Long-term tolerance to allogeneic thymus transplants in complete DiGeorge anomaly

Thymus transplantation in subjects with complete DiGeorge anomaly using postnatal allogeneic HLA-nonmatched cultured thymus tissue provides immunoreconstitution. Tolerance of the newly developed T cells toward the donor thymus has not previously been studied. Mixed lymphocyte cultures were used to test 12 thymus transplant recipients for long-term tolerance toward their thymus allografts. Two subjects tested for responses toward thymus donor peripheral blood mononuclear cells showed significantly less reactivity toward the donors compared to responses against third-party allogeneic cells. Peripheral blood mononuclear cells from 10 other subjects were less responsive toward cryopreserved donor thymic cells than toward allogeneic cells (P=0.00007). Adult control peripheral blood mononuclear cells proliferated strongly in response to the donor thymic cells. Both the subjects and controls showed similar proliferative responses against allogeneic cells and phytohemagglutinin. This study provides in vitro evidence for long-term tolerance of complete DiGeorge anomaly thymus transplantation recipients toward their HLA-nonmatched thymus grafts.     

DiGeorge anomaly with renal agenesis in infants of mothers with diabetes

We report on 2 infants with the DiGeorge anomaly born to diabetic mothers treated with insulin. Both infants had unilateral renal agenesis. One of the mothers has manifestations suggestive of velo-cardio-facial syndrome (VCFS). Cytogenetic studies on both patients and the mother with apparent VCFS were normal. Molecular studies utilizing probes from the DiGeorge critical region did not demonstrate a 22q11 microdeletion in either patient or the mother with apparent VCFS. We conclude that maternal diabetes is a pathogenetic factor in the DiGeorge anomaly, and infants of diabetic mothers who have this anomaly should also be screened for renal agenesis. © 1993 Wiley-Liss, Inc.     

Thymus transplantation restores the repertoires of forkhead box protein 3 (FoxP3)+ and FoxP3− T cells in complete DiGeorge anomaly

The development of T cells with a regulatory phenotype after thymus transplantation has not been examined previously in complete DiGeorge anomaly (cDGA). Seven athymic infants with cDGA and non-maternal pretransplantation T cell clones were assessed. Pretransplantation forkhead box protein 3 (Foxp3)⁺ T cells were detected in five of the subjects. Two subjects were studied in greater depth. T cell receptor variable β chain (TCR-Vβ) expression was assessed by flow cytometry. In both subjects, pretransplantation FoxP3⁺ and total CD4⁺ T cells showed restricted TCR-Vβ expression. The development of naive T cells and diverse CD4⁺ TCR-Vβ repertoires following thymic transplantation indicated successful thymopoiesis from the thymic tissue grafts. Infants with atypical cDGA develop rashes and autoimmune phenomena before transplantation, requiring treatment with immunosuppression, which was discontinued successfully subsequent to the observed thymopoiesis. Post-transplantation, diverse TCR-Vβ family expression was also observed in FoxP3⁺ CD4⁺ T cells. Interestingly, the percentages of each of the TCR-Vβ families expressed on FoxP3⁺ and total CD4⁺ T cells differed significantly between these T lymphocyte subpopulations before transplantation. By 16 months post-transplantation, however, the percentages of expression of each TCR-Vβ family became significantly similar between FoxP3⁺ and total CD4⁺ T cells. Sequencing of TCRBV DNA confirmed the presence of clonally amplified pretransplantation FoxP3⁺ and FoxP3⁻ T cells. After thymus transplantation, increased polyclonality was observed for both FoxP3⁺ and FoxP3⁻ cells, and pretransplantation FoxP3⁺ and FoxP3⁻ clonotypes essentially disappeared. Thus, post-transplantation thymic function was associated with the development of a diverse repertoire of FoxP3⁺ T cells in cDGA, corresponding with immunological and clinical recovery.     

Mosaic tetraploidy in a liveborn infant with features of the DiGeorge anomaly

We report on a liveborn male infant with mosaic tetraploidy who presented with multiple congenital anomalies including features of the DiGeorge anomaly (type I truncus arteriosus with other cardiovascular malformations, thymic hypoplasia, hypocalcemia). No structural chromosome aberrations, namely of chromosome 22, were detected. These findings contribute to the variability of symptoms of the polyploid phenotype. Additionally, the cytogenetic studies in our case emphasize the necessity of investigating fibroblasts in order to evaluate the relevant proportion of aberrant cells in mosaicism.     

