Strategy Optimization and Clinical Analyze of Multiple Nucleotide Polymorphism Analysis in the Chimerism Detection after Allogeneic Hematopoietic Stem Cell Transplantation / 中国实验血液学杂志

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.

Establishment of A Mixed Chimeric Mouse Model of Allogeneic Bone Marrow Transplantation and Its Influencing Factors / 中国实验血液学杂志

OBJECTIVE@#To establish a mouse mixed chimerism (MC) model of nonmyeloablative allogeneic bone marrow transplantation(allo-BMT) and explore its affecting factors.@*METHODS@#The MC model was established by nonmyeloablative allo-BMT followed by high-dose post-transplant cyclophosphamide (PTCY). 123 mice in the experiments was retrospectively analyzed, and the factors related with the chimerism were explored with the univariate and multivariate logistic regression analysis. A multivariate linear regression was performed by R project to obtain a mathematical model for predicting the chimeric level with relevant affecting factors.@*RESULTS@#The model presented mixed chimerism on day 14 after transplantation, and was characterized by a donor lymphocyte infusion (DLI) which significantly promoted donor engraftment on day 15, but transfplantation of PBS in control group was failed. Among 123 mice, 47 (38.21%) mice were MC, while 76 (61.79%) mice were non-MC in 123 mice, respectively; univariate analysis showed that the baseline body weight of mice (P=0.001, 17.84±1.19 g vs 18.50±0.94 g), total body irradiation(TBI，P=0.048) and the using of cyclophosphamide (P=0.16) were affected the chimeric state of mice, while the number of infusing cells and the time of detection showed no significant effects. Multivariate regression analysis showed that under certain conditions, the body weight of mice on day 0 was an independent factor affecting chimeric levels (OR=0.493, 95% CI 0.307-0.791, P=0.003). Through R project multiple linear regression, the math model was achieved, which was chimerism=6.09-12×weight(g)+80.03×TBI(Gy)-4.4×cell-counts (× 10@*CONCLUSION@#The experiment presents a method for establishing a mixed chimeric mice model after non-myeloablative bone marrow transplantation and constructs a mathematical model with relevant factors affected chimerism status.

Bone Marrow Chimerism Detection Using Next Generation Sequencing Based on Single Nucleotide Polymorphisms Following Liver Transplantation: Comparison With Short Tandem Repeat-PCR

No abstract available.

Limited immune tolerance induced by transient mixed chimerism

No abstract available.

Establishment and identification of a H-2 completely mismatched microtransplantation model of leukemia mouse / 中国实验血液学杂志

This study was purposed to establish and identify a H-2 completely mismatched microtransplantation model of leukemia mouse. The recipients were female BALB/c mice, while donors were male C57BL/6J mice. Recipients were inoculated intravenously with 1×10(6) of WEHI-3 cells, a cell line of myelomonocytic leukemia. Donors received 100 µg/kg G-CSF mobilization through hypodermic injection, every 12 hours, and it last 5 days. Chemotherapy regimens was MA (mitoxantrone+cytarabine), and it last 4 days. Recipients were given chemotherapy conditioning without GVHD prophylaxis after inoculation of leukemic cells for 2 days, and within 8 hours after last chemotherapy received donor mobilized spleen mononuclear cells (sMNC). The number of sMNC was (3, 6, 12) ×10(7), respectively. The early death rate, recovery level of WBC in peripheral blood and leukemia load were compared between chemotherapy and microtransplantation groups. The donor chimerism was detected by RT-PCR. From the clinical manifestation and pathological features, the GVHD in recipients was evaluated. The results showed that the early mortality in chemotherapy group was 25%, meanwhile those in the (3, 6, 12)×10(7) groups were 16.67%, 8.33%, 8.33%, respectively. The(3, 6)×10(7) groups has a stronger hematopoietic recovery capability than that in chemotherapy and 12×10(7) groups (P < 0.05) . There were more leukemic cells in chemotherapy mice than that in microtransplantation mice (P < 0.01) , and (12, 6)×10(7) groups had lower leukemia load than that in 3×10(7) group (P < 0.05) . No signs of GVHD were observed in microtransplantation mice. The donor microchimerism could be discovered at eraly 2 weeks after donor cell transfusion. It is concluded that a H-2 completely mismatched microtransplantation model of leukemia mouse has been successfully established, and it will provide a experimental base for studying microtransplantation in clinic.

