Fetal allotransplant recipients are resistant to graft-versus-host disease.

In utero hematopoietic cell transplantation (IUHCT) is an experimental treatment for congenital hemoglobinopathies, including Sickle cell disease and thalassemias. One of the principal advantages of IUHCT is the predisposition of the developing fetus toward immunologic tolerance. This allows for engraftment across immune barriers without immunosuppression and, potentially, decreased susceptibility to graft-versus-host disease (GVHD). We demonstrate fetal resistance to GVHD following T cell-replete allogeneic hematopoietic cell transplantation compared with the neonate. We show that this resistance is associated with elevated fetal serum interleukin-10 conducive to the induction of regulatory T cells (Tregs). Finally, we demonstrate that the adoptive transfer of Tregs from IUHCT recipients to neonates uniformly prevents GVHD, recapitulating the predisposition to tolerance observed after fetal allotransplantation. These findings demonstrate fetal resistance to GVHD following hematopoietic cell transplantation and elucidate Tregs as important contributors.

Regulatory T cells promote alloengraftment in a model of late-gestation in utero hematopoietic cell transplantation.

In utero hematopoietic cell transplantation (IUHCT) has the potential to cure congenital hematologic disorders including sickle cell disease. However, the window of opportunity for IUHCT closes with the acquisition of T-cell immunity, beginning at approximately 14 weeks gestation, posing significant technical challenges and excluding from treatment fetuses evaluated after the first trimester. Here we report that regulatory T cells can promote alloengraftment and preserve allograft tolerance after the acquisition of T-cell immunity in a mouse model of late-gestation IUHCT. We show that allografts enriched with regulatory T cells harvested from either IUHCT-tolerant or naive mice engraft at 20 days post coitum (DPC) with equal frequency to unenriched allografts transplanted at 14 DPC. Long-term, multilineage donor cell chimerism was achieved in the absence of graft-versus-host disease or mortality. Decreased alloreactivity among recipient T cells was observed consistent with donor-specific tolerance. These findings suggest that donor graft enrichment with regulatory T cells could be used to successfully perform IUHCT later in gestation.

No pain is gain: A prospective evaluation of strict non-opioid pain control after pediatric appendectomy.

INTRODUCTION: Opiates are often prescribed after pediatric operations despite safety concerns and lack of evidence confirming superiority compared to other pain control modalities. In this study, we use daily parental surveys to prospectively evaluate a strict non-opioid pain control strategy after laparoscopic appendectomy. METHODS: After IRB approval, children who underwent laparoscopic appendectomy for nonperforated acute appendicitis were recruited to the study. For these patients, our standard practice is to provide instructions to administer alternating acetaminophen and ibuprofen over-the-counter (OTC) postoperatively, and no opiate prescriptions are written. Parents of enrolled children received a daily RedCap survey via text message or e-mail on postoperative days (POD) 1 through 5 to prospectively assess pain control and medication usage. Trends were compared across postoperative days. RESULTS: One hundred twenty patients were enrolled in the study, and none received opiate prescriptions. Postoperative pain survey response rates were 54% on POD1, 47% on POD2, 35% on POD3, 34% on POD4, and 29% on POD5. Pain level was 4.7 ±â€¯2.3 (out of 10) on POD1, and down-trended significantly each postoperative day to reach 0.7 ±â€¯1.2 by POD5. On POD1, 85% of parents administered OTC medications, which reduced significantly to 14% by POD5. Parent-reported success rates to manage pain by OTC regimen were 85% on POD1, 94% on POD2, 91% on POD3, and 100% on POD4 and POD5. CONCLUSION: Strict non-opioid pain control after appendectomy exhibits high performance based upon prospective parental surveys. This strategy should be implemented as standard of care and tested for application to other surgical conditions. LEVEL OF EVIDENCE: Level II.

Pre-Existing Maternal Antibodies Cause Rapid Prenatal Rejection of Allotransplants in the Mouse Model of In Utero Hematopoietic Cell Transplantation.

In utero hematopoietic cell transplantation (IUHCT) is a nonmyeloablative nonimmunosuppressive alternative to postnatal hematopoietic stem cell transplantation for the treatment of congenital hemoglobinopathies. Anti-HLA donor-specific Abs (DSA) are associated with a high incidence of graft rejection following postnatal hematopoietic stem cell transplantation. We determine if DSA present in the mother can similarly cause graft rejection in the fetus following IUHCT. Ten million C57BL/6 (B6, H2kb) bone marrow cells were transplanted in utero into gestational day 14 BALB/c (H2kd) fetuses. The pregnant BALB/c dams carrying these fetuses either had been previously sensitized to B6 Ag or were injected on gestational days 13-15 with serum from B6-sensitized BALB/c females. Maternal-fetal Ab transmission, Ab opsonization of donor cells, chimerism, and frequency of macrochimeric engraftment (chimerism >1%) were assessed by flow cytometry. Maternal IgG was transmitted to the fetus and rapidly opsonized donor cells following IUHCT. Donor cell rejection was observed as early as 4 h after IUHCT in B6-sensitized dams and 24 h after IUHCT in dams injected with B6-sensitized serum. Efficient opsonization was strongly correlated with decreased chimerism. No IUHCT recipients born to B6-sensitized dams or dams injected with B6-sensitized serum demonstrated macrochimeric engraftment at birth compared with 100% of IUHCT recipients born to naive dams or dams injected with naive serum (p < 0.001). In summary, maternal donor-specific IgG causes rapid, complete graft rejection in the fetus following IUHCT. When a third-party donor must be used for clinical IUHCT, the maternal serum should be screened for DSA to optimize the chance for successful engraftment.

