Infectious complications after hematopoietic stem cell transplantation: current status and future perspectives in Korea

Cho, Sung-Yeon; Lee, Hyeon-Jeong; Lee, Dong-Gun

The post-HSCT period is usually divided into the (1) pre-engraftment period (day 0 to days , (2) immediate post-engraftment period (engraftment to day 100), and (3) late post-engraftment period (days 100 to 365). In general, the neutrophil count recovers 2 to 3 weeks after HSCT. However, the functional recovery of various cell types is also important. Immunological recovery takes 3 to 6 months for NK cells, 6 to 12 months for B-cells and CD8 T-cells, and 1 to 2 years for CD4 T-cells [9] . The use of T-cell-depleting agents (anti-thymocyte globulin [ATG] , alemtuzumab, etc.) to reduce the risk of GVHD and graft failure could improve the outcomes of transplantation but may delay immune recovery [10] . Recipients of T-cell-depleted transplantation may be vulnerable to viral infections-such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), or adenovirus-and adoptive immunotherapy may be applied [11] .