Case Of Chimerism Research Articles

Identifi cation of ABO, RH and KEL blood group antigens with serology and genotyping methods

Introduction. Blood transfusion is a strong practice in traumatology, internal medicine, haematology, obstetrics and transplantation, which demands safety of haemotransfusion with estimating the red blood cell group antigens in donor and recipient blood. Routine immunotyping techniques usually provide for an antigen identification to weak subgroups, albeit with certain inherent limitations of serology tests that can be overcome in a genotyping approach.Aim — performance assessment of serology and genotyping methods in the ABO, RH and KEL blood group identification.Materials and methods. A total of 55,489 donor and 1,898 patient blood samples have been analysed. Ambiguous cases of chimerism, panagglutination and inconsistent results were tackled with genotyping. Serology tests were performed with gel cards. Whole blood DNA extraction was performed with Qiagen chemistry. Allele-specific PCR was used for the erythrocyte ABO, RH and KEL antigen genotyping with BAG Diagnostics commercial kits and a 2% agarose gel product detection. Sanger sequencing was used to complement genotyping.Results. A combined use of serology tests and genotyping allowed a successful erythrocyte antigen-based blood group and Rh-status assignment in 26 donors and patients with ambiguous blood typing.Conclusion. Genotyping coupled with serologic methods can be advised in a hampered blood group identification.

Y STR profiling in blood, buccal swab & hair follicles in sex mismatch HSCT: A case of chimerism

Identification of an individual from sample of choice like blood, buccal swab and hair follicles became challenging for forensic examiners after HSCT. HSCT is well accepted treatment for malignant and nonmalignant diseases. Introduction of Y-STR profiling established great precision and higher discriminatory power in forensic case work/identification. Committing a crime by a person after undergone HSCT is a rare situation but not impossible. Keeping this in mind we investigated a 14 year old female patient suffering from Aplastic anemia who received an allo-H SCT from HLA identical brother, admitted in AIIMS, New Delhi, to find out the best sample for forensic identification. Samples were collected from patient and donor as pre transplant and post transplant samples of recipient after a fixed interval of time. DNA profile was generated using Y STR kit. The result determined the phenomenon of chimerism and its impact on Y STR. Hair follicles were found the most suitable samples as these samples did not demonstrate any donor derived DNA up to 90 days.

P048 NGS performance on a transplanted liver biopsy sample: A case study

A male pediatric patient was diagnosed with biliary atresia and was transplanted with liver from a deceased donor. The surgery went well, but years later the patient developed antibodies to Cw12, DR14, DQ7 and DQA1∗04:01 and various DP alleles. The need for high resolution typing to determine the identity of de novo DSA and the lack of any remaining pre-transplant sample on a deceased donor led to the use of NGS to determine chimeric typing. Genomic DNA was extracted from a post-transplant liver biopsy from this patient by using Gentra Puregene Tissue kit. We used the Immucor NGS FLEX HLA typing system for amplification and sequencing of HLA genes HLA -A, B, C, DRB1, DRB3/4/5, DQA1, DQB1, DPA1, and DPB1 followed by analysis with MIA FORA software. The NGS methodology is a clonal sequencing approach which solves the phase ambiguity problems inherent with Sanger-based sequencing when alleles are amplified and sequenced together. The genomic DNA extracted from the transplanted liver biopsy is chimeric, with residual recipient DNA at very low but detectable levels. The presence of chimeric reads is the result of co-amplification of both donor and recipient HLA genes. The majority of sequencing reads with zero mismatches belonged to the donor and were concordant with the deceased donor HLA type provided by UNOS. Unclaimed sequencing reads appeared as grey background and derived from the recipient HLA type (previously obtained with pre-transplant samples). In this case and a few other chimeric cases examined in our laboratory, the MIA FORA NGS software detected the HLA type of donor as the called alleles and showed some unclaimed reads that did not align to the donor type but rather to the HLA type of recipient. We note that if the donor and recipient HLA genes are perfectly matched in one or both alleles then they are indistinguishable. The clonal sequencing nature of the NGS reveals PCR primer specificity by identifying the sequences of all co-amplified genomic regions within the intended target region in the same biopsy sample. This case demonstrates the clinical utility of high resolution HLA typing by NGS technology in the clinical setting to de convolute a solid organ biopsy admixture i.e. the ability to do chimeric typing.

Tribute to dr louis keith: twin and physician extraordinaire/twin research reports: influences on asthma severity; chimerism revisited; DNA strand break repair/media reports: twins born apart; elevated twin frequencies; celebrity father of twins; conjoined twinning.

