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Seventeen patients transplanted with hematopoietic cells to correct severe T lymphocyte immunodeficiency resulting from complete DiGeorge anomaly were identified worldwide, and retrospective data were obtained using a questionnaire-based survey. Patients were treated at a median age of 5 months (range, 2-53 months) between 1995 and 2006. Bone marrow was used in 11 procedures in 9 cases: 6 from matched unrelated donors, 4 from human leukocyte antigen (HLA)-identical siblings, and one haploidentical parent with T-cell depletion. Unmobilized peripheral blood was used in 8 cases: 5 from HLA-identical siblings, one from a matched unrelated donor, one from an HLA-identical parent, and one unrelated matched cord blood. Conditioning was used in 5 patients and graft-versus-host disease prophylaxis in 11 patients. Significant graft-versus-host disease occurred in 9 patients, becoming chronic in 3. Median length of follow-up was 13 months, with transplantation from HLA-matched sibling showing the best results. Median survival among deceased patients (10 patients) was 7 months after transplantation (range, 2-18 months). The overall survival rate was 41%, with a median follow-up of 5.8 years (range, 4-11.5 years). Among survivors, median CD3 and CD4 counts were 806 (range, 644-1224) and 348 (range, 225-782) cells/mm3, respectively, CD4+/CD45RA+ cells remained very low, whereas mitogen responses were normalized.

Adoptive transfer of mature T cells (ATMTC) through bone marrow (BM) transplantation, first attempted over 20 years ago, has recently emerged as a successful therapy for complete 22q deletion syndrome (22qDS). This provides a potential option to thymic transplantation (TT) for immune reconstitution in 22qDS. Compared to thymic transplant, ATMTC is an easier procedure to accomplish and is available at more centers. However, there are differences in the nature of the T-cell reconstitution that results. Predictably, more naïve T cells and recent thymic emigrants are present in patients treated with thymus transplant. There are no significant differences in mortality between the two procedures, but the number of patients is too limited to conclude that the procedures are equally effective. Adoptive transfer should be pursued as a reasonable treatment for 22qDS patients requiring immune reconstitution when thymus transplant is not available.

Background Therapeutic options for DiGeorge syndrome (DGS) with profound T-cell deficiency are very limited. Thymic transplantation has shown promising results but is not easily available. Hematopoietic cell transplantation (HCT) has been successful in restoring immune competence in the short term. Objective Present the long-term follow-up of 2 patients with complete DGS who received bone marrow transplants in the neonatal period from HLA-matched siblings, and perform a multicenter survey to document the status of other patients with DGS who have undergone HCT. Methods Immune function assessment by immunophenotyping, lymphocyte proliferation, T-cell receptor excision circles, single nucleotide polymorphism mapping arrays, spectratyping, cytogenetics, and fluorescence in situ hybridization were used. Results Among reported patients with DGS receiving HCT, survival is greater than 75%. Our patients are in their 20s and in good health. Their hematopoietic compartment shows continuous engraftment with mixed chimerism, normal T-cell function, and humoral immunity. Circulating T cells exhibit a memory phenotype with a restricted repertoire and are devoid of T-cell receptor excision circles. Conclusion These features suggest that T-cell reconstitution has occurred predominantly through expansion of the donors' mature T-cell pool. Although restricted, their immune systems are capable of providing substantial protection to infection and respond to vaccines. We conclude that bone marrow transplant achieves long-lived reconstitution of immune function in complete DGS and is a good alternative to thymic transplantation in patients with a suitable donor. Clinical implications Bone marrow transplant in complete DGS using an HLA-matched sibling donor provides long-lasting immunity and is a suitable and more available alternative to thymic transplantation.

Adenovirus causes significant morbidity and mortality in immunocompromised children. We report how an infusion of HLA-matched sibling donor T lymphocytes rapidly eradicated life-threatening, high-level adenoviremia in a child with complete DiGeorge syndrome (22q11.2 deletion) who went on to reconstitute a diverse, donor-derived, postthymic T-cell repertoire.

