Protective Effects of Cytomegalovirus DNA Copies ≧1000/mL for AML Patients in Complete Remission After Single Cord Blood Transplantation.

INTRODUCTION: Current consensus recommends a protective effect of cytomegalovirus (CMV) infection on relapse after peripheral blood or bone marrow hematopoietic stem cell transplantation. However, in cord blood transplantation (CBT), studies of CMV infection, especially CMV viral load, on relapse are limited. PATIENTS AND METHODS: Wct e retrospectively analyzed the effect of CMV infection on 3-year outcomes in 249 AML patients according to CMV DNA load (DNA copies <1000/mL and DNA copies ≧1000/mL) within 100 days after CBT. Furthermore, eight-colour flow cytometry was used to detect peripheral blood lymphocyte subsets in 38 patients who received CBT in the last year, and 10 healthy volunteers were included as controls. RESULTS: The results showed that CMV DNA load did not affect the cumulative incidence of relapse in the whole study population. However, in patients with complete remission status before transplantation, the high CMV DNA load group showed a significantly reduction of relapse than the low CMV DNA load group (3.9% vs 14.6%, p=0.012, respectively), which was confirmed by multivariate analysis (HR 0.23; 95% CI, 0.07-0.73, p = 0.012). Surprisingly, high or low CMV DNA load did not significantly affect non-relapse mortality or overall survival (18.0% vs 17.0%, p=0.777 and 79.0% vs 74.6%, p=0.781, respectively). Besides, the absolute number of CD8+ T cells were increased in the high CMV DNA load group compared with the low DNA load group 1 month after CBT (0.20×109/L vs 0.10×109/L, p=0.021, respectively). CONCLUSION: DNA copies ≧1000/mL for AML patients in complete remission was associated with a lower incidence of relapse after CBT, which might partly result from the expansion of CMV-related CD8+ T cells.

[Effects of High Cytomegalovirus DNA Load on Immune Reconstitution and Clinical Outcomes after Single Unrelated Cord Blood Transplantation].

OBJECTIVE: To investigate the effects of cytomegalovirus (CMV) DNA load on immune reconstitution and clinical outcomes of patients after unrelated cord blood transplantation (UCBT). METHODS: Eight-color flow cytometry was used to dynamically monitor the changes of peripheral blood lymphocyte subsets of 41 patients at one year after UCBT, and 10 healthy volunteers were enroled as controls. Patients were divided into two groups according to the DNA load of CMV (DNA copies <1000/ml and DNA copies ≥1000/ml). Comparative analyse of the effect of CMV DNA load on lymphocyte subsets and transplantation outcomes were carried out after transplantation. RESULTS: The high CMV DNA load group showed a faster and expanded T cell reconstitution, and the differences between the two groups were statistically significant at one and nine months after transplantation (0.38×109 /L vs 0.25×109 /L, P=0.015 and 2.53×109 /L vs 1.36×109 /L, P=0.006, respectively). Further analysis of T cell subsets suggested that CD8+ T cells presented a higher and faster recovery in the high DNA load group, and the differences between the two groups were statistically significant at one and nine months after transplantation (0.20×109 /L vs 0.10×109 /L, P=0.038 and 1.62×109 /L vs 0.68×109 /L, P=0.003, respectively). In addition, there were no significant differences in levels of B cells, regulatory B cells and NK cells between the two groups. Outcomes after one- and a-half-year transplantation showed that there were no significant difference in relapse, non-relapse mortality and overall survival between the high and the low DNA load groups (7.7% vs 7.5%) (P=0.900) (15.4% vs 21.4%) (P=0.686) and (76.9% vs 78.6%) (P=0.889) respectively. CONCLUSION: The high CMV DNA load induces a faster and long-lasting expansion of T cells, mainly as the expansion of CD8+ T cells after UCBT. Besides, under the current pre-emptive treatment of CMV, the high CMV DNA load does not affect the early survival of patients with acute myeloid leukemia after UCBT.

[Stem radius growth of Picea meyeri and Larix principis-rupprechtii nearby the tree-line of Luya Mountain].

The stem radius growth (SRG) of six samples of Picea meyeri and five samples of Larix principis-rupprechtii nearby the tree-line of Luya Mountain in North China was measured by the dendrometer in the summer phase from July 15 to August 7 and the autumn phase from September 5 to October 9, 2007, with the environmental factors measured simultaneously. In the summer phase, there was no significant difference in the sensitivity of SRG to the environmental factors fluctuation between the two species; but in the relatively cold and dry autumn phase, the SRG of P. meyeri was more sensitive to the fluctuation of environmental factors. The accumulated SRG of the two species increased linearly in summer phase, but decreased first and kept stable then in autumn phase, with the growth increment of P. meyeri fluctuated more than that of L. principis-rupprechtii. The SRG of the two species correlated positively with hydrological factors and negatively with thermal factors, and the SRG of P. meyeri was strongly affected by air humidity and temperature, while that of L. principis-rupprechtii was mainly affected by soil moisture.