Omenn Syndrome in Two Infants with Different Hypomorphic Variants in Janus Kinase 3

Biallelic null or hypomorphic variants in JAK3 cause SCID and less frequently Omenn syndrome. We investigated homozygous hypomorphic JAK3 mutations in two patients, and expression and function of a novel JAK3R431P variant in Omenn syndrome. Immunophenotyping of PBMC from the patient with the novel JAK3R431P variant was undertaken, by flow cytometry and Phosflow after stimulation with IL-2, IL-7, and IL-15. JAK3 expression was investigated by Western blotting. We report two patients with homozygous hypomorphic JAK3 variants and clinical features of Omenn syndrome. One patient had a previously described JAK3R775H variant, and the second had a novel JAK3R431P variant. One patient with a novel JAK3R431P variant had normal expression of JAK3 in immortalised EBV-LCL cells but reduced phosphorylation of STAT5 after stimulation with IL-2, IL-7, and IL-15 consistent with impaired kinase activity. These results suggest the JAK3R431P variant to be hypomorphic. Both patients are alive and well after allogeneic haematopoietic stem cell transplantation. They have full donor chimerism, restitution of thymopoiesis and development of appropriate antibody responses following vaccination. We expand the phenotype of hypomorphic JAK3 deficiency and demonstrate the importance of functional testing of novel variants in disease-causing genes.

Wiskott-Aldrich Syndrome: A study on 577 patients defining the genotype as a predictive biomarker for disease severity

WAS is a multifaceted monogenic disorder with a broad disease spectrum and variable disease severity and a variety of treatment options including allogeneic hematopoietic stem cell transplantation (HSCT) and gene therapy (GT). No reliable biomarker exists to predict disease course and outcome for individual patients. A total of 577 patients with a WAS variant from 26 countries and a median follow-up of 8.9 years (0.3-71.1), totaling 6118 patient-years, were included in this international retrospective study. Overall survival (OS) of the cohort (censored at HSCT or GT) was 82% (95% CI 78-87) at 15 years and 70% (61-80) at 30 years of age. The type of variant was predictive of outcome: patients with a missense variant in exons 1 or 2 or with the intronic hotspot variant c.559+5G>A (class I variants) had a 15-year OS of 93% (89-98) and a 30-year OS of 91% (86-97), compared to 71% (62-81) and 48% (34-68) in patients with any other variant (class II; p<0.0001). The cumulative incidence rates of disease-related complications such as severe bleeding (p=0.007), life-threatening infection (p<0.0001), and autoimmunity (p=0.004) occurred significantly later in patients with a class I variant. The cumulative incidence of malignancy (p=0.6) was not different between classes I and II. This study represents the largest cohort of WAS patients studied so far. It confirms the spectrum of disease severity and quantifies the risk for specific disease-related complications. The class of variant is a biomarker to predict the outcome for WAS patients.

Infections in Children Aged 6 Months to 5 Years Treated with Dupilumab in a Placebo-Controlled Clinical Trial of Moderate-to-Severe Atopic Dermatitis

BACKGROUND

Patients with atopic dermatitis (AD), particularly infants and young children, are at greater risk of developing skin infections. In this study, we assessed infection rates in AD patients aged 6 months to 5 years treated with dupilumab.

METHODS

In LIBERTY AD PRESCHOOL, a double-blind, placebo-controlled, phase III clinical trial, children aged 6 months to 5 years with moderate-to-severe AD were randomized 1:1 to subcutaneous dupilumab or placebo, with concomitant low-potency topical corticosteroids, every 4 weeks for 16 weeks. Exposure-adjusted infection rates were used to compare treatment groups.

RESULTS

The analysis included 162 patients, of whom 83 received dupilumab and 79 received placebo. Total infection rates were not significantly different between the dupilumab and placebo groups (rate ratio [RR] 0.75, 95% CI 0.48-1.19; p = 0.223). Non-herpetic adjudicated skin infections and bacterial infections were significantly less frequent with dupilumab versus placebo (non-herpetic skin infections: RR 0.46, 95% CI 0.21-0.99; p = 0.047; bacterial infections: RR 0.09, 95% CI 0.01-0.67; p = 0.019), and the number of patients using systemic anti-infective medication was significantly lower in the dupilumab group (RR 0.52, 95% CI 0.30-0.89; p = 0.019). There were no significant differences in the number of herpetic infections between the dupilumab and placebo groups (RR 1.17, 95% CI 0.31-4.35; p = 0.817). The number of patients with two or more infection events was significantly higher in the placebo group (RR 0.29, 95% CI 0.12-0.68; p = 0.004), and no severe or serious infections (including eczema herpeticum) were observed among patients receiving dupilumab.

CONCLUSIONS

These data suggest that dupilumab treatment in infants and children younger than 6 years with AD does not increase overall risk of infections and is associated with a reduced risk of bacterial and non-herpetic skin infections compared with placebo, resulting in a reduced need for anti-infective medication.

TRIAL REGISTRATION

The trial was registered with ClinicalTrials.gov with ID number NCT03346434 on November 17, 2017. INFOGRAPHIC.

Real world outcomes of children treated with dupilumab for moderate-to severe atopic dermatitis: A single centre retrospective observational UK study

BACKGROUND

Dupilumab is licenced for treatment of moderate-to-severe atopic dermatitis (AD) in patients six months of age or more.

OBJECTIVES

The aim of this study was to examine real-world outcomes and safety of dupilumab for British children with moderate to severe AD attending a tertiary referral paediatric centre.

METHODS

Skin and quality of life scores, adverse events and discontinuation rates were assessed. Patients ≤18 years old with moderate-to-severe AD were included if they had skin scores recorded at baseline and at least one follow-up visit. Efficacy and safety were assessed using descriptive statistics.

RESULTS

72 children/teenagers aged 7-18 (median 14) years old were included in this retrospective observational survey. Oral systemic immunosuppressants had failed to control AD in 88% of children recruited. All patients commenced on dupilumab had pre-treatment skin scores consistent with moderate-to-severe disease (median (range) EASI 25 (20-31)). EASI scores decreased by 94% (82% - 100%) and remained consistently low over 10 to 52 months of the study, with an EASI scores at final follow-up of 2 (0-6). 11% of children were able to discontinue dupilumab because of disease remission. 19 (26%) had adverse events, most commonly conjunctivitis (12 patients, 17%). Eight (11%) discontinued dupilumab (six with ongoing inflammatory skin flares, one with severe allergic conjunctivitis, one with intercurrent Wilson disease).

CONCLUSION

Dupilumab was highly effective in treating most children with moderate-to-severe AD with good safety outcomes in the real world. However, 10% of children may need alternative therapy because of drug ineffectiveness or side-effects.

Dupilumab Safety and Efficacy in a Phase III Open-Label Extension Trial in Children 6-11 Years of Age with Severe Atopic Dermatitis

BACKGROUND

For children aged 6-11 years with uncontrolled severe atopic dermatitis (AD), 16 weeks of treatment with dupilumab resulted in substantial clinical benefit compared with placebo with an acceptable safety profile. However, longer-term safety and efficacy data are important to inform longitudinal AD management.

OBJECTIVES

This analysis of data from an open-label extension study (LIBERTY AD PED-OLE, NCT02612454) reports the long-term safety, efficacy, and pharmacokinetics of dupilumab in children with severe AD who had participated in the pivotal dupilumab LIBERTY AD PEDS study (NCT03345914).

METHODS

Enrolled patients initially received subcutaneous dupilumab 300 mg every 4 weeks (q4w). The q4w regimen could be uptitrated to dupilumab dose regimens of 200 or 300 mg every 2 weeks (q2w; for body weight < 60 or ≥ 60 kg, respectively) for patients who did not achieve an Investigator's Global Assessment (IGA) score of 0/1 (clear/almost clear skin) at week 16, or prior to week 16 as rescue treatment. Additional patients were uptitrated to a weight-tiered q2w regimen following a protocol amendment. Patients who maintained an IGA score of 0/1 continuously for a 12-week period after week 40 discontinued dupilumab. They were monitored for relapse and were reinitiated on dupilumab if required.

RESULTS

Data for 321 patients (mean age 8.6 years) were analyzed, 254 (79%) of whom had completed the scheduled 52-week visit at the database lock. Most treatment-emergent adverse events were mild/moderate. By week 52, 41% of patients achieved an IGA score of 0/1, and 97%, 82%, and 50%, respectively, had at least a 50%, 75%, and 90% improvement from the parent study baseline in Eczema Area and Severity Index (EASI). By week 52, 29% of patients in the overall population had clear/almost clear skin sustained for 12 weeks and had stopped medication; of these, 40% relapsed and were subsequently reinitiated on treatment, with a mean time to reinitiation of 13.5 (standard deviation 5.2) weeks. Following reinitiation of dupilumab, 41% of the patients with evaluable data at the time of database lock had regained an IGA 0/1 clinical response.

