Corrigendum: HLH as an additional warning sign of inborn errors of immunity beyond familial-HLH in children: a systematic review.

[This corrects the article DOI: 10.3389/fimmu.2024.1282804.].

Expanded Newborn Screening for Inborn Errors of Immunity: The Experience of Tuscany.

BACKGROUND: Inborn errors of immunity (IEIs) include 485 inherited disorders characterized by an increased susceptibility to life-threatening infectious diseases, autoimmunity, and malignant diseases with a high mortality rate in the first years of life. Severe combined immunodeficiency is the most severe of the IEIs, and its detection should be a primary goal in a newborn screening (NBS) program. The term "actionable" has recently been used for all IEIs with outcomes that can be demonstrably improved through early specialized intervention. OBJECTIVE: To evaluate the results of the expanded NBS strategy for IEIs in Tuscany Region (Italy), based on T-cell receptor excision circle, kappa recombining excision circle, and tandem mass-based assays. METHODS: This is a retrospective study collecting data from all infants born in Tuscany from October 10, 2018, to October 10, 2022. Tandem mass assay to identify adenosine deaminase and purine nucleoside phosphorylase deficiency, together with T-cell receptor excision circle and kappa recombining excision circle molecular analysis, was conducted on dried blood spot from the newborns' Guthrie Cards. A new dried blood spot and evaluation by an immunologist were carried out when the results of the first test were outside the diagnostic cutoffs. RESULTS: A total of 94,319 newborns were evaluated. Referral rates for T-cell recombining excision circles (0.031%) and kappa recombining excision circles (0.074%) in this study are in line with the data available in literature. The results from the expanded NBS strategy revealed an incidence rate of 1 per 9431 affected newborns. CONCLUSIONS: This work represents the first description of a sustainable and real-life-based expanded NBS program for IEIs with a high diagnostic incidence facilitating prompt management of identified patients.

HLH as an additional warning sign of inborn errors of immunity beyond familial-HLH in children: a systematic review.

Background: Hemophagocytic Lymphohistiocytosis (HLH) is a rare and life-threatening condition characterized by a severe impairment of the immune homeostasis. While Familial-HLH (FHL) is a known cause, the involvement of other Inborn Errors of Immunity (IEI) in pediatric-HLH remains understudied. Objective: This systematic review aimed to assess the clinical features, triggers, laboratory data, treatment, and outcomes of pediatric HLH patients with IEI other than FHL (IEInotFHL), emphasizing the importance of accurate identification and management. Methods: A systematic search for studies meeting inclusion criteria was conducted in PubMed, EMBASE, MEDLINE, and Cochrane Central. Quality assessment was performed through JBI criteria. Results: A comprehensive search yielded 108 records meeting inclusion criteria, involving 178 patients. We identified 46 different IEI according to IUIS 2022 Classification. Combined immunodeficiencies, immune dysregulation disorders, and phagocyte defects were the IEI most frequently associated with HLH. In 75% of cases, HLH preceded the IEI diagnosis, often with an unrecognized history of severe infections. Triggers reflected the specific infection susceptibilities within IEI groups. Liver and central nervous system involvement were less common than in FHL cases. Treatment approaches and outcomes varied, with limited long-term follow-up data, limiting the assessment of therapeutic efficacy across IEI groups. Conclusion: A comprehensive evaluation encompassing immunological, infectious, and genetic aspects is essential in pediatric-HLH. Relying solely on FHL or EBV susceptibility disorders tests is insufficient, as diverse other IEI can contribute to HLH. Early recognition of HLH as a potential warning sign can guide timely diagnostic investigations and facilitate tailored therapeutic interventions for improved outcomes. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=371425, PROSPERO, CRD42022371425.

Characterization of Autoimmune Thyroid Disease in a Cohort of 73 Paediatric Patients Affected by 22q11.2 Deletion Syndrome: Longitudinal Single-Centre Study.

