Allogenic BMT in children: differential lymphocyte subset reconstitution according to the occurrence of acute GVHD.

To acquire some biological markers associated with the occurrence of acute graft-versus-host disease (aGVHD) after allogeneic bone marrow transplant (BMT) in children, we have studied the lymphocyte subset reconstitution and the percentage of peripheral blood mononuclear cells bearing HLA-DR and HLA-DQ class II molecules. This study included 37 allogeneic BMT: either with (n = 17) or without (n = 20) aGVHD. Within 2 months after transplantation, we observed that patients with aGVHD had a unique mononuclear cell profile characterized by (i) a significant increase in the percentages of CD8bright+CD28- T cells (P = 0.05) and CD3+ T cells (P = 0.001), (ii) an important decrease in the percentage of CD56+ cells (P = 0.0001), and (iii) a decrease in the percentages of HLA-DQ+ and HLA-DR+ monocytes (P = 0.001) and HLA-DQ+ T lymphocytes (P = 0.0001), in comparison with patients without aGVHD. Moreover, statistical studies indicate that there was a positive correlation between CD8bright+CD28- and CD3+ T cells, whereas CD3+ T cells were negatively correlated to CD56+ cells. We did not find any statistical correlation between the percentages of HLA-DQ+ or HLA-DR+ cells and the percentages of these lymphocyte subsets. Therefore, in this study done in children, we suggest that patients with (i) less than 20% of DQ+ monocytes, (ii) less than 25% of CD56+ lymphocytes, and (iii) an enhanced percentage of CD8bright+CD28- T cells are strongly associated with aGVHD. Unfortunately, these biological markers of a GVHD may not precede the clinical manifestations of the disease.