The International Society for Twin Studies has lost a valued friend and colleague. Dr Louis Keith, Emeritus Professor of Obstetrics and Gynecology at Northwestern University, in Chicago, passed away on Sunday, July 6, 2014. His life and work with twins will be acknowledged at the November 2014 International Twin Congress in Budapest, Hungary. Next, twin research reports on the severity of asthma symptoms, a case of chimerism, and factors affecting DNA breakage and repair mechanisms are reviewed. Media reports cover twins born apart, elevated twin frequencies, a celebrity father of twins, and a family's decision to keep conjoined twins together.

Karyotype analysis of domestic dogs (Canis familiaris L.)

Karyotypes of sheltie and poodle breeds population of the city of Moscow are given. Describes the data on chromosomal abnormalities that occur in dogs. There are cases of chimerism and mosaicism for sex chromosomes. It is shown that in the case of chimerism on the sex chromosomes of male, reproductive function was normal.

Mechanism of origin in two cases of chimerism

Chimerism is defined as the presence in a subject of more than one stable and genetically distinct cell line; cases reported so far include both patients with ambiguous genitalia and healthy subjects. The biological mechanisms, which may give origin to chimeras, are complex, and can be understood by analyzing DNA samples of the patients and their parents using molecular techniques. The objective of this study is to identify the mechanism of origin for the 2 cases we report. The first patient is a phenotipically normal girl with normal (external and internal) genitalia; the second patient had ambiguous genitalia and underwent surgery. DNA was purified from blood samples and, limited to Patient 1, from a sample of biliary cyst. Short tandem repeat polymorphisms were analyzed in order to identify the relative parental contribution to the patients. Molecular analyses carried out on the first patient are not fully informative because of two possible explanations (i.e. parthenogenetic and andrognetic chimera), while in the second case the presence of four alleles at some markers allowed us to identify a tetragametic chimera originnated from the fusion of two distinct embryos. Studies carried on one single tissue may not always be conclusive as they do not allow the precise identification of the mechanism of origin. In these cases, studies on more tissues are strongly suggested.

28-OR: Unusual Case of Chimerism After Bone Marrow Transplantation

28-OR: Unusual Case of Chimerism After Bone Marrow Transplantation

A case of chimerism in a paternity study

The STR profile of a phenotipically normal woman typed from blood tissue in a paternity case, revealed more than two alleles in some autosomal loci, result that was interpreted as a chimera due to the coexistence of two genetically distinct cell populations. The aim of this work was to solve the paternity study, elucidate the origin of the chimera, and evaluate its consequence in forensic genetics. Buccal epithelium and hair root tissues showed a single autosomal STR profile. Instead, blood tissue exhibited chimerism in seven out of the twenty autosomal loci tested. The paternity analysis was resolved comparing the unique STR pattern typed from buccal and hair root cells. The detection in blood tissue of the Y allele in Amelogenin locus and typing of a Y-chromosome haplotype confirmed the presence of male cells in the chimeric woman. The deduced male profile cannot be excluded as a son of the alleged father. Based on the results we interpret that the woman subject of the study is a partial or a whole-body chimera. Chimerism may be a pitfall in forensic investigations like paternity testing and crime cases.

Prenatal diagnosis and normal outcome of a 46,XX/46,XY chimera: A Case Report

The phenotypic spectrum of 46,XX/46,XY chimeric patients is variable. It ranges from normal male or female genitalia to different degrees of ambiguous genitalia. Chimerism results from the amalgamation of two different zygotes in a single embryo, whereas mosaicism results from a mitotic error in a single zygote. Several other mechanisms resulting in a chimera have been discussed in the literature. Here, we report on a new case of chimerism (46,XX/46,XY) diagnosed at 17 weeks' gestation on amniocentesis performed because of advanced maternal age. Ultrasound examination revealed normal female external genitalia, and a healthy baby girl was delivered at term. We used polymorphic markers spanning the X chromosome and several autosomes in order to identify the genetic mechanism involved. Mosaicism was excluded because of the presence of 3 alleles at 11 autosomal and 4 X chromosome loci. On autosomes, the origin of this third allele was maternal for two pericentromeric markers (located on 2p11.2 band and 8p11.2 band), paternal for six markers and paternal or maternal for the other three markers. On the X chromosome, the origin of the third allele was maternal for all four markers. Thus, two different paternal and maternal haploid sets were observed. These results are compatible with a tetragametic chimera.

