Dental manifestations in severe combined immunodeficiency following bone marrow transplantation

Long-Term Clinical Outcomes of Severe Combined Immunodeficiency Patients Given Nonablative Marrow Transplants

BACKGROUND

Severe combined immunodeficiency (SCID) is a syndrome characterized by profound T-cell deficiency that is universally fatal in infancy unless immune reconstitution is achieved by hematopoietic stem cell transplantation, gene therapy, or enzyme replacement. Published long-term clinical follow-up is limited for transplanted patients with SCID.

OBJECTIVE

To characterize the long-term outcomes of patients with SCID treated at a single center.

METHODS

We examined the clinical outcomes of 177 successive SCID infants given allogeneic bone marrow over 38 years without pretransplant chemotherapy or post-transplant graft-versus-host disease prophylaxis. A total of 90% received T-cell-depleted haploidentical parental marrow. Clinical status was assessed by questionnaires delivered by mail or electronically. Molecular type of SCID, demographics, and type, date and age of transplant were obtained from a database.

RESULTS

Eighty-eight questionnaires were completed for survivors ranging in age from 2 to 38 years. Survival remained higher in those transplanted before 3.5 months of age. Half of the cohort remained on immunoglobulin replacement. Health conditions reported included rashes, anxiety, depression, warts, and mouth ulcers. Most reported that these were transient, self-resolving issues. Attention-deficit/hyperactivity disorder, warts, and learning disabilities were reportedly more prevalent than in the general population. Most reported having no active concerns about their health. We found substantial scholastic achievement, with half of adult patients reporting college attendance. Most patients had a healthy body mass index.

CONCLUSIONS

Overall, our findings are consistent with those in the last update in 2009 in this population. Age at transplant remains a key variable in survival.

Diagnosis and management of severe combined immunodeficiency in Australia and New Zealand

This consensus document outlines the recommendations from the Australasian Society of Clinical Immunology and Allergy Transplantation and Primary Immunodeficiency group for the diagnosis and management of patients with severe combined immunodeficiency. It also provides a proposed framework for the early investigation, management and supportive care prior to haematopoietic stem cell transplantation.

Long term outcomes of severe combined immunodeficiency: therapy implications

INTRODUCTION

Newborn screening has led to a better understanding of the prevalence of Severe Combined Immunodeficiency (SCID) overall and in terms of specific genotypes. Survival has improved following hematopoietic stem cell transplantation (HCT) with the best outcomes seen following use of a matched sibling donor. However, questions remain regarding the optimal alternative donor source, appropriate use of conditioning and the impact of these decisions on immune reconstitution and other late morbidities. Areas covered: The currently available literature reporting late effects after HCT for SCID and use of alternative therapies including enzyme replacement, alternative donors and gene therapy are reviewed. A literature search was performed on Pubmed and ClinicalTrials.gov using key words 'Severe Combined Immunodeficiency', 'SCID', 'hematopoietic stem cell transplant', 'conditioning', 'gene therapy', 'SCID newborn screening', 'TREC' and 'late effects'. Expert commentary: Newborn screening has dramatically changed the clinical presentation of newborn SCID. While the majority of patients with SCID survive HCT, data regarding late effects in these patients is limited and additional studies focused on genotype specific late effects are needed. Prospective studies aimed at minimizing the use of alkylating agents and reducing late effects beyond survival are needed. Gene therapy is being developed and will likely become a more commonly used treatment that will require separate consideration of survival and late effects.

Current Knowledge and Priorities for Future Research in Late Effects after Hematopoietic Stem Cell Transplantation (HCT) for Severe Combined Immunodeficiency Patients: A Consensus Statement from the Second Pediatric Blood and Marrow Transplant Consortium International Conference on Late Effects after Pediatric HCT