CONCLUSIONS

Consistent with results seen in adults and adolescents, long-term treatment with dupilumab in children aged 6-11 years with severe AD showed an acceptable safety profile and incremental clinical benefit. A substantial proportion of children who stopped dupilumab treatment after achieving clear/almost clear skin subsequently experienced disease recurrence, and required reinitiation of dupilumab, suggesting that continuous treatment may be necessary for maintenance of clinical benefit.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02612454.

Dupilumab Treatment Leads to Rapid and Consistent Improvement of Atopic Dermatitis in All Anatomical Regions in Patients Aged 6 Months to 5 Years

INTRODUCTION

Atopic dermatitis (AD) is heterogeneous in distribution pattern and clinical features. This analysis assessed the effect of dupilumab on the extent and severity of AD across various signs (erythema, edema/papulation, excoriation, lichenification) in different anatomical regions (head and neck, trunk, upper extremities, lower extremities) in patients aged 6 months to 5 years.

METHODS

In LIBERTY AD PRESCHOOL, a double-blind, placebo-controlled, phase III clinical trial, children aged 6 months to 5 years with moderate-to-severe AD were randomized 1:1 to subcutaneous dupilumab or placebo with concomitant low-potency topical corticosteroids (TCS) every 4 weeks for 16 weeks. Changes in AD signs across anatomical regions were assessed using unweighted Eczema Area and Severity Index (EASI) body region scores.

RESULTS

Overall, 162 patients were randomized to dupilumab (n = 83) or placebo (n = 79). A significant improvement in least squares mean EASI area score was seen by week 2 in all four anatomical regions (P < 0.0001 for dupilumab vs. placebo) and sustained throughout treatment. Least squares mean EASI sign scores in erythema, excoriations, and infiltration/papulation showed significant improvement by week 2 in all regions (P < 0.001), while lichenification showed significant improvement in all regions by week 4 (P < 0.001).

CONCLUSION

Dupilumab use with concomitant low-potency TCS treatment resulted in rapid and consistent improvement in AD signs in all anatomical regions, in patients aged 6 months to 5 years with moderate-to-severe AD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03346434 Part B.

A National Survey of Hereditary Angioedema and Acquired C1 Inhibitor Deficiency in the United Kingdom

BACKGROUND

Detailed demographic data on people with hereditary angioedema (HAE) and acquired C1 inhibitor deficiency in the United Kingdom are relatively limited. Better demographic data would be beneficial in planning service provision, identifying areas of improvement, and improving care.

OBJECTIVE

To obtain more accurate data on the demographics of HAE and acquired C1 inhibitor deficiency in the United Kingdom, including treatment modalities and services available to patients.

METHODS

A survey was distributed to all centers in the United Kingdom that look after patients with HAE and acquired C1 inhibitor deficiency to collect these data.

RESULTS

The survey identified 1152 patients with HAE-1/2 (58% female and 92% type 1), 22 patients with HAE with normal C1 inhibitor, and 91 patients with acquired C1 inhibitor deficiency. Data were provided by 37 centers across the United Kingdom. This gives a minimum prevalence of 1:59,000 for HAE-1/2 and 1:734,000 for acquired C1 inhibitor deficiency in the United Kingdom. A total of 45% of patients with HAE were on long-term prophylaxis (LTP) with the most used medication being danazol (55% of all patients on LTP). Eighty-two percent of patients with HAE had a home supply of acute treatment with C1 inhibitor or icatibant. A total of 45% of patients had a supply of icatibant and 56% had a supply of C1 inhibitor at home.

CONCLUSIONS

Data obtained from the survey provide useful information about the demographics and treatment modalities used in HAE and acquired C1 inhibitor deficiency in the United Kingdom. These data are useful for planning service provision and improving services for these patients.

DOCK11 deficiency in patients with X-linked actinopathy and autoimmunity

Dedicator of cytokinesis (DOCK) proteins play a central role in actin cytoskeleton regulation. This is highlighted by the DOCK2 and DOCK8 deficiencies leading to actinopathies and immune deficiencies. DOCK8 and DOCK11 activate CDC42, a Rho-guanosine triphosphate hydrolases involved in actin cytoskeleton dynamics, among many cellular functions. The role of DOCK11 in human immune disease has been long suspected but, to the best of our knowledge, has never been described to date. We studied 8 male patients, from 7 unrelated families, with hemizygous DOCK11 missense variants leading to reduced DOCK11 expression. The patients were presenting with early-onset autoimmunity, including cytopenia, systemic lupus erythematosus, skin, and digestive manifestations. Patients' platelets exhibited abnormal ultrastructural morphology and spreading as well as impaired CDC42 activity. In vitro activated T cells and B-lymphoblastoid cell lines from patients exhibited aberrant protrusions and abnormal migration speed in confined channels concomitant with altered actin polymerization during migration. Knock down of DOCK11 recapitulated these abnormal cellular phenotypes in monocytes-derived dendritic cells and primary activated T cells from healthy controls. Lastly, in line with the patients' autoimmune manifestations, we also observed abnormal regulatory T-cell (Treg) phenotype with profoundly reduced FOXP3 and IKZF2 expression. Moreover, we found reduced T-cell proliferation and impaired STAT5B phosphorylation upon interleukin-2 stimulation of the patients' lymphocytes. In conclusion, DOCK11 deficiency is a new X-linked immune-related actinopathy leading to impaired CDC42 activity and STAT5 activation, and is associated with abnormal actin cytoskeleton remodeling as well as Treg phenotype, culminating in immune dysregulation and severe early-onset autoimmunity.

Phase 3 Trial of Epicutaneous Immunotherapy in Toddlers with Peanut Allergy

BACKGROUND

No approved treatment for peanut allergy exists for children younger than 4 years of age, and the efficacy and safety of epicutaneous immunotherapy with a peanut patch in toddlers with peanut allergy are unknown.

METHODS

We conducted this phase 3, multicenter, double-blind, randomized, placebo-controlled trial involving children 1 to 3 years of age with peanut allergy confirmed by a double-blind, placebo-controlled food challenge. Patients who had an eliciting dose (the dose necessary to elicit an allergic reaction) of 300 mg or less of peanut protein were assigned in a 2:1 ratio to receive epicutaneous immunotherapy delivered by means of a peanut patch (intervention group) or to receive placebo administered daily for 12 months. The primary end point was a treatment response as measured by the eliciting dose of peanut protein at 12 months. Safety was assessed according to the occurrence of adverse events during the use of the peanut patch or placebo.

RESULTS

Of the 362 patients who underwent randomization, 84.8% completed the trial. The primary efficacy end point result was observed in 67.0% of children in the intervention group as compared with 33.5% of those in the placebo group (risk difference, 33.4 percentage points; 95% confidence interval, 22.4 to 44.5; P<0.001). Adverse events that occurred during the use of the intervention or placebo, irrespective of relatedness, were observed in 100% of the patients in the intervention group and 99.2% in the placebo group. Serious adverse events occurred in 8.6% of the patients in the intervention group and 2.5% of those in the placebo group; anaphylaxis occurred in 7.8% and 3.4%, respectively. Serious treatment-related adverse events occurred in 0.4% of patients in the intervention group and none in the placebo group. Treatment-related anaphylaxis occurred in 1.6% in the intervention group and none in the placebo group.

CONCLUSIONS

In this trial involving children 1 to 3 years of age with peanut allergy, epicutaneous immunotherapy for 12 months was superior to placebo in desensitizing children to peanuts and increasing the peanut dose that triggered allergic symptoms. (Funded by DBV Technologies; EPITOPE ClinicalTrials.gov number, NCT03211247.).

