Eosinophilia in children: characteristics, etiology and diagnostic algorithm

Eosinophilia is common in children and may be caused by various disorders. Large-cohort studies, including mild cases, are limited in children. This study aimed to reveal underlying etiologies of childhood eosinophilia and to create a diagnostic algorithm. Children (< 18 years) with absolute eosinophil counts (AECs) ≥ 0.5 × 10⁹/L were reviewed from medical files. Clinical characteristics and laboratory values were recorded. Patients were grouped based on the severity of eosinophilia as mild (0.5-1.5 × 10⁹/L), moderate (≥ 1.5 × 10⁹/L) and severe (≥ 5.0 × 10⁹/L). An algorithm was formed to evaluate these patients. We included 1178 children with mild (80.8%), moderate (17.8%) and severe eosinophilia (1.4%). The most common reasons of eosinophilia were allergic diseases (80%), primary immunodeficiency (PID) (8.5%), infectious diseases (5.8%), malignancies (0.8%) and rheumatic diseases (0.7%). Only 0.3% of children presented with idiopatic hypereosinophilic syndrome. Allergic diseases and PIDs were the most common etiologies in mild/moderate and severe groups, respectively. The median duration of eosinophilia was 7.0 (3.0-17.0) months in the study population and was the shortest in severe cases (2.0 (2.0-5.0) months). Multiple logistic regression analysis demonstrated food allergy [OR:1.866, 95%CI:1.225-2.842, p = 0.004] and PIDs [OR:2.200, 95%CI:1.213-3.992, p = 0.009] as independent factors for childhood eosinophilia. A diagnostic algorithm including mild form was presented for childhood eosinophilia.    Conclusion: Eosinophilia was frequently determined due to secondary causes; allergic diseases in mild/moderate eosinophilia, PIDs in severe group. Etiology of eosinophilia was diverse, and an algorithm concerning the severity of eosinophilia would be practical and rational. What is Known: • In children, eosinophilia is common, and mild eosinophilia occurs frequently. • Malignancies presents frequently with severe eosinophilia. What is New: • Primary immunodeficiencies were not a rare cause of eosinophilia, especially in countries such as the Middle East and eastern Mediterranean countries, where the countries consanguineous marriages are common, and should be investigated in children with eosinophilia who do not have allergic or infectious diseases. • In literature, there are many algorithms about childhood hypereosinophilia. However, mild eosinophilia is extremely important in children. Because all patients with malignancy and most of the patients with rheumatic diseases presented with mild eosinophilia. Therefore, we proposed an algorithm for childhood eosinophilia that includes mild eosinophilia besides moderate and severe cases.

Safety and efficacy of rapid drug desensitization in children

BACKGROUND

Any drug taken at the recommended dosage may cause hypersensitivity reactions (DHR). Rapid drug desensitization (RDD) protocols have been developed in the case of a confirmed or highly suspected HSR to allow safe administration of the medicine when there is no alternative drug or in the presence of a less effective or more toxic alternative. The aim of this study was to evaluate the characteristics of children who underwent desensitization, the safety and efficacy of RDD in children, as well as, the characteristics and management of breakthrough reactions.

METHOD

This retrospective study concerned children who underwent RDD due to physician-diagnosed HSRs during or up to 48 hours after the infusion of various drugs between February 2010-February 2021. Patients with a chronic disease needing chronic drug usage and acute infections seen in patients with chronic diseases were included. The results of RDD were documented.

RESULTS

The study included 48 patients [8.1(IQR = 3.32-13.4) years, 60.4% male] with 58 HSRs of which 62.1% were classified as moderate and 5.2% as severe. Most of the patients were being treated for leukemia (41.7%), solid tumors (29.2%), and infections (6.3%). Skin tests were done for 41 out of 58 HSRs in 35 patients, and twenty of them were positive. A total of 269 RDDs were performed for 18 different drugs. Ninety percent of desensitizations were achieved with no reaction, and 3.7% and 5.6% with mild and moderate reactions, respectively. In multivariate analysis, skin test positivity was the only risk factor for breakthrough reactions (OR = 8.5, CI = 1.72-42.15, p = .009).

CONCLUSION

We demonstrated the safety and efficacy of RDD in childhood, thereby offered the first line treatment options to children with chronic diseases with hypersensitivity reactions (HSRs).

Diversity in STK4 Deficiency and Review of the Literature

BACKGROUND

Serine-threonine kinase-4 (STK4) deficiency is an autosomal recessive (AR) combined immunodeficiency (CID).

