Dangers resulting from DNA profiling of biological materials derived from patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT) with regard to forensic genetic analysis.

The study documents the risk that comes with DNA analysis of materials derived from patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in forensic genetics. DNA chimerism was studied in 30 patients after allo-HSCT, based on techniques applied in contemporary forensic genetics, i.e. real-time PCR and multiplex PCR-STR with the use of autosomal DNA as well as Y-DNA markers. The results revealed that the DNA profile of the recipient's blood was identical with the donor's in the majority of cases. Therefore, blood analysis can lead to false conclusions in personal identification as well as kinship analysis. An investigation of buccal swabs revealed a mixture of DNA in the majority of recipients. Consequently, personal identification on the basis of stain analysis of the same origin may be impossible. The safest (but not ideal) material turned out to be the hair root. Its analysis based on autosomal DNA revealed 100% of the recipient's profile. However, an analysis based on Y-chromosome markers performed in female allo-HSCT recipients with male donors demonstrated the presence of donor DNA in hair cells - similarly to the blood and buccal swabs. In the light of potential risks arising from DNA profiling of biological materials derived from persons after allotransplantation in judicial aspects, certain procedures were proposed to eliminate such dangers. The basic procedures include abandoning the approach based exclusively on blood collection, both for kinship analysis and personal identification; asking persons who are to be tested about their history of allo-HSCT before sample collection and profile entry in the DNA database, and verification of DNA profiling based on hair follicles in uncertain cases.

Correlation between the kinetics of CD3+ chimerism and the incidence of graft-versus-host disease in patients undergoing allogeneic hematopoietic stem cell transplantation.

INTRODUCTION: Graft-versus-host disease (GvHD) remains a significant complication after allogeneic hematopoietic stem cell transplantation (HSCT). Early diagnosis and treatment may improve patient outcomes. A prospective study to investigate the relationship between chimerism kinetics and the development of acute or chronic GvHD was carried out. Split chimerism in association with the onset of GvHD was also analyzed. METHODS: Thirty-three patients with hematologic diseases treated with allogeneic HSCT were analyzed. They were conditioned with myeloablative or reduced intensity regimens and grafted with peripheral blood (PB) or bone marrow stem cells. GvHD prophylaxis consisted of cyclosporine and methotrexate. Chimerism evaluation was performed on PB mononuclear cells and purified cell subsets consisting of separated CD3(+) T cells, monocytes (CD14(+)), and granulocytes (CD15(+)). Chimerism analysis was performed at 30, 60, 120, and a median of 200 days after HSCT. RESULTS: Acute GvHD was diagnosed in 19 patients and chronic GvHD in 16. On day 30, no relation was found between the level of donor chimerism and aGvHD. Upon univariate analysis, decreasing mixed chimerism among CD3(+) and infused CD34(+) cell numbers was significantly correlated with acute GvHD development, while the PB stem cell source, reduced-intensity conditioning regimen, and female donor sex were associated with an increased risk of chronic GvHD. In multivariate analysis, the risk of acute GvHD correlated only with the CD34(+) cell dose, while the risk of extensive chronic GvHD was associated with high CD3(+) donor chimerism on day 30. Patients with versus without split chimerism (T cell vs myeloid lines) did not differ statistically in their incidence of acute GvHD or chronic GvHD. CONCLUSION: Our results supported the belief that chimerism kinetics or longitudinal chimerism evaluation is of greater significance than isolated absolute values of the percentage of chimerism at a single point after HSCT. The observations suggest that longitudinal monitoring of chimerism in CD3(+) T-cell subsets is an acceptable method to predict the development of GvHD among patients undergoing HSCT.

Donor-derived DNA in hair follicles of recipients after allogeneic hematopoietic stem cell transplantation.

The hair follicles of recipients of allogeneic hematopoietic SCT (HSCT) constitute the tissue with the greatest need for regeneration after high-dose chemotherapy. Previous studies have shown a lack of donor-derived DNA in the hair follicles of recipients. Therefore, we carried out a study to determine whether male donor-derived genetic material can be found in female recipients' hair follicles after HSCT. Fluorescent-based PCR with analyses of Y-chromosome STR (Y-STR) and RQ-PCR with the sex-determining region Y (SRY) were used independently to evaluate chimerism status. Our results proved the existence of donor-derived stem DNA in the recipients' hair follicle cells. This report undermines the validity of data indicating that hair follicle cells maintain 100% of recipient origin.