BACKGROUND: Chromosome 22q11.2 Deletion Syndrome (22q11.2DS) is the most frequent microdeletion syndrome and is mainly characterized by congenital cardiac defects, dysmorphic features, hypocalcemia, palatal dysfunction, developmental delay, and impaired immune function due to thymic hypoplasia or aplasia. Thyroid anomalies are frequently reported in patients with 22q11.2DS, although only a few well-structured longitudinal studies about autoimmune thyroid disease (ATD) have been reported. AIM: To longitudinally evaluate the frequency of thyroid anomalies and ATD in patients with 22q11.2DS. PATIENTS AND METHODS: Pediatric patients with a confirmed genetic diagnosis of 22q11.2DS were recruited and followed up on longitudinally. Clinical, biochemical, and immunological data were collected, as well as thyroid function, autoimmunity, and thyroid sonographic data. RESULTS: The study included 73 children with 22q11.2DS, with a mean follow-up duration of 9.51 ± 5.72 years. In all, 16 of the 73 enrolled patients (21.9%) developed ATD before 18 years of age (mean age 12.92 ± 3.66 years). A total of 20.5% developed Hashimoto's Thyroiditis (HT), of whom 50% required L-thyroxine treatment; 1.4% developed Graves Disease. Thyroid hypoplasia was found in 6/16 patients with ATD and left lobe hypoplasia in 9/16 patients. These features were also found in patients affected by 22q11.2DS without ATD. Among patients who developed ATD, at the first altered ultrasound scan, the most frequent anomalies suggestive of thyroiditis were inhomogeneous echotexture, diffuse or irregular hypo-echogenicity, and vascular overflow. CONCLUSION: We strongly recommend periodic screening of thyroid function and for autoimmunity in patients affected by 22q11.2DS. Along with blood tests, ultrasound scans of the thyroid gland should be performed periodically since some patients who go on to develop an ATD could have specific anomalies on ultrasound prior to any other anomaly.

Unbalanced serum immunoglobulins in clinical subtypes of pediatric tuberculosis disease.

Immune response to tuberculosis (TB) has been extensively studied in the past decades and classically involves cellular immunity. However, evidence suggests that humoral immunity may play a relevant role. Past studies regarding serum immunoglobulin (Ig) levels in TB are dated and only involve adult subjects. In this study, we retrospectively studied a cohort of 256 children with TB disease and analyzed 111 patients screened for total serum Ig at diagnosis. According to the severity and extent of organ involvement, subjects were divided into four groups, namely, uncomplicated pulmonary TB (UCPTB, 56.3% of patients), complicated pulmonary TB (CPTB, 22.5%), lymph node extrapulmonary TB (LN-EPTB, 7.2%), and extra-nodal extrapulmonary TB (EN-EPTB, 13.5%). Serum IgG and IgA levels were significantly higher in more severe and extended TB disease. Median IgG levels progressively increased from uncomplicated to complicated pulmonary and nodal forms, reaching their highest values in diffuse extra-pulmonary TB. In parallel, UCPTB showed significantly lower frequencies of patients presenting a substantial increase in IgG levels when compared with the other three groups. No relevant differences in IgM levels were detected. Ig screening at follow-up showed a significant reduction in IgG and IgA levels. Finally, we unveiled three cases of selective IgA and one case of selective IgM deficiencies (SIgMD), the latter with a severe clinical course. Serum IgG and IgA may be a useful clinical tool to assess the severity and monitor the treatment response in pediatric TB disease. Moreover, immunological workup in children with TB disease may unmask primary defects of humoral immunity.

Molecular typing of group B Neisseria meningitidis'subcapsular antigens directly on biological samples demonstrates epidemiological congruence between culture-positive and -negative cases: A surveillance study of invasive disease over a 13-year period.