OBJECTIVE

We aimed to define characteristic clinical and laboratory features to aid the differential diagnosis and determine the most suitable therapy.

METHODS

In addition to nine patients diagnosed, we reviewed 15 patients from medical literature. We compared B lymphocyte subgroups of our cohort with age-matched healthy controls.

RESULTS

In our cohort, the median age at symptom onset and age of diagnosis are 6years-8months (mo)(6-248mo) and 7years-5mo (6-260mo), respectively. The main clinical findings were infections (9/9), autoimmune/inflammatory diseases (7/9), and atopy (4/9). CD4 lymphopenia (9/9), lymphopenia (7/9), intermittent eosinophilia (4/9), transient neutropenia (3/9), low immunoglobulin (Ig) M (4/9), and high IgE (4/9) were common. Decreased recent thymic emigrants, naive and central memory T cells, albeit increased effector memory T cells were present. The increase in plasmablasts (p=0.003) and the decrease in switched memory B cells (p=0.022) were significant. Out of a total of 24 patients, cutaneous viral infections (n=20), recurrent pneumonia (n=18), Epstein Barr Virus (EBV)-associated lymphoproliferation (n=11), atopic dermatitis (n=10), autoimmune cytopenia (n=7), and lymphoma (n=6) were frequently seen. Lymphopenia, CD4 lymphopenia, high Ig G, A, and E were the most common laboratory characteristics.

CONCLUSION

The differential diagnosis with AR-hyperimmunoglobulin E syndrome is crucial as atopy and CD4 lymphopenia are prominent in both diseases. Immunoglobulins and antibacterial/antiviral prophylaxis are the mainstays of treatment. Clinicians may use immunomodulatory therapies during inflammatory/autoimmune complications. However, more data is needed to recommend hematopoietic stem cell transplantation (HSCT) as a safe therapy.

Food protein-induced allergic proctocolitis may have distinct phenotypes

BACKGROUND

Food protein-induced allergic proctocolitis (FPIAP) is a non-immunoglobulin E (IgE)-mediated food allergy, which presents with bloody mucoid stool in infants. Although IgE-mediated allergy and sensitizations to offending foods have been described in other non-IgE-mediated food allergies, it has not been investigated in FPIAP.

OBJECTIVE

To investigate IgE-mediated allergy and sensitization to offending foods in FPIAP.

METHODS

Patients (n = 204) were retrospectively recruited and grouped as FPIAP (n = 180; FPIAP with or without the symptoms of IgE-mediated food hypersensitivity to offending and nonoffending foods at initial consultation), FPIAP-IgE sensitization to offending foods (n = 17), and FPIAP-transition to IgE-mediated allergy to offending foods (n = 7). The study was performed in accordance with the protocol approved by the local ethical committee of the Hacettepe University.

RESULTS

The median age of onset of symptoms and the development of tolerance was 2 months (interquartile range [IQR], 1.0-3.0) and 12 months (IQR, 10.0-14.0), respectively, and of the patients with skin prick test or serum specific IgE tests (n = 196), 38 (19.4%) had evidence of IgE sensitization to offending foods at the initial consultation or during follow-up; 17 (8.6%) had IgE sensitization, 7 (3.6%) indicated a transition to IgE-mediated allergy to FPIAP-induced foods. The median age of tolerance development of the FPIAP-transition group (19 months, IQR, 18.0-29.0) was significantly later than that of the FPIAP group (11 months, IQR, 10.0-14.0; P < .001) and the FPIAP-IgE sensitization group (11.0 months, IQR, 9.5-12.0; P < .001). Tolerance was observed within the study period in almost all the patients.

CONCLUSION

Children with FPIAP may have sensitization or develop IgE-mediated allergy over time to offending foods. In addition, IgE sensitization in FPIAP does not have an unfavorable effect on tolerance development; however, the transition to an IgE-mediated phenotype may delay tolerance for a brief time.

Systemic and large local reactions during subcutaneous grass pollen immunotherapy in children

BACKGROUND

Subcutaneous immunotherapy (SCIT) is the allergen-specific curative treatment of allergic rhinitis. Adverse effects, most of which are local, can be observed during the immunotherapy. These adverse effects have been reported more frequently during the pollen season. The purpose of this study was to estimate the rate of local, large local, and systemic reactions during the treatment, to determine the relationship between adverse reactions and the season in which these reactions occur, as well as the risk factors for adverse reactions during the grass pollen-specific SCIT treatment in children.