337 Dupilumab treatment is not associated with an increased overall risk of infections in patients aged 6 months to 5 years with moderate-to-severe atopic dermatitis

Patients with atopic dermatitis (AD) have an increased risk of infection, including skin infections. Previous studies in children aged 6–11 years and adolescents showed that dupilumab is not associated with an increased risk of overall infections and is associated with a lower incidence of skin infections compared with a placebo. This post-hoc analysis reports the impact of dupilumab treatment on infections, including skin infections, in children aged 6 months to 5 years with moderate-to-severe AD. In LIBERTY AD PRESCHOOL, a double-blind, placebo-controlled trial (NCT03346434, part B), children aged 6 months to 5 years with moderate-to-severe AD (Investigator’s Global Assessment score ≥3) were randomized 1 : 1 to subcutaneous dupilumab every 4 weeks (200 mg if baseline weight was ≥5 to &lt;15 kg, 300 mg if weight was ≥15 to &lt;30 kg) or placebo with concomitant low-potency topical corticosteroids for 16 weeks. Exposure-adjusted rates (patients with ≥1 event per 100 patient-years [nP/100 PY]) and systemic anti-infective medication use (nP/100PY) were used to compare treatment groups. 162 patients were randomized to dupilumab (n = 83) or placebo (n = 79). During the 16-week treatment period, total infections rates were numerically lower in the dupilumab-treated group (nP/100PY: 185.2) compared with the placebo-treated group (nP/100PY: 245.7). Fewer infections of skin-structure and soft tissues were reported in the dupilumab group (nP/100PY: 24.7) compared with the placebo group (nP/100PY: 40.2). Dupilumab-treated patients had significantly lower rates of non-herpetic skin infections (nP/100PY: 42.7) than placebo-treated patients (nP/100PY: 92.7; P &lt; 0.05 vs. placebo). There was no significant difference in rates of herpetic skin infections between the dupilumab (nP/100PY: 20.0) and placebo groups (nP/100PY: 17.1; P = 0.817 vs. placebo). No helminthic infections were reported in either group. Systemic anti-infective medication use was significantly less frequent in the dupilumab group (nP/100PY: 104.7) compared with placebo (nP/100PY: 203.0; P &lt; 0.05 vs. placebo). The overall safety of dupilumab was consistent with the known safety profile. Dupilumab treatment is associated with lower overall infections and significantly lower non-herpetic skin infections than placebo in children aged 6 months to 5 years with moderate-to-severe AD.

Regional risk of tuberculosis and viral hepatitis with tumor necrosis factor-alpha inhibitor treatment: A systematic review

Background: TNFα inhibitors are regularly used to treat autoimmune diseases. Tuberculosis (TB) and viral hepatitis B are considered potential infectious complications, and screening and surveillance are therefore recommended. Current guidelines do not take into account regional differences in endemicity of these infections. Methods: A systematic literature review of TB and viral hepatitis in patients receiving TNFα-inhibitors was performed, searching in PubMed, Embase, MEDLINE and Web of Science databases. Studies were selected against predefined eligibility criteria and assessed using the Newcastle-Ottawa scale. The number of TB and viral hepatitis cases/1,000 TNFα-inhibitor patients were evaluated, and regional variation compared. Results: 105 observational studies involving over 140,000 patients were included. Overall, 1% of patients developed TB or viral hepatitis B. TB cases/1,000 TNFα-inhibitor patients were 4-fold higher in Asia, Africa, and South America than in Europe, North America, and Australasia where only 0%-0.4% of patients developed TB. Hepatitis B cases/1,000 patients were over 15-fold higher in countries with high prevalence (China, Taiwan, South Korea, Thailand) compared with low prevalence (p < 0.00001) where only 0.4% of patients developed hepatitis B. Only three of 143 patients developed viral hepatitis C, and there was insufficient data to allow regional sub-analysis. Conclusion: TB and viral hepatitis B infections in patients treated with TNFα inhibitors are largely confined to countries with high prevalence of these infections. As only 1/2,500 patients in low prevalence countries treated with TNFα inhibitors develop TB or viral hepatitis B, we suggest an individualized, risk-based approach, rather than universal screening for all patients.

Laboratory Safety from a Randomized 16-Week Phase III Study of Dupilumab in Children Aged 6 Months to 5 Years with Moderate-to-Severe Atopic Dermatitis

BACKGROUND AND OBJECTIVE

Previous studies of dupilumab for the treatment of moderate-to-severe atopic dermatitis in adults and adolescents, and severe atopic dermatitis in children aged 6 to < 12 years demonstrate no clinically important changes in laboratory parameters. The objective of this study was to assess laboratory outcomes in children aged 6 months to < 6 years with moderate-to-severe atopic dermatitis treated with dupilumab.

METHODS

In this randomized, placebo-controlled, phase III trial of dupilumab, 161 children aged 6 months to < 6 years with moderate-to-severe atopic dermatitis were enrolled from 31 sites in Europe and North America and randomized 1:1 to receive subcutaneous placebo or dupilumab (5 kg to < 15 kg: 200 mg; 15 kg to < 30 kg: 300 mg) every 4 weeks plus topical corticosteroids for 16 weeks. Hematology, serum chemistry, and urinalysis assessments were analyzed on blood and urine samples collected at screening and weeks 4 and 16; descriptive statistics are provided.

RESULTS

No clinically meaningful changes in laboratory parameters were observed. While two cases of eosinophilia and one case each of neutropenia and leukocytosis were reported as treatment-emergent adverse events in the dupilumab plus topical corticosteroids group, these events were not associated with clinical symptoms and did not lead to treatment discontinuation or study withdrawal.

CONCLUSIONS

These results suggest that routine laboratory monitoring of children aged 6 months to < 6 years treated with dupilumab plus topical corticosteroids is not required. Limitations of this study include short study duration, and exclusion of patients with abnormalities in laboratory test results at screening.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT03346434, part B.

Immunogenicity and safety of seasonal influenza vaccines in children under 3 years of age

INTRODUCTION

Despite children aged 6-35 months developing more severe influenza infections, not all countries include influenza vaccines in their national immunization programs.

AREAS COVERED

This literature review examines the efficacy, immunogenicity, and safety of seasonal trivalent influenza vaccines (TIVs) and quadrivalent influenzae vaccines (QIVs) in children 6-35 months old to determine if greater valency promotes greater protection while maintaining a similar safety profile.

EXPERT OPINION

TIVs and QIVs are safe for children under 3 years old. TIVs and QIVs provided good seroprotection, and immunogenicity (GMT, SCR, and SPR) meeting recommended levels set by CHMP (European) and CBER (USA). However, as QIVs carry two influenza B strains and TIVs only one, QIVs has an overall higher seroprotection against particularly influenza B. Vaccines containing adjuncts had better immunogenicity, particularly after the first dose. Seroprotection of all vaccines lasted 12 months. Increasing the dosage from 0.25 mL to 0.5 mL did not cause more systemic or local side-effects. Further comparisons of efficacy, and wider promotion of influenza vaccines in general are required in preschool children.

A review of the DTaP-IPV-HB-PRP-T Hexavalent vaccine in pediatric patients

INTRODUCTION

Hexaxim is a hexavalent vaccine approved as primary and booster vaccination in infants 6 weeks and older, protecting against diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B and Haemophilus influenzae type b.

AREAS COVERED

To evaluate the immunogenicity and reactogenicity (safety) of Hexaxim (Hexyon, Hexacima) in primary and booster vaccine schedules; long-term antibody persistence; concomitant use with other childhood vaccines and use in immunocompromised infants. Hexaxim was found to be noninferior to other licensed hexavalent vaccines, being highly immunogenic for all toxoids/antigens and with an acceptable safety profile. It can be administered concomitantly with other childhood vaccines. Hexaxim can be given as a booster for infants primed with Infanrix Hexa and given in a pentavalent-hexavalent-pentavalent series. Hexaxim elicits a similar immune response and safety profile in human immunodeficiency virus (HIV) positive infants. It has the benefit of being a ready-to-use liquid formulation, minimizing dosage errors and preparation time.

EXPERT OPINION

Hexaxim has an acceptable safety profile and provides immunity against all six targeted diseases. It is an acceptable alternative to other hexavalent vaccines on the market. Further studies are required on the use of immunocompromised patients as well as the antibody persistence of each of the vaccine components.

Dupilumab in children aged 6 months to younger than 6 years with uncontrolled atopic dermatitis: a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Current systemic treatments for children younger than 6 years with moderate-to-severe atopic dermatitis that is uncontrolled with topical therapies might have suboptimal efficacy and safety. Dupilumab is approved for older children and adults with atopic dermatitis and for other type 2 inflammatory conditions. We aimed to evaluate efficacy and safety of dupilumab with concomitant low-potency topical corticosteroids in children aged 6 months to younger than 6 years with moderate-to-severe atopic dermatitis.

METHODS

This randomised, double-blind, placebo-controlled, parallel-group, phase 3 trial was conducted in 31 hospitals, clinics, and academic institutions in Europe and North America. Eligible patients were aged 6 months to younger than 6 years, with moderate-to-severe atopic dermatitis (Investigator's Global Assessment [IGA] score 3-4) diagnosed according to consensus criteria of the American Academy of Dermatology, and an inadequate response to topical corticosteroids. Patients were randomly assigned (1:1) to subcutaneous placebo or dupilumab (bodyweight ≥5 kg to <15 kg: 200 mg; bodyweight ≥15 kg to <30 kg: 300 mg) every 4 weeks plus low-potency topical corticosteroids (hydrocortisone acetate 1% cream) for 16 weeks. Randomisation was stratified by age, baseline bodyweight, and region. Patient allocation was done via a central interactive web response system, and treatment allocation was masked. The primary endpoint at week 16 was the proportion of patients with IGA score 0-1 (clear or almost clear skin). The key secondary endpoint (coprimary endpoint for the EU and EU reference market) at week 16 was the proportion of patients with at least a 75% improvement from baseline in Eczema Area and Severity Index (EASI-75). Primary analyses were done in the full analysis set (ie, all randomly assigned patients, as randomly assigned) and safety analyses were done in all patients who received any study drug. This study was registered with ClinicalTrials.gov, NCT03346434.

