: AbstractObjective: To investigate the sample selection, result correction and clinical application value of multi nucleotide polymorphism chimerism detection method based on Next-generation sequencing. METHODS: The chimerism samples from November 2018 to June 2020 were collected, and Pearson correlation coefficient (r) was used to analyze the consistency of bone marrow and peripheral blood results detected by MNPseq; according to the different information integrity before transplantation, the calibration model was constructed to analyze the correction value of the micro chimerism results in each model; the clinical results were retrospectively analyzed to verify the reliability and practicability of chimerism results correction and the clinical value of MNPseq method. RESULTS: The results of bone marrow and peripheral blood chimerism detected by MNPseq method were consistent with each other and showed significant correlation (r=0.985, P<0.01). The three groups of calibration models were constructed according to different pre-transplant information. For the no donor and pre-transplant patients information group, the correction value was 1%; while for the group with pre-transplant patients and without donor information, 0.61% of the chimerism rate and 13 heterotopic points were used as the correction value; 0.26% of the chimerism rate and 21.57% of the heterotopic points were used as the correction value for the group with pre-transplantation patients and donor information. After correction, the number of the patients with incomplete chimerism decreased from 276 (74.19%) to 141 (37.91%) (P<0.01). Among 18 (18/141, 12.77%) patients with incomplete chimerism, the results of MNPseq in the patients were 25-39 days earlier than those in STR and flow MRD, and the result showed statistical significance. CONCLUSION MNPseq method can be used to monitor chimerism with peripheral blood instead of bone marrow samples, and the results can be corrected to detect the changes of graft status in vivo in a more timely manner.
Chimerism ; Hematopoietic Stem Cell Transplantation ; Humans ; Nucleotides ; Reproducibility of Results ; Retrospective Studies ; Transplantation Chimera/genetics* ; Transplantation, Homologous

No abstract available.
Adult ; Bone Marrow/*pathology ; Fatal Outcome ; Graft vs Host Disease/etiology ; High-Throughput Nucleotide Sequencing ; Humans ; Liver Cirrhosis/pathology/*therapy ; *Liver Transplantation/adverse effects ; Microsatellite Repeats ; Middle Aged ; Polymerase Chain Reaction ; *Polymorphism, Single Nucleotide ; Transplantation Chimera/*genetics

The microchimerism is a status of the microcell or DNA of an individual in another one with genetic differences. Taking an overall view about the discovery and research of the microchimerism, it was found that although the study of the microchimerism emphasizes the formation, origin, distribution, type, relationship to disease and several other aspects, the objects of the study are always the microchimerism that obtained naturally. As it is known to all, the microchimerism can also be produced in some clinical treatment, such as in the transplant and transfusion, but compared with the microchimerism gained naturally, obviously, the study for the iatrogenic microchimerism formed in the treatment is not elaborate enough. The curative effect of micro transplantation, a new technique for leukemia treatment, is obvious, but its mechanism is unclear, whether that is related to microchimerism still needs further research. This review summarizes the study history and perspective of the microchimerism so as to provide some ideas for studying the action mechanism of microchimerism in micro transplantation.
Chimerism ; DNA ; genetics ; Humans ; Transplantation Chimera

This study was aimed to establish a model for detecting the donor chimerism rate following the multi-donor hematopoietic stem cell transplantations, and simplify its calculation method. Patients with hematologic disease receiving allogeneic hematopoietic stem cell transplantation including single-donor and multi-donor were selected in this study and the donor cell chimerism rates were detected, using STR-PCR combined with capillary electrophoresis. The results indicated that the peaks of the sister alleles coming from the same individual were confirmed to have the approximate areas and can be replaced each other in the situation of mixed chimerism. In the calculation model, the value between reference chimerism and approximate chimerism have no significant difference using the hypothetical peak areas, and the result was confirmed to be accepted basing on typical measurement error between sister alleles (5% - 20%). It is concluded that the areas of share peaks can be replaced by non-share peaks and this conclusion can be used to calculate the double-donor CHM (DD-CHM)(%). Compared to the D alleles, R alleles show more strategic importance because it can lead to more accurate result and allowed simplifying the arithmetic calculations for DD-CHM(%).
Alleles ; Electrophoresis, Capillary ; Hematopoietic Stem Cell Transplantation ; Humans ; Polymerase Chain Reaction ; Postoperative Period ; Tissue Donors ; Transplantation Chimera ; genetics ; Transplantation, Homologous

BACKGROUNDChimerism analysis is an important tool for the surveillance of post-transplant engraftment. It offers the possibility of identifying impending graft rejection and recurrence of underlying malignant or non-malignant disease. Here we investigated the quantitative chimerism kinetics of 21 relapsed leukemia patients after allogeneic hematopoietic stem cell transplantation (HSCT).

METHODSA panel of 29 selected sequence polymorphism (SP) markers was screened by real-time polymerase chain reaction (RT-PCR) to obtain the informative marker for every leukemia patient. Quantitative chimerism analysis of bone marrow (BM) samples of 21 relapsed patients and 20 patients in stable remission was performed longitudinally. The chimerisms of BM and peripheral blood (PB) samples of 14 patients at relapse were compared.