Research advances on microchimerism / 中国实验血液学杂志

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.

Role of chimerism monitoring and donor lymphocyte infusion in eliminating the risk of graft rejection following HSCT in thalassemia patients-review / 中国实验血液学杂志

One of the major obstacle for hematopoietic stem cell transplantation (HSCT) to treat patients with beta-thalassemia is graft rejection (GR). The proportion of donor-derived cells continually declined in mixed chimerism (MC), finally leading to graft failure. Monitoring chimerism after transplant consecutively can early find unstable mixed chimerism and rejection, which provide the basis for donor lymphocyte infusion (DLI); for imminent risk of graft rejection, escalating doses of DLI is a feasible method for converting unstable MC towards stable MC or full donor chimerism. This review focuses on advancement of chimerism monitoring and DLI after HSCT for patients with β-thalassemia major.

Quantitative monitoring of multi-donor chimerism after multi-donor allogeneic hematopoietic stem cell transplantation / 中国实验血液学杂志

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(%).

Quantitative chimerism kinetics in relapsed leukemia patients after allogeneic hematopoietic stem cell transplantation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Chimerism 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).</p><p><b>METHODS</b>A 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.</p><p><b>RESULTS</b>Twenty-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).</p><p><b>CONCLUSIONS</b>This 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.</p>

Anti GVHD effect of the induction of immune tolerance in rats embryo / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate whether the fetal immune tolerance induction could replace the HLA typing for hematopoietic stem cell transplantation.</p><p><b>METHODS</b>Immune tolerance of SD rats was induced by injecting host Wistar rats peripheral blood mononuclear cells into yolk sac of the embryo, afterward the mature male offsprings were used as donor. The host female recipients received lethal dose irradiation and bone marrow transplantation(BMT). The Wistar rats transplanted with bone marrow from donor and unrelated SD rats as well as the rats which received radiation alone were used as control. The survival, histopathologically GVHD, the mental status, food and water intake, coat characteristics, activities were observed. Forty days after BMT, autologous and allogenous skin transplantation between donor and recipient rats was performed to observe the engraftment of solid organ.</p><p><b>RESULTS</b>The survival of the rats received bone marrow grafts from the immune tolerant donor was significantly longer than that of control groups (30 day survival rates were 86.7%, 6.7%, 0%, and 0% respectively), and there was no histopathologically GVHD observed, while in the sham group, the manifestations of GVHD was clearly visible. The skin engraftment rate between the host and the immune tolerant donor was significantly higher than that among non-related rats (84.6% and 0% respectively).</p><p><b>CONCLUSION</b>The induction of immune tolerance in embryo can overcome the HLA barrier and provide a good donor for hematopoietic stem cell and solid organ transplantation.</p>

Quantitative assessment of hematopoietic chimerism by quantitative real-time polymerase chain reaction of sequence polymorphism systems after hematopoietic stem cell transplantation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Analysis 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.</p><p><b>METHODS</b>A 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.</p><p><b>RESULTS</b>Recipient 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.</p><p><b>CONCLUSION</b>This 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.</p>

Establishment and evaluation of quantitative analysis method for donor chimerism of mice / 中国实验血液学杂志

This study was aimed to explore the effectiveness of sequential and quantitative detection method for analysing donor chimerism (DC). In order to simulate a mouse model of haploidentical stem cell transplantation, C57BL/6 male mice were used as donors, while CB6F1 female mice were used as recipients and were divided into 2 groups. The two groups of recipients were irradiated with 2 Gy and 6 Gy from (⁶⁰CO gamma-ray source respectively, and then were inoculated intravenously with bone marrow cells (BMCs) and spleen mononuclear cells (SPMNCs). Quantitative analyses of DC were performed with real-time PCR or flow cytometry (FCM) on different days after transplantation. The results showed that real-time PCR and FCM both have advantages and disadvantages in the detection of DC. When DC amount in group of 6 Gy was > 90% with stable macrochimerism for more than 3 months, the efficacy of detection by FCM was well; while the DC amount in group of 2 Gy was below 10% and gradually transformed to different forms of microchimerism until disappeared, in which condition the use of real time-PCR was more appropriate. It is concluded that FCM can detect macrochimerism with high accuracy but would fail when DC amount is less than 1% due to sensitivity limitation, while the real time-PCR is more sensitive for detecting microchimerism but lack of accuracy for detecting macrochimerism. Combination of the two methods can afford sensitive and accurate tool for quantitative analysis of chimerism in mouse model of transplantation and adoptive immunotherapy.