Achievement of cellular immunity and discordant xenogeneic tolerance in mice by porcine thymus grafts

Specific cellular immune tolerance may be essential for successful xenotransplantation in humans. Thymectomized (ATX), T and NK ceil-depleted immunocompetent mice grafted with xenogeneic fetal pig thymic and liver tissue (FP THY/LIV) result in efficient mouse thymopoiesis and peripheral repopulation of functional mouse CD4^ T cell.Very importantly, the reconstituted mouse T cells are specifically tolerant to pig donor antigens. Studies demonstrated that porcine MHCs mediated positive and negative selection of mouse thymocytes in FP THY grafts, whereas mouse MHCs were involved in negative selection in grafts. Therefore, T cell tolerance to xenogeneic donor antigens could be induced by grafting donor thymus tissue. Xenogeneic thymic replacement might have a potential role in the reconstitution of cellular immunity in patients with AIDS or other immunodeficiencies caused bv thvmus dvsfunction.     

Ectopic intrathyroidal thymus accompanied by intrathyroidal parathyroid as a cause of a solitary thyroid nodule in adult

Ectopic intrathyroidal thymic tissue can form a mass lesion within the thyroid gland and has rarely been reported in children. We report a case of intrathyroidal thymus accompanied by an intrathyroidal parathyroid gland in a 29-year-old woman who visited our hospital due to right neck mass diagnosed as metastatic papillary carcinoma by aspiration cytology in an outside hospital. She had a history of right thyroidectomy due to papillary thyroid carcinoma three years ago. Ultrasonographic examination of the left thyroid gland showed a well-defined hyperechoic nodule, which did not show change in size compared with the previous study. She underwent complete thyroidectomy with right neck dissection. Grossly, the left thyroid had a well demarcated pale yellow nodule measuring 0.9 cm in diameter. On microscopic examination, the nodule was composed of mature fat tissue, ectopic thymic tissue with Hassall’s corpuscles, and an intrathyroidal parathyroid gland. This is an exceedingly rare case of ectopic intrathyroidal thymus with intrathyroidal parathyroid gland, in an adult.     

T cell receptor repertoire and function in patients with DiGeorge syndrome and velocardiofacial syndrome

DiGeorge syndrome (DGS) and velocardiofacial syndrome (VCFS) are associated with chromosome 22q11.2 deletion. Limited information is available on the T cell receptor (TCR) Vbeta repertoire. We therefore investigated TCR Vbeta families in lymphocytes isolated from blood and thymic samples of seven patients with DGS and seven patients with VCFS, all with 22q11.2 deletion. We also studied activities related to TCR signalling including in vitro proliferation, anti-CD3-induced protein tyrosine phosphorylation, and susceptibility to apoptosis. Reduced CD3+ T cells were observed in most patients. Spontaneous improvement of T cell numbers was detected in patients, 3 years after the first study. Analysis of CD4+ and CD8+ TCR Vbeta repertoire in peripheral and thymic cells showed a normal distribution of populations even if occasional deletions were observed. Lymphoproliferative responses to mitogens were comparable to controls as well as anti-CD3-induced protein tyrosine phosphorylation. Increased anti-CD3-mediated apoptosis was observed in thymic cells. Our data support the idea that in patients surviving the correction of cardiac anomalies, the immune defect appears milder than originally thought, suggesting development of a normal repertoire of mature T cells.     

不同器官保存液对大鼠胸腺移植物的影响

目的评价不同保存液对大鼠胸腺移植物的影响。方法分别将大鼠胸腺用乳酸林格液、UW液、HTK液保存后进行异体移植,观察其超微结构的变化并检测ATP、SOD、MDA含量。结果与乳酸林格液相比,UW液、HTK液所保存的大鼠胸腺移植后,其超微结构改变小,ATP、SOD含量多,MDA含量少;HTK液保存的胸腺ATP含量显著高于UW液（P〈0．05）。结论UW液和HTK液有利于移植胸腺的保存,其中HTK液更有利于大鼠移植胸腺中ATP的贮存。     

