Adaptive Immune Deficiency Impairs Neural Activity After Training and Retrieval

Neuroimmune interactions have been studied for decades. Several neurodevelopmental disorders have been associated with immune dysfunction. However, the effects of immune system on neuronal function remain unknown. Herein, based on c-Fos protein expression, we characterized the brain areas that are activated after contextual fear conditioning (CFC) training or retrieval in severe combined immune deficiency (SCID) and wild-type mice. Further, we analyzed the interregional correlations of c-Fos activity that are affected by deficiency in adaptive immunity. Results showed significantly lower c-Fos density in learning and memory-associated brain regions of SCID mice after memory retrieval, but not during the CFC training. Moreover, SCID mice exhibited remarkably discordant interregional neuronal activities of learning neuron circuits after CFC training, which could be the cause of inefficient activation of the memory circuit after retrieval. These results provide a new perspective on how adaptive immunity affects neuronal function. Adaptive immune deficiency impairs the coordination of neural activity after training and retrieval, which might be a potential therapeutic target for neurodevelopmental disorders.

A Novel Non-Coding Variant in DCLRE1C Results in Deregulated Splicing and Induces SCID Through the Generation of a Truncated ARTEMIS Protein That Fails to Support V(D)J Recombination and DNA Damage Repair

Severe Combined Immune Deficiency (SCID) is a primary deficiency of the immune system in which opportunistic and recurring infections are often fatal during neonatal or infant life. SCID is caused by an increasing number of genetic defects that induce an abrogation of T lymphocyte development or function in which B and NK cells might be affected as well. Because of the increased availability and usage of next-generation sequencing (NGS), many novel variants in SCID genes are being identified and cause a heterogeneous disease spectrum. However, the molecular and functional implications of these new variants, of which some are non-coding, are often not characterized in detail. Using targeted NGS, we identified a novel homozygous c.465-1G>C splice acceptor site variant in the DCLRE1C gene in a T-B-NK+ SCID patient and fully characterized the molecular and functional impact. By performing a minigene splicing reporter assay, we revealed deregulated splicing of the DCLRE1C transcript since a cryptic splice acceptor in exon 7 was employed. This induced a frameshift and the generation of a p.Arg155Serfs*15 premature termination codon (PTC) within all DCLRE1C splice variants, resulting in the absence of full-length ARTEMIS protein. Consistently, a V(D)J recombination assay and a G0 micronucleus assay demonstrated the inability of the predicted mutant ARTEMIS protein to perform V(D)J recombination and DNA damage repair, respectively. Together, these experiments molecularly and functionally clarify how a newly identified c.465-1G>C variant in the DCLRE1C gene is responsible for inducing SCID. In a clinical context, this demonstrates how the experimental validation of new gene variants, that are identified by NGS, can facilitate the diagnosis of SCID which can be vital for implementing appropriate therapies.

Clinical, Immunological, and Molecular Features of Severe Combined Immune Deficiency: A Multi-Institutional Experience From India

BackgroundSevere Combined Immune Deficiency (SCID) is an inherited defect in lymphocyte development and function that results in life-threatening opportunistic infections in early infancy. Data on SCID from developing countries are scarce.ObjectiveTo describe clinical and laboratory features of SCID diagnosed at immunology centers across India.MethodsA detailed case proforma in an Excel format was prepared by one of the authors (PV) and was sent to centers in India that care for patients with primary immunodeficiency diseases. We collated clinical, laboratory, and molecular details of patients with clinical profile suggestive of SCID and their outcomes. Twelve (12) centers provided necessary details which were then compiled and analyzed. Diagnosis of SCID/combined immune deficiency (CID) was based on 2018 European Society for Immunodeficiencies working definition for SCID.ResultsWe obtained data on 277 children; 254 were categorized as SCID and 23 as CID. Male-female ratio was 196:81. Median (inter-quartile range) age of onset of clinical symptoms and diagnosis was 2.5 months (1, 5) and 5 months (3.5, 8), respectively. Molecular diagnosis was obtained in 162 patients - IL2RG (36), RAG1 (26), ADA (19), RAG2 (17), JAK3 (15), DCLRE1C (13), IL7RA (9), PNP (3), RFXAP (3), CIITA (2), RFXANK (2), NHEJ1 (2), CD3E (2), CD3D (2), RFX5 (2), ZAP70 (2), STK4 (1), CORO1A (1), STIM1 (1), PRKDC (1), AK2 (1), DOCK2 (1), and SP100 (1). Only 23 children (8.3%) received hematopoietic stem cell transplantation (HSCT). Of these, 11 are doing well post-HSCT. Mortality was recorded in 210 children (75.8%).ConclusionWe document an exponential rise in number of cases diagnosed to have SCID over the last 10 years, probably as a result of increasing awareness and improvement in diagnostic facilities at various centers in India. We suspect that these numbers are just the tip of the iceberg. Majority of patients with SCID in India are probably not being recognized and diagnosed at present. Newborn screening for SCID is the need of the hour. Easy access to pediatric HSCT services would ensure that these patients are offered HSCT at an early age.