We report on the development of steroid-refractory recurrent cytopenias in a child with 22q11.2 deletion syndrome. His first hematological complication was autoimmune hemolytic anemia at 3 months of age. Thereafter, he developed severe autoimmune cytopenias of all 3 hematological lineages with poor response to steroids and intravenous immunoglobulin. At the age of 2½ years, a course of anti-CD20 therapy (Rituximab) was given with transient hematological recovery. Because of persistent symptoms, bone marrow transplantation from a matched unrelated donor was performed. Although the data in the use of anti-CD20 therapy in children with 22q11.2 deletion syndrome and autoimmune cytopenias are limited, our experience suggests its potential benefit.

In the field of organ transplantation, the state of thymic function has not been a major concern but data from bone marrow transplantation studies have unravel the persistence of some thymopoiesis in the adult and, more importantly, the possibility of reinducing it. Given the central role of the thymus in tolerance, these facts have stimulated the interest in the biology of the thymus in humans. Contemporarily, basic research has provided new tools, if imperfect, to monitor thymic function, that is, T-cell receptor excision circles, markers for lymphocytes recently emigrated from the thymus and new imaging techniques. The deployment of these new tools is already changing some paradigms and has now established that re-enactment of thymic activity in the course of bone marrow transplantation or in patients with human immunodeficiency virus on highly active anti-retroviral therapy is beneficial and that can be achieved in the adult. Clinical trials using thymopoiesis-stimulating factors are underway. On the other hand, the discovery that the thymus contains a broad representation of self-antigens and that this depends on the expression of the product of the gene AIRE by the medullary thymic epithelial cells opens the possibility of manipulating central tolerance. Current protocols inducing microchimerism to generate tolerance to solid organ grafts suggest that this could be a feasible therapeutic goal. Therefore, there are many signs indicating that a period of translational research applying the principles of thymic biology and central tolerance to transplantation has already started.

CHARGE association and DiGeorge syndrome (DGS) rarely occur together and only eight cases have been reported in the English literature. Two were associated with esophageal atresia (EA) and severe congenital heart anomalies. We report a third case of EA with tracheoesophageal fistula (EA-TEF) associated with coarctation of the aorta (CoA), CHARGE association, and DGS. The challenge for management in this complicated case is the background DGS which influences surgical outcome because of Ca++ imbalance and immune deficiency that can be life-threatening and require bone marrow transplantation.

Combined immune deficiencies are a heterogeneous group of congenital disorders usually attributable to a single gene defect. The hallmark of these disorders is recurrent infections resulting from defects in both T- and B-cell function. This article reviews the basic components of the immune system as well as the clinical presentation, laboratory findings, and treatment for 3 distinct combined immune deficiencies.

As the initial conduit for respiration and alimentation, the upper aerodigestive tract is an obvious portal of entry for microorganisms. A functioning immune system is required to prevent establishment of infection in the ear, nose, and throat as well as to prevent excessive penetration of microorganisms more distally into the respiratory and gastrointestinal tracts. Host defense of the upper aerodigestive tract depends on mechanisms of cellular and humoral immunity that are active throughout the body, and on specialized functions (such as mucociliary clearance and IgA antibody secretion) that are restricted to mucosal surfaces. Defects of these immune mechanisms lead to recurrent or unusually severe infections. Otolaryngologic presentations are common in the immunodeficient host: many immunodeficient patients initially present with typical infections of the head or neck including sinusitis, otitis media, cervical adenopathy, or infections of the oral cavity. Although most patients with severe immunodeficiency are unlikely to present undiagnosed to an otolaryngologist, otolaryngologists may play a critical role in the initial identification and preliminary work up of patients with more subtle defects. Otolaryngologists will often be confronted with patients who seem infectionprone and must decide which individuals deserve specialty referral or other further work up for suspected immunodeficiency. Suggested triggers for further evaluation of immune status are summarized in Box 1 [1,2]. Many primary immunodeficiencies are associated with syndromes whose nonimmune manifestations are of interest to otolaryngologists (colobomaheart-atresia-retardation-genital-ear [CHARGE] syndrome, Down syndrome, and others). The otolaryngologist is frequently intimately involved in the care of these children for management of nonimmune otolaryngologic

