A Novel Mutation in WAS Gene Causing a Phenotypic Presentation of Wiskott-Aldrich Syndrome: A Case Report.

BACKGROUND: Wiskott-Aldrich syndrome (WAS) is an X-linked disorder characterized by immunodeficiency, thrombocytopenia, and atopic dermatitis. OBSERVATIONS: This infant presented at birth with petechiae and bruising, with severe neonatal thrombocytopenia. Genetic testing for WAS revealed a variant of unknown significance hemizygous missense mutation in the WAS gene. This variant has not previously been reported. On the basis of the patient's clinical course including bleeding, infection, abnormal immune evaluation, and dermatologic sequelae, he was diagnosed with WAS and underwent allogeneic hematopoietic stem cell transplantation. CONCLUSIONS: We report a novel mutation in the WAS gene that causes a phenotypic presentation of Wiskott-Aldrich Syndrome.

Risk factors for Clostridioides (Clostridium) difficile infection following solid organ transplantation in children.

BACKGROUND: Clostridioides (Clostridium) difficile infection (CDI) in pediatric solid organ transplant (SOT) recipients is a growing problem, though CDI risk factors in this population are poorly understood. Our objective was to characterize CDI risk factors in pediatric SOT recipients. METHODS: This retrospective case-control study, performed at a single freestanding academic children's hospital, included all SOT recipients age 1-22 years who were tested for C. difficile by toxin B gene PCR between August 2009 and August 2017. CDI risk factors were assessed by comparing PCR-positive and PCR-negative cases by generalized linear mixed models. RESULTS: Between August 2009 and August 2017, 409 SOTs were performed of which 138 (33.7%), 134 (32.8%), 131 (32.0%), and 6 (1.5%) were kidney, liver, heart, and small intestine transplants, respectively. Of 205 SOT recipients were tested for CDI, with 723 C. difficile PCR tests performed among these patients. 68/205 (33%) patients developed CDI at least once during the study period. Median (interquartile range) time to diagnosis of first CDI following SOT was 8.9 (1.2, 19.6) months. CDI was independently associated with calcineurin inhibitor use at time of C. difficile testing (odds ratio [OR] 2.38, 95% confidence interval [CI] 1.08, 5.24, P = 0.03) and systemic antibiotic exposure within 30 days of C. difficile testing (OR 1.74, 95% CI 1.08, 2.79, P = 0.02). CONCLUSIONS: CDI is a common, relatively late post-transplant complication and independently associated with calcineurin inhibitor and systemic antibiotic exposure. The potential impact of specific immunosuppressive drug and antibiotic selection on CDI risk reduction requires further investigation.

In vitro testing for allergic and immunologic diseases.

In vitro tests are used to assist in the diagnosis of both allergic and immunologic diseases. Unfortunately, there is no single test that is pathognomonic for most allergic diseases. The most commonly ordered in vitro test by allergists is allergen specific IgE (sIgE), which is used to help diagnose IgE mediated hypersensitivity to foods, aeroallergens and venoms. Multiple assays exist, although none of these assays have been adopted as the industry standard. Epicutaneous skin test is also a fundamental test in the diagnosis of IgE mediated hypersensitivity. In addition, total IgE, basophil activation test (BAT), and serum tryptase may also be useful in elucidating allergic diseases. Immunologists rely on laboratory testing to diagnose primary immunodeficiency diseases. These tests include serum quantitative immunoglobulins, lymphocyte immunophenotyping by flow cytometry and immune cell functional testing. Furthermore, genetic testing is invaluable in the diagnosis of many primary Immunodeficiencies.

Stinging insect allergy and venom immunotherapy.

