Allogeneic hematopoietic cell transplantation (HCT) offers the potential to cure hematologic malignancies. Absent an HLA matched donor, HLA mismatched unrelated donors may be used although risks of graft-versus-host disease (GvHD) and treatment related mortality (TRM) are higher. Identification and avoidance of amino acid substitutions and position types (AASPT) conferring higher risks of TRM and GvHD would potentially improve the success of transplantation from single HLA mismatched unrelated donors. Using random forest and logistic regression analyses, we identified 19 AASPT associated with greater risks for at least one adverse transplant outcome: grade III-IV acute GvHD, TRM, lower disease free survival or worse overall survival relative to HLA matched unrelated donors and to other AASPT. When tested in an independent validation cohort of 3,530 patients, none of the AASPT from the training set were validated as high-risk, however. Review of the literature shows that failure to validate original observations is the rule and not the exception in immunobiology and emphasizes the importance of independent validation prior to clinical application. Our current data do not support avoiding any specific class I AASPT for unrelated donors. Additional studies should be performed to fully understand the role of AASPT in HCT outcomes.

The nucleotide sequences of the entire protein coding regions of the thymidine kinase (TK) genes of macropodid herpesvirus type 1 (MaHV-1) and type 2 (MaHV-2) were determined. The coding region of the MaHV-1 TK gene was 984 bp long and was predicted to encode a polypeptide of 327 amino acids. The coding region of the MaHV-2 TK gene was 1020 bp long and encoded a polypeptide of 340 amino acids. Comparisons of their deduced amino acid sequences with those of fifteen other herpesviruses revealed close homology to those of other alphaherpesviruses, particularly to human herpesvirus type 1 (HHV-1) and type 2 (HHV-2).