Retrospective evaluation of the relationship of CMV viremia/reactivation and invasive fungal infection in patients with hematopoietic stem cell transplantation

Introduction: Hematopoietic stem cell transplantation (HSCT) is used as an effective treatment option in the treatment of many malign and non-malign diseases in childhood. The complications that develop early or late after HSCT affect the prognosis and life quality of patients. The infections that develop after transplantation are an important cause of morbidity and mortality. In patients with HSCT, invasive fungal infection (IFI) and cytomegalovirus (CMV) viremia/reactivation are common. The percentage of morbidity and mortality increases because of the fungal infection and CMV infection/reactivation that develop after transplantation. Thanks to the developments recently achieved in supportive care precautions, better understanding of immunosuppression mechanisms, and utilization of reduced intensity conditioning regımens, and of strategies of new antimicrobial medications and prophylaxis, morbidity and mortality have decreased. CMV infection cause a change in the structure of cell skeleton and cause an increase in macrophage migration inhibitor factor secretion. As a result of this, macrophage migration indicates deterioration. Especially alveolar macrophages are one of the important defense mechanisms against Aspergillus. Besides, CMV genome can also code the proteins that can deteriorate antigen presentation. Ganciclovir used in CMV infection/reactivation can also cause neutropenia by making bone marrow suppression. The relationship between CMV infection and IFI has not yet been totally enlightened. Contradictory results have been obtained in the conducted studies. CMV reactivation after HSCT has been determined to increase IFI development risk in the studies made in adult age group in particular in recent years. In several studies, it has been indicated that CMV peak level in the course of CMV viremia and CMV reactivation more than once have nothing to do with IFI development. There are limited numbers of studies conducted on this topic in childhood age group. Objective: In this study, it is aimed to determine the relationship between CMV viremia/reactivation and IFI in child patients with allogenic and autologous HSCT, to determine the risk factors for CMV and IFI that develop after transplantation and to find the incidence of these infections, to determine and compare CMV peak levels before and after transplantation, to determine CMV and IFI incidence in patients determined with Graft versus host disease (GVHD), to find and compare posttransplant IFI development times, to assess the effects of posttransplant application of steroids on viral and fungal infection, to examine the reasons for mortality existence in the first posttransplant 180 days, and to determine CMV end organ damage rates in those with CMV infection/reactivation. Hypothesis: CMV reactivation in patients with HSCT increases IFI risk. The regimes used for GVHD and transplantation cause increase in the incidence of other posttransplant opportunistic infection together with CMV. Method: This study is composed of 113 child patients with allogenic and autologous HSCT and with accessible data in Bone Marrow Transplantation Unit, Pediatrics Department of the Ege University in January 2014–December 2017. The data of patients were accessed from policlinic follow-up files and electronical hospital records. All subjects and children in control group with no CMV reactivation development were assessed in terms of IFI according to definitions revised in 2008 by European Organization for Research and Treatment of Cancer/ Invasive Fungal Infections Cooperative Group (EORTC) and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (MSG). The existence of CMV and fungal infection in the follow-up before and after transplantation, utilization of ganciclovir, CMV peak levels, CMV end organ damage development, usage of steroids, conditioning regimes, GVHD prophylaxis, stem cell product specifications, donor-recipient adaptation, donor-recipient CMV serology status, GVHD development, with which diagnosis HSCT was made, neutrophil engraftment days, antifungal and antiviral prophylaxis, whether there is mortality in the first 180 days after transplantation, and if there is- the reason for it have been assessed at full length. The patients whose data to direct the study have not been achieved and those IFI subjects classified as possible were excluded from the study. Data: 64 of the patients were male (56.6%) and 49 of them were female (43.3%), and when they were administered HSCT, the average age was 88.5 months, median being 83.5 months (2-215 months). In the follow-up, 11 patients were applied stem cell transplantation for the second time. Allogenic stem cell transplantation was applied to 122 patients and autologous stem cell transplantation to 2 patients. GVHD prophylaxis was given to 118 patients. In the serology monitored before transplantation, CMV lgM positivity was found only in one donor. CMV lgM was positive in 3 of the recipients and was negative in 119 of them. Before transplantation, there were CMV infection history in 23 patients, ganciclovir usage in 26 patients, and fungal infection history in 28 patients. Peak CMV level before transplantation was 20338±172919 IU/ml on the average. Neutrophil engraftment day was 17.7 days on the average, median being 18 days (9-37), and because in three patients neutrophil numbers always remained over 1000/µl, neutrophil engraftment day could not be stated. Acyclovir was used as an antiviral prophylaxis to patients with HSCT. As antifungal prophylaxis, 93 patients were given fluconazole, 16 patient were given voriconazole, 2 patients were given Amphotericin B, 3 patients posaconazole, 4 patients fluconazole+voriconazole, 3 patients voriconazole+micafungin, 1 patient micafungin, 1 patient fluconazole+amphotericin B, 1 patient voriconazole+amphotericin B. In the follow-up, grade 1 acute GVHD developed in 16 patients, grade 2 in 16 patients, grade 3 in 12 patients, grade 4 in 4 patients (aGVHD). Chronic GVHD (cGVHD) was found in 12 patients, three of whom had score 1, four of whom had score 2, five of whom had score 3 cGVHD. After transplantation, ganciclovir usage was found because of steroid in 73 patients and CMV reactivation in 61 patients. Peak CMV levels after transplantation was 23879±81359 IU/ml on the average. After transplantation, 33 patients were diagnosed with probable or proven IFI. Posttransplant IFI development was observed in 18 (29%) of 61 patients with CMV reactivation development after transplantation. Accordingly, risk does not increase in those with CMV reactivation after transplantation in terms of proven IFI (P=0.473). aGVHD risk was observed to increase in those with CMV reactivation development after transplantation (P=0.013). No statistical significant relationship was found between acute and chronic GVHD and IFI (P=0.965 and 0.625, respectively). cGVHD score was seen to be higher in those with CMV reactivation development after transplantation (P=0.049). No statistically significant relationship was found although CMV reactivation was seen more in those using steroids after transplantation (P=0.136). Steroid usage after transplantation was observed to increase the IFI development risk (P=0.021). In the first 180 days after transplantation 16 deaths were seen, four of which had fungal infection reasons. When the effect of CMV reactivation, aGVHD and cGVHD over survival was evaluated by Cox regression analysis, it was determined not to be statistically significant (P=0.436, 0.810, 0.503, respectively); yet, the effect of IFI over survival after transplantation is statistically significant (P<0.001). 78.2% non-relapse mortality was seen in the first one year after transplantation. Discussion: In a heterogeneous group of patients with HSCT by using different preparation regime, donor and stem cell source with different indications in childhood period, IFI rate was found to be 29.5% in subjects with CMV reactivation development in the assessment made after HSCT. In those with CMV reactivation development, it was determined that IFI risk did not increase but aGVHD risk increased and cGVHD score was higher. In those with steroid usage after transplantation, the risk of IFI development was seen to increase. Long-term follow-ups of the patients with HSCT in childhood period in terms of CVM viremia/ reactivation were important in respect of mortality and morbidity.