Thymus Transplantation Research Articles

Fetal Liver-Derived Stem Cells Ameliorate Immune Functions in Leptin Receptor-Deficient Mice

Fetal liver (FL) contains hepatic stem cells, hematopietic stem cells, and mesenchymal stem cells, as well as pluripotent stem cells and very small embryonic-like stem cells. FL has thus been available as a source of stem cells for regenerative medicine. Our previous report suggested that combining FL cell transplantation with the transplantation of fetal thymus prevented tumor growth in tumor-bearing mice. Moreover, in animal models, intra bone marrow-bone marrow transplantation (IBM-BMT) has proven to be the best approach for allogenic BMT. We here propose that transplanting FL cells by IBM-BMT can improve immune functions in leptin receptor-deficient (db/db) mice. FL cells were collected from FLs of C57BL/6 mice at 16 days post coitum, and then transplanted by IBM-BMT to leptin receptor deficent mice, an animal model of type 2 diabetes with obesity. Our results showed that the body weight was significantly lowered in the treated db/db mice than in the sham-treated db/db mice. The plasma IL-6 level significantly decreased and adiponectin level significantly increased after the transplantation of FL cells. Blood glucose levels also significantly decreased although not to within the normal range. This is the first report that the transplantation of FL cells may improve immune function, resulting in increased adiponectin levels, and decreased body weight in db/db mice. DisclosuresNo relevant conflicts of interest to declare.

Fetal thymus graft enables recovery from age-related hearing loss and expansion of CD4-Positive T cells expressing IL-1 receptor type 2 and regulatory T Cells

BackgroundAccumulating evidence has indicated the relationship between the systemic immune system and the central nervous system including the inner ear.ResultsWe have shown that age-related developments of T-cell dysfunction, hearing loss, and degeneration of cochlear spiral ganglion (SG) neurons observed in 6-month-old mice were recovered in 12 months old mice which previously given fetal thymus transplants twice. We have also demonstrated that CD4+ T cells expressing interleukin 1 receptor type 2 (IL-1R2) and naturally occurring regulatory T cells (nTregs), which expanded in aged 12-month-old mice, were reduced in the thymus-grafted mice of the same age.ConclusionIt is conceivable that the rejuvenation of systemic immune function by fetal thymus grafts contributes not only to the activation of cellular immunity but also to the decrease of IL-1R2+ CD4+ T cells or nTregs, which cells accelerate both age-related hearing loss (AHL) and neurodegeneration of the cochlear neurons. Further studies on the interactions among IL-1R2 expression on CD4+ T cells, Tregs, and neuronal cells and also on the relationships between fetal thymus grafting and the rejuvenation of systemic immunity should be designed in order to advance towards therapeutic effects on neurosenescence, including AHL.

Isolation and transplantation of different aged murine thymic grafts.

The mechanisms that regulate the efficacy of thymic selection remain ill-defined. The method presented here allows in vivo analyses of the development and selection of T cells specific for self and foreign antigens. The approach entails implantation of thymic grafts derived from various aged mice into immunodeficient scid recipients. Over a relatively short period of time the recipients are fully reconstituted with T cells derived from the implanted thymus graft. Only thymocytes seeding the thymus at the time of isolation undergo selection and develop into mature T cells. As such, changes in the nature and specificity of the engrafted T cells as a function of age-dependent thymic events can be assessed. Although technical expertise is required for successful thymic transplantation, this method provides a unique strategy to study in vivo a wide range of pathologies that are due to or a result of aberrant thymic function and/or homeostasis.