METHODS

We retrospectively collected and analyzed the data of 261 children who administered grass pollen SCIT between 2008 and 2018.

RESULTS

A total of 261 children (177, 67.8% male), who received grass pollen SCIT, with a mean (±SD) age of 12.0 ± 3.0 years at the initiation of SCIT were enrolled to the study. The number of the patients who experienced local and large local reactions was 109 and 30, respectively. In addition, the number of the patients with systemic reactions was 35. After the 12 284 injections, local reactions occurred in 357 (2.9%), and this was followed by systemic reaction as 55 (0.4%) and large local reactions as 40 (0.3%). Frequency of local (P < .001) and systemic reactions (P = .003) was higher during grass pollen season than out of the grass pollen season. In multivariate analysis, initiation of SCIT during the grass pollen season [OR:7.351, 95%CI:1.532-35.279, P = .013] and experiencing local reactions [OR:4.214, 95%CI:2.159-8.224, P < .001] were independent predictors for the development of large local and systemic reactions.

CONCLUSION

SCIT, in which only mild-to-moderate systemic reactions occurred, is safe for the treatment of allergic rhinitis in children. Our study revealed that previous local reactions and initiation of immunotherapy during the grass pollen season were the predictors for large local and systemic reactions during SCIT in children.

Three patients with glucose-6 phosphatase catalytic subunit 3 deficiency

Objectives Severe congenital neutropenia (SCN) is a primary immunodeficiency (PID) characterized by persistent severe neutropenia, recurrent infections, and oral aphthous lesions. Severe congenital neutropenia is caused by various genetic defects such as ELANE, GFI, HAX-1, JAGN1, SRP54, and glucose-6 phosphatase catalytic subunit 3 (G6PC3) deficiency. Clinical features of the patients with G6PC3 deficiency vary from neutropenia to several systemic features in addition to developmental delay. Case presentation In this report, we presented three unrelated patients diagnosed with G6PC3 deficiency. All these patients had short stature, prominent and superficial vascular tissue, cardiac abnormalities (Atrial septal defect (secondary), mitral valve prolapse with mitral insufficiency, pulmonary hypertension) and lymphopenia. Patient 1 (P1) and 2 (P2) had urogenital abnormalities, P2 and P3 had thrombocytopenia. Conclusions We have shown that lymphopenia and CD4 lymphopenia do not rarely accompany to G6PC3 deficiency. Characteristic facial appearance, systemic manifestions, neutropenia could be the clues for the diagnosis of G6PC3 deficiency.

Phenotypical characterization of tree nuts and peanut allergies in east Mediterranean children

INTRODUCTION/OBJECTIVES

The characteristics of tree nuts (TNs) and peanut (PN) allergies vary in different regions of the world. We aim to identify the characteristics of TNs/PN allergies in Turkish children.

PATIENTS AND METHODS

A total of 227 children [4.8 (3.2-6.8) years] with TN and/or PN allergies were included. The phenotypical features of TNs/PN allergic children and the risk factors for multiple TNs/PN allergies were evaluated.

RESULTS

Allergy to TNs/PN developed at a median age of 12.0 (10.0-18.0) months. The most common TNs/PN responsible for food allergies were the hazelnut (63.9%) and the pistachio (54.6%). Of TNs/PN allergic children, 54.2% experienced reactions with at least two types of . Current ages 6-10 years [OR:2.455, 95% CI:1.255-4.852, p=0.009] and family history of atopy [OR:2.156, 95% CI:1.182-3.932, p=0.012] were the risk factors for multiple TNs/PN allergies. Most of the patients with cashew nut and pistachio allergies exhibited co-sensitization and co-allergy to both of these TNs/PN. Although the rarest TNs/PN allergy was seen with almond, the possibility of allergy to other TNs or PN was highly increased in the patients with almond allergy compared to other TNs/PN.

CONCLUSIONS

Children with TNs/PN allergy living in an East Mediterranean region differ from the counterparts living in Western countries by an earlier age of onset of the TNs/PN allergy symptoms, increasing possibility to have multiple TNs/PN allergy at older ages, and different spectrum of TN/PN allergies (hazelnut followed by pistachio/cashew) that all indicate the consumption habits which are important determinants of TN/PN allergy development.