A novel single nucleotide polymorphism-based method for quantitative assessment of chimerism after allogeneic stem cell transplantation / 中华血液学杂志

<p><b>OBJECTIVE</b>To develop a novel single nucleotide polymorphism (SNP)-PCR based method for quantitative detection of chimerism after allogeneic haemopoietic stem cell transplantation (allo-HSCT), and to explore its feasibility, accuracy and superiority.</p><p><b>METHODS</b>18 SNP loci were sereened to identify informative markers for detecting chimerism in each donor/recipient pair before transplantation. Then the chimerism rate of each informative marker was analyzed by real-time quantitative PCR (RQ-PCR). The accuracy and sensitivity were verified by multiple proportion dilution and analogy chimerism compared with quantitative detection of short tandem repeat (STR)-PCR, fluorescence in situ hybridization (FISH) and fusion gene.</p><p><b>RESULTS</b>(1) The average slope of the 17 time amplications of the internal control plasmid was -3.39, the average intercept was 39.97, correlation coefficients were more than 0.995, which was close to the theoretical level. The intra- and interassay variability was 0.50% and 1.1%, respectively, which were both in the allowed ranges. A linear correlation with artificial mixed chimerism is above 0.99 and a sensitivity of 0.01% proved reproducible. (2) At least one informative marker could be found in over 95% of 40 donor/recipient pairs. The results of the chimerisms derived from SNP-PCR were consistent with that from STR-PCR (96.7%), FISH and fusion gene analasis (P > 0.05); the quantitative results of special fusion gene transcripts were negtive in complete chimerism samples, and positive in mixed chimerism samples.</p><p><b>CONCLUSIONS</b>This new assay which overcome the PCR competition and plateau biases of STR-PCR provides an accurate, reliable and rapid quantitative assessment of mixed chimerism after allo-transplantation. It is highly promising for of clinical application and may take the place of STR-PCR in the conventional chimerisim assessment.</p>

Quantitative chimerism analysis of regulatory T cell subsets based on immunomagnetic sorting / 中国实验血液学杂志

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.

Suppression of tumor growth in renal cancer treatment with tumor vaccination after haploidentical bone marrow cell reconstitution / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate whether whole tumor cell vaccination strategies in combination with bone marrow transplantation (BMT) can stimulate graft-versus-tumor effect (GVT).</p><p><b>METHODS</b>Twenty-six BALB/c mice were randomly divided into 3 groups: BMT group (group A, n = 10), BMT + vaccination group (group B, n = 10), control group (group C, n = 6). (BALB/c × C57BL/6) F1 mice [CB6F1, H-2K(b/d)] were used as donors. BALB/c mice of group C were only inoculated with Renca cell (2.6 × 10(6)). Mice of group A and B were conditioned with 8 Gy irradiation, followed by infusion by bone marrow cell of CB6F1 mice on day 1, then inoculated with Renca cell (2.6 × 10(6)) on day 8. All mice of group B were immunized subcutaneous on the back with 5 × 10(5) irradiated Renca tumor cells on day 9 and day 16. All mice of group C were inoculated with Renca cell (2.6 × 10(6)) on day 8. In group A and B, all mice were analyzed by fluorescence activated cell sorter (FACS) on day 14, and 28 day after BMT. Mice were killed on day 32 after inoculation with tumor cell and collected blood sample. All tumors were taken out to be weighed and then fixed in 10% buffered formalin, embedded in paraffin, and cut into 5 µm slices. The slices were stained with HE and examined by TdT mediated-dUTP nick end labeling (TUNEL). Liver, skin, intestine, and spleen were biopsied for histopathological examination.</p><p><b>RESULTS</b>The results of chimera showed that engraftments of group A, B were full donor chimerism, and the chimerism of those remained above 90% and preserved even after 28 days. The tumor weight, tumor volume increment in the group B was lower than group A and C (P < 0.05). The tumor suppressing rates of the group A and B were 54%, 60% respectively. The area ratio of tumor necrosis and apoptosis index (AI) of the tumor in the group B were higher than group A and C (P < 0.05). Graft-versus-host disease was not observed in each group.</p><p><b>CONCLUSION</b>The mechanism of GVT after haploidentical allogeneic bone marrow transplantation with tumor vaccination may be the promotion of tumor necrosis and apoptosis.</p>