Severe combined immunodeficiency (SCID) is 1 of the most common indications for pediatric hematopoietic cell transplantation (HCT) in patients with primary immunodeficiency. Historically, SCID was diagnosed in infants who presented with opportunistic infections within the first year of life. With newborn screening (NBS) for SCID in most of the United States, the majority of infants with SCID are now diagnosed and treated in the first 3.5 months of life; however, in the rest of the world, the lack of NBS means that most infants with SCID still present with infections. The average survival for SCID patients who have undergone transplantation currently is >70% at 3 years after transplantation, although this can vary significantly based on multiple factors, including age and infection status at the time of transplantation, type of donor source utilized, manipulation of graft before transplantation, graft-versus-host disease prophylaxis, type of conditioning (if any) utilized, and underlying genotype of SCID. In at least 1 study of SCID patients who received no conditioning, long-term survival was 77% at 8.7 years (range out to 26 years) after transplantation. Although a majority of patients with SCID will engraft T cells without any conditioning therapy, depending on genotype, donor source, HLA match, and presence of circulating maternal cells, a sizable percentage of these will fail to achieve full immune reconstitution. Without conditioning, T cell reconstitution typically occurs, although not always fully, whereas B cell engraftment does not, leaving some molecular types of SCID patients with intrinsically defective B cells, in most cases, dependent on regular infusions of immunoglobulin. Because of this, many centers have used conditioning with alkylating agents including busulfan or melphalan known to open marrow niches in attempts to achieve B cell reconstitution. Thus, it is imperative that we understand the potential late effects of these agents in this patient population. There are also nonimmunologic risks associated with HCT for SCID that appear to be dependent upon the genotype of the patient. In this report, we have evaluated the published data on late effects and attempted to summarize the known risks associated with conditioning and alternative donor sources. These data, while informative, are also a clear demonstration that there is still much to be learned from the SCID population in terms of their post-HCT outcomes. This paper will summarize current findings and recommend further research in areas considered high priority. Specific guidelines regarding a recommended approach to long-term follow-up, including laboratory and clinical monitoring, will be forthcoming in a subsequent paper.

How I treat severe combined immunodeficiency

Severe combined immunodeficiency (SCID) arises from different genetic defects associated with lymphocyte development and function and presents with severe infections. Allogeneic hematopoietic stem cell transplantation is an extremely effective way of restoring immunity in these individuals. Numerous multicenter studies have identified the factors determining successful outcome, and survival for SCID has shown great improvement. Advances in understanding the genetic basis of disease also mean that we increasingly tailor transplant protocols to the specific SCID form. Wherever possible, we attempt to transplant SCID patients without the use of cytoreductive conditioning, but it is clear that this is only successful for specific SCID forms and, although survival is good, in specific patients there are ongoing humoral defects. We aim to use matched related and unrelated donors (including cord blood) whenever possible and have limited the use of mismatched haploidentical donors. The development of autologous hematopoietic stem cell gene therapy provides another treatment of the X-linked and adenosine deaminase–deficient forms of SCID, and we discuss how we have integrated gene therapy into our treatment strategy. These developments together with the advent of universal newborn screening for SCID should allow for a highly favorable outcome for this otherwise lethal condition.

SCID patients with ARTEMIS vs RAG deficiencies following HCT: increased risk of late toxicity in ARTEMIS-deficient SCID

A subgroup of severe combined immunodeficiencies (SCID) is characterized by lack of T and B cells and is caused by defects in genes required for T- and B-cell receptor gene rearrangement. Several of these genes are also involved in nonhomologous end joining of DNA double-strand break repair, the largest subgroup consisting of patients with T(-)B(-)NK(+)SCID due to DCLRE1C/ARTEMIS defects. We postulated that in patients with ARTEMIS deficiency, early and late complications following hematopoietic cell transplantation might be more prominent compared with patients with T(-)B(-)NK(+)SCID caused by recombination activating gene 1/2 (RAG1/2) deficiencies. We analyzed 69 patients with ARTEMIS and 76 patients with RAG1/2 deficiencies who received transplants from either HLA-identical donors without conditioning or from HLA-nonidentical donors without or with conditioning. There was no difference in survival or in the incidence or severity of acute graft-versus-host disease regardless of exposure to alkylating agents. Secondary malignancies were not observed. Immune reconstitution was comparable in both groups, however, ARTEMIS-deficient patients had a significantly higher occurrence of infections in long-term follow-up. There is a highly significant association between poor growth in ARTEMIS deficiency and use of alkylating agents. Furthermore, abnormalities in dental development and endocrine late effects were associated with alkylation therapy in ARTEMIS deficiency.

Association of cyclophosphamide use with dental developmental defects and salivary gland dysfunction in recipients of childhood antineoplastic therapy

BACKGROUND

The aim of this study was to examine the effect of antineoplastic therapy on dental development and saliva function in recipients of childhood antineoplastic therapy.

METHODS

Patients attending the long-term follow-up clinic at Children's Hospital at Westmead, NSW, Australia, were included if they had received treatment prior to 16 years of age and were in remission for more than 5 years. A dental examination and saliva test were performed for each participant. Holtta's Defect Index (HDI) was used to assess tooth aplasia, microdontia, and root-crown ratio on an orthopantomogram (OPG). Multivariable-adjusted regression analyses were used to estimate the association of patient characteristics and treatment modalities with dental outcomes.