A clinical case of the X-linked moesin deficiency

With the increasing availability of genetic testing, the population of patients diagnosed with CVID breaks down into groups depending on monogenic defects. There is more and more evidence that adults can have combined immunodeficiencies with a late onset. This article discusses a clinical case of X-linked moesin-associated immunodeficiency (X-MAID). This is a recently described immunodeficiency, which mostly manifests itself at an early age with severe lymphopenia and hypogammaglobulinemia, fluctuating monocytopenia and neutropenia, a weak immune response to vaccine antigens, and increased susceptibility to bacteria and type 3 human herpesvirus. X-MAID, X-linked immunodeficiency with a recessive mode of inheritance, is caused by genetic defects in the MOESIN gene (membrane organizing spike elongation protein, MSN). Until recently, there were records of 10 people with this mutation, 9 of which have the phenotype of severe combined immunodeficiency (SCID). The patient described in this article has been under observation since the age of 12 and diagnosed with SCID due to an IgG decrease accompanied by infectious-purulent processes of the respiratory tract and diarrheal syndrome. However, the patient did not entirely fit into the typical clinical picture of CVID due to a severe therapy-torpid papillomavirus infection, the increased number of switched memory B-cells, IgG isolated decrease, persistent severe leukopenia and lymphopenia of CD4+ cells. In accordance with the clinical picture and the results of the immunological examination, combined immunodeficiency was surmised. After a full exome DNA sequencing chrX: g.64951012C T missense type mutation was found in exon 5 of the MSN gene (change in the ENSP00000353408.5:p.Arg171Trp protein). X-MAID was therefore confirmed. Of the 9 described patients with a similar mutation, 8 had a clinical picture of severe combined immune deficiency. This clinical case confirms the possibility of a milder clinical phenotype development with a late onset under the guise of CVID and shows the need for molecular genetic examination of the adult population of patients with impaired antibody synthesis. The verification of the diagnosis allows not only to determine the prognosis and tactics of the therapy, but also to carry out genetic family counseling and to offer a possibility of giving birth to healthy offspring.

Preventing Transmission of Vaccine-Associated Viral Infections from a Patient With Severe Combined Immune Deficiency