Amniotic Fluid Concentrations of Glial Fibrillary Acidic Protein Do Not Correlate with Prenatal Metrics in Fetuses with Myelomeningocele.

INTRODUCTION: We investigated the correlation of amniotic fluid (AF) concentrations of glial fibrillary acidic protein (GFAP) with prenatal features of myelomeningocele (MMC) and neurodevelopmental outcome after fetal MMC (fMMC) surgery. MATERIALS AND METHODS: AF was collected during fMMC surgery between December 2012 and November 2015. AF-GFAP concentration was determined by ELISA. Retrospective chart review identified the characteristics of the defect. Data regarding delivery and 1-year neurodevelopmental outcome was collected from The Children's Hospital of Philadelphia fMMC Registry. RESULTS: Eighty-two AF samples were collected from fMMC surgeries. Perinatal data were obtained from 77 subjects, and 1-year follow-up data from 65 subjects. GFAP concentrations were significantly elevated in MMC compared to myeloschisis (24.1 ± 2.9 and 10.3 ± 1.5 ng/mL; p < 0.0001). A larger percentage of subjects with myeloschisis defects delivered before their scheduled due date (myeloschisis 88.5%; MMC 55.0%; p = 0.003) and delivered at an earlier mean gestational age (34.6 ± 0.4 weeks, n = 26) compared to those with MMC defects (35.2 ± 0.4 weeks, n = 51) (p = 0.04). DISCUSSION: AF-GFAP levels differentiate between MMC and myeloschisis, and raise interesting questions regarding the clinical significance between the 2 types of defects.

Vector serotype screening for use in ovine perinatal lung gene therapy.

PURPOSE: Successful in utero or perinatal gene therapy for congenital lung diseases, such as cystic fibrosis and surfactant protein deficiency, requires identifying clinically relevant viral vectors that efficiently transduce airway epithelial cells. The purpose of the current preclinical large animal study was to evaluate lung epithelium transduction of adeno-associated viral (AAV) vector serotypes following intratracheal delivery. METHODS: Six different AAV vector serotypes (AAV1, AAV5, AAV6, AAV8, AAV9, and AAVrh10) expressing the green fluorescent protein (GFP) as the transgene were injected into the right upper lobe of perinatal sheep via bronchoscopy. At 1 week, samples were harvested, analyzed by fluorescent stereomicroscopy and immunohistochemistry, and quantified using a radial grid and quantitative real-time polymerase chain reaction (qPCR). RESULTS: Fluorescent stereomicroscopy demonstrated GFP expression in the right upper lobe following injection of all AAV serotypes assessed except AAV5. Immunohistochemistry analysis confirmed GFP expression in small- and medium-sized airways following intratracheal injection of AAV1, 6, 8, 9, and rh10. However, only AAV8 and AAVrh10 resulted in transgene expression in large airways. These results were confirmed by qPCR, yet, after 40 cycles, AAV1 did not show GFP gene amplification. CONCLUSION: Adeno-associated viral vector serotypes 6, 8, 9, and rh10 demonstrated efficient GFP transgene expression at early time points, and AAV8 demonstrated efficient transduction of all airway sizes with high pulmonary GFP expression tested using qPCR.

The Intravenous Route of Injection Optimizes Engraftment and Survival in the Murine Model of In Utero Hematopoietic Cell Transplantation.

In utero hematopoietic cell transplantation (IUHCT) has the potential to treat a number of congenital hematologic disorders. Clinical application is limited by low levels of donor engraftment. Techniques that optimize donor cell delivery to the fetal liver (FL), the hematopoietic organ at the time of IUHCT, have the potential to enhance engraftment and the clinical success of IUHCT. We compared the 3 clinically applicable routes of injection (intravenous [i.v.], intraperitoneal [i.p.], and intrahepatic [i.h.]) and assessed short- and long-term donor cell engraftment and fetal survival in the murine model of IUHCT. We hypothesized that the i.v. route would promote direct donor cell homing to the FL, resulting in increased engraftment and allowing for larger injectate volumes without increased fetal mortality. We demonstrate that the i.v. route results in (1) rapid diffuse donor cell population of the FL compared with delayed diffuse engraftment after the i.p. and i.h. routes; (2) higher FL and spleen engraftment at early prenatal time points; (3) enhanced stable long-term peripheral blood donor cell engraftment; and (4) improved survival at higher injectate volumes, allowing for higher donor cell doses and increased long-term engraftment. These findings support the use of an i.v. route for clinical protocols of IUHCT.

In utero stem cell transplantation and gene therapy: Recent progress and the potential for clinical application.

Advances in prenatal diagnosis have led to the prenatal management and treatment of a variety of congenital diseases. Although surgical treatment has been successfully applied to specific anatomic defects that place the fetus at a risk of death or life-long disability, the indications for fetal surgical intervention have remained relatively limited. By contrast, prenatal stem cell and gene therapy await clinical application, but they have tremendous potential to treat a broad range of genetic disorders. If there are biological advantages unique to fetal development that favor fetal stem cell or gene therapy over postnatal treatment, prenatal therapy may become the preferred approach to the treatment of any disease that can be prenatally diagnosed and cured by stem cell or gene therapy. Here, we review the field including recent progress toward clinical application and imminent clinical trials for cellular and gene therapy.