BACKGROUND: Surveillance of serogroup B Neisseria meningitidis (MenB) subcapsular antigen variant distribution in invasive disease (IMD) is fundamental for multicomponent vaccine coverage prediction. IMD incidence in Tuscany in 2018 was 0.37/100,000 inhabitants, with MenB representing 57% of cases. More than 50% of MenB responsible for IMD cannot be grown in culture, and molecular characterization of these cases is often lacking. The aim of the present study was to describe the distribution of MenB subcapsular antigens, comparing their distribution in culture-positive and culture-negative cases. METHODS: Molecular data regarding clonal complexes and subcapsular antigen variants of the 55 MenB-IMD occurring in Tuscany from 2007 to 2019 were made available, and their distribution between culture-positive and culture-negative cases was compared. Genetic-MATS and MenDeVAR prediction systems were used to assess multicomponent vaccine coverage predictions. RESULTS: Culture-positive and culture-negative cases presented a similar percentage representation of fHbp subfamilies. Clonal complex 162 was almost constantly associated with fHbp B231/v1.390, Neisserial-heparin-binding-antigen (NHBA) peptide 20, and PorinA P1.22,14 (BAST-3033): these were the most represented antigenic variants, both in culture-positive and culture-negative groups. Point-estimate 4CMenB coverage prediction was 88.5% (84.6%-92.3%). CONCLUSIONS: Our data demonstrate that non-cultivable meningococci, responsible for IMD, possess genetic variants of subcapsular antigens that are representative of what has been observed in culture. The vaccine-related antigenic epidemiology of MenB is thus similar in both groups. One of the first on-field applications of gMATS and MenDeVAR identifies their major advantage in their accessibility and in the possibility of dynamic data implementation that must be pursued continuously in the future.

Efficacy and safety of human intravenous immunoglobulin 5% (Ig VENA) in pediatric patients affected by primary immunodeficiency.

Patients affected by primary immunodeficiencies are characterized for high susceptibility for severe infections. Our data demonstrate Kedrion 5% intravenous immunoglobulin G (IVIg) treatment effective and safe as replacement therapy for children and adolescents affected by primary immunodeficiency. The particularities of our study are the selection of a long period of follow-up (71 patient-years of follow-up), and to the best of our knowledge, our study is one of few that assesses the safety and efficacy of intravenous immunoglobulin treatment of primary immunodeficiency specifically in a pediatric population.

Invasive Haemophilus influenzae Type b Disease in the Post Hexavalent Era: Ten Years of Molecular Surveillance in Tuscany.

BACKGROUND: The epidemiologic characteristics of invasive Haemophilus influenzae type b disease (HIBD) have markedly changed since the introduction of the Haemophilus influenzae type b (Hib) conjugate vaccine worldwide. The immunization schedule against Haemophilus influenzae type b differs in Europe. METHODS: This is a retrospective observational study which evaluates all the data included in the molecular surveillance register for invasive infectious diseases at the Laboratory of Molecular Diagnosis at Meyer Children's University Hospital from December 2008 to December 2018 with a diagnosis of invasive HIBD in children <5 years of age. RESULTS: We identified 4 cases of HIBD: all the cases presented signs or symptoms of invasive infection and the H. influenzae type b was identified in cerebrospinal fluid, or blood or bronchoalveolar lavage by molecular test. The crude incidence for Hib invasive disease in Tuscany is 0.26/100,000 p-y in children younger than 5 years, significantly different from the incidence rate before the introduction of the Hib vaccination. Vaccination effectiveness can be estimated at 97.9% and the impact of hexavalent (2p+1) vaccine at 99.6%. CONCLUSIONS: This work confirms the high impact of the hexavalent vaccine 2p+1 schedule for HIBD in children <5 years, emphasizing the role of molecular test for HIBD diagnosis and surveillance.

Vaccines Safety in Children and in General Population: A Pharmacovigilance Study on Adverse Events Following Anti-Infective Vaccination in Italy.