Susceptibility of neonatal T cells and adult thymocytes to peripheral tolerance to allogeneic stimuli

We studied the tolerization of neonatal thymocytes (NT), neonatal splenocytes (NS) and adult thymocytes (AT), transferred to syngeneic nude (nu/nu) hosts previously injected with semi-allogeneic splenocytes, without any supportive immunosuppressive treatment. This protocol allows the study of peripheral tolerance in the absence of the thymus. BALB/c neonatal T cells and ATs were able to expand in syngeneic BALB/c nu/nu mice and functionally reconstituted an allogeneic response, rejecting (BALB/c x B6.Ba) F1 splenocytes transferred 3-4 weeks after injection of BALB/c cells. However, if (BALB/c x B6.Ba) F1 cells were injected into BALB/c nude hosts 30 days before transfer of NT, NS or AT cells, the F1 population was preserved and specific tolerance to B6 allografts was established. Furthermore, transfer to lymphopenic F1 nu/nu showed that tolerance could be established only for neonatal populations, showing that unique properties of neonatal T cells allow their tolerization in both lymphopenic and non-lymphopenic conditions, in the absence of suppressive immunotherapy. These results bring empirical support to the possibility of T-cell engraftment in immunodeficient patients showing partial identity with donor major histocompatibility complex (MHC) genes; the manipulation of immunological maturity of donor T cells may be the key for successful reconstitution of immunocompetence without induction of graft-versus-host disease.     

Induction of tolerance to alloantigens in adult mice

Tolerance to allogeneic C57BL/6 (H-2^b) cells was induced in CBA (H-2^k mice. A combination of three types of intervention was used for tolerogenic treatment: thymectomy on adult mice, injection of a large dose of donor's spleen cells, and injection of 200 mg/kg cyclophosphamide 24 h later. Long (up to 5 months) survival of transplanted allogeneic C57BL/6 hearts was observed in animals treated in this way. Tolerance to antigens of the H-2 complex was confirmed in mixed lymphocyte culture. No chimerism was present in the recipients' lymphoid tissue.Laboratory of Immunologic Tolerance, N. F. Gamaleya Institute of Epidemiology and Microbiology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR P. A. Vershilova.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 3, pp. 320–322, March, 1980.     

Decreased expression of calcium receptor in parathyroid tissue in patients with hyperparathyroidism secondary to chronic renal failure

The response of parathyroid cells to serum calcium is regulated by a calcium-sensing receptor protein (CaR). In patients with chronic renal failure, hypocalcemia contributes to the parathyroid hyperplasia and increased parathyroid hormone secretion characteristic of secondary hyperparathyroidism (sHPT). However, patients with uremia also display reduced sensitivity to extracellular calcium; this seems to be owing to an alteration of the receptor mechanism. This study examined calcium receptor expression in the parathyroid tissue of patients with sHPT, using immunohistochemical technicques and comparison with normal tissue and parathyroid glands of patients with primary hyperparathyroidism. In all the glands studied, immunostaining was more intense in chief cells than in oxyphilic, transitional, and clear cells. The parathyroid glands of patients with sHPT displayed significantly reduced expression of CaR with respect to morphologically normal ones; a very similar reduction is reported in adenomas. Furthermore, in glands displaying multinodular hyperplasia, expression was less marked in nodule-forming cells than in internodular areas. The decreased expression of calcium receptors in the parathyroid tissue of uremic patients was thought to be owing to the different cell populations present; these parathyroid glands contained predominantly transitional, oxyphilic, and clear cells, which normally express fewer receptors than chief cells, which are more abundant in normal glands.     

门静脉输注供体脾细胞诱导基因大鼠心脏移植耐受

目的通过门静脉输注同种异基因脾细胞、腹腔给予环磷酰胺诱导同种心脏移植耐受 ,并探讨其耐受机理。方法经门静脉给予受体大鼠 3× 10 8个异基因供体脾细胞 ,2 d后腹腔注射 80 m g/kg的环磷酰胺 ,10 d后实施心脏移植手术。观察、记录移植物的存活时间 ,通过 ML R、DTH、IL- 2逆转实验及过继性转移实验 ,探讨耐受机理。结果异基因心脏移植物的存活时间明显延长 ;ML R和 DTH实验证明 :受体大鼠的免疫应答受抑制 ,且该耐受表现为供体特异性 ;IL- 2逆转实验、过继性转移实验表明 :该耐受与克隆失活、抑制细胞和“感染”耐受机理有关。结论本诱导方案对于大鼠心脏移植存活时间的延长是一有效的方法 ,移植耐受的形成涉及多种机制。     