Background: The transmissibility of vaccine-strain viruses from immunocompromised patients, such as those with severe combined immune deficiency (SCID) is unknown. The infection control management of a patient diagnosed with SCID and infected with vaccine-strain varicella zoster virus (VZV) and measles virus is described below. A previously healthy, full-term boy was vaccinated at 14 months with measles mumps rubella varicella (MMR) vaccine. He had received prior vaccinations, including rotavirus, without adverse effects. During the 6 weeks after vaccination, the patient developed signs and symptoms clinically consistent with chicken pox and measles. An immune work-up revealed SCID. Methods: The Alberta Health Services (AHS) SCID protocol was followed to manage the patient upon admission at 17 months of age. Multiple meetings with various stakeholders were held to ensure appropriate precautions were followed to minimize the risk of pathogen transmission. Results: The patient was placed on airborne and contact precautions in a negative-pressure room. The pressure differential of the room to the corridor was continually monitored and displayed at the entry to the room. Staff known to be immune to VZV or measles were not required to wear an N95 respirator. All intrahospital movement of the patient was coordinated with the respective care teams and departments, including infection prevention and control, facilities maintenance and engineering, respiratory therapy, and diagnostic imaging. A mask was placed on the patient when movement outside the room was required. VZV testing was positive for the Oka/vaccine strain on all samples tested (ie, nasopharyngeal, skin, blood, and cerebrospinal fluid). Nasopharyngeal swabs and blood were PCR positive for measles genotype A/vaccine strain virus. Both viruses were persistently positive in spite of treatment with acyclovir, valganciclovir, varicella zoster immune globulin, and intravenous immune globulin. Conclusions: There is currently no documented transmission of measles vaccine-strain virus, and transmission of VZV vaccine-strain virus is rare. According to the AHS SCID protocol, the use of airborne and contact precautions for a patient identified with measles and/or VZV supersedes the use of a positive-pressure room for patients identified with SCID. Newborn screening for SCID was implemented in Alberta in June 2019. As a result, more SCID patients will be diagnosed earlier in their course, and therefore prior to most routine vaccinations. However, newborn screening will not pick up some types of combined immune deficiencies. Some children may still be at risk of vaccine-associated illnesses due to undiagnosed underlying immune deficiencies.Funding: NoneDisclosures: None

12 Cost-Benefit Analysis of Newborn Screening for Severe Combined Immune Deficiency: literature review and results transferability

Background The purpose of screening for Severe Combined Immune Deficiency (SCID) is to enable timely diagnosis and treatment for this condition. Untreated SCID is uniformly fatal by 2 years of age. Hematopoietic stem cell transplantation is an effective treatment for SCID, and the success rate depends on the age at which it is performed. Earlier treatment improves survival, long term quality of life and decreases costs of treating patients, specifically by shortening hospitalization days. Screening, however, carries short-term implementation costs, that could potentially be a barrier to adding SCID to the newborn screening (NBS) panels. Objectives This literature review aimed to evaluate the cost-effectiveness of NBS for SCID and perform basic economic analysis review on available published sources. We also assessed the published results and clinical inputs for transferability between different centers. Design/Methods We conducted a systematic search of medical electronic databases: Google Scholar, Ovid, Medline, PubMed, CINAHL, EMBASE, the Cochrane Library, Science Citation Index and Evidence-Based Medicine and hand searched related references. We used the Preferred Reporting Items for Systematic review and Meta-analyses (PRISMA-2009) statement to report the findings. We extracted the details of individual study characteristics from each publication, assessed study quality, evaluated the effect sizes and assessed the influence of study design on the estimated effect size. The presence of small effect sizes was investigated using Funnel plots and Egger’s tests. Search terms included: newborn, SCID, newborn screening, cost-effectiveness, cost-benefit, cost-effectiveness analysis, cost-utility analysis, medical costs, the value of a statistical life, quality-adjusted life-years (QALYs) We included cross-sectional, case-control, and cohort studies that have been published in peer-reviewed journals, data from regional/national surveys. Results 298 records identified through database searching, 192 records removed. A total of 106 articles were found to be eligible for screening, 72 sources were excluded after abstracts review. Forty-four full -text articles were assessed for eligibility, and 14 were excluded (lack of relevance, misleading abstract). Thirty articles were included in the final literature review. We were looking for Level I evidence studies as a high-quality randomized trial or prospective study, sensible costs and alternatives, values obtained from many studies with multiway sensitivity analyses, a systematic review of Level I RCTs and Level I studies. A comparative economic analysis was performed on reviewed sources to determine the average cost-benefit of NBS for SCID among different centers. We used standard conversion to calculate total health costs and charges in US dollars. An average cost of screening for SCID per sample varies between 3.0 -6.0 US$, and at present, there are no known missed cases in SCID NBS programs. The average cost of treatment and QALY were the most common variables used in all reviewed sources and presented in Table 1. Charges for hospital care were more than 5 times higher for late-diagnosed cases of SCID compare to the early diagnosed cases (within the first 2 months of life). These results found to be none-specific to the particular countries, and have high potential transferability among different centers. Conclusion Our literature review analysis supports the cost-effectiveness of NBS for SCID. The opportunity of early treatment is a strong economic rationale for the addition of SCID screening to NBS programs.