Impact of newborn screening for SCID on the management of congenital athymia.

BACKGROUND: Newborn screening (NBS) programs for severe combined immunodeficiency facilitate early diagnosis of severe combined immunodeficiency and promote early treatment with hematopoietic stem cell transplantation, resulting in improved clinical outcomes. Infants with congenital athymia are also identified through NBS because of severe T-cell lymphopenia. With the expanding introduction of NBS programs, referrals of athymic patients for treatment with thymus transplantation have recently increased at Great Ormond Street Hospital (GOSH) (London, United Kingdom). OBJECTIVE: We studied the impact of NBS on timely diagnosis and treatment of athymic infants with thymus transplantation at GOSH. METHODS: We compared age at referral and complications between athymic infants diagnosed after clinical presentation (n = 25) and infants identified through NBS (n = 19) who were referred for thymus transplantation at GOSH between October 2019 and February 2023. We assessed whether age at time of treatment influences thymic output at 6 and 12 months after transplantation. RESULTS: The infants referred after identification through NBS were significantly younger and had fewer complications, in particular fewer infections. All deaths occurred in the group of those who did not undergo NBS, including 6 patients before and 2 after thymus transplantation because of preexisting infections. In the absence of significant comorbidities or diagnostic uncertainties, timely treatment was achieved more frequently after NBS. Treatment when younger than age 4 months was associated with higher thymic output at 6 and 12 months after transplantation. CONCLUSION: NBS contributes to earlier recognition of congenital athymia, promoting referral of athymic patients for thymus transplantation before they acquire infections or other complications and facilitating treatment at a younger age, thus playing an important role in improving their outcomes.

A Rare De Novo Mutation in the TRIM8 Gene in a 17-Year-Old Boy with Steroid-Resistant Nephrotic Syndrome: Case Report.

Idiopathic nephrotic syndrome is the most common chronic glomerular disease in children. Treatment with steroids is usually successful; however, in a small percentage of patients, steroid resistance is observed. The most frequent histologic kidney feature of steroid-resistant nephrotic syndrome (SRNS) is focal segmental glomerulosclerosis (FSGS). Genetic testing has become a valuable diagnostic tool in defining the etiology of SRNS, leading to the identification of a genetic cause. The TRIM8 gene is expressed in various tissues, including kidney cells and the central nervous system (CNS). An association between a mutation in the TRIM8 gene and an early onset of FSGS has been proposed but is not well described. We present a 17-year-old boy with epilepsy, early mild developmental delay, a low IgG serum level, and proteinuria, secondary to FSGS. A Next-Generation Sequencing (NGS)-based analysis revealed a heterozygous de novo pathogenic variant in the TRIM8 gene (c.1200C>G, p.Tyr400Ter). TRIM8 gene sequencing should be considered in individuals with early onset of FSGS, particularly accompanied by symptoms of cortical dysfunction, such as epilepsy and intellectual disability.

Incomplete penetrance for isolated congenital asplenia in humans with mutations in translated and untranslated RPSA exons.

Isolated congenital asplenia (ICA) is the only known human developmental defect exclusively affecting a lymphoid organ. In 2013, we showed that private deleterious mutations in the protein-coding region of RPSA, encoding ribosomal protein SA, caused ICA by haploinsufficiency with complete penetrance. We reported seven heterozygous protein-coding mutations in 8 of the 23 kindreds studied, including 6 of the 8 multiplex kindreds. We have since enrolled 33 new kindreds, 5 of which are multiplex. We describe here 11 new heterozygous ICA-causing RPSA protein-coding mutations, and the first two mutations in the 5'-UTR of this gene, which disrupt mRNA splicing. Overall, 40 of the 73 ICA patients (55%) and 23 of the 56 kindreds (41%) carry mutations located in translated or untranslated exons of RPSA. Eleven of the 43 kindreds affected by sporadic disease (26%) carry RPSA mutations, whereas 12 of the 13 multiplex kindreds (92%) carry RPSA mutations. We also report that 6 of 18 (33%) protein-coding mutations and the two (100%) 5'-UTR mutations display incomplete penetrance. Three mutations were identified in two independent kindreds, due to a hotspot or a founder effect. Finally, RPSA ICA-causing mutations were demonstrated to be de novo in 7 of the 23 probands. Mutations in RPSA exons can affect the translated or untranslated regions and can underlie ICA with complete or incomplete penetrance.