Bruton's XLA and DiGeorge syndrome patients show that two basic immune systems are distinct from each other in humans - thymus-dependent cell-mediated immunodeficiencies vs. antibody-based immunodeficiencies. The appendix-sacculus lymphoid organ of rabbits, like the bursa of Fabricius, represents a central lymphoid organ. Chronic granulomatous disease of childhood (CGD) revealed that phagocytosis killing of catalase-positive microorganisms employ oxidative burst. Bone marrow transplantation (BMT) proved life saving in severe combined immunodeficiency (SCID). The first BMT cured XSCID and the second BMT cured a complicating aplastic anemia launching BMT as a treatment of many diseases. Now 75 fatal diseases have been cured by myeloablative BMT. BMT also cured experimental autoimmune diseases. BMT alone did not cure lupus with polyarthritis in MRL/lpr mice or polyarthritis in NZB/KN mice, but BMT plus bone (stromal cell) transplants cured these diseases. Autoimmune diseases and lethal glomerulonephritis were prevented or cured in BXSB mice by mixed allogeneic plus syngeneic BMT. X-linked Hyper IgM syndrome (XHIM) was also cured by BMT from a 2-year-old MHC-matched sibling donor. Nonmyeloablative BMT plus mesenchymal stem cells (stromal cells) was effective treatment for a form of collagen-vascular disease and also a lethal form of hypophosphatasia. Mannan-binding lectin, an opsonin that activates the complement system when mutated and at low levels in blood, opens a door to frequent infections throughout childhood and adult life. This new immunodeficiency is based on genetic mutations that involve a native defense system.

Genetic defects in T-cell function lead to susceptibility to infections or to other clinical problems that are more grave than those seen in disorders resulting in antibody deficiency alone. Those affected usually present during infancy with either common or opportunistic infections and rarely survive beyond infancy or childhood. The spectrum of T-cell defects ranges from the syndrome of severe combined immunodeficiency, in which T-cell function is absent, to combined immunodeficiency disorders in which there is some, but not adequate, T-cell function for a normal life span. Recent discoveries of the molecular causes of many of these defects have led to a new understanding of the flawed biology underlying the ever-growing number of defects. Most of these conditions could be diagnosed by means of screening for lymphopenia or for T-cell deficiency in cord blood at birth. Early recognition of those so afflicted is essential to the application of the most appropriate treatments for these conditions at a very early age. The latter treatments include both transplantation and gene therapy in addition to immunoglobulin replacement. Fully defining the molecular defects of such patients is also essential for genetic counseling of family members and prenatal diagnosis.

The human thymus is a complex chimeric organ comprised of central (thymic epithelial space) and peripheral (perivascular space) components that functions well into adult life to produce naive T lymphocytes. Recent advances in identifying thymic emigrants and development of safe methods to study thymic function in vivo in adults have provided new opportunities to understand the role that the human thymus plays in immune reconstitution in aging, in bone marrow transplantation, and in HIV-1 infection. The emerging concept is that there are age-dependent contributions of thymic emigrants and proliferation of postthymic T cells to maintain the peripheral T cell pool and to contribute to T cell regeneration, with the thymus contributing more at younger ages and peripheral T cell expansion contributing more in older subjects. New studies have revealed a dynamic interplay between postnatal thymus output and peripheral T cell pool proliferation, which play important roles in determining the nature of immune reconstitution in congenital immunodeficiency diseases, in bone marrow transplantation, and in HIV-1 infection. In this paper, we review recent data on human postnatal thymus function that, taken together, support the notion that the human thymus is functional well into the sixth decade and plays a role throughout life to optimize human immune system function.

BMT was carried out on a patient with DiGeorge syndrome who suffered recurrent infections after birth. At 13 months of age, 8.0 x 10(8)/kg of bone marrow nuclear cells were infused from an HLA-identical sibling using only anti-thymocyte globulin to prevent rejection. Donor DNA was not detected on microsatellite polymorphism by PCR. At 19 months of age, a second BMT from the same donor was carried out using busulfan and cyclophosphamide as conditioning. DNA examination of bone marrow showed chimerism at day 18 and complete donor origin at day 28. Seven months post-BMT, the numbers of CD3-, CD4- and CD8-positive cells were in the normal range. BMT is thus an effective therapy for DiGeorge syndrome.

