Genetic errors of immunity distinguish pediatric nonmalignant lymphoproliferative disorders.

BACKGROUND: Pediatric nonmalignant lymphoproliferative disorders (PLPDs) are clinically and genetically heterogeneous. Long-standing immune dysregulation and lymphoproliferation in children may be life-threatening, and a paucity of data exists to guide evaluation and treatment of children with PLPD. OBJECTIVE: The primary objective of this study was to ascertain the spectrum of genomic immunologic defects in PLPD. Secondary objectives included characterization of clinical outcomes and associations between genetic diagnoses and those outcomes. METHODS: PLPD was defined by persistent lymphadenopathy, lymph organ involvement, or lymphocytic infiltration for more than 3 months, with or without chronic or significant Epstein-Barr virus (EBV) infection. Fifty-one subjects from 47 different families with PLPD were analyzed using whole exome sequencing. RESULTS: Whole exome sequencing identified likely genetic errors of immunity in 51% to 62% of families (53% to 65% of affected children). Presence of a genetic etiology was associated with younger age and hemophagocytic lymphohistiocytosis. Ten-year survival for the cohort was 72.4%, and patients with viable genetic diagnoses had a higher survival rate (82%) compared to children without a genetic explanation (48%, P = .03). Survival outcomes for individuals with EBV-associated disease and no genetic explanation were particularly worse than outcomes for subjects with EBV-associated disease and a genetic explanation (17% vs 90%; P = .002). Ascertainment of a molecular diagnosis provided targetable treatment options for up to 18 individuals and led to active management changes for 12 patients. CONCLUSIONS: PLPD defines children at high risk for mortality, and whole exome sequencing informs clinical risks and therapeutic opportunities for this diagnosis.

AR101 Oral Immunotherapy for Peanut Allergy.

BACKGROUND: Peanut allergy, for which there are no approved treatment options, affects patients who are at risk for unpredictable and occasionally life-threatening allergic reactions. METHODS: In a phase 3 trial, we screened participants 4 to 55 years of age with peanut allergy for allergic dose-limiting symptoms at a challenge dose of 100 mg or less of peanut protein (approximately one third of a peanut kernel) in a double-blind, placebo-controlled food challenge. Participants with an allergic response were randomly assigned, in a 3:1 ratio, to receive AR101 (a peanut-derived investigational biologic oral immunotherapy drug) or placebo in an escalating-dose program. Participants who completed the regimen (i.e., received 300 mg per day of the maintenance regimen for approximately 24 weeks) underwent a double-blind, placebo-controlled food challenge at trial exit. The primary efficacy end point was the proportion of participants 4 to 17 years of age who could ingest a challenge dose of 600 mg or more, without dose-limiting symptoms. RESULTS: Of the 551 participants who received AR101 or placebo, 496 were 4 to 17 years of age; of these, 250 of 372 participants (67.2%) who received active treatment, as compared with 5 of 124 participants (4.0%) who received placebo, were able to ingest a dose of 600 mg or more of peanut protein, without dose-limiting symptoms, at the exit food challenge (difference, 63.2 percentage points; 95% confidence interval, 53.0 to 73.3; P<0.001). During the exit food challenge, the maximum severity of symptoms was moderate in 25% of the participants in the active-drug group and 59% of those in the placebo group and severe in 5% and 11%, respectively. Adverse events during the intervention period affected more than 95% of the participants 4 to 17 years of age. A total of 34.7% of the participants in the active-drug group had mild events, as compared with 50.0% of those in the placebo group; 59.7% and 44.4% of the participants, respectively, had events that were graded as moderate, and 4.3% and 0.8%, respectively, had events that were graded as severe. Efficacy was not shown in the participants 18 years of age or older. CONCLUSIONS: In this phase 3 trial of oral immunotherapy in children and adolescents who were highly allergic to peanut, treatment with AR101 resulted in higher doses of peanut protein that could be ingested without dose-limiting symptoms and in lower symptom severity during peanut exposure at the exit food challenge than placebo. (Funded by Aimmune Therapeutics; PALISADE ClinicalTrials.gov number, NCT02635776 .).

Varying Doses of Epicutaneous Immunotherapy With Viaskin Milk vs Placebo in Children With Cow's Milk Allergy: A Randomized Clinical Trial.