Background: The concern for adverse events following immunization (AEFI) and anti-vaccination movements that lacked scientific evidence-based supports may reduce vaccine uptake in the general population. Thus, the aims of the present study were to characterize AEFI in general population (all age groups), in terms of frequency, preventability, and seriousness and to define predictors of their seriousness in children. Methods: A retrospective study was performed on suspected AEFI reports for children and adults who received any form of vaccinations, collected in Tuscany, Italy, between 1 January and 31 December 2017. Patients' characteristics, suspected vaccines, and AEFI description were collected. Causality and preventability were assessed using WHO and Schumock and Thornton algorithms, respectively. Logistic regression was used to estimate the reporting odds ratios of potential predictors of AEFI seriousness in children. Results: A total of 223 suspected AEFI reports were collected, and the majority of them were defined as non-serious (76.7%). Reports were mostly related to one vaccine, and to a median of two to five strains/toxoids. The total number of simultaneously administered strains/toxoids and the presence of allergens did not correlate with AEFI seriousness. Considering vaccines with a high number of administered doses (≥60,000 doses), the rates estimated for serious AEFI reports were always very low, ranging between 0.01 and 0.2/1,000 doses. Twenty-four vaccines (8,993 doses) were not related to any AEFI. Conclusion: Results of present study showed that AEFI were very rare; the vast majority of them was non-serious and, despite the claims of anti-vaccination movements, the simultaneous administration of vaccines was safe and did not influence the risk of reporting a serious AEFI, particularly in children.

Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Severe Invasive Disease Caused by Serotype 3 Streptococcus Pneumoniae in Italian Children.

The effectiveness and impact of the 13-valent pneumococcal conjugate vaccine (PCV13) against invasive pneumococcal diseases (IPD) due to serotype 3 (ser3) has been questioned. However, the impact of PCV13 on different clinical presentations of ser3-IPD has not been studied so far. The impact of PCV13 on different clinical presentations of ser3-IPD in a population of Italian children aged 0-8 years was evaluated, comparing pre- and post-PCV13 introduction period. Real-time polymerase chain reaction (PCR) was used for the diagnosis and serotyping of IPD. During the observation period (1 January 2006-1 August 2018), ser3 was detected in 60/284 (21.1%) children under 8 with serotyped IPD. The incidence of sepsis and meningitis was 0.24 per 1,000,000 person-years (p-y) in pre-PCV13 and 0.02 per 1,000,000 p-y in post-PCV13. No cases occurred in vaccinated children. In the post-PCV13 period, case reduction was 13% for all ser3 IPD and 92% for sepsis and meningitis. Vaccination impact may be underestimated due to significant improvement in pneumococcal surveillance in post-PCVC13. Our data suggest a significant impact of PCV13 on meningitis and sepsis due to ser3 and a lower impact against pneumonia. While waiting for increasingly effective anti-pneumococcal vaccines, PCV13, which guarantees protection against the most severe clinical presentations of ser3-IPD, is currently the most effective prevention option available.

Diagnosis of immunodeficiency caused by a purine nucleoside phosphorylase defect by using tandem mass spectrometry on dried blood spots.

BACKGROUND: Purine nucleoside phosphorylase (PNP) deficiency is a rare form of autosomal recessive combined primary immunodeficiency caused by a enzyme defect leading to the accumulation of inosine, 2'-deoxy-inosine (dIno), guanosine, and 2'-deoxy-guanosine (dGuo) in all cells, especially lymphocytes. Treatments are available and curative for PNP deficiency, but their efficacy depends on the early approach. PNP-combined immunodeficiency complies with the criteria for inclusion in a newborn screening program. OBJECTIVE: This study evaluate whether mass spectrometry can identify metabolite abnormalities in dried blood spots (DBSs) from affected patients, with the final goal of individuating the disease at birth during routine newborn screening. METHODS: DBS samples from 9 patients with genetically confirmed PNP-combined immunodeficiency, 10,000 DBS samples from healthy newborns, and 240 DBSs from healthy donors of different age ranges were examined. Inosine, dIno, guanosine, and dGuo were tested by using tandem mass spectrometry (TMS). T-cell receptor excision circle (TREC) and kappa-deleting recombination excision circle (KREC) levels were evaluated by using quantitative RT-PCR only for the 2 patients (patients 8 and 9) whose neonatal DBSs were available. RESULTS: Mean levels of guanosine, inosine, dGuo, and dIno were 4.4, 133.3, 3.6, and 3.8 µmol/L, respectively, in affected patients. No indeterminate or false-positive results were found. In patient 8 TREC levels were borderline and KREC levels were abnormal; in patient 9 TRECs were undetectable, whereas KREC levels were normal. CONCLUSION: TMS is a valid method for diagnosis of PNP deficiency on DBSs of affected patients at a negligible cost. TMS identifies newborns with PNP deficiency, whereas TREC or KREC measurement alone can fail.