Chest Wall, Thymus, and Heart Transplant: Pushing the Boundary of Solid Organ and Vascularized Composite Allotransplantation

Background: The purpose of this study is to design a proof-of-concept cadaveric model to describe technical aspects of allograft harvest and recipient inset of an en bloc chest wall, thymus, and heart transplant. Materials and Methods: Two surgical simulations were performed involving procurement and inset. Four cadavers were obtained and identified as donor or recipient. Debriefing following each simulation addressed technical feasibility, anatomical considerations, degree of difficulty, length of surgery, and formulating a bailout strategy. An intraoperative vascular dye perfusion study was performed to determine the vascular territories of the chest wall and the need for bilateral arterial inflow to the chest.Results: Both transplant procedures were successfully completed. Mean donor age was 88.5 y old (range: 83–94). Allograft harvest mean duration was 94.5 minutes (range: 89–100). Graft inset duration was 90.5 minutes (range: 88–93), with a mean duration of 33 minutes (range: 25–41) of chest wall fix...

Egress of mature murine regulatory T cells from the thymus requires RelA.

The mechanism of egress of mature regulatory T cells (Tregs) from the thymus to the periphery remains enigmatic, as does the nature of those factors expressed in the thymic environment. In this study, we examined the fate of thymic Tregs in TNF-α/RelA double-knockout (TA-KO) mice, because TA-KO mice retain a Treg population in the thymus but have only a small Treg population at the periphery. Transplantation of whole TA-KO thymus to under the kidney capsule of Rag1-null mice failed to induce the production of donor-derived splenic Tregs expressing neuropilin-1, which is reported to be a marker of naturally occurring Tregs, indicating that TA-KO thymic Tregs either do not leave the thymus or are lost at the periphery. We next transplanted enriched TA-KO thymic Tregs to the peripheries of TA-KO mice and traced mouse survival. Transplantation of TA-KO thymic Tregs rescued the lethality in TA-KO mice, demonstrating that TA-KO thymic Tregs remained functional at the periphery. The TA-KO thymic Treg population had highly demethylated CpG motifs in the foxp3 locus, indicating that the cells were arrested at a late mature stage. Also, the population included a large subpopulation of Tregs expressing IL-7Rα, which is a possible marker of late-stage mature Tregs. Finally, TA-KO fetal liver chimeric mice developed a neuropilin-1(+) splenic Treg population from TA-KO cells, suggesting that Treg arrest was caused by a lack of RelA in the thymic environment. Taken together, these results suggest that egress of mature Tregs from the thymus depends on RelA in the thymic environment.

Stem cell transplantation upregulates Sirt1 and antioxidant expression, ameliorating fatty liver in type 2 diabetic mice.

Nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance, oxidative stress, and obesity. The db/db mouse model displays increased levels of insulin resistance, obesity, and an over-accumulation of hepatic triglycerides, making it an excellent model for studying NAFLD. In db/db mice, intra-bone marrow-bone marrow transplantation plus thymus transplantation (IBM-BMT+TT) improves type 2 diabetes mellitus (T2 DM) by normalizing the T-cell imbalance. We hypothesized that this approach would improve Sirt1 expression in the liver and benefit liver development.The db/db mice were treated with IBM-BMT+TT, and plasma MCP-1, IL-6, adiponection, LDL, Sirt1, and HO-1 levels were then assessed. Stem cell transplantation decreased the levels of plasma inflammatory cytokines and LDL while it increased the expression of Sirt1 and HO-1, resulting in decreased progression of fatty liver. Moreover, Sirt1 and HO-1 expression were both detected in the thymus and many HO-1-positive cells were observed in the bone marrow.This is the first report of stem cell transplantation improving the antioxidant function in the liver, thymus, and bone marrow of db/db mice by increasing the levels of Sirt1 and HO-1. This approach may prove useful in the treatment of nonalcoholic steatohepatitis and its clinical manifestations.

