Troy C. Quigg

Immune reconstitution and survival of 100 SCID patients post-hematopoietic cell transplant: A PIDTC natural history study

The Primary Immune Deficiency Treatment Consortium (PIDTC) is enrolling children with severe combined immunodeficiency (SCID) to a prospective natural history study. We analyzed patients treated with allogeneic hematopoietic cell transplantation (HCT) from 2010 to 2014, including 68 patients with typical SCID and 32 with leaky SCID, Omenn syndrome, or reticular dysgenesis. Most (59%) patients were diagnosed by newborn screening or family history. The 2-year overall survival was 90%, but was 95% for those who were infection-free at HCT vs 81% for those with active infection (P = .009). Other factors, including the diagnosis of typical vs leaky SCID/Omenn syndrome, diagnosis via family history or newborn screening, use of preparative chemotherapy, or the type of donor used, did not impact survival. Although 1-year post-HCT median CD4 counts and freedom from IV immunoglobulin were improved after the use of preparative chemotherapy, other immunologic reconstitution parameters were not affected, and the potential for late sequelae in extremely young infants requires additional evaluation. After a T-cell-replete graft, landmark analysis at day +100 post-HCT revealed that CD3 < 300 cells/μL, CD8 < 50 cells/μL, CD45RA < 10%, or a restricted Vβ T-cell receptor repertoire (<13 of 24 families) were associated with the need for a second HCT or death. In the modern era, active infection continues to pose the greatest threat to survival for SCID patients. Although newborn screening has been effective in diagnosing SCID patients early in life, there is an urgent need to identify validated approaches through prospective trials to ensure that patients proceed to HCT infection free. The trial was registered at www.clinicaltrials.gov as #NCT01186913.

Lung function before and after pediatric allogeneic hematopoietic stem cell transplantation: a predictive role for DLCOa/VA.

Background: Pre-allogeneic hematopoietic stem cell transplantation (aHSCT) and post-aHSCT lung function of 41 eligible patients at Riley Hospital for Children were assessed to identify risk factors for post-aHSCT morbidity and mortality. Observations: One year post-aHSCT pulmonary function tests were significantly lower compared with baseline. These findings recovered at 2 years post-aHSCT. Refractory disease before aHSCT correlated with lower pulmonary function tests after aHSCT. Graft-versus-host disease was significantly associated with higher post-aHSCT residual volume. Importantly, low pre-aHSCT carbon monoxide diffusing capacity adjusted for hemoglobin and alveolar volume was predictive of death. Conclusions: Among survivors, lung function improves over time after pediatric aHSCT. Measurement of carbon monoxide diffusing capacity adjusted for hemoglobin and alveolar volume before pediatric aHSCT should be further investigated as a predictor of pulmonary dysfunction and mortality.

Ages and Stages Questionnaires-3 Developmental Screening of Infants and Young Children With Cancer:

The Ages and Stages Questionnaires–3® (ASQ-3) for developmental screening in our young oncology patients was pilot tested in children 4 to 48 months of age with newly diagnosed cancer. Subjects were screened within 28 days of diagnosis (baseline), at 6 and 12 months. Twenty-six of 30 enrolled parents (87%) completed all 3 screens. Screens were completed by parents within 15 minutes. ASQ-3 screening identified unsuspected developmental delays as follows: 7 at baseline, 4 at 6 months, and 3 at 12 months. ASQ-3 developmental screening is feasible, identifies early developmental delays in young children with cancer, and helps initiate appropriate referrals.

SCID genotype and 6-month posttransplant CD4 count predict survival and immune recovery

The Primary Immune Deficiency Treatment Consortium (PIDTC) performed a retrospective analysis of 662 patients with severe combined immunodeficiency (SCID) who received a hematopoietic cell transplantation (HCT) as first-line treatment between 1982 and 2012 in 33 North American institutions. Overall survival was higher after HCT from matched-sibling donors (MSDs). Among recipients of non-MSD HCT, multivariate analysis showed that the SCID genotype strongly influenced survival and immune reconstitution. Overall survival was similar for patients with RAG, IL2RG, or JAK3 defects and was significantly better compared with patients with ADA or DCLRE1C mutations. Patients with RAG or DCLRE1C mutations had poorer immune reconstitution than other genotypes. Although survival did not correlate with the type of conditioning regimen, recipients of reduced-intensity or myeloablative conditioning had a lower incidence of treatment failure and better T- and B-cell reconstitution, but a higher risk for graft-versus-host disease, compared with those receiving no conditioning or immunosuppression only. Infection-free status and younger age at HCT were associated with improved survival. Typical SCID, leaky SCID, and Omenn syndrome had similar outcomes. Landmark analysis identified CD4+ and CD4+CD45RA+ cell counts at 6 and 12 months post-HCT as biomarkers predictive of overall survival and long-term T-cell reconstitution. Our data emphasize the need for patient-tailored treatment strategies depending upon the underlying SCID genotype. The prognostic significance of CD4+ cell counts as early as 6 months after HCT emphasizes the importance of close follow-up of immune reconstitution to identify patients who may need additional intervention to prevent poor long-term outcome.

The genetic landscape of severe combined immunodeficiency in the United States and Canada in the current era (2010-2018)

In a 250 patient cohort from the US and Canada in the current era (2010-2018), we show that over 90% of patients with severe combined immunodeficiency (SCID) can be genetically-characterized.