Atypical Hemolytic Uremic Syndrome (aHUS) and Adenosine Deaminase (ADA)-Deficient Severe Combined Immunodeficiency (SCID)-Two Diseases That Exacerbate Each Other: Case Report.

Hemolytic uremic syndrome (HUS) is defined by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury (AKI). Atypical HUS (aHUS), distinguished by its etiology, is caused by uncontrolled overactivation of the alternative complement pathway. The correct diagnosis of aHUS is complex and involves various gene mutations. Severe combined immunodeficiency (SCID), characterized by severe T-cell lymphocytopenia and a lack of antigen-specific T-cell and B-cell immune responses, is of seldom occurrence. In 10-15% of pediatric patients, SCID is caused by adenosine deaminase (ADA) deficiency. The authors describe the case of a boy who suffered from both aHUS and ADA-deficient SCID. At the age of 9 months, the patient presented acute kidney injury with anuria and coagulopathy. The diagnosis of aHUS was established on the basis of alternative complement pathway deregulation and disease-associated gene mutations. Further examination revealed immune system failure and, at the age of 13 months, the ADA deficiency was confirmed by genetic tests and the boy was diagnosed with ADA-SCID. ADA SCID has recently been described as a possible triggering factor of aHUS development and progression. However, more research is required in this field. Nevertheless, it is crucial in clinical practice to be aware of these two co-existing life-threatening diseases.

Knowledge Discovery from Medical Data and Development of an Expert System in Immunology.

Artificial intelligence is one of the fastest-developing areas of science that covers a remarkably wide range of problems to be solved. It has found practical application in many areas of human activity, also in medicine. One of the directions of cooperation between computer science and medicine is to assist in diagnosing and proposing treatment methods with the use of IT tools. This study is the result of collaboration with the Children's Memorial Health Institute in Warsaw, from where a database containing information about patients suffering from Bruton's disease was made available. This is a rare disorder, difficult to detect in the first months of life. It is estimated that one in 70,000 to 90,000 children will develop Bruton's disease. But even these few cases need detailed attention from doctors. Based on the data contained in the database, data mining was performed. During this process, knowledge was discovered that was presented in a way that is understandable to the user, in the form of decision trees. The best models obtained were used for the implementation of expert systems. Based on the data introduced by the user, the system conducts expertise and determines the severity of the course of the disease or the severity of the mutation. The CLIPS language was used for developing the expert system. Then, using this language, software was developed producing six expert systems. In the next step, experimental verification was performed, which confirmed the correctness of the developed systems.

BCG Moreau Vaccine Safety Profile and NK Cells-Double Protection Against Disseminated BCG Infection in Retrospective Study of BCG Vaccination in 52 Polish Children with Severe Combined Immunodeficiency.

OBJECTIVES: The aim of the study was to estimate the rate of adverse reactions to live BCG Moreau vaccine, manufactured by Biomed in Poland, in severe combined immunodeficiency (SCID) patients. MATERIAL: The profiles of 52 SCID patients vaccinated at birth with BCG, hospitalized in Children's Memorial Health Institute, Warsaw (CMHI), in the years 1980-2015 were compared with those of 349 BCG-vaccinated SCID patients from other countries analyzed by Beatriz E. Marciano et al. in a retrospective study (Marciano et al. J Allergy Clin Immunol. 2014;133(4):1134-1141). RESULTS: Significantly less disseminated BCG infections (10 out of 52 SCID, 19%) occurred in comparison with Marciano study-119 out of 349, 34% (p = 0.0028), with no death in patients treated with SCID anti-TB drug, except one in lethal condition. In our study, disseminated BCG infection was observed only in SCID with T-B+NK- phenotype and significantly lower NK cell counts (p = 0.0161). NK cells do not influence on the frequency of local BCG reaction. A significantly higher number of hematopoietic stem cells transplantations (HSCT) were performed in CMHI study (p = 0.0001). Anti-TB treatment with at least two medicines was provided. CONCLUSION: The BCG Moreau vaccine produced in Poland, with well-documented genetic characteristics, seems to be safer than other BCG substrains used in other regions of the world. Importantly, NK cells seem to play a role in protecting SCID patients against disseminated BCG complications, which NK- SCID patients are more prone to. HSCT and TB therapy could be relevant due to the patients' survival and the fact that they protect against BCG infection.