FINDINGS

Between June 30, 2020, and Feb 12, 2021, 197 patients were screened for eligibility, 162 of whom were randomly assigned to receive dupilumab (n=83) or placebo (n=79) plus topical corticosteroids. At week 16, significantly more patients in the dupilumab group than in the placebo group had IGA 0-1 (23 [28%] vs three [4%], difference 24% [95% CI 13-34]; p<0·0001) and EASI-75 (44 [53%] vs eight [11%], difference 42% [95% CI 29-55]; p<0·0001). Overall prevalence of adverse events was similar in the dupilumab group (53 [64%] of 83 patients) and placebo group (58 [74%] of 78 patients). Conjunctivitis incidence was higher in the dupilumab group (four [5%]) than the placebo group (none). No dupilumab-related adverse events were serious or led to treatment discontinuation.

INTERPRETATION

Dupilumab significantly improved atopic dermatitis signs and symptoms versus placebo in children younger than 6 years. Dupilumab was well tolerated and showed an acceptable safety profile, similar to results in older children and adults.

FUNDING

Sanofi and Regeneron Pharmaceuticals.

An Integrated Taxonomy for Monogenic Inflammatory Bowel Disease

BACKGROUND & AIMS

Monogenic forms of inflammatory bowel disease (IBD) illustrate the essential roles of individual genes in pathways and networks safeguarding immune tolerance and gut homeostasis.

METHODS

To build a taxonomy model, we assessed 165 disorders. Genes were prioritized based on penetrance of IBD and disease phenotypes were integrated with multi-omics datasets. Monogenic IBD genes were classified by (1) overlapping syndromic features, (2) response to hematopoietic stem cell transplantation, (3) bulk RNA-sequencing of 32 tissues, (4) single-cell RNA-sequencing of >50 cell subsets from the intestine of healthy individuals and patients with IBD (pediatric and adult), and (5) proteomes of 43 immune subsets. The model was validated by addition of newly identified monogenic IBD defects. As a proof-of-concept, we explore the intersection between immunometabolism and antimicrobial activity for a group of disorders (G6PC3/SLC37A4).

RESULTS

Our quantitative integrated taxonomy defines the cellular landscape of monogenic IBD gene expression across 102 genes with high and moderate penetrance (81 in the model set and 21 genes in the validation set). We illustrate distinct cellular networks, highlight expression profiles across understudied cell types (e.g., CD8⁺ T cells, neutrophils, epithelial subsets, and endothelial cells) and define genotype-phenotype associations (perianal disease and defective antimicrobial activity). We illustrate processes and pathways shared across cellular compartments and phenotypic groups and highlight cellular immunometabolism with mammalian target of rapamycin activation as one of the converging pathways. There is an overlap of genes and enriched cell-specific expression between monogenic and polygenic IBD.

CONCLUSION

Our taxonomy integrates genetic, clinical and multi-omic data; providing a basis for genomic diagnostics and testable hypotheses for disease functions and treatment responses.

Surveillance and control of meningococcal disease in the COVID-19 era: A Global Meningococcal Initiative review

This review article incorporates information from the 4th Global Meningococcal Initiative summit meeting. Since the introduction of stringent COVID-19 infection control and lockdown measures globally in 2020, there has been an impact on IMD prevalence, surveillance, and vaccination compliance. Incidence rates and associated mortality fell across various regions during 2020. A reduction in vaccine uptake during 2020 remains a concern globally. In addition, several Neisseria meningitidis clonal complexes, particularly CC4821 and CC11, continue to exhibit resistance to antibiotics, with resistance to ciprofloxacin or beta-lactams mainly linked to modifications of gyrA or penA alleles, respectively. Beta-lactamase acquisition was also reported through horizontal gene transfer (bla_ROB-1) involving other bacterial species. Despite the challenges over the past year, progress has also been made on meningococcal vaccine development, with several pentavalent (serogroups ABCWY and ACWYX) vaccines currently being studied in late-stage clinical trial programmes.

Simple Measurement of IgA Predicts Immunity and Mortality in Ataxia-Telangiectasia

Patients with ataxia-telangiectasia (A-T) suffer from progressive cerebellar ataxia, immunodeficiency, respiratory failure, and cancer susceptibility. From a clinical point of view, A-T patients with IgA deficiency show more symptoms and may have a poorer prognosis. In this study, we analyzed mortality and immunity data of 659 A-T patients with regard to IgA deficiency collected from the European Society for Immunodeficiencies (ESID) registry and from 66 patients with classical A-T who attended at the Frankfurt Goethe-University between 2012 and 2018. We studied peripheral B- and T-cell subsets and T-cell repertoire of the Frankfurt cohort and survival rates of all A-T patients in the ESID registry. Patients with A-T have significant alterations in their lymphocyte phenotypes. All subsets (CD3, CD4, CD8, CD19, CD4/CD45RA, and CD8/CD45RA) were significantly diminished compared to standard values. Patients with IgA deficiency (n = 35) had significantly lower lymphocyte counts compared to A-T patients without IgA deficiency (n = 31) due to a further decrease of naïve CD4 T-cells, central memory CD4 cells, and regulatory T-cells. Although both patient groups showed affected TCR-ß repertoires compared to controls, no differences could be detected between patients with and without IgA deficiency. Overall survival of patients with IgA deficiency was significantly diminished. For the first time, our data show that patients with IgA deficiency have significantly lower lymphocyte counts and subsets, which are accompanied with reduced survival, compared to A-T patients without IgA deficiency. IgA, a simple surrogate marker, is indicating the poorest prognosis for classical A-T patients. Both non-interventional clinical trials were registered at clinicaltrials.gov 2012 (Susceptibility to infections in ataxia-telangiectasia; NCT02345135) and 2017 (Susceptibility to Infections, tumor risk and liver disease in patients with ataxia-telangiectasia; NCT03357978)

Genetic, Immunological, and Clinical Features of 32 Patients with Autosomal Recessive STAT1 Deficiency

Autosomal recessive (AR) STAT1 deficiency is a severe inborn error of immunity disrupting cellular responses to type I, II, and III IFNs, and IL-27, and conferring a predisposition to both viral and mycobacterial infections. We report the genetic, immunological, and clinical features of an international cohort of 32 patients from 20 kindreds: 24 patients with complete deficiency, and 8 patients with partial deficiency. Twenty-four patients suffered from mycobacterial disease (bacillus Calmette-Guérin = 13, environmental mycobacteria = 10, or both in 1 patient). Fifty-four severe viral episodes occurred in sixteen patients, mainly caused by Herpesviridae viruses. Attenuated live measles, mumps, and rubella and/or varicella zoster virus vaccines triggered severe reactions in the five patients with complete deficiency who were vaccinated. Seven patients developed features of hemophagocytic syndrome. Twenty-one patients died, and death was almost twice as likely in patients with complete STAT1 deficiency than in those with partial STAT1 deficiency. All but one of the eight survivors with AR complete deficiency underwent hematopoietic stem cell transplantation. Overall survival after hematopoietic stem cell transplantation was 64%. A diagnosis of AR STAT1 deficiency should be considered in children with mycobacterial and/or viral infectious diseases. It is important to distinguish between complete and partial forms of AR STAT1 deficiency, as their clinical outcome and management differ significantly.

Therapeutic options for CTLA-4 insufficiency

BACKGROUND

Heterozygous germline mutations in cytotoxic T lymphocyte-associated antigen-4 (CTLA4) impair the immunomodulatory function of regulatory T cells. Affected individuals are prone to life-threatening autoimmune and lymphoproliferative complications. A number of therapeutic options are currently being used with variable effectiveness.

OBJECTIVE

Our aim was to characterize the responsiveness of patients with CTLA-4 insufficiency to specific therapies and provide recommendations for the diagnostic workup and therapy at an organ-specific level.

METHODS

Clinical features, laboratory findings, and response to treatment were reviewed retrospectively in an international cohort of 173 carriers of CTLA4 mutation. Patients were followed between 2014 and 2020 for a total of 2624 months from diagnosis. Clinical manifestations were grouped on the basis of organ-specific involvement. Medication use and response were recorded and evaluated.

RESULTS

Among the 173 CTLA4 mutation carriers, 123 (71%) had been treated for immune complications. Abatacept, rituximab, sirolimus, and corticosteroids ameliorated disease severity, especially in cases of cytopenias and lymphocytic organ infiltration of the gut, lungs, and central nervous system. Immunoglobulin replacement was effective in prevention of infection. Only 4 of 16 patients (25%) with cytopenia who underwent splenectomy had a sustained clinical response. Cure was achieved with stem cell transplantation in 13 of 18 patients (72%). As a result of the aforementioned methods, organ-specific treatment pathways were developed.

