Statistics
We used Pearson’s χ2 qualitative test or Fisher’s exact test to analyze
the association of lymphocyte recovery with the following categorical
independent variables: gender, age group (≥ and <8 years),
disease type (malignant, non-malignant), disease phase (early,
advanced), donor type (MSD, haploidentical, unrelated), ABO
compatibility (compatible, incompatible), stem cell source (peripheral
blood stem cells [PBSC], bone marrow [BM]), conditioning regimen
(myeloablative conditioning [MAC], reduced-intensity conditioning
[RIC]), and use of serotherapy (yes, no). Mann-Whitney U test was
used to assess the association of lymphocyte recovery with the dose of
total nucleated cells (TNC) and CD34+ infused, and Kruskal-Wallis test
to compare lymphocyte counts according to the donor.
Time-dependent variables were calculated from the date of the HSCT to
the event. Respective cumulative incidences (CI) were estimated using
Gray’s method, accounting for competing risks. Death without an event
was considered a competing risk for all variables, however, for aGvHD
graft failure was also included. To evaluate the effect of significant
variables on such outcomes we performed Fine-Gray competing risks
univariate and multivariate regression. Overall survival (OS) was
analyzed using the Kaplan-Meier method and differences between groups
were estimated using log-rank test. Univariate and multivariate Cox
regression models were used to assess the impact of the significant
variables. Only significant variables in univariate analyses were
included in multivariate models. Due to the small sample size, it was
not possible to evaluate subgroups of immune recovery for outcomes. AllP -values <0.05 were considered statistically
significant. Statistical analyses were performed using SPSS version 25.0
(SPSS Inc., Chicago, IL, USA), and EZR version 1.40 (Saitama Medical
Center, Jichi Medical University, Japan).