Thymus transplantation for complete DiGeorge syndrome: European experience.

BACKGROUND: Thymus transplantation is a promising strategy for the treatment of athymic complete DiGeorge syndrome (cDGS). METHODS: Twelve patients with cDGS underwent transplantation with allogeneic cultured thymus. OBJECTIVE: We sought to confirm and extend the results previously obtained in a single center. RESULTS: Two patients died of pre-existing viral infections without having thymopoiesis, and 1 late death occurred from autoimmune thrombocytopenia. One infant had septic shock shortly after transplantation, resulting in graft loss and the need for a second transplant. Evidence of thymopoiesis developed from 5 to 6 months after transplantation in 10 patients. Median circulating naive CD4 counts were 44 × 106/L (range, 11-440 × 106/L) and 200 × 106/L (range, 5-310 × 106/L) at 12 and 24 months after transplantation and T-cell receptor excision circles were 2,238/106 T cells (range, 320-8,807/106 T cells) and 4,184/106 T cells (range, 1,582-24,596/106 T cells). Counts did not usually reach normal levels for age, but patients were able to clear pre-existing infections and those acquired later. At a median of 49 months (range, 22-80 months), 8 have ceased prophylactic antimicrobials, and 5 have ceased immunoglobulin replacement. Histologic confirmation of thymopoiesis was seen in 7 of 11 patients undergoing biopsy of transplanted tissue, including 5 showing full maturation through to the terminal stage of Hassall body formation. Autoimmune regulator expression was also demonstrated. Autoimmune complications were seen in 7 of 12 patients. In 2 patients early transient autoimmune hemolysis settled after treatment and did not recur. The other 5 experienced ongoing autoimmune problems, including thyroiditis (3), hemolysis (1), thrombocytopenia (4), and neutropenia (1). CONCLUSIONS: This study confirms the previous reports that thymus transplantation can reconstitute T cells in patients with cDGS but with frequent autoimmune complications in survivors.

Genetic defects in PI3Kδ affect B-cell differentiation and maturation leading to hypogammaglobulineamia and recurrent infections.

BACKGROUND: Mutations in PIK3CD and PIK3R1 cause activated PI3K-δ syndrome (APDS) by dysregulation of the PI3K-AKT pathway. METHODS: We studied precursor and peripheral B-cell differentiation and apoptosis via flowcytometry. Furthermore, we performed AKT-phosphorylation assays and somatic hypermutations (SHM) and class switch recombination (CSR) analysis. RESULTS: We identified 13 patients of whom 3 had new mutations in PIK3CD or PIK3R1. Patients had low total B-cell numbers with increased frequencies of transitional B cells and plasmablasts, while the precursor B-cell compartment in bone marrow was relatively normal. Basal AKT phosphorylation was increased in lymphocytes from APDS patients and natural effector B cells where most affected. PI3K mutations resulted in altered SHM and CSR and increased apoptosis. CONCLUSIONS: The B-cell compartment in APDS patients is affected by the mutations in PI3K. There is reduced differentiation beyond the transitional stage, increased AKT phosphorylation and increased apoptosis. This B-cell phenotype contributes to the clinical phenotype.

Comprehensive activities to increase recognition of primary immunodeficiency and access to immunoglobulin replacement therapy in Poland.