CONCLUSION

Systemic immunosuppressants and abatacept may provide partial control but require ongoing administration. Allogeneic hematopoietic stem cell transplantation offers a possible cure for patients with CTLA-4 insufficiency.

Immune Response and Safety of Viral Vaccines in Children with Autoimmune Diseases on Immune Modulatory Drug Therapy

Introduction: Children with autoimmune diseases often require treatment with systemic immunosuppressives. Efficacy and safety of vaccination, particularly live-attenuated viral vaccines in these patients remain a concern. Areas covered: To evaluate the immunogenicity and safety of viral vaccines in children and young people treated with systemic immunosuppressive drugs for autoimmune diseases. A systemic literature review was performed using Pubmed including English papers in subjects less than 21 years old. Viral vaccines were generally immunogenic and safe in children receiving immunosuppressive drugs, including biologics. Use of low-dose prednisolone or disease-modifying antirheumatic drugs did not significantly impact on vaccine immunogenicity, although there was anecdotal evidence of reduced immunogenicity in patients receiving high-dose prednisolone/methylprednisolone and pulse cyclophosphamide. Patients on biologics mounted adequate seroprotective responses, but antibody titers tended to be lower. Both live-attenuated and inactivated vaccines were well tolerated with no serious adverse events. Autoimmune disease activity was not adversely affected by vaccination. Expert opinion: Current evidence indicates that administration of viral vaccines to children with autoimmune diseases receiving most systemic immunosuppressive drugs is immunogenic and safe. MMR can safely be given to most patients receiving biologics, but patients on high-dose prednisolone and pulse cyclophosphamide should avoid MMR and other live viral vaccines.

Laboratory Safety of Dupilumab in Patients Aged 6-11 Years with Severe Atopic Dermatitis: Results from a Phase III Clinical Trial

BACKGROUND

Previous studies of dupilumab in adolescents and adults with moderate-to-severe atopic dermatitis (AD) showed no clinically meaningful adverse changes in laboratory parameters.

OBJECTIVE

The aim of this study was to assess laboratory outcomes in children aged 6-11 years with severe AD in a randomized, placebo-controlled, phase III trial of dupilumab.

METHODS

Children aged 6-11 years with severe AD were randomized 1:1:1 to 16 weeks of dupilumab 300 mg every 4 weeks, 100 or 200 mg every 2 weeks, or matching placebo, all with concomitant topical corticosteroids (TCS). Blood samples were collected at baseline and Weeks 4, 8, and 16; urine samples were collected at baseline and Weeks 4 and 16.

RESULTS

Of 367 patients enrolled in the study, 362 were included in the safety analysis, 351 completed study treatment, and 4 withdrew due to treatment-emergent adverse events not related to laboratory abnormalities. Both dupilumab + TCS groups showed overall trends toward increases in mean blood levels of eosinophils and alkaline phosphatase, and decreases in mean blood levels of platelets, neutrophils, and lactate dehydrogenase levels, without corresponding mean changes in the placebo + TCS group. None of these changes were associated with symptoms or clinically meaningful adverse outcomes, and none led to treatment modification. No clinically significant changes or trends were observed for other measured laboratory parameters.

CONCLUSION

There were no clinically meaningful adverse changes in routine laboratory parameters attributable to treatment with dupilumab + TCS. Changes in platelet counts and lactate dehydrogenase levels likely reflect reduced inflammation. These results confirm similar findings in adults and adolescents, and suggest that there is no need for routine laboratory monitoring of children aged 6-11 years treated with dupilumab + TCS for severe AD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03345914. Does treatment with dupilumab require routine laboratory monitoring in 6- to 11-year-old children with severe atopic dermatitis? (MP4 180482 kb).

A Rapid Shift from Chronic Hyperoxia to Normoxia Induces Systemic Anaphylaxis via Transient Receptor Potential Ankyrin 1 Channels on Mast Cells

Extensive activation of mast cells is the major switch that triggers systemic anaphylaxis, resulting in the subsequent release of anaphylactic mediators into circulation. We previously demonstrated that rapid changes in oxygen tension lead to mast cell degranulation, and the released tryptase triggers retinal angiogenesis in a murine oxygen-induced retinopathy model. However, whether a rapid shift from hyperoxia to normoxia (relative hypoxic stress) is a risk factor for systemic anaphylaxis remains unknown. In this study, we demonstrated that the relative hypoxia stress induces systemic mast cell activation via transient receptor potential ankyrin 1 (TRPA1) channels, which immediately leads to hypothermia and increased vascular permeability in adult mice. Although mast cell-deficient or TRPA1-deficient mice did not exhibit anaphylactic symptoms following a rapid sift to normoxia, preinjection with bone marrow-derived cultured mast cells (BMCMCs) derived from wild-type TRPA1-expressing mice restored anaphylactic responses. In addition, we found that the rapid reductions in oxygen tension in a culture atmosphere triggered the degranulation of BMCMCs derived from wild-type TRPA1-expressing mice but not that of BMCMCs derived from TRPA1-deficient mice. In human LAD2 mast cells, the relative hypoxic stress led to the degranulation, which was suppressed by the addition of a TRPA1 inhibitor. Gradual reductions from hyperoxia to normoxia led to no anaphylactic symptoms. Our results demonstrated that TRPA1-triggered mast cell degranulation is a novel pathway that induces anaphylactic shock without Ag-Ab reactions. These findings introduce a potential role for oxygen in inducing mast cell-dependent anaphylaxis and highlight the need to reconsider chronic pure oxygen therapy for anoxic diseases.

Staphylococcus aureus second immunoglobulin-binding protein drives atopic dermatitis via IL-33

BACKGROUND

Staphylococcus aureus is the dominant infective trigger of atopic dermatitis (AD). How this bacterium drives type 2 allergic pathology in the absence of infection in patients with AD is unclear.

OBJECTIVE

We sought to identify the S aureus-derived virulence factor(s) that initiates the cutaneous type 2-promoting immune response responsible for AD.

METHODS

In vitro human keratinocyte cell culture, ex vivo human skin organ explants, and the eczema-prone Nishiki-nezumi Cinnamon/Tokyo University of Agriculture and Technology strain mouse were used as model systems to assess type 2-promoting immune responses to S aureus. Identification of the bioactive factor was accomplished using fast protein liquid chromatography and mass spectrometry. Bioactivity was confirmed by cloning and expression in an Escherichia coli vector system, and S aureus second immunoglobulin-binding protein (Sbi) mutant strains confirming loss of activity.

RESULTS

S aureus was unique among staphylococcal species in its ability to induce the rapid release of constitutive IL-33 from human keratinocytes independent of the Toll-like receptor pathway. Using the eczema-prone Nishiki-nezumi Cinnamon/Tokyo University of Agriculture and Technology strain mouse model, we showed that IL-33 was essential for inducing the immune response to S aureus in vivo. By fractionation and candidate testing, we identified Sbi as the predominant staphylococcus-derived virulence factor that directly drives IL-33 release from human keratinocytes. Immunohistology of skin demonstrated that corneodesmosin, a component of corneodesmosomes that form key intercellular adhesive structures in the stratum corneum, was disrupted, resulting in reduction of skin barrier function.

CONCLUSIONS

S aureus-derived Sbi is a unique type 2-promoting virulence factor capable of initiating the type 2-promoting cytokine activity underlying AD.

Dupilumab provides favourable long-term safety and efficacy in children aged ≥ 6 to < 12 years with uncontrolled severe atopic dermatitis: results from an open-label phase IIa study and subsequent phase III open-label extension study

Background

Children aged ≥ 6 to < 12 years with severe atopic dermatitis (AD) have limited treatment options. In a 16‐week, randomized, placebo‐controlled, phase III trial in children, dupilumab, a monoclonal antibody inhibiting interleukin (IL)‐4/IL‐13 signalling, significantly improved signs and symptoms with acceptable safety; longer‐term safety and efficacy data are lacking.

Objectives

To report the pharmacokinetic profile and long‐term safety and efficacy of dupilumab in children (aged ≥ 6 to < 12 years) with severe AD.

Methods

Children (aged ≥ 6 to < 12 years) with severe AD were enrolled in a global, multicentre, phase IIa, open‐label, ascending‐dose, sequential cohort study and subsequent open‐label extension (OLE) study. Patients received single‐dose dupilumab 2 or 4 mg kg⁻¹ followed by 8‐week pharmacokinetic sampling, then 2 or 4 mg kg⁻¹ weekly for 4 weeks (phase IIa), followed by the same weekly regimen (OLE). Primary endpoints were dupilumab concentration–time profile and treatment‐emergent adverse events (TEAEs); secondary assessments included Eczema Area and Severity Index (EASI) and Peak Pruritus Numeric Rating Scale (PP‐NRS) score.