Objective: DiGeorge syndrome is characterized by developmental defects of the heart, parathyroid glands, and thymus. The objective of this study was to determine whether T-cell function spontaneously improves in patients with DiGeorge syndrome who have profoundly depressed T-cell proliferative responses to mitogens at presentation, regardless of the T-cell count. Study design: We conducted a retrospective chart review of eight patients with DiGeorge syndrome who had no proliferative responses to mitogens on presentation. Results: Despite lack of responsiveness of the patients' peripheral blood lymphocytes to mitogens, T cells were occasionally detected, and the patients' cells often responded to IL-2 and in mixed lymphocyte reactions. Unresponsiveness to mitogens and clinical immunodeficiency persisted without immune-based therapy. One patient is alive and well after immunoreconstitution from thymic transplantation. The others either died early of complications of their disease such as gastroesophageal reflux with aspiration (2 patients) or infection (2 patients) or died after attempts at immunorestorative therapy with IL-2, thymus transplantation, or bone marrow transplantation (3 patients). Conclusion: Eight patients with DiGeorge syndrome who were first seen with no mitogen responsiveness did not improve spontaneously. We recommend HLA-identical bone marrow transplantation or thymic transplantation for these patients as soon as the diagnosis is confirmed. (J Pediatr 1998;132:15-21)

Review of liver biopsy or autopsy material from 33 patients with severe combined immunodeficiency or combined immunodeficiency and four patients with DiGeorge syndrome revealed a wide range of hepatic pathology. The most common abnormality was graft-versus-host disease (16 patients), followed by viral infection (4 patients had adenovirus hepatitis, 3 had cytomegalovirus hepatitis). Centrilobular fibrosis with or without veno-occlusive disease was seen in five patients. Three patients had nonspecific hepatitis, four had changes attributed to total parenteral nutrition, and two had lymphoproliferative disorders involving the liver. Both patients with lymphoproliferative disorders had received transplants. Two patients had resolving necrosis probably secondary to non-A, non-B hepatitis. One had atypical mycobacterial infection. Hemosiderosis was a common nonspecific abnormality, seen in nine patients. All patients with hepatic graft-versus-host disease had received transplants or nonirradiated blood products. Hepatic graft-versus-host disease varied in severity from hepatic necrosis with destruction of both large and small bile ducts in a transfusion-associated case to subtle damage to interlobular bile ducts. Even minimal bile duct changes correlated with the clinical impression of graft-versus-host disease in these patients. Late chronic graft-versus-host disease was not seen in any patient, although acute graft-versus-host disease sometimes occurred late after transplant.

Thymic function was evaluated by quantitation of circulating thymic factor in patients with several forms of severe infantile immunodeficiency diseases. Direct quantitation of thymic factor in serum of patients with severe combined immunodeficiency revealed heterogeneity of this syndrome by this parameter, as was also shown by study of susceptibility of the marrow cells to differentiation in vitro. Thymic factor was not detectable in one patient with severe combined immunodeficiency, but was present in normal or near-normal concentrations in three others. Circulating levels of this hormonal activity were also not detectable in a patient with DiGeorge athymic syndrome. Following marrow or fetal liver transplantation, which corrected the severe combined immunodeficiency thymic factor levels either increased slightly or did not change appreciably. Fetal thymic transplantation, which together with fetal liver transplantation corrected the immunodeficiency in one patient with severe combined immunodeficiency, was associated with increase of thymic factor to normal levels. Fetal thymus transplantation alone, which was employed to correct the immunodeficiency of DiGeorge athymic syndrome, caused an increase in thymic factor activity to normal or near normal levels in this patient.

Circulating thymic-hormone activity was assayed by measuring Thy 1-2 antigen induction on null lymphocytes from athymic mice incubated with human plasma or serum. Plasma from 19 normal children aged under 10 had inductive activity equivalent to 10-6-16-2 ng thymopoitin/ml. Plasma from 15 infants were severe combined immuno-deficiency, 2 of whom had appreciable immunoglobulin synthesis, and from 2 infants with DiGeorge syndrome had little or no inductive activity. Successful reconstitution with thymus or bone-marrow grafts and with red-cell infusions (if adenosine-deaminase deficiency is present) was followed by a rise in circulating thymic-hormone activity.

