CD4 and graft versus host disease: For all vaccines, we observed that the antibody level at M13 did not significantly differ according to age, sex, type of hematological malignancy, delay between transplantation and vaccination, type of transplant conditioning, GvHD at inclusion, or (except when mentioned below) blood levels of gammaglobulins, CD4 + T lymphocytes, or CD8 + T lymphocytes at inclusion.