The Hymenoptera order is divided into three families: Apidae, Vespidae, and Formicidae. Apidae include the honeybee, bumblebee, and sweat bee, which are all docile and tend to sting mostly on provocation. The Africanized killer bee, a product of interbreeding between the domestic and African honeybee, is very aggressive and is mostly found in Mexico, Central America, Arizona, and California. The yellow jacket, yellow hornet, white (bald) faced hornet, and paper wasp all belong to the Vespidae family. The Formicidae family includes the harvester ant and the fire ant. When a "bee" sting results in a large local reaction, defined as >10 cm induration and lasting > 24 hours, the likelihood of anaphylaxis from a future sting is approximately 5%. For comparison, when there is a history of anaphylaxis from a previous Hymenoptera sting and the patient has positive skin test results to venom, at least 60% of adults and 20-32% of children will develop anaphylaxis with a future sting. Both patient groups should be instructed about avoidance measures and about carrying and knowing when to self-inject epinephrine, but immunotherapy with Hymenoptera venom is indicated for those patients with a history of anaphylaxis from the index sting and not for patients who have experienced a large local reaction. Immunotherapy is highly effective in that, by 4 years of injections, the incidence of subsequent sting-induced reactions is 3%. This incidence may increase modestly after discontinuation of injections but has not been reported to be > 10% in follow up.

Food allergy: Diagnosis and treatment.

Immunoglobulin E-mediated food reactions usually develop within minutes of food ingestion. Although most reactions are not life-threatening, fatalities do occur. Risk factors for fatal food-induced anaphylaxis include the presence of asthma (a risk factor for anaphylaxis in general), failure to use epinephrine autoinjectors promptly, a history of severe reactions, known food allergy, denial of symptoms, and adolescent and young adult age. The most commonly implicated foods are cow's milk, egg, peanut, soy, tree nuts, fish, shellfish, and wheat. Peanut, tree nuts, and seafood are the most common food allergens in adults, whereas cow's milk, peanut, egg, soy, and wheat are more common in children. The major food allergens are glycoproteins, which are generally water soluble and stable to the effects of heat, proteases, and acids. Recent studies showed that natural tolerance can be acquired at a later age than previously thought, even during adolescence. Allergies to peanut, tree nuts, and seafood are frequently life-long. Patients and their caregivers should be taught when and how to administer injectable epinephrine. In terms of primary prevention, there is evidence that early introduction, followed by ongoing regular consumption of peanut has a protective effect on the development of peanut allergy.

Proof-of-concept study evaluating humoral primary immunodeficiencies via CJ:KREC ratio and serum BAFF level.

Humoral primary immunodeficiencies are the most prevalent form of primary immunodeficiency (PID). Currently, there is no convenient method to quantify newly formed B cells. The aim of this proof-of-concept study was to quantitate the ratio of coding joints (CJs) to Kappa-deleting recombination excision circles (KRECs) and serum B cell activating factor (BAFF) in patients with humoral primary immunodeficiency and assess if they correlate with disease severity. This IRB-approved study was conducted at one academic children's hospital. Patients with humoral PIDs and healthy controls were included. CJ and KREC levels were measured via qPCR. Serum BAFF levels were measured using Mesoscale. 16 patients with humoral PID and 5 healthy controls were included. The mean CJ:KREC ratio in the CVID, antibody deficiency syndromes, and controls groups, respectively were 13.04 ± 9.5, 5.25 ± 4.1, and 4.38 ± 2.5 (p = 0.059). The mean serum BAFF levels in CVID, antibody deficiency syndromes and controls were 216.3 ± 290 pg/mL, 107.9 ± 94 pg/mL and 50.9 ± 12 pg/mL, respectively (p = 0.271). When the CVID patients were subdivided into CVID with or without lymphoproliferative features, the BAFF level was substantially higher in the CVID with lymphoproliferation cohort (mean 372.4 ± 361 pg/mL, p = 0.031). Elevated CJ:KREC ratio was observed in CVID, although statistical significance was not achieved, likely due to the small sample size. Serum BAFF levels were significantly higher in CVID patients with lymphoproliferative features. We speculate that the CJ:KREC ratio and serum BAFF levels can be utilized in patients with humoral PID, once more extensive studies confirm this exploratory investigation.

B Cell Lymphocytosis in Juvenile Dermatomyositis.

