Detection of CMV glycoprotein types in blood samples taken from immunocompromised patients

Abstract

CMV is a herpes virus and ubiquitouspathogen with high ability to avoid the host immune system and establish persistent infection for many years. It is associated withsevere diseases in congenitally infected infants and immunocompromised individuals, for instance, AIDS and transplant recipient patients. As the virus responsible for the majority of the mortality and morbidity cases in the bone marrow and solid organ transplant individuals it is also involved in allograft rejection. The gH, gB, gN, gM, gL and gO are envelope glycoproteins of the virus. They are involved in many processes in the infected cell for example, attachment and penetration. The published literature suggested that the glycoproteins are undergoing continuous mutations which are under control in a healthy person. However, in immunocompromised patients CMV is capable of escaping from the immune system and becoming pathogenic or neuroinvasive. In this study 30 blood samples were collected from the clinical virology department at Manchester Royal Infirmary (MRI) Hospital in order to test the hypothesis of a relationship between these glycoprotein types and disease outcome in that group of patients. All the samples were screened for the presence of HCMV and then subjected to amplification by PCR specific for gB, gN, gM, gL genes. Finally, restriction fragment length polymorphisms (RFLP) assay was applied to the samples to identify the genotypes. Viral DNA was reported in all 30 samples but not all were positive for all the glycoprotein PCR assays. The number/ percentage of each glycoprotein positive PCR among the clinical samples was as follows; gN 11/30 (36.7%), gM 13/30 (43.13%), gB 27/30 (90%) and gL 22/30 (73.3%). RFLP was performed on all positive samples to detect the genotype. The most common genotypes found were gB3 (60%) then gL3 (46.7%) and gM1 (33.3%). No results were obtained for gN after RFLP as the enzymes did not appear to have cut the DNA product. These finding are compared with previous studies in the literature and the credibility of this technique to provide consistent results is evaluated.