Background. Autologous hematopoietic stem cell transplantation remains in demand for patients with hematological malignancies. The pool of hematopoietic stem cells is known to be heterogeneous. e studied various factors associated with previous treatment, patient and disease characteristics, as well as the composition of the C34+ pool in peripheral blood (), associated with the number of C34+ cells in the first leukocyte concentrate (LC).Aim. To determine the factors associated with C34+ , C34+ C143+ , C34+ C38– HLA-DR+/– and C34+ C38+/– HLA-DR– cells count in the first LC of patients with hematological malignancies.Materials and methods. Subpopulations of hematopoietic stem cells in the and first LC were studied in 80 patients with hematological malignancies (male to female ratio 1:1, median age 51 years). The control group included 24 healthy donors. Flow cytometry was used to determine the number of C34+, C34+ C38– HLA-DR+/–, C34+ C38+/– HLA-DR– and C34+ C143+ cells. Immunophenotyping was performed on samples of patients before mobilization and on the 1st day of leukapheresis, as well as on first LC samples on the 1st day of hematopoietic stem cells collection.Results. It was shown that the presence of early progenitor cells with C34+ C38– HLA-DR+/– immunophenotype in the before mobilization is associated with a higher first LC C34+ cells number (p = 0.003). In the presence of C34+ C38– HLA-DR+/– cells in the before mobilization, the median number of C34+ cells in the first LC was 2.6 %, and in their absence – 0.71 %. hen using granulocyte colonystimulating factor as monotherapy, the C34+ C143+ cells number in the first LC was significantly lower than when using chemotherapy and granulocyte colonystimulating factor (p = 0.03). However, the majority (9 of 16) of patients in the granulocyte colonystimulating factor monotherapy group had renal failure before mobilization. No factors associated with the number of C34+ C38– HLA-DR+/– cells in the first LC were found. In patients >60 years old, the number of C34+ C38+/– HLA-DR– cells in the first LC was lower than in patients ˂ 60 years old, the number of C34+ C38+/– HLA-DR– cells in the first LC was lower than in patients ˂ 60 years old (p = 0.043). In patients with infectious complications during hematopoietic stem cell mobilization, the number of C34+ C38+/– HLA-DR– cells in the first LC was lower than in patients without them (p = 0.019).Conclusion. The first LC number of C34+ cells is associated with number of C34+ C38– HLA-DR+/– cells, i. e. cells of the early differentiation stage with a high proliferation potential. A relationship was established between C34+ C143+ cells number before mobilization and first LC C34+ cells count: in the paired model – within the borderline values (p = 0.05), and in the multifactorial covariance model – with high significance (p = 0.0033). It has been proven that with increasing patient age and in the presence of infectious complications, the number of longterm repopulating C34+ C38+/– HLA-DR– cells decreases.