RESULTSTwenty-one patients experienced leukemia relapse at a median of 135 days (range, 30 - 720 days) after transplantation. High recipient chimerism in BM was found in all patients at relapse, and increased recipient chimerism in BM samples was observed in 90% (19/21) of patients before relapse. With 0.5% recipient DNA as the cut-off, median time between the detection of increased recipient chimerism and relapse was 45 days (range, 0 - 120 days), with 76% of patients showing increased recipient chimerism at least 1 month prior to relapse. Median percentage of recipient DNA in 20 stable remission patients was 0.28%, 0.04%, 0.05%, 0.05%, 0.08%, and 0.05% at 1, 2, 3, 6, 9, and 12 months, respectively, after transplantation. This was concordant with other specific fusion transcripts and fluorescent in situ hybridization examination. The recipient chimerisms in BM were significantly higher than those in PB at relapse (P = 0.001).

CONCLUSIONSThis SP-based RT-PCR assay is a reliable method for chimerism analysis. Chimerism kinetics in BM can be used as a marker of impending leukemia relapse, especially when no other specific marker is available. Based on our findings, we recommend examining not only PB samples but also BM samples in HSCT patients.

Adolescent ; Adult ; Child ; Female ; Hematopoietic Stem Cell Transplantation ; adverse effects ; Humans ; Leukemia ; genetics ; therapy ; Male ; Middle Aged ; Reverse Transcriptase Polymerase Chain Reaction ; Transplantation Chimera ; genetics ; Transplantation, Homologous ; adverse effects ; Young Adult

BACKGROUNDAnalysis of changes in recipient and donor hematopoietic cell origin is extremely useful to monitor the effect of hematopoietic stem cell transplantation (HSCT) and sequential adoptive immunotherapy by donor lymphocyte infusions. We developed a sensitive, reliable and rapid real-time PCR method based on sequence polymorphism systems to quantitatively assess the hematopoietic chimerism after HSCT.

METHODSA panel of 29 selected sequence polymorphism (SP) markers was screened by real-time PCR in 101 HSCT patients with leukemia and other hematological diseases. The chimerism kinetics of bone marrow samples of 8 HSCT patients in remission and relapse situations were followed longitudinally.

RESULTSRecipient genotype discrimination was possible in 97.0% (98 of 101) with a mean number of 2.5 (1-7) informative markers per recipient/donor pair. Using serial dilutions of plasmids containing specific SP markers, the linear correlation (r) of 0.99, the slope between -3.2 and -3.7 and the sensitivity of 0.1% were proved reproducible. By this method, it was possible to very accurately detect autologous signals in the range from 0.1% to 30%. The accuracy of the method in the very important range of autologous signals below 5% was extraordinarily high (standard deviation <1.85%), which might significantly improve detection accuracy of changes in autologous signals early in the post-transplantation course of follow-up. The main advantage of the real-time PCR method over short tandem repeat PCR chimerism assays is the absence of PCR competition and plateau biases, with demonstrated greater sensitivity and linearity. Finally, we prospectively analyzed bone marrow samples of 8 patients who received allografts and presented the chimerism kinetics of remission and relapse situations that illustrated the sensitivity level and the promising clinical application of this method.

CONCLUSIONThis SP-based real-time PCR assay provides a rapid, sensitive, and accurate quantitative assessment of mixed chimerism that can be useful in predicting graft rejection and early relapse.

Adolescent ; Adult ; Child ; Female ; Genotype ; Hematopoietic Stem Cell Transplantation ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; genetics ; Real-Time Polymerase Chain Reaction ; methods ; Reproducibility of Results ; Transplantation Chimera ; genetics ; Young Adult

The aim of study was to explore the feasibility of quantitative chimerism analysis of regulatory T (Treg) cells using immune sorting coupling short tandem repeat (STR) method. 14 sets of artificial chimera samples were prepared by mixed lymphocytes according to different proportion. The CD4(+)CD25(+) Treg cells were harvested by negative and positive selection of immunomagnetic beads, then the STR polymorphisms of 16 loci in sorted Treg cells was analyzed. The results showed that the DNA amount extracted from sorted Treg cells was fit for STR detection. All STR alleles specific for recipient or donor could be detected and the quantitative results were consistent with theoretic values in over 10% recipient chimeras. But only partial recipient alleles could be detected and the quantitative results were different from theoretic values in less then 1% recipient chimeras. It is concluded that a quantitative chimerism analysis of Treg cell based on immune sorting is established. The sensitivity and accuracy for chimera detection are 1% to 10%, and this method can be used to monitoring hematopoietic chimerism following allogeneic hematopoietic stem cell transplantation.
Chimerism ; Hematopoietic Stem Cell Transplantation ; methods ; Humans ; Immunomagnetic Separation ; T-Lymphocyte Subsets ; immunology ; T-Lymphocytes, Regulatory ; immunology ; Transplantation Chimera ; genetics ; immunology