Importance: No approved treatment exists for allergen-specific immunoglobulin E (IgE)-mediated cow's milk allergy (CMA), a common childhood food allergy. Objective: To assess dose, efficacy, and safety of epicutaneous immunotherapy with Viaskin milk in children with IgE-mediated CMA. Design, Setting, and Participants: A phase 1/2, 2-part, randomized, double-blind, placebo-controlled dose-ranging clinical trial in children aged 2 to 17 years with IgE-mediated CMA was conducted between November 2014 through December 2017. It took place at 17 trial sites in the US and Canada. Current CMA was confirmed by double-blind, placebo-controlled food challenge at study entry. Part A assessed the short-term safety of 150 µg, 300 µg, or 500 µg of Viaskin milk; part B evaluated the efficacy and safety of the 3 doses vs placebo over 12 months of treatment. Of the 308 screened participants with physician-diagnosed CMA, 198 met eligibility criteria (including an eliciting dose 300 mg or less) and were randomized. Intervention: Safety of Viaskin milk (150-µg, 300-µg, or 500-µg doses) was evaluated over a 3-week period (part A). In part B, 180 additional participants were randomized to receive Viaskin milk at doses of 150 µg, 300 µg, or 500 µg or placebo (1:1:1:1) for 12 months. Main Outcomes and Measures: The primary outcome was the proportion of treatment responders, defined as a 10-fold or more increase in the cumulative reactive dose of cow's milk protein (reaching at least 144 mg) or a cumulative reactive dose of cow's milk protein at 1444 mg or more at the month 12 double-blind, placebo-controlled food challenge. Results: A total of 95.5% of the randomized participants (mean [SD] age, 8 [4.17] years; 124 of 198 were male [62.6%]) completed treatment. The highest response rate was observed in participants who received Viaskin milk at the 300-µg dose with 24 of 49 responders (49.0%) overall vs 16 of 53 responders (30.2%) in the placebo group (odds ratio, 2.19; 95% CI, 0.91-5.41; P = .09), highest in the 2 to 11 years age group (22 of 38 [57.9%] vs 13 of 40 [32.5%]; P = .04). Most treatment-emergent adverse events were mild or moderate application-site reactions. One participant in the 500-µg Viaskin milk dose group experienced treatment-related anaphylaxis. Conclusions and Relevance: In this randomized clinical trial, 12 months of daily epicutaneous immunotherapy with a dose of Viaskin milk at 300 µg was associated with a statistically significant treatment response in 2- to 11-year-old children with IgE-mediated CMA. Treatment-related anaphylaxis and treatment-related discontinuation rates were low. Further research is needed to explore Viaskin milk as a viable treatment option for children with IgE-mediated CMA. Trial Registration: ClinicalTrials.gov Identifier: NCT02223182.

Successful Use of Cidofovir in an Immunocompetent Child With Severe Adenoviral Sepsis.

Adenovirus infection is common in childhood and is generally associated with self-limited disease. Cidofovir, a viral DNA polymerase inhibitor, is used to treat adenovirus infection in select populations but is not often recommended for immunocompetent patients because of limited antiviral activity and nephrotoxicity. Here, we report a case of fulminant adenovirus infection associated with lymphopenia and multiple organ failure requiring extracorporeal membrane oxygenation support in a previously healthy child. After 1 week of supportive therapy, the patient had persistent organ failure and continued to have adenoviremia of >560 000 copies per mL. Weekly doses of cidofovir with concurrent probenecid for renal protection was initiated. Adenovirus blood load declined after the first cidofovir dose, becoming undetectable after 3 doses. The patient was successfully decannulated from extracorporeal membrane oxygenation, extubated, and eventually discharged at his functional baseline without need for ongoing respiratory support. Lymphopenia improved after viremia resolved, and a subsequent immunologic workup revealed no evidence of primary immunodeficiency. The viral isolate was genotyped as adenovirus type 7. This case reveals the successful use of cidofovir for management of severe adenovirus infection in a previously healthy child. To date, there are no universally accepted recommendations for the use of cidofovir in this population. Further study is warranted to determine the potential role of cidofovir in treating severe adenovirus infections in immunocompetent children.

Geographic Variability and Pathogen-Specific Considerations in the Diagnosis and Management of Chronic Granulomatous Disease.

Chronic granulomatous disease (CGD) is a rare but serious primary immunodeficiency with varying prevalence and rates of X-linked and autosomal recessive disease worldwide. Functional defects in the phagocyte nicotinamide adenine dinucleotide phosphate oxidase complex predispose patients to a relatively narrow spectrum of bacterial and fungal infections that are sometimes fastidious and often difficult to identify. When evaluating and treating patients with CGD, it is important to consider their native country of birth, climate, and living situation, which may predispose them to types of infections that are atypical to your routine practice. In addition to recurrent and often severe infections, patients with CGD and X-linked female carriers are also susceptible to developing many non-infectious complications including tissue granuloma formation and autoimmunity. The DHR-123 oxidation assay is the gold standard for making the diagnosis and it along with genetic testing can help predict the severity and prognosis in patients with CGD. Disease management focuses on prophylaxis with antibacterial, antifungal, and immunomodulatory medications, prompt identification and treatment of acute infections, and prevention of secondary granulomatous complications. While hematopoietic stem-cell transplantation is the only widely available curative treatment for patients with CGD, recent advances in gene therapy may provide a safer, more direct alternative.

What to Do with an Abnormal Newborn Screen for Severe Combined Immune Deficiency.

Newborn screening for severe combined immunodeficiency has been implemented in all 50 states. This screening identifies newborns with T-cell lymphopenia. After an abnormal screening, additional testing is needed to determine if the child has severe combined immunodeficiency. Because screening programs vary, it is imperative for the clinical immunologist to understand how screening is done in their state and to prepare an effective assessment protocol for the management of these patients. Part of this assessment should include training and helping to ensure the effective delivery of this news to the family, a skill neither intuitive nor classically taught to immunologists.

Considerations in the Diagnosis of Chronic Granulomatous Disease.

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency that is caused by defects in the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. The disease presents in most patients initially with infection, especially of the lymph nodes, lung, liver, bone, and skin. Patients with CGD are susceptible to a narrow spectrum of pathogens, and Staphylococcus aureus, Burkholderia cepacia complex, Serratia marcescens, Nocardia species, and Aspergillus species are the most common organisms implicated in North America. Granuloma formation, most frequently in the gastrointestinal and genitourinary systems, is a common complication of CGD and can be seen even before diagnosis. An increased incidence of autoimmune disease has also been described in patients with CGD and X-linked female carriers. In patients who present with signs and symptoms consistent with CGD, a flow cytometric dihydrorhodamine neutrophil respiratory burst assay is a quick and cost-effective way to evaluate NADPH oxidase function. The purpose of this review is to highlight considerations for and challenges in the diagnosis of CGD.