Results

Of 38 children enrolled, 37 completed phase IIa and 33 continued to the OLE. Nonlinear, target‐mediated pharmacokinetics characterized dupilumab concentrations (week 24–48 mean serum concentrations: 2 mg kg⁻¹, 61–77 mg L⁻¹; 4 mg kg⁻¹, 143–181 mg L⁻¹). TEAEs were mostly mild to moderate and transient; none led to treatment discontinuation. The most commonly reported TEAEs were nasopharyngitis (2 mg kg⁻¹, 47%; 4 mg kg⁻¹, 56%) and AD exacerbation (29% and 13%, respectively). Single‐dose dupilumab rapidly improved AD with further improvements through week 52. Mean EASI and PP‐NRS improved by −37%/−33% and −17%/−20% at week 2 (phase IIa) and −92%/−84% and −70%/−58% at week 52 (OLE), respectively.

Conclusions

These safety and efficacy results support the use of dupilumab as a continuous long‐term treatment for children aged ≥ 6 to < 12 years with severe AD.

What is already known about this topic?

Severe atopic dermatitis (AD) has a marked negative impact on patient quality of life and can cause financial burden owing to a lack of effective treatments.

Dupilumab significantly improved signs and symptoms of AD with an acceptable safety profile in a 16‐week randomized, double‐blind, placebo‐controlled phase III study in children aged ≥ 6 to < 12 years with severe AD.

What does this study add?

This study extends information on the safety, efficacy and pharmacokinetic profile of dupilumab treatment for up to 52 weeks in children aged ≥ 6 to < 12 years with severe AD.

The results support the use of dupilumab as a continuous long‐term treatment for children aged ≥ 6 to < 12 years with severe AD.

Linked Comment: Sibbald. Br J Dermatol 2021; 184:792–793.

Neutrophil dysfunction triggers inflammatory bowel disease in G6PC3 deficiency

The glucose-6-phosphatase catalytic subunit 3 (G6PC3) encodes a ubiquitously expressed enzyme that regulates cytoplasmic glucose availability. Loss-of-function biallelic G6PC3 mutations cause severe congenital neutropenia and a diverse spectrum of extra-hematological manifestations, among which inflammatory bowel disease (IBD) has been anecdotally reported. Neutrophil function and clinical response to granulocyte colony-stimulating factor (G-CSF) and hematopoietic stem cell transplantation (HSCT) were investigated in 4 children with G6PC3 deficiency-associated IBD. G6PC3 deficiency was associated with early-onset IBD refractory to treatment with steroids and infliximab. The symptoms of IBD progressed despite G-CSF treatment. In vitro studies on the patients' blood showed that neutrophils displayed higher levels of activation markers (CD11b, CD66b, and CD14), excessive IL-8 and reactive oxygen species, and increased apoptosis and secondary necrosis. Secondary necrosis was exaggerated after stimulation with Escherichia coli and could be partially rescued with supplemental exogenous glucose. HSCT led to normalization of neutrophil function and remission of gastrointestinal symptoms. We conclude that neutrophils in G6PC3 deficiency release pro-inflammatory mediators when exposed to gut bacteria, associated with intestinal inflammation, despite treatment with G-CSF. HSCT is an effective therapeutic option in patients with G6PC3 deficiency-associated IBD refractory to immune suppressants.

Antibody persistence following meningococcal ACWY conjugate vaccine licensed in the European Union by age group and vaccine

INTRODUCTION

Meningococcal disease caused by Neisseria meningitidis is a major cause of meningitis and septicemia with high rates of morbidity and mortality worldwide. MenACWY-TT and MenACWY-CRM₁₉₇ are meningococcal conjugate vaccines approved for use in children and adults in the UK. The aim of this review was to evaluate and compare antibody responses and persistence in different age groups after MenACWY-TT and MenACWY-CRM₁₉₇.

AREAS COVERED

Randomized trials showed that MenACWY-TT is immunogenic at all ages. MenACWY-CRM₁₉₇ is immunogenic for infants and adults, but there is a lack of data for children aged 1 to 2 years. Studies on MenACWY-TT indicated that serum bactericidal antibody (SBA) utilizing baby rabbit complement (rSBA) titers were significantly higher and more stable than SBA using human complement (hSBA) titers, compared with hSBA titers, which were lower and declined more rapidly by 1 year following post-primary MenACWY-TT and MenACWY-CRM₁₉₇ vaccination, especially for MenA.

EXPERT OPINION

MenACWY-TT and MenACWY-CRM₁₉₇ are both well tolerated and induce similar antibody persistence and immunogenicity against all four serogroups for individuals more than one year old. rSBA assay is a more robust assay than the hSBA assay when vaccinating with MenACWY-TT, while rSBA and hSBA assays had similar antibody persistence when vaccinating with MenACWY-CRM₁₉₇.

Type 2 immunity in the skin and lungs

There has been extensive progress in understanding the cellular and molecular mechanisms of inflammation and immune regulation in allergic diseases of the skin and lungs during the last few years. Asthma and atopic dermatitis (AD) are typical diseases of type 2 immune responses. interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin are essential cytokines of epithelial cells that are activated by allergens, pollutants, viruses, bacteria, and toxins that derive type 2 responses. Th2 cells and innate lymphoid cells (ILC) produce and secrete type 2 cytokines such as IL-4, IL-5, IL-9, and IL-13. IL-4 and IL-13 activate B cells to class-switch to IgE and also play a role in T-cell and eosinophil migration to allergic inflammatory tissues. IL-13 contributes to maturation, activation, nitric oxide production and differentiation of epithelia, production of mucus as well as smooth muscle contraction, and extracellular matrix generation. IL-4 and IL-13 open tight junction barrier and cause barrier leakiness in the skin and lungs. IL-5 acts on activation, recruitment, and survival of eosinophils. IL-9 contributes to general allergic phenotype by enhancing all of the aspects, such as IgE and eosinophilia. Type 2 ILC contribute to inflammation in AD and asthma by enhancing the activity of Th2 cells, eosinophils, and their cytokines. Currently, five biologics are licensed to suppress type 2 inflammation via IgE, IL-5 and its receptor, and IL-4 receptor alpha. Some patients with severe atopic disease have little evidence of type 2 hyperactivity and do not respond to biologics which target this pathway. Studies in responder and nonresponder patients demonstrate the complexity of these diseases. In addition, primary immune deficiency diseases related to T-cell maturation, regulatory T-cell development, and T-cell signaling, such as Omenn syndrome, severe combined immune deficiencies, immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, and DOCK8, STAT3, and CARD11 deficiencies, help in our understanding of the importance and redundancy of various type 2 immune components. The present review aims to highlight recent advances in type 2 immunity and discuss the cellular sources, targets, and roles of type 2 mechanisms in asthma and AD.

Refractory very early-onset inflammatory bowel disease associated with cytosolic isoleucyl-tRNA synthetase deficiency: A case report

BACKGROUND

Aminoacyl tRNA synthetases/ligases (ARSs) are highly conserved enzymes involved in attaching amino acids to tRNA promoting protein synthesis. Although deficiencies of ARSs localized to the mitochondria classically present with neuropathology, the clinical features of cytosolic ARS deficiencies are more variable. They have previously been associated with neonatal hepatitis, but never with early-onset inflammatory bowel disease.

CASE SUMMARY

A nine-year-old Bangladeshi boy presented with neonatal liver failure and deranged clotting, transaminitis and cholestasis. His parents were first cousins. Two older brothers and a sister were well. The patient suffered from loose stools from early infancy which became more troublesome and persistent from five years old with ten bloody motions a day. Repeated endoscopies showed persistent pancolitis, which was refractory to mesalazine, corticosteroids, azathioprine, sirolimus and anti-TNF (adalimumab) therapy, but has improved recently with subcutaneous methotrexate.Whole Genome Sequencing revealed a novel pathogenic missense variant (c.290A > G) in the cytosolic isoleucyl-tRNA synthetase gene, leading to an amino acid substitution (p.Asp97Gly). Pathogenic variants in other genes associated with inflammatory bowel disease (IBD) (ADAM17, EGFR, FOXP3, IL10RA, IL10RB, IL21R, NCF4, STAT3) were excluded. Cytokine assays demonstrated markedly elevated IL-2, IL-5, IL-13, IL-9 and IL-10 by the patient’s CD4⁺ T-cells, while IL-17A, IL-17F, IFNβ were lower, and TNFα not significantly different when compared to healthy controls.

CONCLUSION

This case report provides evidence that recessive mutations in cytosolic isoleucyl-tRNA synthetase are a novel monogenic cause of IBD, which should be considered, particularly in infants and children with a history of neonatal hepatitis and very early-onset IBD poorly responsive to treatment.