Fetal Liver-Derived Stem Cells Ameliorate Adipocyte Functions in Obese Mice

Fetal liver (FL) contains hepatic stem cells, hematopietic stem cells, and mesenchymal stem cells, as well as pluripotent stem cells and very small embryonic-like stem cells. FL has thus been available as a source of stem cells for regenerative medicine. Our previous report suggested that combining FL cell transplantation with the transplantation of fetal thymus prevented tumor growth in tumor-bearing mice. Moreover, in animal models, intra bone marrow-bone marrow transplantation (IBM-BMT) has proven to be the best approach for allogenic BMT. We here propose that transplanting FL cells by IBM-BMT can improve adipocyte functions in obese mice. FL cells were collected from FLs of C57BL/6 mice at 16 days post coitum, and then transplanted by IBM-BMT to db/db mice, an animal model of type 2 diabetes with obesity. Our results showed that the body weight was significantly lower in the treated db/db mice than in the sham-treated db/db mice. The plasma IL-6 level significantly decreased and adiponectin level significantly increased after the transplantation of FL cells. Blood glucose levels also significantly decreased although not to within the normal range. This is the first report that the transplantation of FL cells may improve adipocyte functions, resulting in decreased body weight in obese mice.

Various Ages Thymus Transplantation Has Differential Ability of Anti Tumor Effects

[Objective] Our previously work has demonstrated that allogeneic bone marrow transplantation (allo-BMT) combined with thymus transplantation (TT) was effective in restoring donor-derived T cell function and was beneficial for enhancing graft versus tumor (GVT) effects. However, since the thymic cell functions differ with age, the most effective age of thymus should be explored. In the present study, we examined the effects of allo-BMT plus thymus transplantation (TT) from various ages (fetal, newborn, adult) to determine it’s anti tumor effects.[Methods] BALB/c mice (H-2d ) bearing Meth-A sarcoma (H-2d )were treated with allo-BMT combined with or without TT from various age B6 mice(H-2b), the tumor size and survival period of the recipient BALB/c mice were examined, histological studies were performed in the liver, intestine, and the engrafted thymus from the recipients 4 weeks after the BMT. Surface markers on lymphocytes from the spleen were analyzed by 3-color fluorescence staining using a FACScan system to determine chimerism. Cytokine production was examined for monitoring lymphocyte function.[Results]. All mice treated with BMT with or without TT showed fully donor-derived chimerism. The tumor size were significantly smaller in the mice treated with BMT plus TT than those treated with BMT alone. Interestingly, the mice treated with BMT plus newborn or fetal thymus showed the greatest degree of tumor regression. The survival rate in mice treated with BMT plus newborn thymus was significantly prolonged compared with those treated with BMT plus adult thymus or BMT plus fetal thymus. Histologically, both the cortex and medullar areas were clearly shown in each group. Normal T-cell differentiation was also observed in the engrafted thymus. The number of CD4+ T cells significantly increased in the mice treated with BMT plus TT compared with those treated BMT alone. The numbers were highest in the mice treated with BMT plus newborn thymus or BMT plus fetal thymus. Microscopic founding of small intestine and liver indicated no evidence of GVHD in all mice treated with BMT combined with or without TT. The production of IL-2 and IFN-γ was significantly elevated in the mice treated with BMT plus TT compared with those treated with BMT alone. However, the production of IL-2 has no significantly difference in all various age thymus transplantation groups. In contrast, the production of IFN-γ was the highest in the mice treated with BMT plus newborn thymus transplantation.[Conclusion]. The present study indicated that allo-BMT combined with TT induces high thymopoiesis, elicit strong GVT effects, and is effective for the host with cancer. And the combination of allo-BMT with newborn thymus is the most effect. We thus found that donor-derived T cells play an important role in the treatment of leukemia. As human thymus tissue can be obtained from patient with congenital heart disease or from aborted fetuses, so the results of the present study suggest this strategy will become a new way for the treatment of malignant tumors in human. DisclosuresNo relevant conflicts of interest to declare.