UNLABELLED: The study presents an overview on current situation of primary immunodeficiency (PID) patients in Poland and the 2014 annual report of the Polish Working Group for Immunodeficiency (PWGID). The group was set up in 2005 to improve diagnosis, treatment, and care of patients with immunodeficiencies and currently includes 15 pediatric and 13 adult centers. According to PWGID report 4099, PID patients are recognized in Poland, with the prevalence 10.6/100,000. The majority of them (54.2 %) have predominantly antibody deficiency (PAD). In 2014 alone, a total number of 731 newly diagnosed individuals are reported. As predicted, the vast majority (70 %) of them have PAD. Approximately one third of PAD patients require immunoglobulin replacement therapy. Within the entire cohort, an intravenous route of immunoglobulin therapy dominates (67.3 %). However, within the age groups, distribution of immunoglobulin therapy varies and seems to be age related. Among children, 36 % receive subcutaneous immunoglobulin, while with adults 26 %. CONCLUSION: Analysis of numbers of either newly recognized or treated patients indicates its dynamic increase in recent years. This is the result of comprehensive activities by PWGID supported by governmental institutions, outstanding foundations, and patient's organization. WHAT IS KNOWN: • Immunoglobulins' treatment has substantially changed the life of individuals with PAD. Patients with common variable immunodeficiency (CVID) or X-linked agammaglobulinemia (XLA) can live and lead a near normal life. Early diagnosis of the disease followed by earlier implementation of appropriate treatment, including gammaglobulin replacement therapy, improves the quality of life. • Targeted efforts of health care professionals and government are required to optimize diagnostic and therapeutic approach for PAD. What is New: • Comprehensive activities of PWGID lead to better recognition of PID individuals and should improve reporting Polish PIDs to the ESID database. • Following the joint efforts of immunologists, patient's, and governmental organizations in the end of 2014, the Therapeutic Program for Treatment Adults with PID was introduced, leading to universal access to currently available treatment options and to improve the quality of life.

Nijmegen Breakage Syndrome: Clinical and Immunological Features, Long-Term Outcome and Treatment Options - a Retrospective Analysis.

PURPOSE: Nijmegen Breakage Syndrome (NBS) is a rare inherited condition, characterized by microcephaly, chromosomal instability, immunodeficiency, and predisposition to malignancy. This retrospective study, characterizing the clinical and immunological status of patients with NBS at time of diagnosis, was designed to assess whether any parameters were useful in disease prognosis, and could help determine patients qualified for hematopoietic stem cell transplantation. METHODS: The clinical and immunological characteristics of 149 NBS patients registered in the online database of the European Society for Immune Deficiencies were analyzed. RESULTS: Of the 149 NBS patients, 91 (61%), of median age 14.3 years, remained alive at the time of analysis. These patients were clinically heterogeneous, with variable immune defects, ranging from negligible to severe dysfunction. Humoral deficiencies predisposed NBS patients to recurrent/chronic respiratory tract infections and worsened long-term clinical prognosis. Eighty malignancies, most of lymphoid origin (especially non-Hodgkin's lymphomas), were diagnosed in 42% of patients, with malignancy being the leading cause of death in this cohort. Survival probabilities at 5, 10, 20 and 30 years of age were 95, 85, 50 and 35%, respectively, and were significantly lower in patients with than without malignancies. CONCLUSIONS: The extremely high incidence of malignancies, mostly non-Hodgkin's lymphomas, was the main risk factor affecting survival probability in NBS patients. Because treatment of NBS is very difficult and frequently unsuccessful, the search for an alternative medical intervention such as hematopoietic stem cell transplantation is of great clinical importance.

Wiskott-Aldrich Syndrome protein deficiency perturbs the homeostasis of B-cell compartment in humans.

Wiskott-Aldrich Syndrome protein (WASp) regulates the cytoskeleton in hematopoietic cells and mutations in its gene cause the Wiskott-Aldrich Syndrome (WAS), a primary immunodeficiency with microthrombocytopenia, eczema and a higher susceptibility to develop tumors. Autoimmune manifestations, frequently observed in WAS patients, are associated with an increased risk of mortality and still represent an unsolved aspect of the disease. B cells play a crucial role both in immune competence and self-tolerance and defects in their development and function result in immunodeficiency and/or autoimmunity. We performed a phenotypical and molecular analysis of central and peripheral B-cell compartments in WAS pediatric patients. We found a decreased proportion of immature B cells in the bone marrow correlating with an increased presence of transitional B cells in the periphery. These results could be explained by the defective migratory response of WAS B cells to SDF-1α, essential for the retention of immature B cells in the BM. In the periphery, we observed an unusual expansion of CD21(low) B-cell population and increased plasma BAFF levels that may contribute to the high susceptibility to develop autoimmune manifestations in WAS patients. WAS memory B cells were characterized by a reduced in vivo proliferation, decreased somatic hypermutation and preferential usage of IGHV4-34, an immunoglobulin gene commonly found in autoreactive B cells. In conclusion, our findings demonstrate that WASp-deficiency perturbs B-cell homeostasis thus adding a new layer of immune dysregulation concurring to the increased susceptibility to develop autoimmunity in WAS patients.

Facilitated subcutaneous immunoglobulin treatment patterns in pediatric patients with primary immunodeficiency diseases.