Impact on quality of life and safety of sublingual and subcutaneous immunotherapy in children with severe house dust mite and pollen-associated allergic rhinoconjunctivitis

Background

Pollen and house dust mite (HDM) subcutaneous immunotherapy (SLIT) and pollen subcutaneous immunotherapy (SCIT) are effective therapies for children with allergic rhinoconjunctivitis (AR). There are no previous direct comparative studies investigating quality of life (QoL) of all three immunotherapy regimes. The aim of this study was to compare QoL and safety in children receiving these immunotherapies for AR.

Methods

Demographic characteristics, Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and Visual Analogue (VAS) scores were assessed in 249 children undergoing HDM and pollen immunotherapy at a UK specialist paediatric centre between 2007 and 2019.

Results

All three immunotherapy regimes led to a > 50% improvement in QoL and VAS after 3 years of therapy, with significant improvements by the end of the first year (p < 0.05) and further improvements between 1 and 3 years (p < 0.05). Age, gender, ethnicity and route of administration had no significant bearing on efficacy. Older, polysensitised children and those receiving HDM SLIT were all more likely to discontinue their treatment (all with p < 0.05). The only patient to suffer from anaphylaxis requiring intramuscular adrenaline, and 80% experiencing exacerbations of their asthma had received pollen SCIT.

Conclusions

Pollen SCIT and pollen and HDM SLIT all lead to significant improvements in QoL. The risk of anaphylaxis is low, but SCIT is associates with a 1 in 5 chance of asthma flares in the days after its administration. Discontinuation of therapy is more frequent in older, polysensitised children, and those undergoing HDM immunotherapy.

Infant Alveolar Macrophages Are Unable to Effectively Contain Mycobacterium tuberculosis

Infants are more likely to develop lethal disseminated forms of tuberculosis compared with older children and adults. The reasons for this are currently unknown. In this study we test the hypothesis that antimycobacterial function is impaired in infant alveolar macrophages (AMϕs) compared with those of adults. We develop a method of obtaining AMϕs from healthy infants using rigid bronchoscopy and incubate the AMϕs with live virulent Mycobacterium tuberculosis (Mtb). Infant AMϕs are less able to restrict Mtb replication compared with adult AMϕs, despite having similar phagocytic capacity and immunophenotype. RNA-Seq showed that infant AMϕs exhibit lower expression of genes involved in mycobactericidal activity and IFNγ-induction pathways. Infant AMϕs also exhibit lower expression of genes encoding mononuclear cell chemokines such as CXCL9. Our data indicates that failure of AMϕs to contain Mtb and recruit additional mononuclear cells to the site of infection helps to explain the more fulminant course of tuberculosis in early life.

Impaired lymphocyte function and differentiation in CTPS1-deficient patients result from a hypomorphic homozygous mutation

Cytidine triphosphate (CTP) synthetase 1 (CTPS1) deficiency is caused by a unique homozygous frameshift splice mutation (c.1692-1G>C, p.T566Dfs26X). CTPS1-deficient patients display severe bacterial and viral infections. CTPS1 is responsible for CTP nucleotide de novo production involved in DNA/RNA synthesis. Herein, we characterized in depth lymphocyte defects associated with CTPS1 deficiency. Immune phenotyping performed in 7 patients showed absence or low numbers of mucosal-associated T cells, invariant NKT cells, memory B cells, and NK cells, whereas other subsets were normal. Proliferation and IL-2 secretion by T cells in response to TCR activation were markedly decreased in all patients, while other T cell effector functions were preserved. The CTPS1T566Dfs26X mutant protein was found to be hypomorphic, resulting in 80%-90% reduction of protein expression and CTPS activity in cells of patients. Inactivation of CTPS1 in a T cell leukemia fully abolished cell proliferation. Expression of CTPS1T566Dfs26X failed to restore proliferation of CTPS1-deficient leukemia cells to normal, except when forcing its expression to a level comparable to that of WT CTPS1. This indicates that CTPS1T566Dfs26X retained normal CTPS activity, and thus the loss of function of CTPS1T566Dfs26X is completely attributable to protein instability. This study supports that CTPS1 represents an attractive therapeutic target to selectively inhibit pathological T cell proliferation, including lymphoma.

Dupilumab in adolescents with uncontrolled moderate-to-severe atopic dermatitis: results from a phase IIa open-label trial and subsequent phase III open-label extension

Background

Dupilumab (monoclonal antibody inhibiting IL‐4/IL‐13 signalling) is approved for use in adolescents aged ≥ 12 years with inadequately controlled moderate‐to‐severe atopic dermatitis (AD). Dupilumab significantly improved AD signs/symptoms in a 16‐week, randomised, placebo‐controlled phase III trial in adolescents (NCT03054428).

Objectives

To characterize the pharmacokinetics of dupilumab, and long‐term safety and efficacy in adolescents.

Methods

This was a global, multicentre, phase IIa, open‐label, ascending‐dose, sequential cohort study with a phase III open‐label extension (OLE) in adolescents with moderate‐to‐severe AD. In the phase IIa study, patients received one dupilumab dose (2 mg kg⁻¹ or 4 mg kg⁻¹) and 8 weeks of pharmacokinetic sampling. Thereafter, patients received the same dose weekly for 4 weeks, with 8‐week safety follow‐up. Patients then enrolled in the OLE, continuing 2 mg kg⁻¹ or 4 mg kg⁻¹ dupilumab weekly. Primary end points were dupilumab concentration–time profile and incidence of treatment‐emergent adverse events (TEAEs). Secondary outcomes included Eczema Area and Severity Index (EASI).

Results

Forty adolescents received dupilumab in the phase IIa study; 36 enrolled in the OLE. Dupilumab showed nonlinear, target‐mediated pharmacokinetics. Mean ± SD trough dupilumab concentrations in serum at week 48 (OLE) were 74 ± 19 mg L⁻¹ and 161 ± 60 mg L⁻¹ for 2 mg kg⁻¹ and 4 mg kg⁻¹, respectively. Dupilumab was well tolerated over 52 weeks; the most common TEAEs were nasopharyngitis (week 52: 41% [2 mg kg⁻¹], 47% [4 mg kg⁻¹]) and AD exacerbation (29%, 42%). After one dupilumab dose in the phase IIa study, EASI improved from baseline to week 2 [mean ± SD reduction −34% ± 20% (2 mg kg⁻¹) and −51% ± 29% (4 mg kg⁻¹)]. With continuing treatment, EASI scores improved further [week 52: −85% ± 12% (2 mg kg⁻¹) and −84% ± 20% (4 mg kg⁻¹)].

Conclusions

In adolescents with moderate‐to‐severe AD, dupilumab's pharmacokinetic profile was similar to that in adults. These 52‐week safety and efficacy data support long‐term use of dupilumab in this patient population.

What's already known about this topic?

Adolescents with moderate‐to‐severe atopic dermatitis (AD) have high unmet medical need, with significant disease burden and limited treatment options.

Dupilumab (monoclonal antibody against interleukin‐4 receptor α) is approved for the treatment of adolescents with moderate‐to‐severe AD who are inadequately responsive to standard of care (U.S.A.) or candidates for systemic therapy (European Union).

A 16‐week, randomized, placebo‐controlled phase III trial in adolescents demonstrated significant improvements in AD signs/symptoms with an acceptable safety profile.

What does this study add?

These studies demonstrate the long‐term safety and efficacy of dupilumab in adolescents with moderate‐to‐severe AD for up to 52 weeks of treatment, thus extending and reinforcing the findings from the 16‐week dupilumab phase III trial.

The data from these studies also support the use of dupilumab in combination with current standard of care (topical corticosteroids), which was not evaluated in the 16‐week phase III monotherapy trial.

Linked Comment: https://doi.org/10.1111/bjd.18627.

https://doi.org/10.1111/bjd.18661 available online

Staphylococcus aureus Internalized by Skin Keratinocytes Evade Antibiotic Killing

Staphylococcus aureus causes the majority of skin and soft tissue infections. Half of patients treated for primary skin infections suffer recurrences within 6 months despite appropriate antibiotic sensitivities and infection control measures. We investigated whether S. aureus internalized by human skin keratinocytes are effectively eradicated by standard anti-staphylococcal antibiotics. S. aureus, but not S. epidermidis, were internalized and survive within keratinocytes without inducing cytotoxicity or releasing the IL-33 danger signal. Except for rifampicin, anti-staphylococcal antibiotics in regular clinical use, including flucloxacillin, teicoplanin, clindamycin, and linezolid, did not kill internalized S. aureus, even at 20-fold their standard minimal inhibitory concentration. We conclude that internalization of S. aureus by human skin keratinocytes allows the bacteria to evade killing by most anti-staphylococcal antibiotics. Antimicrobial strategies, including antibiotic combinations better able to penetrate into mammalian cells are required if intracellular S. aureus are to be effectively eradicated and recurrent infections prevented.

