Infectious Complications after Haploidentical Hematopoietic Stem Cells Transplantation in Patients with High-Risk Tumors of Hematopoietic and Lymphoid Tissues: A Single-Center Experience

Abstract

Aim. To determine the incidence of viral, bacterial, and fungal infections in post-transplant period and to assess the prognostic value of infections and their influence on early and long-term results of haploidentical hematopoietic stem cells transplantation (haplo-HSCT). Materials & Methods. Retrospective study included 61 patients older than 18 years with high-risk oncohematological diseases. In the period from 2015 to 2018 all patients received haplo-HSCT. Median follow-up after haplo-HSCT was 12.5 months (376 days, range 6-1202). Patients were divided into two groups. The first group (n = 26) received haplo-HSCT as salvage therapy. It included patients with refractory tumors without remission by the start of haplo-HSCT and patients with early relapses after HLA-matched related or unrelated allo-HSCT. The second group (n = 35) received haplo-HSCT on reaching the optimal pretransplant status (“non-salvage”). Results. The incidence of cytomegalovirus (CMV) reactivation, invasive mycosis, and bacterial infections was 70.4 %, 11.5 %, and 75.4 %, respectively. CMV reactivation and invasive mycosis did not affect either the 35- or the 100-day overall survival (OS). For the first time bacterial infections were stratified based on severity according to Sepsis 3 consensus, which allowed to identify groups of patients with unfavorable prognosis. Severe bacterial infections (sepsis and septic shock) correlated with worse early and long-term results, especially in patients without remission by the start of haplo-HSCT, whereas febrile neutropenia/bloodstream infection did not affect OS. On the whole, mortality associated with bacterial infections was 26.2 %. Conclusion. The main factor affecting early lethality after haplo-HSCT is a severe bacterial infection. The key risk factor is lack of remission by the start of haplo-HSCT. Sepsis 3 criteria can be applied in the period of postcytostatic cyto-penia to identify the group of patients with most unfavorable prognosis (septic shock). The implementation of current infection control methods (genotyping of multiple drug resistant strains and timely determining the strategy of antimicrobial chemotherapy on the basis of the results obtained) into everyday clinical practice can improve the treatment outcomes in this category of patients.