Aim: This retrospective study investigated real-world hyaluronidase-facilitated subcutaneous immunoglobulin (fSCIG) treatment patterns in pediatric patients with primary immunodeficiency diseases (PIDs) in Poland. Methods: Clinical and demographic information, fSCIG treatment parameters and clinical outcomes were extracted from medical records of 28 participants (aged ≤18 years) with PIDs who received fSCIG. Results: 18 participants (64.3%) started fSCIG with a ramp-up (median duration: 35.5 days). 27 patients (96.4%) were administered fSCIG every 4 weeks and one patient every 3 weeks. 25 patients (89.3%) used one infusion site. No serious bacterial infections occurred. Conclusion: Data support the feasibility of administering fSCIG to children and adolescents with PIDs every 3-4 weeks using a single infusion site and indicate flexibility in modifying fSCIG infusion parameters. Clinical Trial Registration: NCT04636502 (ClinicalTrials.gov).

Antibodies, also known as immunoglobulins, are proteins that are made by the immune system to help fight infections. In primary immunodeficiency diseases (PIDs), part of the immune system may be missing or not working properly. This study looked at the use of an antibody treatment called hyaluronidase-facilitated subcutaneous immunoglobulin (or fSCIG) in Polish children aged 18 years or younger with PIDs. Information on patients, their disease, how fSCIG was being used and how patients responded to treatment was taken from medical records. Out of 28 patients, 18/28 (64.3%) had their fSCIG dose slowly increased, which took an average of 35.5 days. Overall, 27/28 patients were treated with fSCIG every 4 weeks (96.4%), and 25/28 patients used one place to inject fSCIG (89.3%). No serious infections caused by bacteria happened during the study. The study results suggest that children with PIDs could be treated every 3 to 4 weeks with fSCIG, and that flexibility in how fSCIG is injected may offer options suited to individual patients.

Common variable immune deficiency in children--clinical characteristics varies depending on defect in peripheral B cell maturation.

Common variable immune deficiency (CVID) is a heterogeneous disease associated with ineffective production of antibodies. It is usually diagnosed in adulthood, but a variable proportion of children develop CVID. Early identification of patients with potentially worse prognosis may help to avoid serious complications. The goal of this study was to associate the clinical phenotype of patients with early onset CVID with peripheral B-cell maturation profile. Four color flow cytometry was used to define distribution of peripheral B-cell subsets in 49 children with early-onset CVID. All clinical data were extracted from medical records. A proportion of patients demonstrated diminishing with time total B-lymphocytes pool, beyond physiological age-related changes. Irrespective from duration of the follow-up period the B-cell maturation profile in individual patients remained unchanged. We identified six different aberrant peripheral B cell maturation profiles associated with different clinical characteristics. Patients with an early B-cell maturation block earlier required replacement therapy and were at significantly greater risk of enteropathy, granuloma formation, cytopenia, and lymphoproliferation. B-cell maturation inhibited at the natural effector stage was associated with higher risk of autoimmune manifestations other than autoimmune cytopenia. Prevalence of male patients was observed among patients with B-cell maturation inhibited at naïve B-cell stage. In conclusion, the diagnostic process in patients with suspected early-onset CVID shall include routine analysis of peripheral B-cell maturation to provide surrogate markers identifying patients at greater risk of developing certain complications.

Subcutaneous immunoglobulin 20% (Ig20Gly) treatment regimens in pediatric patients with primary immunodeficiencies - real-world data from the IG TATRY study.

BACKGROUND: Subcutaneous administration of immunoglobulins is associated with fewer systemic adverse events and easier infusion compared to intravenous administration. Ig20Gly is a 20% immunoglobulin formulation effective and safe in patients with primary immune deficiency diseases (PIDDs). Real-world data are scarce, therefore our study aimed to examine the real-life treatment regimen and clinical outcomes of Ig20Gly in Polish children with PIDDs. RESEARCHDESIGN: We retrospectively analyzed the medical documentation of 75 pediatric patients aged 0-17 years (mean 9.9) who received Ig20Gly (Cuvitru®; Baxalta US, Inc.; part of Takeda, MA, U.S.A.). RESULTS: The median exposure to treatment of the study population was 22.3 months. At the end of the study, 59 (78.7%) were still on Ig20Gly. The median monthly dose was 0.40 g/kg. The median treatment interval was 7.7 days. Most patients (96%) used one infusion site. The median infusion rate increased with patient age. The median IgG level in the study population, 8.0 g/L, was stable. There was one case of serious bacterial infection. CONCLUSION: This is the largest, long-term real-world study to date on the treatment patterns of Ig20Gly in pediatric patients with PIDDs. The results of this study support the feasibility and tolerability of Ig20Gly usage in PIDD patients across the pediatric age spectrum. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov (NCT04636502).