The inclusion of ADA-SCID in expanded newborn screening by tandem mass spectrometry.

Severe combined immunodeficiency due to adenosine-deaminase defect (ADA-SCID) is usually deadly in childhood because of severe recurrent infections. When clinical diagnosis is done, permanent damages due to infections or metabolite accumulation are often present. Gene therapy, bone marrow transplantation or enzyme replacement therapy may be effective if started early. The aim of this study was to set-up a robust method suitable for screening with a minimized preparation process and with inexpensive running costs, for diagnosing ADA-SCID by tandem mass spectrometry. ADA-SCID satisfies all the criteria for inclusion in a newborn screening program. We describe a protocol revised to incorporate adenosine and 2-deoxyadenosine testing into an expanded newborn screening program. We assessed the effectiveness of this approach testing dried blood spots from 4 genetically confirmed early-onset and 5 delayed-onset ADA-SCID patients. Reference values were established on 50,000 healthy newborns (deoxyadenosine <0.09µmol/L, adenosine <1.61µmol/L). We also developed a second tier test to distinguish true positives from false positives and improve the positive predictive value of an initial abnormal result. In the first 18 months, the pilot project has identified a newborn with a genetically confirmed defect in adenosine deaminase (ADA) gene. The results show that the method having great simplicity, low cost and low process preparations can be fully applicable to a mass screening program.

Distribution of invasive meningococcal B disease in Italian pediatric population: implications for vaccination timing.

Neisseria meningitidis group B (MenB) is a leading cause of meningitis and sepsis. A new vaccine has been recently licensed. The aim of the present study was to evaluate the epidemiology of MenB disease in pediatric age and define the optimal age for vaccination. All patients aged 0-18 years admitted with a diagnosis of meningitis or sepsis to the 83 participating Italian pediatric hospitals were included in the study. Blood and/or cerebrospinal fluid (CSF) samples were tested by Realtime-PCR and/or culture. One hundred and thirty-six cases (mean age 5.0 years, median 2.7) of MenB disease were found. Among these, 96/136 (70.6%) were between 0 and 5 years, 61/136 (44.9%) were between 0 and 2 years. Among the latter, 39/61 (63.9%) occurred during the first year of life with highest incidence between 4 and 8 months. A case-fatality rate of 13.2% was found, with 27.8% cases below 12 months. Sepsis lethality was 24.4%. RT-PCR was significantly more sensitive than culture: 82 patients were tested at the same time by both methods, either in blood or in CSF; MenB was found by RT-PCR in blood or CSF in 81/82 cases (98.8%), culture identified 27/82 (32.9%) infections (Cohen's Kappa 0.3; McNemar's: p<10⁻5). The study shows that the highest incidence of disease occurs in the first year of age, with a peak between 4 and 8 months of life; 30% of deaths occur before 12 months. The results suggest that the greatest prevention could be obtained starting MenB vaccination in the first months of life; a catch-up strategy up to the fifth year of life could be considered. Our results also confirm that Realtime PCR is significantly more sensitive than culture. In those countries where only isolate positive infections are counted as cases, the incidence of MenB infection results highly underestimated.

Evaluation of bivalent human papillomavirus (HPV) vaccine safety and tolerability in a sample of 25 year old Tuscan women.

The aim of this study was to gather data on the safety of the HPV-16/18 AS04-adjuvated vaccine among women aged 25, evaluating the frequency and severity of adverse events reported after vaccination and to compare the results obtained with previously published data regarding a sample of Italian preadolescents. Every woman residing in the province of Florence and in the age group targeted by the cervical cancer screening was invited to participate. Participants registered daily, for 14 d post-vaccination, solicited local and systemic reactions, as well as unsolicited adverse events in a developed ad hoc safety diary card. Data were collected in a database in Access and analyzed using STATA 11 SE statistical software. A total of 271 participants were recruited in the study group. All three diary cards were completed and delivered by 186 subjects (85.7% of participants). In all, a total of 616 diary cards were collected: 216 after the 1st dose, 209 after the 2nd dose and 191 after the 3rd dose. No severe symptoms were registered. The most frequently reported adverse reaction proved to be pain at the site of injection (83.4% of doses), followed by local swelling (20.8%) and pyrexia (14.6%). The safety and tolerability of the HPV-16/18 AS04-adjuvated vaccine in this sample of adult women aged 25 did not differ much from that previously observed in a sample of preadolescents Italian girls. Fever and local pain were however more frequently registered in our sample of adult women.

