title: X chromosome methylation-based chimerism assay for sex-mismatched hematopoietic stem cell transplantation.
abstract: Analysis of hematopoietic chimerism is important for monitoring engraftment, graft failure, and disease recurrence. Although several techniques are now available, their sensitivity is unsatisfactory. In sex-mismatched stem cell transplantation (SCT) with a female donor, Y chromosome-specific sequences have proven the most sensitive marker. However, in the case of a male donor, no such reliable marker has been available to date. In this study, we report a novel method we developed to detect microchimerism in female recipients who receive SCT from male donors. The X-linked human androgen receptor gene (HUMARA) contains a highly polymorphic CAG trinucleotide repeat. Near this polymorphic site are methyl-sensitive HpaII restriction enzyme sites. After HpaII digestion, unmethylated male HUMARA sequences are completely digested, while methylated female ones remain intact among the male origin cells. This allows a highly efficient detection of a small number of female cells. Combined with the nested PCR technique, the X chromosome methylation-based chimerism assay could attain a 10(-4) level of sensitivity, which is 1000-fold higher than that of conventional assays. The applicability of the method was confirmed in two transplant cases. This highly sensitive method can also be applied to detect minimal residual disease or microchimerism in conditions other than hematopoietic SCT.
authors.affiliation: Third Department of Internal Medicine, Gunma University School of Medicine, Gunma, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yamane
authors.forename: M
authors.initials: M
authors.lastname: Karasawa
authors.forename: T
authors.initials: T
authors.lastname: Maehara
authors.forename: N
authors.initials: N
authors.lastname: Tsukamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Nojima
mesh_terms: D000328:Adult; D001782:Blood Donors; D019175:DNA Methylation; D005260:Female; D006084:Graft Rejection / Q000175:diagnosis; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D008297:Male; D008722:Methods; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000175:diagnosis; D016133:Polymerase Chain Reaction; D011944:Receptors, Androgen / Q000235:genetics; D012680:Sensitivity and Specificity; D018183:Transplantation Chimera / Q000235:genetics*; D014184:Transplantation, Homologous; D014960:X Chromosome / Q000235:genetics*
chemical_list: C410798:AR protein, human; D011944:Receptors, Androgen