Frequency of HLA Class I and Class II Alleles in Patients with CVID from Turkey

BACKGROUND

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency. Certain gene loci are pointed out in several studies in CVID patients. Until now, monogenic defects have been identified in only 2-10% of CVID patients; therefore, association of the disease with HLA alleles may be important for elucidating immunological and genetic mechanisms behind CVID. The aim of this study is to investigate the relationship between CVID and HLA alleles.

METHODS

HLA class I/II alleles were analyzed in 65 patients with CVID and alleles that may be related to disease susceptibility were determined by comparing with 300 healthy controls. We also evaluated HLA allele frequencies in CVID patients with gastrointestial system (GIS) involvement and autoimmune manifestations.

RESULTS

When compared with controls, frequencies of B*27, B*35, C*04, and DRB1*04 alleles were significantly different in patients with CVID (p < .05). Frequencies of C*12, DRB1*13, and DRB1*15 alleles were more frequent in controls, indicating protective alleles (p < .05). There was a statistically significant difference for DQ2 and DQ8 haplotypes between patients with GIS involvement and controls.

CONCLUSION

In comparison with literature, distinctive HLA alleles found in our study may originate from the diversity in gene pool between the populations. These data may provide clues for disease susceptibility.

Predictors for late tolerance development in food protein-induced allergic proctocolitis

Background: Food protein-induced allergic proctocolitis (FPIAP) is a non-immunoglobulin E (IgE) mediated food allergy that typically presents with blood-mixed mucoid stool. Objective: To identify the predictors that affect the tolerance development in infants with FPAIP and laboratory as well as clinical differences between patients with early and with late tolerance. Methods: A total of 185 infants with FPIAP were included. The patients were grouped and analyzed based on laboratory tests and clinical characteristics. Results: The median (interquartile range [IQR]) age of onset of symptoms was 2.0 months (1.0-3.0 months). Symptoms began in severe cases in patients (n = 23) at a younger median (IQR) age (1.5 months [0.7-2.0 months]) than the group with nonsevere presentation (median 2.0 months [IQR 1.5-3.0 months]) (p < 0.001). The frequency of neutropenia (<1500/mm³) (p = 0.045) and eosinophilia (450 mm³) (p = 0.018) was increased in severe cases. Concomitant IgE-related food allergy (odds ratio [OR] 3.595 [95% confidence interval {CI}, 1.096-11.788], p = 0.035), non-IgE-mediated multiple food allergy (OR 3.577 [95% CI, 1.595-8.018], p = 0.002), feeding with cow's milk-based formula (at least once during infancy) (OR 2.517 [95% CI, 1.188-5.333], p = 0.016), and late complementary feeding (OR 5.438 [95% CI, 2.693-10.981], p < 0.001) were the predictors for late tolerance development. The estimated optimal cutoff value for introduction of complementary foods for the resolution of allergy was 5.5 months, with 69.4% sensitivity, 74.4% specificity, and an area under the curve of 0.737 (95% CI, 0.626-0.812) (p < 0.001). Conclusion: This study showed that the early introduction of complementary feeding accelerates tolerance development in FPAIP. A longer duration of an elimination diet has no impact on the resolution of allergy. Physicians should consider conservative avoidance measures and earlier introduction of complementary feeding in FPIAP.

Factors predicting anaphylaxis in children with tree nut allergies

Background: Tree nut (TN) allergies are the most common cause of fatal anaphylaxis and generally are ongoing food allergies throughout life. Objective: To investigate the predicting factors for TN anaphylaxis in children. Methods: Children with TN allergy were divided into anaphylactic and nonanaphylactic groups, those who had an anaphylactic reaction with at least one type of TN and those with any type of reaction other than anaphylaxis with TNs, respectively. Children with TN allergies were evaluated for the predictors of anaphylaxis by using multivariate logistic regression analysis. Results: A total of 184 children (ages 4.9 years; 3.2-6.9 years) with TN allergy were included in the study. Of these, 90 experienced an anaphylactic type of reaction on exposure to at least one type of TNs. Comparisons of the two groups showed that concomitant asthma, skin-prick test, specific immunoglobulin E, total immunoglobulin E, and serum basal tryptase (sBT) levels were significantly higher in the anaphylactic group compared with the nonanaphylactic group. In multivariate analysis, female gender (odds ratio [OR] 4.905 [95% confidence interval {CI}, 1.266-19.001], p = 0.021), sBT levels (OR 2.287 [95% CI, 1.431-3.654], p < 0.001), concomitant egg white allergy (OR 4.135 [95% CI, 1.016-16.481], p = 0.048), and concomitant asthma (OR 3.874 [95% CI, 1.109-13.526], p = 0.034) were risk factors for anaphylaxis. The optimal cutoff value for sBT was 2.06 ng/mL, with a sensitivity of 85.9% and a specificity of 69%, as well as an area under the curve 0.810 (95% CI, 0.717-0.903, p < 0.001). The sBT levels of 1.94 ng/mL and 5.30 ng/mL predicted clinical reactivity at 50% and 95% probabilities. Conclusion: Different aspects, including gender, higher mast cell load and/or activation, and a stronger atopic background (e.g., coexisting egg allergy, asthma), contributed to the development of anaphylactic reactions to TNs in children.

