies /ml) and development of CMV disease observed significant difference (P.value = 0.00), in which, 14/17 (82%) of patients had clinical symptoms of CMV disease with high viral loads and 22/23 (95.7%) of patients had no clini¬cal symptoms of CMV disease with low viral loads (<1000 copies/ml). The most common presenting symptoms of CMV disease were fever, fever and leucopenia, and gastrointestinal disease. The distribution of gB genotypes in Sudanese renal transplant recipients observed that gb3 was the most frequent genotype (80%) while gB4 was (20%) and no mixed genotypes were detected. In conclusion, qRT-PCR from plasma samples is very sensitive for detection of CMV replication and was more sensitive than ELISA technique in detecting CMV in renal transplant patients. Viral loads were lower with asymptomatic patients. CMV gB3 was considered the most predominant glycoprotein B genotype in Sudanese renal transplant recipients with CMV disease.