Induction of transplantation tolerance through regulatory cells: from mice to men

Organ transplantation results in the activation of both innate and adaptive immune responses to the foreign antigens. While these responses can be limited with the use of systemic immunosuppressants, the induction of regulatory cell populations may be a novel strategy for the maintenance of specific immunological unresponsiveness that can reduce the severity of the detrimental side effects of current therapies. Our group has extensively researched different regulatory T-cell induction protocols for use as cellular therapy in transplantation. In this review, we address the cellular and molecular mechanisms behind regulatory T-cell suppression and their stability following induction protocols. We further discuss the use of different hematopoietically derived regulatory cell populations, including regulatory B cells, regulatory macrophages, tolerogenic dendritic cells, and myeloid-derived suppressor cells, for the induction of transplantation tolerance in light of new clinical trials developing therapies with some of these populations.     

CTLA-4 Ig腺病毒基因治疗联合供体细胞输注诱导混合嵌合体和大鼠心脏移植耐受

目的　在心脏移植手术中实施CTLA 4Ig腺病毒基因治疗并联合术后输注供体骨髓细胞 ,诱导异基因大鼠心脏移植耐受 ,并对相关机制进行研究。方法　将异基因DA大鼠的心脏移植给受体LEW大鼠 ,同时经门静脉输注供体DA的脾细胞 (SC ,3× 10 8)、CTLA 4Ig腺病毒 [( 1～ 5 )× 10 9PFU ml],第 4天由舌静脉输注DA的骨髓细胞 (BMC ,3× 10 8)。观察、记录心脏移植物的存活时间。并对皮肤移植的受体作同样处理 ,观察皮肤移植存活情况。通过MLR、IL 2逆转实验及嵌合体的测定 ,探讨耐受机理 ,并检测了CTLA 4Ig的体内表达、TH1 TH2型细胞因子的表达。结果　单用CTLA 4Ig腺病毒基因治疗 ,或CTLA 4Ig腺病毒基因治疗联合单独的供体脾细胞或骨髓细胞能不同程度地延长异基因心脏移植物的存活 ,但不能延长皮肤移植物的存活。脾细胞、CTLA 4Ig腺病毒和骨髓细胞(SC Ad BMC)处理组的心脏移植物存活时间明显超过其它各耐受诱导组 ,并且能够诱导皮肤耐受。RT PCR实验证明 ,在受体内不同的组织CTLA 4Ig基因的表达量有所不同 ,并且随着时间的推移表达下降。TH1和TH2型细胞因子的检测显示 ,耐受大鼠体内未发现这两类细胞因子的偏移现象。MLR证明耐受大鼠的免疫应答表现为供体特异性降低 ,IL 2逆转实验、嵌合体检测表明 ,该耐受可能与     

H-2Kb基因转移诱导小鼠心肌移植免疫耐受

目的探讨H-2Kb基因转移诱导小鼠心肌移植免疫耐受的可行性。方法通过逆转录病毒载体介导的基因转移技术,将供体小鼠(C57BL/6)的H-2Kb基因(小鼠MHC-类基因)导入到受体小鼠(BALB/c)的造血细胞。结果H-2Kb基因可以稳定地整合进小鼠造血细胞的基因内,并在受体内表达较长时间。正常对照小鼠的心肌移植物平均存活时间(MST)为9.4±1.84d。诱导耐受组小鼠的心肌移植物MST为45.7±6.001d,比对照组明显延长(P<0.05)。结论H-2Kb基因转移诱导了供体特异性的免疫耐受,为临床移植控制排斥反应提供了一种新的方法     

Biomarkers and possible mechanisms of operational tolerance in kidney transplant patients

A small number of patients do not reject their graft after weaning from immunosuppressive treatment. Here, we analyze the studies carried out to try to understand the mechanisms involved in this operational transplant tolerance and evaluate the hypotheses proffered on these potential mechanisms.