The United Kingdom Primary Immune Deficiency (UKPID) registry 2012 to 2017

This is the second report of the United Kingdom Primary Immunodeficiency (UKPID) registry. The registry will be a decade old in 2018 and, as of August 2017, had recruited 4758 patients encompassing 97% of immunology centres within the United Kingdom. This represents a doubling of recruitment into the registry since we reported on 2229 patients included in our first report of 2013. Minimum PID prevalence in the United Kingdom is currently 5·90/100 000 and an average incidence of PID between 1980 and 2000 of 7·6 cases per 100 000 UK live births. Data are presented on the frequency of diseases recorded, disease prevalence, diagnostic delay and treatment modality, including haematopoietic stem cell transplantation (HSCT) and gene therapy. The registry provides valuable information to clinicians, researchers, service commissioners and industry alike on PID within the United Kingdom, which may not otherwise be available without the existence of a well-established registry.

Hematopoietic stem cell transplant effectively rescues lymphocyte differentiation and function in DOCK8-deficient patients

Bi-allelic inactivating mutations in DOCK8 cause a combined immunodeficiency characterised by severe pathogen infections, eczema, allergies, malignancy and impaired humoral responses. These clinical features result from functional defects in most lymphocyte lineages. Thus, DOCK8 plays a key role in immune cell function. Hematopoietic stem cell transplantation (HSCT) is curative for DOCK8 deficiency. While previous reports have described clinical outcomes for DOCK8 deficiency following HSCT, the effect on lymphocyte reconstitution and function has not been investigated. Our study determined whether defects in lymphocyte differentiation and function in DOCK8-deficient patients were restored following HSCT. DOCK8-deficient T and B lymphocytes exhibited aberrant activation and effector function in vivo and in vitro. Frequencies of αβ T and MAIT cells were reduced while γδT cells were increased in DOCK8-deficient patients. HSCT improved, abnormal lymphocyte function in DOCK8-deficient patients. Elevated total and allergen-specific IgE in DOCK8-deficient patients decreased over time following HSCT. Our results document the extensive catalogue of cellular defects in DOCK8-deficient patients, and the efficacy of HSCT to correct these defects, concurrent with improvements in clinical phenotypes. Overall, our findings provide mechanisms at a functional cellular level for improvements in clinical features of DOCK8 deficiency post-HSCT, identify biomarkers that correlate with improved clinical outcomes, and inform the general dynamics of immune reconstitution in patients with monogenic immune disorders following HSCT.

Hypomorphic caspase activation and recruitment domain 11 (CARD11) mutations associated with diverse immunologic phenotypes with or without atopic disease

BACKGROUND

Caspase activation and recruitment domain 11 (CARD11) encodes a scaffold protein in lymphocytes that links antigen receptor engagement with downstream signaling to nuclear factor κB, c-Jun N-terminal kinase, and mechanistic target of rapamycin complex 1. Germline CARD11 mutations cause several distinct primary immune disorders in human subjects, including severe combined immune deficiency (biallelic null mutations), B-cell expansion with nuclear factor κB and T-cell anergy (heterozygous, gain-of-function mutations), and severe atopic disease (loss-of-function, heterozygous, dominant interfering mutations), which has focused attention on CARD11 mutations discovered by using whole-exome sequencing.

OBJECTIVES

We sought to determine the molecular actions of an extended allelic series of CARD11 and to characterize the expanding range of clinical phenotypes associated with heterozygous CARD11 loss-of-function alleles.

METHODS

Cell transfections and primary T-cell assays were used to evaluate signaling and function of CARD11 variants.

RESULTS

Here we report on an expanded cohort of patients harboring novel heterozygous CARD11 mutations that extend beyond atopy to include other immunologic phenotypes not previously associated with CARD11 mutations. In addition to (and sometimes excluding) severe atopy, heterozygous missense and indel mutations in CARD11 presented with immunologic phenotypes similar to those observed in signal transducer and activator of transcription 3 loss of function, dedicator of cytokinesis 8 deficiency, common variable immunodeficiency, neutropenia, and immune dysregulation, polyendocrinopathy, enteropathy, X-linked-like syndrome. Pathogenic variants exhibited dominant negative activity and were largely confined to the CARD or coiled-coil domains of the CARD11 protein.

CONCLUSION

These results illuminate a broader phenotypic spectrum associated with CARD11 mutations in human subjects and underscore the need for functional studies to demonstrate that rare gene variants encountered in expected and unexpected phenotypes must nonetheless be validated for pathogenic activity.

Mast cell disorders: From infancy to maturity

Mast cells are typically linked to immediate hypersensitivity and anaphylaxis. This review looks beyond this narrow role, focusing on how these cells have evolved and diversified via natural selection promoting serine protease gene duplication, augmenting their innate host defense function against helminths and snake envenomation. Plasticity of mast cell genes has come at a price. Somatic activating mutations in the mast cell growth factor KIT gene cause cutaneous mastocytosis in young children and systemic mastocytosis with a more guarded prognosis in adults who may also harbor other gene mutations with oncogenic potential as they age. Allelic TPSAB1 gene duplication associated with higher basal mast cell tryptase is possibly one of the commonest autosomal dominantly inherited multi-system diseases affecting the skin, gastrointestinal tract, circulation and musculoskeletal system. Mast cells are also establishing a new-found importance in severe asthma, and in remodeling of blood vessels in cancer and atherosclerotic vascular disease. Furthermore, recent evidence suggests that mast cells sense changes in oxygen tension, particularly in neonates, and that subsequent degranulation may contribute to common lung, eye, and brain diseases of prematurity classically associated with hypoxic insults. One hundred and forty years since Paul Ehrlich's initial description of "mastzellen," this review collates and highlights the complex and diverse roles that mast cells play in health and disease.

Phenotype, penetrance, and treatment of 133 cytotoxic T-lymphocyte antigen 4-insufficient subjects

BACKGROUND

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a negative immune regulator. Heterozygous CTLA4 germline mutations can cause a complex immune dysregulation syndrome in human subjects.

OBJECTIVE

We sought to characterize the penetrance, clinical features, and best treatment options in 133 CTLA4 mutation carriers.

METHODS

Genetics, clinical features, laboratory values, and outcomes of treatment options were assessed in a worldwide cohort of CTLA4 mutation carriers.

RESULTS

We identified 133 subjects from 54 unrelated families carrying 45 different heterozygous CTLA4 mutations, including 28 previously undescribed mutations. Ninety mutation carriers were considered affected, suggesting a clinical penetrance of at least 67%; median age of onset was 11 years, and the mortality rate within affected mutation carriers was 16% (n = 15). Main clinical manifestations included hypogammaglobulinemia (84%), lymphoproliferation (73%), autoimmune cytopenia (62%), and respiratory (68%), gastrointestinal (59%), or neurological features (29%). Eight affected mutation carriers had lymphoma, and 3 had gastric cancer. An EBV association was found in 6 patients with malignancies. CTLA4 mutations were associated with lymphopenia and decreased T-, B-, and natural killer (NK) cell counts. Successful targeted therapies included application of CTLA-4 fusion proteins, mechanistic target of rapamycin inhibitors, and hematopoietic stem cell transplantation. EBV reactivation occurred in 2 affected mutation carriers after immunosuppression.

CONCLUSIONS

Affected mutation carriers with CTLA-4 insufficiency can present in any medical specialty. Family members should be counseled because disease manifestation can occur as late as 50 years of age. EBV- and cytomegalovirus-associated complications must be closely monitored. Treatment interventions should be coordinated in clinical trials.

Severity and threshold of peanut reactivity during hospital-based open oral food challenges: An international multicenter survey

BACKGROUND

Peanut allergy is classically managed by food avoidance. Immunotherapy programs are available at some academic centers for selected patients reacting to small amounts of peanut during food challenge. We aimed to determine and compare reaction thresholds and prevalence of anaphylaxis during peanut oral challenges at multiple specialist allergy centers.

METHODS

A retrospective, international survey of anonymized case records from seven specialist pediatric allergy centers from the UK and Ireland, as well as the Australian HealthNuts study. Demographic information, allergy test results, reaction severity and threshold during open oral peanut challenges were collated and analyzed.

RESULTS

Of the 1634 children aged 1-18 years old included, 525 (32%) failed their peanut challenge. Twenty-eight percent reacted to 25 mg, while 38% only reacted after consuming 1 g or more of whole peanut. Anaphylaxis (55 [11%]) was 3 times more common in teenagers than younger children and the likelihood increased at all ages as children consuming more peanut at the challenge. Children who developed anaphylaxis to 25-200 mg of whole peanut were significantly older. Previous history of reaction did not predict reaction threshold or severity.

CONCLUSIONS

More than a third of the children in this large international cohort tolerated the equivalent of one peanut in an oral challenge. Anaphylaxis, particularly to small amounts of peanut, was more common in older children. Tailored immunotherapy programs might be considered not only for children with low, but also higher reaction thresholds. Whether these programs could prevent heightened sensitivity and anaphylaxis to peanut with age also deserves further study.