Variables not listed in Table 4—including alternative conditioning regimens, hematopoietic recovery status, GVHD prophylaxis, lymphocyte subpopulation counts, absolute lymphocyte counts, and serial measurements of immunoglobulins (IgM, IgA, IgG), complements (C3, C4), and blood LDH at reactivation—showed no significant association with PTLD in univariate analysis. This evidence concerns the gene CD40LG and post-transplant lymphoproliferative disease.