RESULTS

One hundred six participants (61% male) were recruited (response rate = 88%). The mean HDI score was 24.7 ± 17.8. A cumulative dose of cyclophosphamide >7500 mg/m(2) increased the HDI score by 13.06 (P = .01). Recipients of cyclophosphamide also had significantly increased odds of exhibiting very low saliva flow (<0.7 mL/min) (odds ratio = 12.43; 95% confidence interval, 2.08-74.35; P = .006).

CONCLUSIONS

Children and adolescents who received high doses of cyclophosphamide were at increased risk of dental disturbances. Cyclophosphamide recipients were also at greater risk of exhibiting very low saliva flow. This study applied the HDI to patients receiving all forms of antineoplastic treatment and highlights the dose-dependent relation between cumulative dose of cyclophosphamide and dental disturbances.

Gene therapy improves immune function in preadolescents with X-linked severe combined immunodeficiency

Retroviral gene therapy can restore immunity to infants with X-linked severe combined immunodeficiency (XSCID) caused by mutations in the IL2RG gene encoding the common gamma chain (gammac) of receptors for interleukins 2 (IL-2), -4, -7, -9, -15, and -21. We investigated the safety and efficacy of gene therapy as salvage treatment for older XSCID children with inadequate immune reconstitution despite prior bone marrow transplant from a parent. Subjects received retrovirus-transduced autologous peripherally mobilized CD34(+) hematopoietic cells. T-cell function significantly improved in the youngest subject (age 10 years), and multilineage retroviral marking occurred in all 3 children.

CAMPATH-1M T-cell depleted BMT for SCID: long-term follow-up of 19 children treated 1987-98 in a single center

BACKGROUND

SCID can be cured by BMT. Depletion of mature T cells from BM has enabled HLA non-identical stem-cell transplantation. We report the outcome of 30 patients treated with 37 T-cell depleted BMT procedures using CAMPATH-1M in vitro between 1987-98 in a single center.

METHODS

Immune reconstitution and quality-of-life were assessed in 19 longterm survivors. All but two received pre-transplant conditioning. T- and B-cell chimerism, numbers and function were analyzed during a median follow-up of 5.3 years (range 1.33-12).

RESULTS

The overall engraftment rate was 59%, six children required repeated BMT and the survival rate was 63%. All have donor T cells, 58% normal T-cell numbers and 74% normal T-cell function. Of 17 evaluated, 16 patients (94%) have normal IgM and IgG levels, and production of specific Abs to protein Ags, but only 5/16 (31%) have a good response to pneumococcal polysaccharide. Early and late post-BMT complications were rare and there were no delayed deaths. Only one child continues on long-term i.v. Ig 4-years post-BMT. Eleven children died (37%).

DISCUSSION

CAMPATH-1M T-cell depleted BMT for SCID resulted in 63% survival. Deaths of 11 children were mainly due to pre-existing infections. Seventeen of 19 long-term survivors have normal immune function and good quality-of-life.

Bone marrow transplantation for T-B- severe combined immunodeficiency disease in Athabascan-speaking native Americans

A distinct form of autosomal recessive T-B- severe combined immunodeficiency disease occurs with a high frequency among Athabascan-speaking Native Americans (SCIDA), including Navajo and Apache Indians from the southwestern US and Dene Indians from the Canadian Northwest Territories. The SCIDA gene has been linked to markers on chromosome 10p although its identity and role in the pathogenesis of this disease are unknown. We report our experience in treating 18 Navajo and Dene children with SCIDA between 1984 and 1999; 16 underwent bone marrow transplants (BMT). All children were symptomatic within 2 months of birth, had the T-B- NK(+)SCID phenotype and 67% presented with oral and/or genital ulcers. Three children had evidence of maternal engraftment prior to transplant. Two children died shortly after diagnosis. Three children required more than one BMT and 12 are alive with T cell reconstitution at a median follow-up of 7 years. Three children developed normal B cell immunity, two of whom received ablative conditioning therapy with either radiation or busulfan. Three of the four children who died received therapy with either radiation or busulfan and two of eight long-term survivors who were also recipients of cytotoxic chemotherapy have failed to develop secondary teeth. These results demonstrate the efficacy of BMT in treating infants with this distinct form of SCID, although B cell reconstitution remains a problem even with HLA-matched donors. Without conditioning, T cell engraftment is likely when closely HLA-matched donors are used. With T cell depletion of haplocompatible marrow, conditioning with immunosuppressive therapy may be necessary; however, children with SCIDA who were treated with intensive immunosuppressive and myeloablative therapy had a poor outcome.