Selective loss of function variants in IL6ST cause Hyper-IgE syndrome with distinct impairments of T-cell phenotype and function

Hyper-IgE syndromes comprise a group of inborn errors of immunity. STAT3-deficient hyper-IgE syndrome is characterized by elevated serum IgE levels, recurrent infections and eczema, and characteristic skeletal anomalies. A loss-of-function biallelic mutation in IL6ST encoding the GP130 receptor subunit (p.N404Y) has very recently been identified in a singleton patient (herein referred to as P^N404Y) as a novel etiology of hyper-IgE syndrome. Here, we studied a patient with hyper-IgE syndrome caused by a novel homozygous mutation in IL6ST (p.P498L; patient herein referred to as P^P498L) leading to abrogated GP130 signaling after stimulation with IL-6 and IL-27 in peripheral blood mononuclear cells as well as IL-6 and IL-11 in fibroblasts. Extending the initial identification of selective GP130 deficiency, we aimed to dissect the effects of aberrant cytokine signaling on T-helper cell differentiation in both patients. Our results reveal the importance of IL-6 signaling for the development of CCR6-expressing memory CD4⁺ T cells (including T-helper 17-enriched subsets) and non-conventional CD8⁺T cells which were reduced in both patients. Downstream functional analysis of the GP130 mutants (p.N404Y and p.P498L) have shown differences in response to IL-27, with the p.P498L mutation having a more severe effect that is reflected by reduced T-helper 1 cells in this patient (P^P498L) only. Collectively, our data suggest that characteristic features of GP130-deficient hyper-IgE syndrome phenotype are IL-6 and IL-11 dominated, and indicate selective roles of aberrant IL-6 and IL-27 signaling on the differentiation of T-cell subsets.

Characteristics of drug-induced anaphylaxis in children and adolescents

BACKGROUND

Although data on anaphylaxis in the general population exist for different allergens, there is still lack of detailed etiologic data on drug-induced anaphylaxis (DIA), particularly in children.

OBJECTIVE

To define the etiology of DIA, to determine the accuracy of drug-related anaphylaxis histories, along with the severity and culprit drug associations among individuals <18 years old.

METHODS

Patients with a history of drug hypersensitivity reaction (DHR) referred to our center between January 2012 and February 2016 were included. After the collection of European Network for Drug Allergy questionnaire results, initial skin tests and/or provocation tests were performed for the offending drug.

RESULTS

Among 561 children and adolescents referred due to a suspected DHR, 113 (19%) (median age [interquartile range], 9.6 years [5.4-13.8 years]; 55% boys) had anaphylaxis in their history. At the end of diagnostic evaluation of the patients, 84 (74% of the patients with a history of DIA) were actually hypersensitive to the offending drug. Major drugs that resulted in DIA were antibiotics (33%), nonsteroidal anti-inflammatory drugs (25%), and chemotherapeutics (19%). The majority of patients reported grade 2 (moderate) (45%) and grade 3 (severe) (33%) anaphylactic reactions. A history of systemic illness (41.7 versus 7.1%; p = 0.001), concomitant intake of other drugs regularly (36.9 versus 10.3%; p = 0.007), and the use of chemotherapeutics as the culprit drug (19 versus 0%; p = 0.011) were more frequent, whereas the use of antibiotics was less frequent (34.5 versus 75.9%; p < 0.001) among patients with actual DIA compared to drug tolerant patients.

CONCLUSION

Three-fourths of the children and adolescents referred due to a suspected history of DIA were found to actually be drug hypersensitive. Prediagnosed systemic illness and different types of drugs would have an impact on the risk of DIA; however, atopic disease or a family history of drug hypersensitivity did not have an impact on actual DIA.