Prevalence of chimerism after non-myeloablative hematopoietic stem cell transplantation / Prevalência do quimerismo após transplante de células hematopoiéticas não-mieloablativo

Context and objective: Non-myeloablative hematopoietic stem cell transplantation (NMA-HSCT) is performed in onco-hematological patients who cannot tolerate ablative conditioning because of older age or comorbidities. This approach does not completely eliminate host cells and initially results in mixed chimerism. Long-term persistence of mixed chimerism results in graft rejection and relapse. Involvement of graft-versus-host disease is concomitant with complete chimerism and graft-versus-tumor effect. The aim of this study was to evaluate the prevalence of chimerism in onco-hematological patients who underwent NMA-HSCT. Desingn and setting: Observational clinical study on chimerism status after human leukocyte antigen-identical NMA-HSCT at the Discipline of Hematology and Hemotherapy of Universidade Federal de São Paulo. Methods: We sequentially analyzed the amplification of APO-B, D1S80, DxS52, FVW, 33.6, YNZ-2 and H-ras primers using variable number of tandem repeats (VNTR) on 17 pairs and fluorescent in situ hybridization (FISH) with the XY probe and SRY primer on 13 sex-unmatched pairs. RESULTS: The informativeness of the primers using VNTR was 60 percent for APO-B, 75 percent D1S80, 36 percent DxS52, 14 percent FVW, 40 percent YNZ-22 and 16 percent H-ras. The SRY primer was informative in female receptors with male donors. The XY-FISH method was informative in 100 percent of the sex-unmatched pairs. Conclusion: These methods were sensitive and informative. In VNTR, the association of APO-B with D1S80 showed 88 percent informativeness. The quantitative FISH method was more sensitive, but had the disadvantage of only being used for sex-unmatched pairs.

Contexto e objetivo: O transplante de células hematopoiéticas não-mieloablativo é realizado em pacientes com doenças onco-hematológicas que não suportam condicionamentos ablativos devido à elevada idade ou ao acometimento por comorbidades. Esta abordagem não elimina completamente as células do hospedeiro, resultando, inicialmente, em quimerismo misto. A persistência do quimerismo misto na evolução de longo prazo resulta na rejeição ao enxerto e recaída. O acometimento pela doença do enxerto contra hospedeiro é concomitante ao quimerismo completo e ao efeito enxerto versus tumor. O objetivo deste estudo foi avaliar a prevalência do quimerismo em doenças onco-hematológicas tratadas com o transplante não-mieloablativo de células hematopoiéticas. Tipo de estudo e local: Estudo clínico observacional do estado de quimerismo após transplante antígenos leucocitários humanos-idêntico não-mieloabaltivo realizado na Disciplina de Hematologia e Hemoterapia da Universidade Federal de São Paulo. Métodos: Analisamos sequencialmente a amplificação dos primers APO-B, D1S80, DxS52, FVW, 33,6, YNZ-22, H-ras pelo VNTR (variable number of tandem repeats) em 17 pares e FISH (fluorescent in situ hybridization) pela sonda XY e do primer SRY em 13 pares de não relacionados a sexo. Resultado: A informatividade dos primers pelo VNTR foi de 60 por cento para APO-B; 75 por cento D1S80; 36 por cento DxS52; 14 por cento FVW; 40 por cento YNZ-22 e 16 por cento H-ras. O primer SRY foi informativo em receptores femininos com doadores masculinos. O método XY-FISH foi informativo em 100 por cento dos pares de não relacionado a sexo. Conclusão: Estes métodos foram sensíveis e informativos. No VNTR, a associação do APO-B com D1S80 mostrou 88 por cento de informatividade. O FISH, método quantitativo, foi mais sensível, porém com desvantagem de ser usado somente nos pares não relacionados a sexo.