Chimerism After Solid Organ Transplantation

To the Editor: In a recent volume of the American Journal of Transplantation, Koopmans and colleagues (1Koopmans M Hovinga ICLK Baelde HJ et al.Chimerism in kidneys, livers and hearts of normal women: Implications for transplantation studies.Am J Transplant. 2005; 5: 1495-1502Abstract Full Text Full Text PDF PubMed Scopus (59) Google Scholar) describe a phenomenon coined “background chimerism” in organs from females who had born sons or received blood transfusions. The presented data further confirmed the hypothesis that besides the setting of organ transplantation in situ chimerism can be found in different solid organs. The authors carefully employed a well‐established technique of Y‐chromosome in situ hybridization to detect male‐derived cells in female organs and confirmed their findings by a Y‐specific qualitative PCR. In the majority of the analyzed specimens, only few Y‐chromosome‐positive cells were detected, comprising probably less than one cell in thousand. Only two women had up to 10% of Y‐chromosome‐positive cells in their kidneys. Whereas all studies applying Y‐chromosome in situ hybridization to demonstrate chimerism of transplanted organs are challenged, by this study we have applied a different approach. Using a highly sensitive and specific short tandem PCR (DNA fingerprinting), more than 100 transplant specimens have been investigated. Up to now, not more than two different genotypes were observed in transplanted organs with this technique (2Mengel M Jonigk D Marwedel M et al.Tubular chimerism occurs regularly in renal allografts and is not correlated to outcome.J Am Soc Nephrol. 2004; 15: 978-986Crossref PubMed Scopus (39) Google Scholar, 3Kleeberger W Rothamel T Glockner S Flemming P Lehmann U Kreipe H High frequency of epithelial chimerism in liver transplants demonstrated by microdissection and STR‐analysis.Hepatology. 2002; 35: 110-116Crossref PubMed Scopus (110) Google Scholar, 4Kleeberger W Versmold A Rothamel T et al.Increased chimerism of bronchial and alveolar epithelium in human lung allografts undergoing chronic injury.Am J Pathol. 2003; 162: 1487-1494Abstract Full Text Full Text PDF PubMed Scopus (165) Google Scholar, 5Mengel M Jonigk D Wilkens L et al.Chimerism of metanephric adenoma but not of carcinoma in kidney transplants.Am J Pathol. 2004; 165: 2079-2085Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar). If background chimerism is quantitatively playing a significant role, at least three different DNA fingerprints (donor, recipient and background) should be detectable. Furthermore, chimeric, i.e. recipient‐derived, cells were found in tumors which developed in an allograft definitely after the organ was transplanted. This shows that chimerism beyond any doubt occurs de novo in the setting of organ transplantation (5Mengel M Jonigk D Wilkens L et al.Chimerism of metanephric adenoma but not of carcinoma in kidney transplants.Am J Pathol. 2004; 165: 2079-2085Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar). Dilution experiments to determine the sensitivity and specificity of the STR‐PCR method demonstrated that a minimum of five cells of one individual (e.g. recipient) can be specifically detected against a background of >100 cells of another individual (e.g. donor). Hence, the STR approach is limited by a threshold of 3–5% what might explain why background chimerism has escaped from detection in this assay. Consequently, when background chimerism is suggested as a possible explanation for the phenomenon of intra‐organ mixed chimerism, it is mandatory to consider quantitative aspects. In this regard, it is evident that background chimerism in most instances is not sufficient to cause an admixture of nondonor alleles exceeding 5% and more. Furthermore, in all chimeric cases that were detected by STR analysis after solid organ transplantation, a recipient derivation of nondonor cells could be proved by allele‐specific identification. The evidence for background chimerism presented by Koopmanns and coworkers does not rule out that a significant incorporation of possibly adult stem‐cell‐derived parenchymal cells of recipient origin takes place in most instances being causative for chimerism of transplanted organs. However, obviously the amount of chimeric cells, independently of its source (recipient‐derived or background chimerism), is low and in transplanted kidneys it is too small to provide a significant source for tubular epithelial cell regeneration (2Mengel M Jonigk D Marwedel M et al.Tubular chimerism occurs regularly in renal allografts and is not correlated to outcome.J Am Soc Nephrol. 2004; 15: 978-986Crossref PubMed Scopus (39) Google Scholar). Therefore, the future challenge will lie in the elucidation of the molecular mechanisms involved in the migration, homing and transdifferentiation of circulating progenitor cells into a damaged organ. This will be the prerequisite to evolve any therapeutical potential of chimerism, independent of its source.

DIZYGOTIC TWINS WITH XX-XY CHIMERISM.

CHIMERAS, dizygotic twins who have two populations of blood cells, arise when haematopoietic cells are exchanged or shared at some time in early embryonic life. The first case of chimerism in man was reported by Dunsford et al.1.