Thymus Transplantation Plus Allogeneic Bone Marrow Transplantation Can Induce Strong Graft-Versus Leukemia Effects with Low Risk of Graft-Versus-Host Disease

Abstract: [Objective] Allogeneic bone marrow transplantation (allo-BMT) has been used for the treatment of refractory leukemia and donor lymphocyte infusion (DLI) was used for the purpose of graft versus leukemia (GVL) effects. However, DLI is associated with a risk of graft versus host disease (GVHD). Thus, new cellular-based methods are desired. In the present study, we performed thymus transplantation (TT) plus allo-BMT to explore it’s anti leukemia effects. [Methods] Recipient B6 mice (H-2b) bearing leukemia (EL-4 cells, H-2b) were irradiated 8 Gy. The next day, bone marrow cells from BALB/c mice (H-2d) were transplanted into the B6 mice. Simultaneously, DLI and thymus transplantation from the same donor were carried out. The survival period of the recipient B6 mice were examined, histological studies were performed in the liver, intestine, and the engrafted thymus from the recipients 4 weeks after the BMT. Surface markers on lymphocytes from the spleen were analyzed by 3-color fluorescence staining using a FACScan system to determine chimerism. [Results]. All mice treated with BMT showed fully donor-derived chimerism(H-2d). The survival rate in mice treated with BMT plus TT was significantly prolonged compared with those treated with BMT alone or BMT plus DLI. Histologically, both the cortex and medullar areas of the engrafted thymus under the renal capsule were clearly shown. Normal T-cell differentiation was also observed in the engrafted thymus. Microscopic founding of small intestine and liver in the BMT plus TT group indicated mild GVHD, whereas those treated with BMT plus DLI showed moderated to serious GVHD. The number of the CD4+ cells was significantly greater in the mice treated with BMT+TT compared with those with BMT alone or those with BMT + DLI. The percentage of FoxP3+ regulatory T cells among CD4+ cells was higher in the mice treated with BMT + TT comparable to those treated with BMT + DLI. The results for CD8+ T cells were similar to those for CD4+ cells. [Conclusion]. Allo-BMT combined with TT induces high thymopoiesis, and can elicit strong GVL effects with mild GVHD reaction. We thus found that donor-derived T cells play an important role in the treatment of leukemia. Also the details of the mechanisms are still unknown, one possibilities may be the continuous supplementation of T cells from the allogeneic thymus. The results of the present study suggest this strategy will become a new way for the treatment of refractory or relapse leukemia in human. DisclosuresNo relevant conflicts of interest to declare.

Sirt1 Expression Related with Sarcoma Growth after Stem Cell Transplantation Combined with Depletion of Myeloid-Derived Suppressor Cells

Sirtuins (Sirt) play a number of roles in various aging-related diseases such as obesity, diabetes and cancer, and Sirt1 plays a double role in cancer. The combination of bone marrow transplantation (BMT) and thymus transplantation (TT) has been shown to prevent the growth of malignant tumors. Myeloid-derived suppressor cells (MDSCs) can differentiate from bone marrow stem cells under pathological conditions such as cancer, and prevent the potent action of T cells and NK cells, thereby promoting tumor growth. Thus, depleting MDSCs is important when treating cancer. We therefore investigated the relationship between Sirt1 expression and sarcoma growth in sarcoma-bearing mice treated with BMT+TT and the depletion of MDSCs using Gr-1 Ab. Our results showed that only granulocytic MDSCs (G-MDSCs) were depleted by the Gr-1 Ab in these mice. Moreover, the sarcomas decreased significantly in size in the Gr-1 antibody group when compared with the BMT group. This was due to the increase in the percentage of T cells and decrease in the percentage of G-MDSCs. Furthermore, Sirt1 expression decreased significantly in the sarcoma. These findings suggest that inactive Sirt1 may prevent sarcoma growth in sarcoma-bearing mice that receive stem cell transplants and depletion of MDSCs. DisclosuresNo relevant conflicts of interest to declare.

Clinical course and outcome predictors of critically ill infants with complete DiGeorge anomaly following thymus transplantation.