Comparison of STR-PCR and FISH value for monitoring chimerism after sex-mismatched allogeneic hematopoietic stem cell transplantation / 中国实验血液学杂志

This study was purposed to compare the significance of multiplex short tandem repeat polymerase chain reaction (STR-PCR) and fluorescent in situ hybridization (FISH) for monitoring chimerism after sex-mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT). The chimerism of bone marrow or peripheral blood cells from 38 patients was analyzed by STR-PCR and FISH on days 14, 28 and at 3 months after allo-HSCT. The results indicated that on day 14, the complete chimerism (CC) was detected in 14 of 30 cases by STR-PCR and in 8 of 30 cases by FISH (p > 0.05). On day 28, the CC was detected in 26 of 31 cases by STR-PCR and in 15 of 31 cases by FISH (p < 0.01). At 3 months, the CC was observed in 22 of 24 cases by STR-PCR and 17 of 24 cases by FISH (p > 0.05). 14 cases were found to have a graft rejection or relapse among 28 cases which were continuously monitored more than 3 months post the transplants. Donor cell decrease in 9 of 14 cases was proved by FISH alone. It is concluded that FISH is more sensitive than STR-PCR in early monitoring chimerism status of post-transplant and in predicting graft rejection or disease relapse.

Transfusion-associated microchimerism -- review / 中国实验血液学杂志

Blood transfusion is a newly recognized cause of microchimerism, it seems to be common in severe traumatic injuries. In this review, the frequency, cause and prevention of transfusion-associated microchimerism (TA-MC), its current progress of knowledge and unanswered questions were summarized. In addition, the pregnancy-associated microchimerism and transplantation-associated microchimerism were discussed in this review.

Adenovirus-mediated CTLA4 immunoglobulin based conditioning for non-myeloablative allogeneic hematopoietic cell transplantation to induce tolerance to hind limb allografts in rats / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate a non-toxic AdCTLA4-Ig-based protocol for non-myeloablative allogeneic hematopoietic cell transplantation to induce donor-specific tolerance to hind limb allografts in rats.</p><p><b>METHODS</b>Fully mismatched, 4 to 8 week old Brown Norway (RT1(n)) and Lewis (RT1(1)) rats were used as cell/organ donors and recipients, respectively. Recipients were treated with AdCTLA4-Ig (5 x 10(9) PFU, day -30, 0, 30), standard immunosuppressive therapy (MP: 10 mg x kg(-1) x d(-1), MMF: 20 mg x kg(-1) x d(-1), RAPA: 0.2 mg x kg(-1) x d(-1);day -33 - 100), soon after total body irradiation (3 Gy, day -30) and donor bone marrow (100 x 10(6), day -30) transplantation (BMT). Thirty days after BMT, chimeric animals received hind limb transplantations. And 100 days after hind limb transplantations, immunosuppressive therapy was changed for low-dosed CsA (8 mg x kg(-1) x d(-1), day 100-), until the allografts were rejected.</p><p><b>RESULTS</b>In Group C, hematopoietic chimerism was (38.8 +/- 10.6)% at day 0, and was stable (29.3 +/- 11.9)% at 330 days post-BMT. There was no graft versus host disease in both Group C and Group D. When the standard immunosuppressive therapy was stopped and changed for low-dosed CsA, chimeric recipients (Lewis, RT1(1)) permanently accepted (> 200 days) donor specific (Brown Norway, RT1(n)) hind limb allografts in Group C, yet rapidly rejected in Group A (8 +/- 2) d, Group B (18 +/- 3) d and in Group C (20 +/- 2) d. Lymphocytes of graft tolerant animals' demonstrated hyporesponsiveness in mixed lymphocyte cultures in a donor-specific manner in Group C. Tolerant graft histology showed no obliterative arteriopathy or chronic rejection.</p><p><b>CONCLUSION</b>The AdCTLA4-Ig based conditioning regimen with donor BMT produce stable mixed chimerism and induce donor-specific tolerance to hind limb allografts.</p>

Short tandem repeat panel settled for quantitative chimerism analysis following allogeneic stem cell transplantation and its application / 中国实验血液学杂志

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.