In this study, we determined if B lymphocytosis may serve as a JDM biomarker for disease activity. Children with untreated JDM were divided into two groups based on age-adjusted B cell percentage (determined through flow cytometry): 90 JDM in the normal B cell group and 45 in the high B cell group. We compared through T-testing the age, sex, ethnicity, duration of untreated disease (DUD), disease activity scores for skin (sDAS), muscle (mDAS), total (tDAS), CMAS, and neopterin between these two groups. The patients in the high B cell group had a higher tDAS (p = 0.009), mDAS (p = 0.021), and neopterin (p = 0.0365). Secondary analyses included B cell values over time and BAFF levels in matched patients with JM (juvenile myositis) and concurrent interstitial lung disease (ILD); JM alone and healthy controls Patient B cell percentage and number was significantly higher after 3-6 months of therapy and then significantly lower on completion of therapy (p =< 0.0001). The JM groups had higher BAFF levels than controls 1304 vs. 692 ng/mL (p = 0.0124). This study supports B cell lymphocytosis as a JDM disease-activity biomarker and bolsters the basis for B cell-directed therapies in JDM.

In-utero exposure to immunosuppressive medications resulting in abnormal newborn screening for severe combined immunodeficiency: a case series on natural history and management.

Exposure to immunosuppressive medication in utero is an important cause of secondary T cell lymphopenia in infancy, which can be detected via T cell receptor excision circle (TREC) quantification on severe combined immunodeficiency (SCID) newborn screening (NBS). At present, there is a paucity of literature surrounding management of these infants. A protocol including recommendations for vaccinations and follow-up is needed to augment care. Patients referred to immunology for abnormal TREC results on NBS were identified as having in utero exposure to immunosuppressive medications and were followed until lymphopenia improved. The natural history of these patients' lymphopenia was used to develop general management guidelines. Four infants with low TRECs secondary to in utero immunosuppressive exposure were evaluated. Medication exposures included azathioprine, infliximab, hydroxychloroquine, and fingolimod. All infants were born full term. TRECs ranged from 101-206 (normal value in IL ≥ 250 at time of testing, B-actin control). T cell lymphopenia (CD3 < 1500) was present in 50% of cases. Undetectably low effector CD4 naïve T cell population was present in 100% of cases. Mitogen proliferation was uniformly normal. Severity of TREC abnormality did not correlate with presence of T cell lymphopenia. Immune abnormalities normalized in 75% patients by age 4 months. All age-appropriate vaccinations, including live vaccines, were administered to all patients by age 4 months. It is critical to assess for in utero immunosuppressive exposure in infants with abnormal TREC results on NBS. In the infants evaluated, secondary T cell lymphopenia associated with maternal immunosuppressive use resolved or significantly improved by age 4 months. Once abnormal TREC count is deemed to be secondary to in utero immunosuppression and there are no other contraindications, infants may safely receive live vaccination, are able to drink breast milk, and do not require prophylactic anti-microbials.

Coding joint: kappa-deleting recombination excision circle ratio and B cell activating factor level: predicting juvenile dermatomyositis rituximab response, a proof-of-concept study.

BACKGROUND: This pilot study's primary aim was to determine if oligoclonal B cell expansion in children with Juvenile Dermatomyositis (JDM) predicts response to Rituximab therapy. We evaluated: (1) tissue B cell depletion efficacy by measuring the ratio of Coding joint (CJ) to Kappa-deleting recombination excision circle (KREC) DNA, and (2) serum BAFF level upon B cell recovery. METHODS: CJ and KREC values were measured via qPCR assessment of serial PBMC stored (- 80 °C) in the CureJM Center's BioRepository. Serum BAFF was quantitated by Mesoscale® technology. Oligoclonal B cell expansion was defined as a CJ:KREC ≥ 8 prior to Rituximab therapy. Detection of a CJ:KREC ratio ≤ 2.5 in the first sample after Rituximab was designated as adequate B cell depletion. A significant clinical response to therapy was defined as improvement in Disease Activity Score (DAS) by at least 2 points on consecutive visits within the first 12 months of therapy. RESULTS: Six out of nine children with JDM showed oligoclonal B cell expansion prior to Rituximab (CJ:KREC ≥ 8). Of those 6 patients, 4 had evidence of effective B cell depletion after Rituximab (CJ:KREC ≤ 2.5), and all 4 of those subjects displayed a significant clinical response to Rituximab. Serum BAFF level increased in 8/9 children after Rituximab. CONCLUSIONS: In this proof-of-concept study, JDM patients with oligoclonal B cell expansion prior to Rituximab have more favorable clinical outcomes after Rituximab. We speculate: (1) B cell depletion post-Rituximab predicts JDM clinical response; (2) increased BAFF post-Rituximab may contribute to disease flare.