To identify risk factors for PICU admission and mortality of infants with complete DiGeorge anomaly treated with thymus transplantation. We hypothesized that age at transplantation and the presence of congenital heart disease would be risk factors for emergent PICU admission, and these factors plus development of septicemia would increase morbidity and mortality. Retrospective review. Academic medical-surgical PICU. All infants with complete DiGeorge anomaly treated with thymus transplantation between January 1, 1993, and July 1, 2010. None. Consent was obtained from 71 infants with complete DiGeorge anomaly for thymus transplantation, and 59 infants were transplanted. Median age at transplantation was 5.0 months (range, 1.1-22.1 mo). After transplantation, 12 of 59 infants (20%) required 25 emergent PICU admissions. Seven of 12 infants (58%) survived to PICU discharge with six surviving 6 months posttransplantation. Forty-two of 59 infants (71%) transplanted had congenital heart disease, and 9 of 12 (75%) who were admitted to the PICU had congenital heart disease. In 15 of 25 admissions (60%), intubation and mechanical ventilation were necessary. There was no difference between median ventilation-free days between infants with and without congenital heart disease (33 d vs 23 d, p = 0.544). There was also no correlation between ventilation-free days and age of transplantation (R, 0.17; p = 0.423). Age at transplantation and the presence of congenital heart disease were not associated with risk for PICU admission (odds ratio, 0.95; 95% CI, 0.78-1.15 and odds ratio, 1.27; 95% CI, 0.30-5.49, respectively) or PICU mortality (odds ratio, 0.98; 95% CI, 0.73-1.31 and odds ratio, 0.40; 95% CI, 0.15-1.07, respectively). Most transplanted infants did not require emergent PICU admission. Age at transplantation and the presence of congenital heart disease were not associated with PICU admission or mortality.

An organized and functional thymus generated from FOXN1-reprogrammed fibroblasts.

SummaryA central goal of regenerative medicine is to generate transplantable organs from cells derived or expanded in vitro. Although numerous studies have demonstrated production of defined cell-types in vitro1, creation of a fully intact organ has not been reported. The transcription factor Forkhead box N1 (FOXN1) is critically required for development of thymic epithelial cells (TECs)2,3 a key cell-type of the thymic stroma4. Here, we show that enforced Foxn1 expression is sufficient to reprogramme fibroblasts into functional TECs, an unrelated cell-type across a germ-layer boundary. These Foxn1-induced TECs (iTECs) supported efficient development of both CD4+ and CD8+ T cells in vitro. Upon transplantation, iTEC established a complete, fully organized and functional thymus, that contained all of the TEC sub-types required to support T cell differentiation and populated the recipient immune system with T cells. iTEC thus demonstrate that cellular reprogramming approaches can be used to generate an entire organ, and open the possibility of widespread use of thymus transplantation to boost immune function in patients.

The increase of the average and maximum span of life by the allogenic thymic cells transplantation in the animals’ anterior chamber of eye

The age-dependent, lifespan-extending effect of grafting allogenic thymic tissue into a recipient’s immune-privileged anterior chamber of eye was studied. Grafting thymic tissues from young to old animals was shown to lead to a significant extension of the recipient’s average and maximum lifespans.

Gr-1 Ab administered after bone marrow transplantation plus thymus transplantation suppresses tumor growth by depleting granulocytic myeloid-derived suppressor cells.

It has been shown that allogeneic intra-bone marrow–bone marrow transplantation (IBM-BMT) plus thymus transplantation (TT) is effective in treating recipients with malignant tumors. Although TT increases the percentage of T cells in the early term after BMT, the myeloid-derived suppressor cells (MDSCs) are still the dominant population. We used the Gr-1 Ab to deplete the granulocytic MDSCs (G-MDSCs) in tumor-bearing mice that had received BMT+TT. Two weeks after the BMT, the mice injected with Gr-1 Ab showed smaller tumors than those in the control group. In addition, Gr-1 Ab significantly increased the percentages and numbers of CD4+ and CD8+ T cells, and decreased the percentages and numbers of MDSCs and G-MDSCs. No side effects of the Gr-1 Ab on recipient or donor thymus were observed. These findings indicate that Gr-1 Ab administered after BMT+TT may enhance the effectiveness of tumor suppression.