The defect in humoral immunity in patients with Nijmegen breakage syndrome is explained by defects in peripheral B lymphocyte maturation.

Patients with an immunodeficiency in the course of Nijmegen breakage syndrome (NBS) that is caused by mutations in the NBN/NBS1 gene are prone to recurrent infections and malignancies, due to a defective DNA double-strand breaks repair mechanism. Four-color flow cytometry was used to analyze changes in B lymphocyte subsets reflecting the most important stages of peripheral B cell maturation. It was demonstrated that the humoral immune defect observed in NBS patients was caused by reduced numbers of B lymphocytes, but also by their aberrant maturation. Reduced relative and absolute counts of naïve and memory B cells were accompanied by a significant accumulation of the natural effector B lymphocytes. The elevated proportion of IgM-only memory and reduced proportion of IgM-negative cells within the memory B cell pool suggests that there is class-switch recombination defect in this population of cells in NBS patients, resulting in inadequate production of immunoglobulins. Because of the reduced T-cell counts, the T-cell dependent antigen response is severely impaired resulting in a lower frequency of memory B-cells. The T-cell independent B-cell differentiation pathway seems less affected. The reduced IgG and IgA levels in patients with NBS are caused both by ineffective class switch, at least due to poor T cell help, and low number of memory B cells. This study illustrates that the NBN gene product nibrin plays an important role at different levels in the B-cell system.

Loss of juxtaposition of RAG-induced immunoglobulin DNA ends is implicated in the precursor B-cell differentiation defect in NBS patients.

The Nijmegen breakage syndrome (NBS) is a rare inherited condition, characterized by microcephaly, radiation hypersensitivity, chromosomal instability, an increased incidence of (mostly) lymphoid malignancies, and immunodeficiency. NBS is caused by hypomorphic mutations in the NBN gene (8q21). The NBN protein is a subunit of the MRN (Mre11-Rad50-NBN) nuclear protein complex, which associates with double-strand breaks. The immunodeficiency in NBS patients can partly be explained by strongly reduced absolute numbers of B lymphocytes and T lymphocytes. We show that NBS patients have a disturbed precursor B-cell differentiation pattern and significant disturbances in the resolution of recombination activating gene-induced IGH breaks. However, the composition of the junctional regions as well as the gene segment usage of the reduced number of successful immunoglobulin gene rearrangements were highly similar to healthy controls. This indicates that the NBN defect leads to a quantitative defect in V(D)J recombination through loss of juxtaposition of recombination activating gene-induced DNA ends. The resulting reduction in bone marrow B-cell efflux appeared to be partly compensated by significantly increased proliferation of mature B cells. Based on these observations, we conclude that the quantitative defect will affect the B-cell receptor repertoire, thus contributing to the observed immunodeficiency in NBS patients.

Lack of relationship between 25-hydoxyvitamin D concentration and a titer of antibodies to hepatitis B surface antigen in children under 12 years of age.

The effect of vitamin D levels on the response to the hepatitis B vaccine in childhood and the induced levels of antibodies against the hepatitis B surface antigen (anti-HBs) is not yet well understood. The study aimed to investigate the relationship between age, serum 25-hydroxyvitamin D (25(OH)D) concentration and anti-HBs titer among children under 12 years old. Serum 25(OH)D concentration and anti-HBs titer were determined in 352 healthy Caucasian children with the average age of 4.2 (2.5; 6.3) years. All children were vaccinated with 3 doses of hepatitis B vaccine (Engerix-B, GlaxoSmithKline Pharmaceuticals Limited) in infancy according to the Centers for Disease Control and Prevention recommendations. Only 14.5% of children had an optimal concentration of 25(OH)D ≥ 30 ng/mL and 71.9% children had a seroprotective anti-HBs titer ≥ 10 mIU/mL. Significant negative correlations were found between 25(OH)D, anti-HBs titer and age (r = -0.420, p = 0.000; r = -0.425, p = 0.000, respectively), and a weak positive correlation between 25(OH)D concentration and anti-HBs titer (r = 0.243, p = 0.000). Analysis of six clusters of children demonstrated that age is the main factor affecting anti-HBs titer. One third of children under 12 years of age had nonprotective anti-HBs titer < 10 mIU/mL and around 40% had vitamin D deficiency. We conclude that vitamin D status has no impact on anti-HBs titer in children vaccinated against hepatitis B virus in infancy. Age, so time since the receipt of the last dose of hepatitis B vaccine, is the main factor influencing a decline in anti-HBs titer.

