Comparison of microtransplantation,chemotherapy and allogeneic transplantation in post-remission therapy for Philadelphia chromosome-positive acute lymphoblastic leukemia

Patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph⁺ ALL) have poor prognosis, and the efficacy of chemotherapy plus tyrosine kinase inhibitors (TKIs) followed by mismatched donor stem cell infusion (microtransplantation, MST) has not been determined. We retrospectively summarized 45 patients including 11 undergoing MST with TKIs, 17 receiving allogeneic transplant and 17 undergoing chemotherapy with TKIs. Improved 4-year overall survival rate was observed in the MST group (91%) compared with either transplant group (31%, P = .005) or chemotherapy group (36%, P = .013). The MST group also had higher 2-year and 4-year leukemia-free survival rates (91% and 72%, respectively) compared with either transplant group (33%, P = .005 and 33%, P = .021, respectively) or chemotherapy group (41%, P = .017 and 31%, P = .023, respectively). 2-year and 4-year cumulative incidences of hematologic relapse were lower in the MST group (9% and 28%, respectively) compared with those in the chemotherapy group (56%, P = .025 and 67%, P = .034, respectively). In patients undergoing MST, donor microchimerism was detected (1.07 × 10^-5 to 6.6 × 10^-4 copies from 9 to 1499 days) in 7 patients, and donor/patient-derived HLA*0201/2402⁺WT1⁺CD8⁺ T cells were found from 0.05% to 0.67% in 6 patients. MST may provide a favorable treatment for patients with Ph⁺ ALL.     

Prospective study of microchimerism in transplant recipients

BACKGROUND: We evaluated peripheral blood microchimerism in 48 consecutive organ transplant recipients (35 kidneys, ten livers, one kidney-liver, one kidney-pancreatic islet, one kidney pancreas) up to 12 months post-transplantation. Patients were categorized according to the presence or absence of rejection episodes, and the patterns of microchimerism in the two groups were then compared. METHODS: DNA was extracted from donor, pre-transplant, and post-transplant peripheral blood samples. Several polymerase chain reaction (PCR)-based assays were developed for the detection of microchimerism. Assay sensitivities ranged from 0.0001 to 3%. RESULTS: Microchimerism was detected only in sex-mismatched cases (male donors and female recipients) using nested PCR for a Y-chromosome marker. There were ten such cases (six kidneys, two livers, and two combined organ transplants). In patients without rejection (n = 7), there was a peak of donor-DNA at 1-3 wk post-transplantation followed by a second peak between 3 wk and 4 months. In patients with biopsy-proven rejection (n = 3), the peaks were absent and the levels of microchimerism were extremely low (< 0.001%). Microchimerism levels declined in all 10 patients and were barely detectable 1 yr post-transplantation. Microchimerism was not detected in the remaining 38 patients despite using a battery of sensitive PCR-based assays. CONCLUSIONS: In our study, microchimerism was detected using the Y-chromosome PCR assay only and the level of donor-DNA in a given patient varied over time. This study highlights the difficulties in establishing a correlation between microchimerism and transplant tolerance.     

DIP–STR: Highly Sensitive Markers for the Analysis of Unbalanced Genomic Mixtures

Samples containing highly unbalanced DNA mixtures from two individuals commonly occur both in forensic mixed stains and in peripheral blood DNA microchimerism induced by pregnancy or following organ transplant. Because of PCR amplification bias, the genetic identification of a DNA that contributes trace amounts to a mixed sample represents a tremendous challenge. This means that standard genetic markers, namely microsatellites, also referred as short tandem repeats (STR), and single‐nucleotide polymorphism (SNP) have limited power in addressing common questions of forensic and medical genetics. To address this issue, we developed a molecular marker, named DIP–STR that relies on pairing deletion–insertion polymorphisms (DIP) with STR. This novel analytical approach allows for the unambiguous genotyping of a minor component in the presence of a major component, where DIP–STR genotypes of the minor were successfully procured at ratios up to 1:1,000. The compound nature of this marker generates a high level of polymorphism that is suitable for identity testing. Here, we demonstrate the power of the DIP–STR approach on an initial set of nine markers surveyed in a Swiss population. Finally, we discuss the limitations and potential applications of our new system including preliminary tests on clinical samples and estimates of their performance on simulated DNA mixtures.     

