Evidence for predictive validity of blood assays to evaluate individual radiosensitivity.

PURPOSE: An escalation in standard irradiation dose ensuring improved local tumor control is estimated, but this strategy would require the exclusion of the most sensitive individuals from treatment. Therefore, fast and reliable assays for prediction of the individual radiosensitivity are urgently required. METHODS AND MATERIALS: Seven parameters in lymphocytes of 40 patients with leukemia were analyzed before, during, and after total body irradiation (TBI) and in vitro X-ray irradiation. These were: cell proliferation, nuclear damage, activation of cytokines, and numbers of total leukocytes of CD34+ hematopoietic blood stem cells and of CD4+ and CD8+ lymphocytes. Additionally, antioxidative capacity of blood plasma, uric acid, and hemoglobin levels were measured. Blood samples of 67 healthy donors were used as controls. RESULTS: In vivo and in vitro irradiations showed comparable results. A dose-response relationship was found for most parameters. Three parameters were associated with severe acute oral mucositis (Grade 3 or 4 vs. Grade 0 to 2): leukocytes fewer than 6200/microL after 4 Gy TBI, a rate of >19% lymphocytes with reduced DNA and protein content ("necroses") after 4 Gy in vitro irradiation, and a small antioxidative capacity in blood plasma (<0.68 mMol) after 8 Gy TBI. CONCLUSION: Three simple blood assays were associated with oral mucositis that are posed here hypothetically as an early symptom of enhanced radiosensitivity in leukemic patients: leukocyte count, damaged lymphocyte score, and the antioxidative capacity after exposure.

High-grade loss of leukocytes and hematopoietic progenitor cells caused by erythrocyte-lysing procedures for flow cytometric analyses.

All current-flow cytometric techniques use erythrocyte-lysing procedures before leukocyte analysis. We investigated the impact of four lysing procedures with different flow cytometric techniques on the loss of leukocytes and hematopoietic progenitor cells in blood samples. A total of 280 determinations out of 10 samples were measured by two flow cytometers (FCMs), using a FACS-Calibur (Becton Dickinson) and a particle-analyzing system (PAS) with a "true volumetric unit" (Partec). All samples were prepared with four different commercially available erythrocyte-lysing reagents (n = 10, respectively). CD34(+) cells were determined in relation to counted leukocytes with both FCMs (dual platform determinations, 2-PF). In addition, further immunologic and nuclear staining determinations of cells with and without erythrocyte-lysing procedures were performed in the "true volumetric unit" (single platform mode 1-PF) using the PAS system (n = 10, respectively). In the 2-PF mode, both systems showed identical results for CD34(+) cells (r = 0.997). The comparison of 1-PF and 2-PF modes with immunologic stainings revealed a mean decrease of 34.5% for absolute amounts of CD45(+) cells [in detail: Becton-Dickinson (BD) lysis 40%; Ortho Diagnostics (OD) lysis 31%; Uti lyse (UL) 38%; Cylyse (CL) 29%] and of 41.3% for absolute concentration of CD34(+) cells [in detail: BD lysis 45%; OD lysis 40%; UL lysis 45%; CL lysis 34%] by the lysing procedures. In contrast, the nuclear stainings revealed a mean leukocyte loss of only 5% for the nonlysed samples and of 12% for lysed samples. All investigated lysing procedures induced a large loss of leukocytes and progenitor cells, obviously due to cell membrane destruction as demonstrated for identical samples in the 1-PF and 2-PF modes by immunologic and nuclear staining methods.