Characteristics of T lymphocytes, including differentiation antigens, capacity to form E rosettes, and proliferative responses to some phytomitogens and to allogeneic stimuli were looked for in peripheral blood lymphocytes from patients with certain immunodeficiency diseases. In vitro induction of some T-cell characteristics on a fraction of bone marrow cells was possible in all normal donors, in patients with Di George syndrome. and in patients with common variable immunodeficiencies, but it was severely altered in all infants with severe combined immunodeficiency diseases (SCID). Although SCID appear to be a very heterogeneous syndrome, some evidence is presented indicating that most cases of SCID may result from a block in early events of T-cell differentiation. After bone marrow transplantation from a compatible donor, T lymphocytes developed from the donor's cells and the sequential stages of maturation confirmed our previously described model based on in vitro experiments: appearance of the HTLA+ phenotype, then of the capacity to form E rosettes and later of the responses to allogeneic cells or to phytomitogens. In Di George syndrome treated with fetal thymus transplantation, the recipient's T-cell precursors differentiated and proliferated under the influence of the grafted thymus, following a comparable sequence of events.

The immune system contains multiple components that provide protection against specific groups of microorganisms. The degree of specialization of function is clearly illustrated in patients with immunodeficiency syndromes in whom the nature of the defect determines the sites of the infections and the susceptibility to certain organisms. Chronic mucocutaneous candidiasis is an especially dramatic illustration of the role of the T-lymphocyte system in defense against opportunistic fungal infections, especially of the skin and mucous membranes. There is considerable heterogeneity of the immune abnormalities in patients with chronic mucocutaneous candidiasis. The most consistent defects involve subnormal production of lymphokines by T-cells in response to Candida antigens. However, some patients have more global defects and are unresponsive to all antigens and may have reduced responsiveness to mitogens as well. Successful therapy of this infection requires a combination of treatments, including such antifungal drugs as clotrimazole, ketoconazole, or amphotericin B and correction of the underlying immune defect with such agents as transfer factor.

A female infant with DiGeorge syndrome associated with severe T-cell immunodeficiency underwent a successful bone marrow transplantation from her HLA-identical, mixed leukocyte culture-nonreactive brother at 5 months of age. Mature circulating T cells and mitogen-induced proliferative responses were detectable at 10 days posttransplant, and by 8 months post-transplant functional T- and B-cell reconstitution was documented by normal responses to mitogens and normal levels of serum immunoglobulins as well as in vitro and in vivo T-cell reactivity to specific antigens and production of specific antibody to T cell-dependent antigens in vivo. Phytohemagglutinin-induced interleukin-2 production and cell surface interleukin-2 receptor expression improved posttransplant, with normal production values observed by 8 months posttransplant. Histologic examination of appendix and thoracic lymph node obtained 9 and 17 months posttransplant, respectively, revealed near-normal lymphoid architecture, with germinal center formation providing morphologic confirmation of reconstitution. Stable split lymphoid chimerism with T cells of donor origin and B cells remaining recipient in origin was documented by sex chromosome analysis. Two years posttransplant the subject remains free of serious infections. In conclusion, this case indicates that bone marrow transplantation can produce peripheral immunoreconstitution without need for significant thymic influence, most likely by providing a source of postthymic T cells, and that bone marrow transplantation should be considered a therapeutic option in patients with DiGeorge syndrome associated with severe T-cell deficiency.

Correction of T-cell defects by either thymic hormone treatment or thymus transplantation has proven to be more difficult clinically than historically anticipated. Because the precise action of thymic hormones is unknown and because these hormones act upon post-thymic cells, therapeutic attempts may fail owing to lack of sufficient substrate population. Results of thymic transplantation suggest that this procedure may be best utilized for the treatment of mild T-cell defects, rather than as complete replacement treatment for severe deficiency. Future clinical trials of thymic transplantation or thymic hormone appear justified in narrowly circumscribed and well-characterized conditions.

A Hispanic infant girl with DiGeorge syndrome underwent successful bone marrow transplantation (BMT) at age 28 1/2 weeks. She had typical facies, a cardiac defect, hypoparathyroidism, severe T and B cell immunodeficiency, and low levels of facteur thymique serique (FTS). In vitro incubation of the peripheral blood lymphocytes with thymosin alpha 1 showed no increase in the number of T cells on two occasions. A fetal thymus for transplantation was not available, and further review of past experience with thymic cells or factors revealed inconsistent and incomplete responses. Because of the patient's worsening clinical and immunologic status, BMT was performed, with her histocompatible brother as donor. The patient has had a good clinical and immunologic response to BMT, with evidence of T cell engraftment, improved B cell function, and increased levels of serum FTS. This experience indicates that minimal thymic influence is necessary for successful BMT and that patients with DiGeorge syndrome with significant T cell deficiency may benefit from this treatment.