Selective organ specific inflammation in offspring harbouring microchimerism from strongly alloreactive mothers

The origins of autoimmunity are not yet understood despite significant advances in immunology. The trafficking of maternal cells to the offspring represents the very first immunological event in foetal life and is reinforced during lactation. The persistence of maternal cells in offspring's tissues and circulation has been associated with several autoimmune disorders. However a direct causal effect has never been demonstrated. Maternal T cells specifically targeting foetal insulin producing cells have been shown to generate islet inflammation without directly participating in this process. Our objective was to evaluate if alloreactive maternal cells could directly trigger a graft-versus host like reaction or indirectly influence the development of the offspring's regulatory T cells favouring autoimmunity. We adopted a breeding strategy comparing genetically identical offspring from either strongly alloreactive transgenic mothers compared to immunodeficient mothers. We detected maternal alloreactive T cells in the offspring and early signs of inflammation in small intestine of 6 weeks old offspring. Interestingly, CD4⁺ Foxp3⁺ regulatory T cell frequency was diminished in mesenteric lymph nodes from eight months old offspring born of alloreactive mothers compared to offspring of immunodeficient mothers. Our study favours a hypothesis where highly alloreactive maternal cell microchimerism indirectly predisposes offspring to autoimmunity.     

Epidemiology and pathogenesis of scleroderma

Scleroderma is a heterogenous connective tissue disorder characterized by fibrosis of the skin, with or without internal organ involvement. The aetiology of scleroderma may involve both environmental and genetic factors. Abnormalities involving the immune system, vascular tissue and extracellular matrix have been demonstrated. Recent research has focused on microchimerism as a risk factor for the development of scleroderma. This article reviews the epidemiology and pathogenesis of this disorder.     

Behavior of male-specific minor histocompatibility antigen in skin and limb transplantation

BACKGROUND: Although the role of male-specific minor histocompatibility antigen H-Y has been increasingly understood in both experimental and clinical organ transplantation, little has been investigated on musculoskeletal tissue transplantation. This study was performed to describe the behavior of male-specific minor histocompatibility H-Y antigen in rat skin and whole limb transplantation. MATERIALS AND METHODS: Using three different strains of inbred rats (Lewis, F344, and Dark Agouti), 75 donor hindlimbs and eighteen skin grafts were isogenically transplanted to the sex-mismatched recipients. Recipients were observed up to 48 weeks postoperatively. Rejection was monitored by the appearance of the skin of the grafted limb and histology. Systemic microchimerism was assessed by polymerase chain reaction using Y-chromosome specific primers. RESULTS: Skin rejection didn't occur in all limb transplant recipients and histology did not show any rejection findings in all components of the limb graft through 48 weeks. Successful functional recovery was expected. Stable and high level of chimerism (>1%) was detected in the lymphoid tissues in nontreated female recipients. Male skin grafts were rejected by Lewis and F344 female recipients within 6 weeks postoperatively. All female skin grafts survived in male recipients. CONCLUSION: Our results suggest that H-Y antigen can induce graft rejection in rat skin graft but causes no rejection reaction in whole limb transplantation. Systemic chimerism may play an important role for acceptance of sex-mismatched limb graft.     

成年小鼠的耐受机制及其在异基因骨髓移植中的应用

静脉注射异基因脾细胞和骨髓细胞加腹腔注射环磷酰胺和抗胸腺细胞血清可诱导成年小鼠异基因皮肤移植耐受。体内、外细胞转移实验均未显示耐受小鼠脾细胞中存在抑制细胞活性。直接荧光染色的流式细胞仪分析结果表明，耐受小鼠胸腺内形成了微量混合嵌合体。以耐受小鼠作为异基因骨髓移植的供体，可完全避免移植物抗宿主病的发生，耐受骨髓可在受体中建立稳定的嵌合体，使受体小鼠对供体来源的肿瘤产生了特异耐受。     

The evidence of maternal microchimerism in biliary atresia using fluorescent in situ hybridization

Background

Biliary atresia (BA) is a cholestatic disease of unknown etiology. It has recently been suggested that graft-vs-host disease caused by microchimerism is an etiology in the development of autoimmune disease. Moreover, the liver is a frequent target organ of graft-vs-host disease. The aim of this study is to identify the presence and extent of maternal microchimerism and to determine whether it plays a role in the etiology of BA.