Case report: Severe combined immunodeficiency with ligase 1 deficiency and Omenn-like manifestation.

DNA ligase I deficiency is an extremely rare primary immunodeficiency with only 6 patients reported in the literature. Most common manifestations include radiosensitivity, macrocytic anemia, lymphopenia with an increased percentage of gamma-delta T cells, and hypogammaglobulinemia requiring replacement therapy. Two-month-old girl with delayed development, T-B-NK+ SCID, and macrocytic anemia presented features of Omenn syndrome. Whole exome sequencing revealed two novel, heterozygous variants (c.2312 G>A, p.Arg771Gly and c.776+5G>T, p.Pro260*) in the LIG1 gene (NM_000234.1). Hematopoietic stem cell transplantation from a fully matched unrelated donor was performed at the age of 4 months using GEFA03 protocol. Mixed donor-recipient chimerism was observed, with 60-70% chimerism in the mononucleated cell compartment and over 90% in T-lymphocyte compartment, but autologous myeloid recovery. Stable CD4+ and CD8+ T-cell counts above 200/µL were achieved after 2 months, but the patient remained transfusion-dependent. Despite satisfactory immunological reconstitution, the second transplantation due to constitutional hemolytic defect has been considered. In light of possible re-transplantation, an issue of optimal conditioning protocol with sufficient myeloid engraftment is important. For the first time Omenn syndrome is described in a compound heterozygote carrying two the novel variants p.Arg771Gly and p.Pro260* in the LIG1 gene. Patients diagnosed with SCID and Omenn syndrome showing macrocytic anemia, should be screened for DNA ligase I deficiency.

National experience with adenosine deaminase deficiency related SCID in Polish children.

Introduction: Deficiency of adenosine deaminase (ADA) manifests as severe combined immunodeficiency (SCID), caused by accumulation of toxic purine degradation by-products. Untreated patients develop immune and non-immune symptoms with fatal clinical course. According to ESID and EBMT recommendations enzyme replacement therapy (ERT) should be implemented as soon as possible to stabilize the patient's general condition, normalize transaminases, treat pulmonary proteinosis, bone dysplasia, and protect from neurological damage. Hematopoietic stem cell transplantation (HSCT) from a matched related donor (MRD) is a treatment of choice. In absence of such donor, gene therapy (GT) should be considered. HSCT from a matched unrelated donor (MUD) and haploidentical hematopoietic stem cell transplantation (hHSCT) are associated with worse prognosis. Material and methods: We retrospectively evaluated the clinical course and results of biochemical, immunological and genetic tests of 7 patients diagnosed in Poland with ADA deficiency since 2010 to 2022. Results: All patients demonstrated lymphopenia affecting of T, B and NK cells. Diagnosis was made on the basis of ADA activity in red blood cells and/or genetic testing. Patients manifested with various non-immunological symptoms including: lung proteinosis, skeletal dysplasia, liver dysfunction, atypical hemolytic-uremic syndrome, and psychomotor development disorders. Five patients underwent successful HSCT: 3 patients from matched unrelated donor, 2 from matched sibling donor, and 1 haploidentical from a parental donor. In 4 patients HSCT was preceded by enzyme therapy (lasting from 2 to 5 months). One patient with multiple organ failure died shortly after admission, before the diagnosis was confirmed. None of the patients had undergone gene therapy. Conclusions: It is important to diagnose ADA SCID as early as possible, before irreversible multi-organ failure occurs. In Poland HSCT are performed according to international immunological societies recommendations, while ERT and GT are less accessible. Implementation of Newborn Screening (NBS) for SCID in Poland could enable recognition of SCID, including ADA-SCID.