To evaluate the roles of 8 short tandem repeats (STR) loci as STR panel in quantitative analysis of chimerism following transplantation, the primers were synthesized and marked with different dyes for D3S3045, D4S2366, D4S2639, D5S818, D13S317, D18S1002, D20S481 and D22S689. The blood samples of 15 cases received allogeneic stem cell transplantation were collected before and after transplantation, then DNA was extracted and amplified with these primers, and was further analysed under ABI Genetic Analyser 3100 to select suitable informative STR locus. Donor/recipient dilution series were prepared to get standard curves in selected loci, the DNAs extracted at different days after transplantation were used to quantitatively analyze the chimerism in patients according to the values of peak area or peak height of fluorescent signals. The standard curves can be used to calculate the chimerism by plotting the respective R/D quotient value against the percentage of recipient DNA. The results indicated that the calculated chimerism was in concordance with the donor/recipient dilution. The STR panel succeeded in identifying at least one informative marker and quantitative monitoring the chimerism after HSCT in 15 donor-recipient pairs and a relapsed case was diagnosed. It is concluded that the STR panel and its detection method can accurately and quantitatively monitor the chimerism after allogeneic HSCT, which is more economical and flexible than using commercial kits.
DNA ; genetics ; DNA Primers ; Hematopoietic Stem Cell Transplantation ; Humans ; Microsatellite Repeats ; Transplantation Chimera ; genetics

OBJECTIVETo analyze the mechanisms of surrogate tolerogenesis induced by chimeric donors.

METHODSHematopoietic stem cells (HSCs) from human cord blood were transplanted into fetal rats via intrauterine injection and infused into the liver of the neonatal rats to establish chimeric rat models with human HSCs. Four weeks after birth, flow cytometry was performed to analyze the percentages of human CD45 (hCD45), CD55 (hCD55) and CD59 (hCD59)-positive cells in the peripheral blood cells of the chimeric rats. The distributions of hCD55- and hCD59-positive cells in different hCD45/SSC gating regions were observed. The resistance of the peripheral blood lymphocytes to complements-mediated cytolysis was assessed by complement-dependent cytotoxicity (CDC) test in the chimeric rats and compared with that in control rats. The correlation between CDC and the human complement-regulating proteins in the chimeric rats were analyzed statistically.

RESULTSOn hCD45/SSC gating, the percentages of hCD55- and hCD59-positive cells in hCD45-positives region were (53.69-/+18.23)% and (31.8-/+27.5)%, accounting for (2.0-/+1.32)% and (0.76-/+0.56)% of the total cell population, respectively, which were significantly lower than the cell percentages in the extensive region (t=2.71, P=0.043 and t=3.64, P=0.015). The cytolytic rate of PBLs incubated with normal human serum was (22.32-/+15.10)% in the chimeric rats, significantly lower than that in the non-chimeric rats [(60.7-/+22.65)%, t=4.16, P<0.001). In the chimeric rats, hCD55-positive cell percentage was inversely correlated in the peripheral blood karyocytes the cytolysis rate in CDC (r=-0.679, P=0.031), and positively correlated to hCD45-positive cell percentage (r=0.658, P=0.038).

CONCLUSIONThe hCD45-positives region is the cluster of chimeric human cells expressing human complement-regulating proteins. The peripheral blood lymphocytes from chimeric donor can resist the cytolysis mediated by human complement. The presence of allogenic CD55 and CD59 antigens in chimeric donors may be the basis of surrogate tolerogenesis for xenotransplantation.

Animals ; CD55 Antigens ; blood ; CD59 Antigens ; blood ; Complement System Proteins ; analysis ; Cord Blood Stem Cell Transplantation ; methods ; Female ; Humans ; Leukocyte Common Antigens ; blood ; Male ; Models, Animal ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Transplantation Chimera ; blood ; genetics ; immunology ; Transplantation Tolerance ; Transplantation, Heterologous

The purpose of this study was to analyze the STR loci expression after allergenic cord hematopoietic stem cell transplantation in patient with Ducennes muscular dystropy (DMD) patient. PCR-SSO was used to identify the HLA antigens and alleles, STR-PCR was used to detect the chimera status. Quantity analysis of donor chimeras was performed by multiplex PCR amplification of STR marker and capillary electrophoresis with fluorescence detection. The results showed that patient appear to be HLA identical to the donor cord blood at the tested level. Persistent full donor chimerism was found in breast bone marrow. The patient with stable MC (DC < 5%) had a probability of long term survival with molecular remission MC status appeared in forearm muscle, tongue, liver, spleen, stomach, right temporal lobe, diaphragmatic muscle, bronchus, left ventricle and right kidney. In conclusion, the donor gene can express in parenchymatoas organs, the donor chimerism was detected in breast bone marrow and some other organs.
Child ; Cord Blood Stem Cell Transplantation ; Genetic Loci ; genetics ; Humans ; Male ; Microsatellite Repeats ; genetics ; Muscular Dystrophies ; genetics ; therapy ; Transplantation Chimera ; Transplantation, Homologous