Engineering an ectopic thymus in the lymph node to induce central tolerance and long-term allograft acceptance (TRAN3P.896)

Abstract Background: Allogeneic transplant rejection is one of the major problems plaguing the field of organ transplants. Our previous studies have established the lymph node as a functional site for thymus transplant. In this study, we hypothesized that conditioning transplant recipients with thymic cells immune-matched to the donor will induce long-term acceptance of a subsequent allograft. Methods: We transplanted Balb/c-GFP thymuses into the lymph nodes of FAH-/- mice on a 129sv background. After 6 weeks, the animals were challenged with donor-matched skin grafts or hepatocyte transfer and monitored for long-term allograft acceptance. We also assessed tolerance induction by performing mixed lymphocyte reaction assays (MLR), immunostaining of native and ectopic thymus, as well as thymic dendritic cell (tDC)-T cell co-cultures. Results: Mice receiving thymus transplants successfully accepted subsequent allografts long-term. MLR reactions demonstrated Balb/c-specific tolerance in these mice. We also observed migration of cells (mostly tDCs) from the ectopic to the native thymus. tDC-T cell co-cultures revealed that migrating DCs from the ectopic as well as native thymus were instrumental in generating the increased numbers of Tregs observed in recipient mice. Conclusion: We were able to achieve long-term allograft acceptance in mice receiving thymic transplants, which was possibly mediated by the increased Treg induction associated with cross-talk between the two thymuses.

Xenograft Tolerance and Immune Function of Human T Cells Developing in Pig Thymus Xenografts

Transplantation of xenogeneic thymus tissue allows xenograft tolerance induction in the highly disparate pig-to-mouse model. Fetal swine thymus (SW THY) can support the generation of a diverse human T cell repertoire that is tolerant of the pig in vitro. We demonstrate that SW THY generates all human T cell subsets, including regulatory T cells (Tregs), in similar numbers as fetal human thymus (HU THY) grafts in immunodeficient mice receiving the same human CD34(+) cells. Peripheral T cells are specifically tolerant to the mouse and to the human and porcine donors, with robust responses to nondonor human and pig Ags. Specific tolerance is observed to pig skin grafts sharing the THY donor MHC. SW THY-generated peripheral Tregs show similar function, but include lower percentages of naive-type Tregs compared with HU THY-generated Tregs. Tregs contribute to donor-pig specific tolerance. Peripheral human T cells generated in SW THY exhibit reduced proportions of CD8(+) T cells and reduced lymphopenia-driven proliferation and memory-type conversion, accelerated decay of memory-type cells, and reduced responses to protein Ags. Thus, SW thymus transplantation is a powerful xenotolerance approach for human T cells. However, immune function may be further enhanced by strategies to permit positive selection by autologous HLA molecules.

Humanized Mice for Studying Human Immune Responses and Generating Human Monoclonal Antibodies.

The new-generation humanized (Hu) mouse models permit multilineage human hematopoiesis and generate T cells, B cells, macrophages, and dendritic cells required for a coordinated human immune response. Therefore, any desired antigen or human-specific pathogens that can infect humanized mice can be used to generate human antibody responses. Two leading humanized mouse models are currently being used. The Hu-HSC model uses the transplantation of human hematopoietic stem cells (HSCs), whereas the BLT mouse model is created by transplantation of human fetal liver, thymus, and HSC. A number of human pathogens such as HIV-1, dengue, Epstein-Barr virus, and hepatitis C virus have been studied in these systems. Responder antigen-specific B cells from these animals can be collected and used to generate human monoclonals by B-cell immortalization or by single-cell PCR methods to "rescue" antibody-producing genes for ectopic expression. Both models generate cellular and humoral immune responses. However, the antibodies generated are primarily of the IgM type because of the inefficient immunoglobulin class switch resulting in the suboptimal production of antigen-specific affinity-matured IgG. The current Hu mouse models thus far have permitted the analysis of human "antibodyome," and recent reports demonstrated their utility in generating human monoclonal antibodies. Ongoing efforts at further refinements are expected to make these systems more efficient in the near future.