Methods

The liver biopsy specimens of 6 male patients with BA (BA group) and 6 males with other liver diseases (non-BA group) were assayed for X- and Y-chromosome using fluorescent in situ hybridization. The cells with 2 sex chromosomes in the nuclei were counted. Cells with 1 X- and 1 Y-chromosomes were considered to be host cells, and those with 2 X-chromosome were considered to be of maternal origin.

Results

The frequency of cells with XX chromosomes per 1000 host cells in the BA group and the non-BA group were 3.00 ± 0.75 and 0.99 ± 0.50, respectively (P = .005). Moreover, the age at the time of biopsy did not affect the number of chimeric cells.

Conclusion

The presence of female cells in the liver of male patients with BA was significantly higher than in males with other liver disease. Maternal microchimerism is therefore suggested to contribute to the pathogenesis of BA.     

Unmanipulated HLA-Haploidentical Bone Marrow Transplantation for the Treatment of Fatal, Nonmalignant Diseases in Children and Adolescents

Fetomaternal microchimerism has been demonstrated, and immunologic tolerance to unshared HLA antigens between mother and offspring may be suggested. We used T-cell-repleted bone marrow transplantation (BMT) from their HLA-haploidentical mothers to treat 6 patients with fatal nonmalignant diseases. The number of mismatched HLA loci in the graft-versus-host disease (GVHD) direction was 3 in 4 patients and 2 in 2 patients. The number in the host-versus-graft direction was 3 in 4 patients, 2 in 1 patient, and 1 in 1 patient. Microchimerism of inherited paternal antigens was demonstrated in 5 donors, and microchimerism of noninherited maternal antigens was detected in 3 recipients. GVHD prophylaxis consisted of short-course methotrexate, tacrolimus, and mycophenolate mofetil (3 patients) or short-course methotrexate, tacrolimus, and methylprednisolone (1 patient). Engraftment was achieved in 5 patients who had received preconditioning, and T-cell engraftment was confirmed in 1 patient with severe combined immunodeficiency. Acute GVHD developed in 3 patients: grade 1 in 2 patients and grade 2 in 1 patient. Chronic GVHD was observed in 5 patients: localized type in 3 patients and extended type in 2 patients. Five patients were alive 11 to 30 months after BMT and 1 patient died of chronic GVHD. Unmanipulated haploidentical BMT from a maternal donor may be the treatment of choice of poor-prognosis nonmalignant diseases.     

甲状腺内胎儿微嵌合体在产后Graves病发病的影响

目的：探讨甲状腺内胎儿微嵌合体对女性产后Graves病发病的影响.方法：选用Y染色体α卫星区特异性DNA探针,利用荧光原位杂交技术,检测24例GD和10例甲状腺腺瘤患者甲状腺石蜡标本中的胎儿嵌合体的存在.结果：24例产后GD患者甲状腺标本中13例发现存在着Y染色体,10例甲状腺腺瘤对照组中仅2例存在有Y染色体.两组间胎儿微嵌合体的出现率存在显著性差异（54.2%vs20%,P〈0.05）.比较GD患者中胎儿嵌合体阳性和阴性病例的的临床资料,显示胎儿嵌合体阳性组患者的妊娠次数（平均2.77±0.38次）显著多于胎儿微嵌合体阴性组（平均1.36±0.27次）（P〈0.05）.结论：胎儿微嵌合体在GD患者甲状腺内出现的机率的确较非AITD的患者更高,提示胎儿微嵌合体可能参与产后GD的发生.