Genetic DNA profile in urine and hair follicles from patients who have undergone allogeneic hematopoietic stem cell transplantation

Implications of Vascularized Composite Allotransplantation in Plastic Surgery on Legal Medicine

Background: When a patient receives a transplant—be it classically an organ or bone marrow or, more recently, composite allotransplantations of the limb or face—it can result in artificial chimerism. Such chimerism raises considerations in forensic medicine, a field that relies on the collection and identification of biological samples from crime scenes. Beyond this chimerism, composite allotransplantations create further challenges. Methods: After screening the literature and press releases, we provide a brief history and summary of some of the technologies used in forensic identification, explaining their advantages and pitfalls in the light of transplantation and cautioning against misidentifying those who evade justice by taking advantage of such considerations. Results: With face transplantation, patients can receive the skin, hair, salivary glands, teeth, and oral and nasal mucosa of their donors, components which hold great importance in forensic science. Modern technologies such as computer-assisted facial recognition, although gradually becoming more accurate over time, also face new challenges in this post-transplantation era as facial recognition software can be misled by surgical alterations of the face or face transplantation. With limb transplantation, there is an impact on fingerprint identification. Conclusions: Both surgical transplantation techniques and forensic technologies have seen incomprehensibly great innovation in the past century. Given the growing rate of successful composite transplantation in the USA and worldwide, it is now important for law enforcement agents to be aware of the new possibility of having two sets of genetic material, hair, saliva, fingerprints, or even facial recognition data for the same individual.

Significance of Stem Cells in Forensic Dentistry

In forensic point of view and for genetic study, biological samples collected at a crime scene serve as a significant tool, in order to resolve crimes by identifying the person. In some scenarios, individual identification gets masked by chimera persons, where the chimera person cells will have different DNA. The use of biological traces which are recorded by a person’s touch while handling items raises the chance of forensic study system. Therefore, DNA profiling can be obtained from items that were touched, which inturn becomes an useful means for forensic mode of investigation. Chimerism investigations are recognized processes to examine the condition of Hematopoietic Stem Cell Transplantation (HSCT) to analyze peripheral blood and recipient’s bone marrow samples for non-malignant and malignant hematologic diseases. In adults, ectomesenchymal cells identified in oral and maxillofacial tissues are promising for future dental stem cell therapies, because the oral tissues area rich source for stem cells. Dental stem cells have various expressive profiles and exist in specific niches. Apart from these applications, this review article highlights dental stem cells significances in forensic dental investigations.

The impact of chimerism on DNA-based human identification from skin surface cells of post-allogenic hematopoietic stem cell transplantation (HCST) patients

The use of biological traces recovered from touched or handled items increased with the advance of the forensic analysis system. Thus, DNA profiles obtained from touch DNA became a useful tool in forensic investigation. However, a chimeric person with more than one chromosomal population can be challenging for a forensic analyst. We investigated the genetic profile in blood, buccal swab, and skin swabs from twenty-four recipients aged 21-63 years who underwent a matched sibling allogeneic hematopoietic stem cell transplantation with no sign of skin graft versus host disease. Autosomal short tandem repeats genotyping was performed to evaluate chimerism status at 15 loci along with gender marker Amelogenin. According to our results, donor chimerism was detected in all recipient's blood samples, while in buccal swabs, five recipients showed no presence of donor-derived cells in their genotype. Epithelial cells swabbed from hand fingertips were not devoid of donor-derived cells since all recipients showed high chimerism (39.69%-96.66%) in their genotypes. A significant change in chimerism was seen among various types of biological samples (p<0.05). No correlations were observed between chimerism and recipient age, gender, or time after transplant (p> 0.05). The loci D21S11, D8S1179, and FGA were the most informative, whereas D13S317, Vwa, and TOPX were the least informative STR markers. We concluded that touch DNA from a person who has undergone a successful allogeneic HSCTs should not be considered as reliable evidence for human identifications. Therefore, necessary precautions must be taken to avoid false identification and miscarriage of justice.

Isolation and Characterization of a Fetal-Maternal Microchimeric Stem Cell Population in Maternal Hair Follicles Long after Parturition

Fetal-maternal microchimerism describes the acquisition of fetal stem cells (FSC) by the mother during pregnancy and their long-term persistence after parturition. FSC may engraft in a variety of maternal tissues especially if there is organ/tissue injury, but their role and mechanism of persistence still remains elusive. Clinical applications due to their pluripotency, immunomodulatory effects and accessibility make them good candidates for ex-vivo manipulation and autologous therapies. The hair follicles contain a distinctive niche for pluripotent stem cells (PSC). To date, there is no published evidence of fetal microchimerism in the hair follicle. In our study, follicular unit extraction (FUE) technique allowed easy stem cell cultures to be obtained while simple hair follicle removal by pull-out technique failed to generate stem cells in culture. We identified microchimeric fetal stem cells within the primitive population of maternal stem cells isolated from the hair follicles with typical mesenchymal phenotype, expression of PSC genes and differentiation potential towards osteocytes, adypocites and chondrocytes. This is the first study to isolate fetal microchimeric stem cells in adult human hair long after parturition. We presume a sanctuary partition mechanism with PSC of the mother deposited during early embryogenesis could explain their long-term persistence.