Immature reticulocyte fraction is an early predictor of bone marrow recovery post chemotherapy in patients with acute leukemia.

OBJECTIVE: To establish the benefits of immature reticulocyte fraction (IRF) measurement using an automated hematology cells analyzer over absolute neutrophil count (ANC) in predicting bone marrow recovery post induction chemotherapy. METHODS: A prospective observational study was carried out in the Departments of Pathology, Medicine, and Pediatrics, Universiti Kebangsaan Malaysia, Medical Center (UKMMC), Kuala Lumpur, Malaysia during a period of 19 months from April 2009 to December 2010 to assess the bone marrow recovery in patients with acute leukemia. A total of 22 patients in remission induction phases were enrolled in this study. The blood specimens were collected from day zero after chemotherapy, and every 3 days until patients recovered hematologically. All blood samples were measured for ANC and IRF using an automated hematology analyzer (Beckman-Coulter LH750). RESULTS: The percentage of patients showing IRF recovery earlier than ANC recovery was 63.6% (14 out of 22 patients). There was a significant difference in the mean number of days for IRF recovery as compared with ANC recovery (14.05 and 17.18 days), p=0.005. CONCLUSION: This study proved that IRF was more useful in predicting bone marrow recovery in a patient with acute leukemia post induction chemotherapy compared with ANC. The IRF is not affected by infection, is easily measured, and inexpensive; thus, it is a reliable parameter to evaluate bone marrow reconstitution.

Compartmentalization of allogeneic T-cell responses in the bone marrow and spleen of humanized NOD/SCID mice containing activated human resident myeloid dendritic cells.

OBJECTIVE: Human allogeneic (allo)-T-cell responses within recipient lymphoid tissues and the degree to which they are altered in the presence of activated tissue-resident dendritic cells (DC) remain unknown. This study examined allo-T-cell recruitment and the early allo-T-cell responses that occur in the bone marrow (BM) and spleen (SP) of humanized (hu) nonobese diabetic (NOD)/severe combined immunodeficient (SCID) recipients containing activated human tissue-resident myeloid DC (MDC). MATERIALS AND METHODS: Human naïve allo-T cells were transferred into polyinosinic:polycytidylic acid [poly(I:C)]-treated or untreated huNOD/SCID recipients containing human tissue-resident DC derived from transplanted CD34(+) cells. Activation of human tissue-resident MDC mediated by poly(I:C) treatment, recruitment, proliferation, and effector differentiation of allo-T cells in the BM and SP of huNOD/SCID recipients were analyzed in vivo by flow cytometry. RESULTS: Poly(I:C) treatment induced transient activation of human MDC within a maximum of 8 hours, as evidenced in the BM by an increased proportion of MDC-expressing CD86 while in the SP by MDC expressing CD86 and producing interleukin-12. Poly(I:C)-pretreated huNOD/SCID recipients showed changes in the recruitment of allo-T cells in the BM and SP and developed different allo-T cell responses within the BM and SP compartments. In the BM, allo-T cells underwent multiple divisions and increased numbers of interferon-gamma(+) and tumor necrosis factor-alpha(+) effector cells, while the majority of splenic allo-T cells underwent a single division and had fewer effector allo-T cells. CONCLUSIONS: Our experimental transplantation model demonstrates that early allo-T-cell responses are regulated by compartmentalization in the BM and secondary lymphoid tissues; events potentially occurring after allotransplantation in human recipients.