Diurnal Variations in Skin Prick Testing.

Background: Prior research suggests that skin prick testing (SPT) might be larger in the afternoon, with unclear clinical significance. Methods: This retrospective chart review analyzed SPT results from patients between June 2008 and June 2017, organized into 4 time groups for analysis (Group 1: 7:00 AM -10:29 AM, Group 2: 10:30 AM -11:59 AM, Group 3: 12:00 PM -2:29 PM, and Group 4: 2:30 PM -8:15 PM). Results: In total, 12,982 (n) patient test results had positive histamine and were included in final analysis. Histamine wheal size was not significantly increased in the PM compared with AM (P = 0.89). Food allergen and aeroallergen wheal sizes were not significantly increased in PM. Histamine erythema size was increased in the PM compared with AM (P ≤ 0.01). Food allergen and aeroallergen erythema sizes trended toward an increase in the PM. Conclusions: There were not significant differences in SPT wheal size based on time of day for histamine, food allergens, or aeroallergens. SPT can be reliably performed at any time of day.

Ischemia in broca area is associated with broca aphasia more reliably in acute than in chronic stroke.

BACKGROUND AND PURPOSE: We aimed to determine if ischemia involving Broca area predicts Broca aphasia more reliably in acute or chronic stroke. METHODS: We included consecutive right-hand-dominant patients with left hemisphere ischemic stroke (<48 hours from onset for acute stroke or >6 months after stroke for chronic stroke). MRI scans were analyzed for ischemic lesions or hypoperfusion in Broca area (Brodmann areas 44 and 45). Patients were scored on the Western Aphasia Battery to classify aphasia syndromes; chi(2) tests were used to identify significant associations. RESULTS: The presence of infarct involving any part of Broca area and the presence of Broca or global aphasia was much stronger in acute (chi(2)=38.1; df1; P<0.0001) than in chronic stroke (chi(2)=0.54; df1; P=0.46; not significant). The association between infarct or hypoperfusion covering all of Broca area and the presence of Broca or global aphasia was much stronger in acute (chi(2)=35.8; df1; P<0.0001) than in chronic stroke (chi(2)=1.2; df1; p=0.27; not significant). In a subset of 20 patients studied longitudinally, the associations were significant only acutely, not chronically (chi(2)=20; df1; P<0.0001 vs. chi(2)=0; df1; p=1; not significant for ischemia involving part of Broca area, and chi(2)=16.4; df1; P<0.0001 vs chi(2)=3.2; df1; p=0.08; not significant for ischemia covering all of Broca area). CONCLUSIONS: Broca aphasia is more reliably associated with infarct/ hypoperfusion of Broca area in acute stroke. Many chronic stroke patients with damage to part or all of Broca area had neither Broca nor global aphasia. Broca or global aphasia was sometimes present initially in these patients but resolved by 6 months. Our results indicate that the acute aphasia syndrome may allow the clinician to predict the compromised vascular territory, even when structural imaging shows only a small (or no) infarct.

Lesion analysis of cortical regions associated with the comprehension of Nonreversible and Reversible yes/no questions.

We investigated the association between yes/no sentence comprehension and dysfunction in anterior and posterior left-hemisphere cortical regions in acute stroke patients. More specifically, we manipulated whether questions were Nonreversible (e.g., Are limes sour?) or Reversible (e.g., Is a horse larger than a dog?) to investigate the regions associated with semantic and syntactic processing. In addition, we administered lexical tasks (i.e., Picture-Word Verification, Picture Naming) to help determine the extent to which deficits in sentence processing were related to deficits in lexical processing. We found that errors on the lexical tasks were associated with ischemia in posterior-temporal Brodmann Areas (BA 21, 22, 37) and inferior parietal regions (BA 39, 40). Nonreversible question comprehension was associated with volume of tissue dysfunction, while Reversible question comprehension was associated with posterior regions (BA 39, 40) as well as one anterior region (BA 6). We conclude that deficits in Nonreversible questions required extensive dysfunction that affected language processing across multiple levels, while Reversible question comprehension was associated with regions involved in semantics as well as working memory that indirectly influenced syntactic processing. Overall, this suggests that yes/no question comprehension relies on multiple regions and that the importance of certain regions increases in relation to semantic, phonological, and syntactic complexity.