Tandem mass spectrometry, but not T-cell receptor excision circle analysis, identifies newborns with late-onset adenosine deaminase deficiency.

BACKGROUND: Adenosine deaminase (ADA)-severe combined immunodeficiency (SCID) is caused by genetic variants that disrupt the function of ADA. In its early-onset form, it is rapidly fatal to infants. Delayed or late-onset ADA-SCID is characterized by insidious progressive immunodeficiency that leads to permanent organ damage or death. Quantification of T-cell receptor excision circles (TRECs) or tandem mass spectrometry (tandem-MS) analysis of dried blood spots (DBSs) collected at birth can identify newborns with early-onset ADA-SCID and are used in screening programs. However, it is not clear whether these analyses can identify newborns who will have delayed or late-onset ADA-SCID before symptoms appear. OBJECTIVE: We performed a retrospective study to evaluate whether tandem-MS and quantitative TREC analyses of DBSs could identify newborns who had delayed-onset ADA-SCID later in life. METHODS: We tested stored DBSs collected at birth from 3 patients with delayed-onset ADA-SCID using tandem-MS (PCT EP2010/070517) to evaluate levels of adenosine and 2'-deoxyadenosine and real-time PCR to quantify TREC levels. We also analyzed DBSs from 3 newborns with early-onset ADA-SCID and 2 healthy newborn carriers of ADA deficiency. RESULTS: The DBSs taken at birth from the 3 patients with delayed-onset ADA-SCID had adenosine levels of 10, 25, and 19 µmol/L (normal value, <1.5 µmol/L) and 2'-deoxyadenosine levels of 0.7, 2.7, and 2.4 µmol/L (normal value, <0.07 µmol/L); the mean levels of adenosine and 2'-deoxyadenosine were respectively 12.0- and 27.6-fold higher than normal values. DBSs taken at birth from all 3 patients with delayed-onset ADA deficiency had normal TREC levels, but TRECs were undetectable in blood samples taken from the same patients at the time of diagnosis. CONCLUSION: Tandem-MS but not TREC quantification identifies newborns with delayed- or late-onset ADA deficiency.

Pneumococcal DNA is not detectable in the blood of healthy carrier children by real-time PCR targeting the lytA gene.

The diagnosis of invasive pneumococcal disease (IPD) is currently based on culture methods, which lack sensitivity, especially after antibiotic therapy. Molecular methods have improved sensitivity and do not require viable bacteria; however, their use is complicated by reports of low specificity with some assays. The present study investigated the specificity of a real-time PCR targeting lytA for the detection of IPD. A group of 147 healthy children, aged 6 months to 16 years (mean 6.4 years, median 4.9 years, interquartile range 6.4 years), who were in hospital for routine examinations, were tested for pneumococcal carrier status and for the presence of detectable pneumococcal DNA in their blood by real-time PCR targeting the pneumococcal lytA gene. In addition, 35 culture-positive biological samples were analysed. Urine was examined for the presence of pneumococcal DNA and C-polysaccharide antigen. Carriage was detected in 77 of the 147 subjects (52.4 %); however, regardless of carrier status, none of the subjects had a positive result from blood. Analysis of the culture-positive biological samples yielded positive results in 100 % (15/15) of cerebrospinal fluid samples and 95 % (19/20) of blood samples. All urine samples from healthy carriers were negative for DNA, whilst antigenuria was detected in 44/77 carriers (57.1 %). In conclusion, real-time PCR is both sensitive and specific and can be a useful tool in the routine diagnosis of IPD. Its sensitivity, which surpasses that of other methods for this purpose, does not come at the cost of reduced specificity.