Complete DiGeorge anomaly in the absence of neonatal hypocalcemia and velofacial and cardiac defects

Lifelong Immune Modulation Versus Hematopoietic Cell Therapy for Inborn Errors of Immunity

Advances in diagnosis of inborn errors of immunity (IEI) and an understanding of the molecular and immunologic mechanisms of these disorders have led to both the development of new therapies and improved approaches to hematopoietic cell transplantation (HCT). For example, monoclonal antibodies (mAbs) and small molecules, such as Janus tyrosine kinase inhibitors, that can modulate immunologic pathways have been designed for or repurposed for management of IEI. A better understanding of molecular mechanisms of IEI has led to use of drugs typically considered "immunosuppressive" to modulate the immune response, such as mammalian target of rapamycin inhibitors in disorders of phosphoinositide 3-kinase gain of function. Since the first HCT in a patient with severe combined immunodeficiency (SCID) in 1968, transplantation strategies have improved, with more than 90% probability of survival after allogeneic HCT in SCID and hence HCT is now the therapeutic standard for SCID and many other IEI. When tailoring treatment for IEI, multiple disease-specific and individual factors should be considered. In diseases such as SCID or agammaglobulinemia, the choice between HCT or medical management is straightforward. However, in many IEI, the choice between the options is challenging. This review focuses on the factors that should be taken into account in the quest for the optimal treatment for patients with IEI.

Placental transfer of maternally-derived IgA precludes the use of guthrie card eluates as a screening tool for primary immunodeficiency diseases

There is a need for neonatal screening tools to improve the long-term clinical outcome of patients with primary immunodeficiency diseases (PID). Recently, a PCR-based screening method for both TRECs and KRECs using Guthrie card samples has been developed. However, the applicability of these excision circle assays is limited to patients with severe T or B cell lymphopenia (SCID, XLA and A-T), whereas the most common forms of PID are not detected. Absence of serum IgA is seen in a major fraction of patients with immunological defects. As serum IgA in newborns is considered to be of fetal origin, eluates from routinely collected dried blood spot samples might thus be suitable for identification of children with PID. To assess the applicability of such screening assays, stored Guthrie card samples were obtained from 47 patients with various forms of primary immunodeficiency diseases (SCID, XLA, A-T, HIGM and IgAD), 20 individuals with normal serum IgA levels born to IgA-deficient mothers and 51 matched healthy newborns. Surprisingly, normal serum IgA levels were found in all SCID, XLA, A-T and HIGM patients and, additionally, in all those IgAD patients born to IgA-sufficient mothers. Conversely, no serum IgA was found in any of the 16 IgAD patients born by IgA-deficient mothers. Moreover, half of the IgA-sufficient individuals born by IgA-deficient mothers also lacked IgA at birth whereas no IgA-deficient individuals were found among the controls. IgA in neonatal dried blood samples thus appears to be of both maternal and fetal origin and precludes its use as a reliable marker for neonatal screening of primary immunodeficiency diseases.

Tetralogy of Fallot with complete DiGeorge syndrome: report of a case and a review of the literature

Complete DiGeorge syndrome (CDGS) has a severe T-cell immunodeficiency and is fatal without thymus or bone marrow transplantation. Associated congenital heart disease (CHD) further complicates the clinical management. We report an infant with tetralogy of Fallot, confluent and hypoplastic pulmonary arteries, right aortic arch, and aberrant left subclavian artery. He was athymic with no CD3+ T cells. CDGS was diagnosed with 22q11.2 deletion. The patient underwent central aortopulmonary shunt at 12 days of age. The patient died at 5 weeks of age awaiting thymus transplantation. We performed a review of the literature regarding CDGS and CHD. We found 43 cases including conotruncal defects (20) and nonconotruncal defects (23). The overall mortality rate was 67%. Among 30 cases undergoing transplantation (bone marrow 16 and thymus 12, bone marrow + thymus 2), the mortality rate was 53%. The patients with conotruncal defects were more likely to die before transplantation (45% vs. 16%, P =.04). The main cause of death was infection before and after transplantation. We conclude that children with CDGS and CHD have a high mortality. Bone marrow and thymus transplantation can improve the survival, but the overall management of these high risk patients remains challenging.

Multicenter survey on the outcome of transplantation of hematopoietic cells in patients with the complete form of DiGeorge anomaly

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/mm(3), respectively, CD4(+)/CD45RA(+) cells remained very low, whereas mitogen responses were normalized.

Immunologic reconstitution in 22q deletion (DiGeorge) syndrome

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.

Long-term results of bone marrow transplantation in complete DiGeorge syndrome

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.

Deletion 22q11: spectrum of associated disorders

Velocardiofacial syndrome, also called Shprintzen syndrome or DiGeorge sequence, is one of the most common genetic disorders in humans. Caused by a microdeletion on chromosome 22, it manifests in a remarkable variety of symptoms in multiple systems. The most frequent anomalies involve palatal function, facial features and congenital cardiac defects. In addition, learning disabilities and psychiatric issues are common. The aim of this article is to provide a concise review of the clinical characteristics of this complex disorder. Recognition of the features associated with velocardiofacial syndrome allows for an inclusive diagnosis and more comprehensive care.

Unrelated partially matched lymphocyte infusions in a patient with complete DiGeorge/CHARGE syndrome

We present an infant with cDGS overlapping with CHARGE syndrome, who suffered from T-cell deficiency treated with screened healthy DLI from an unrelated donor (8/10 match). The first dose of DLI (1.1 x 10(6) CD3+/kg) was administered at the age of six months, the second one (0.9 x 10(6) CD3+/kg) 36 days later. No conditioning was employed, GvHD prophylaxis consisting of CsA was used only during the second infusion. Since day+10 after the first DLI, split chimerism showing T-cell engraftment has been documented. Proliferative response to PHA was detected on day+145. The treatment was complicated by severe acute GvHD (grade II-III) after the first DLI and prolonged chronic liver cholestatic GvHD developing after the second DLI. Vigorous EBV proliferation four wk after the second DLI was accompanied by peripheral expansion of CD8+ donor cells. The patient, 26-months old, is clinically well and has slowly started to gain his developmental milestones. We believe that infusions of small doses of DLI from an unrelated donor represent a potentially helpful therapeutic option in patients with cDGS/CHARGE phenotype.