Xenotransplantation: immunological hurdles and progress toward tolerance

The discrepancy between organ need and organ availability represents one of the major limitations in the field of transplantation. One possible solution to this problem is xenotransplantation. Research in this field has identified several obstacles that have so far prevented the successful development of clinical xenotransplantation protocols. The main immunologic barriers include strong T-cell and B-cell responses to solid organ and cellular xenografts. In addition, components of the innate immune system can mediate xenograft rejection. Here, we review these immunologic and physiologic barriers and describe some of the strategies that we and others have developed to overcome them. We also describe the development of two strategies to induce tolerance across the xenogeneic barrier, namely thymus transplantation and mixed chimerism, from their inception in rodent models through their current progress in preclinical large animal models. We believe that the addition of further beneficial transgenes to Gal knockout swine, combined with new therapies such as Treg administration, will allow for successful clinical application of xenotransplantation.

Studies On Cohort Of Infants With Di-George Syndrome Detected By New York State Newborn Screening For Severe Combined Immunodeficiency (SCID)

S U N D A Y 332 Studies On Cohort Of Infants With Di-George Syndrome Detected By New York State Newborn Screening For Severe Combined Immunodeficiency (SCID) Dr. Doerthe A. Andreae, MD, Dr. Stephanie Albin, MD, Dr. Harshna Mehta, MD, Dr. Charlotte Cunningham-Rundles, MD, PhD, FAAAAI; The Icahn School of Medicine at Mount Sinai, New York, NY, Mt. Sinai Medical Center, New York, NY. RATIONALE: To assess immune and clinical status of infants with DiGeorge Syndrome referred toMount Sinai from the NewYork State (NYS) newborn screening program for severe lymphopenia. METHODS: We collected clinical and laboratory data on infants with DiGeorge Syndrome referred to Mount Sinai, one of 8 referral centers in New YorkState. Patientswith levels of T-cell receptor excision circles (TRECs) of below 125 were referred. Data collected included TREC values, CD3, CD4, CD8, NK and B cell absolute numbers as well as genotype and phenotype. RESULTS: In the first 33 months of newborn screening we saw 6 patients at Mount Sinai finally diagnosed with Di-George syndrome. 5 of these patients were female. 4 patients had undetectable TREC levels at birth (ranging from average 0 to 188 (?) and 0 to 889 on 2-4 follow up visits). All but one of those patients also had congenital heart defects of different degrees. T-cell lymphopenia ranged from 0 to 2189/cu mm absolute CD3. At least half of the patients were known to have a 22q11 deletion. One patient with 22q11 deletion had hypocalcemia and lymphopenia but no cardiac involvement. Another patient had complete DiGeorge Syndrome without chromosomal deletion due to maternal diabetes and subsequently successfully underwent thymic transplantation. A third patient with a maternal history of Di-George syndrome and 22q11 deletion was found to have Di-George syndrome with the same chromosomal abnormality. CONCLUSIONS: Newborn screening for SCID can identify patients with Di-George syndrome with varying degrees of lymphopenia.

Development of a new allogeneic hematopoietic stem cell transplantation method with co-thymus transplantation from the same donor —mechanism and application for intractable diseases—

Allogeneic Hematopoietic stem cell transplantation (allo-HSCT) is effective for several diseases, including leukemia, solid tumors, and immunodeficiency. However, there are still some intractable diseases that cannot be treated with HSCT alone. We have developed a new HSCT method, allo-HSCT + thymus transplantation (TT) from the same donor, which induces elevated T cell function with mild graft-versus-host disease (GVHD) in comparison to conventional HSCT alone and HSCT + donor lymphocyte infusion (HSCT + DLI). This method leads to improvement of immune function and the ability of engraftment, and is effective for treatment of autoimmune chronic pancreatitis and sialoadenitis in aging, lupus nephritis in hosts with radioresistance, and supralethal irradiation, in which conventional HSCT alone is ineffective. This method may become a valuable form of clinical therapy for intractable diseases.