Early detection, reactivation of cytomegalovirus DNA & immediate early (IE)-mRNA expression in hematopoietic stem cell-transplant patients

Background: Human cytomegalovirus (HCMV) reactivation is a major cause of morbidity and mortality among stem cell transplant recipients post-transplantation.Aim: HCMV immediate-early messenger RNA (IE-mRNA) was evaluated as marker of post-transplant HCMV reactivation in bone marrow transplant recipients. Method: ology: An in-house real-time reverse transcriptase PCR targeting IE-mRNA was developed to estimate HCMV mRNA levels post-transplantation. Blood samples collected in K2-EDTA tubes from patients (n = 162) admitted with Department of Clinical Hematology were transported in cold condition for routine HCMV DNA screening. For HCMV IE-mRNA quantification, peripheral blood mononuclear cells (PBMCs) were separated from whole blood and stored in RNA later at -70 degrees C until testing. Samples were collected weekly once for first 3 weeks post-transplantation and thereafter from week 4-12, samples were collected twice weekly. A total of 2467 samples were collected from 162 study participants. Results: Thirty five patients (21.6 %) had post-transplant HCMV reactivation. Twenty five patients with complete follow-up were selected for monitoring HCMV DNA. HCMV IE-mRNA PCR was performed for 15 patients and 7 (46.6 %) patients had detectable mRNA levels. HCMV IE-mRNA was detected in all patients with increasing HCMV DNA levels except for one patient in whom IE-mRNA appeared 3 days before HCMV DNA was detected. One patient had detectable HCMV IE-mRNA during declining HCMV DNA level. However the patient showed an increased HCMV DNA one week later, indicating the importance of HCMV mRNA in predicting HCMV replication. Conclusion: Quantification of HCMV IE-mRNA may be a valuable tool to predict progression of HCMV infection post-transplantation, with further prospective studies needed for validation.