TRDV1 and graft versus host disease: Simple effect analysis of binary logistic regression showed that the invariable clonality of TRDV1 gene repertoire after G-CSF mobilization was associated with low incidence of GVHD (r = 0.616, P = 0.004), and the alteration of other TRDV or TRGV subfamilies had no significant association with GVHD.