Are the most common food allergens in an Iranian atopic population compatible with worldwide reports? A systemic review and meta-analysis with molecular classification of frequent allergens

Background: Undesirable immunological responses to alimentary allergens are one of the hallmarks of atopic diseases. The prevalence of common food allergens is dissimilar among different communities with distinct nutritional habits and genetic characteristics. Aim: To assess the prevalence of the most common food allergens in Iran, using different reliable studies. Methods: All studies determining sensitization to common food allergens that were indexed in PubMed, Web of Science, Google Scholar, ProQuest, Scopus, Iran Medex, and Magiran were included in this review. To perform a meta-analysis, STATA 14 and metaprop command was applied. A logistic-normal random-effects model with Freeman-Tukey double arcsin transformation was applied to combine the findings of different studies and evaluate their heterogeneity. Random pooled estimate (ES) (pooled prevalence), 95% confidence interval (95% CI) and p-value were determined. Results: A total of 23 studies with data from a total of 6126 children and adults met the inclusion criteria for entering this meta-analysis. The respective pooled prevalence of a positive family history of allergy and positive specific IgE to at least one food allergen was 72% (95% CI: 66-77%) and 41% (95% CI: 33-49%), respectively. Our results in the total population revealed that allergic sensitization to egg yolk, cow’s milk (CM), egg white, and wheat were 25% (95% CI: 16%-35%), 24% (95% CI: 19-29%), 23% (95% CI: 18%-28%), and 9% (95% CI: 6%-14%), respectively. Walnut, peanut, and soybean sensitization was detected in 23% (95% CI: 17%-31%), 23% (95% CI: 13%-33%), and 20% (95% CI: 12%-28%) of patients, respectively. Random pooled ES for sensitization to shrimp and fish was 32% (95% CI: 21-45%) and 12% (95% CI: 6-20%), respectively. The result of analysis in different age groups revealed that allergic sensitization to milk, egg white, and egg yolk declines in higher age groups; while shrimp sensitization increases in older patients. In patients with atopic dermatitis, egg white was the most frequent food allergen 29% (95% CI = 18-42%); while wheat was the least frequent 8% (95% CI = 4-14%). Conclusions: Considering the prevalence of different food allergens, the results of the current meta-analysis revealed that egg yolk and cow’s milk had the second and third rate after shrimp, respectively. The high prevalence of sensitization to shrimp may be attributed to its high consumption in coastal areas and/or cross-reactivity of shrimp with some aeroallergens such as mites

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Wheat anaphylaxis due to skin contact in an exclusively breastfed 2.5-month-old infant

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Clinical, laboratory, and molecular findings for 63 patients with severe combined immunodeficiency: a decade's experience

Introduction: Severe combined immunodeficiency (SCID) is a life-threatening pediatric disease. We report on the clinical evaluation, immunological assessment, molecular analysis, and outcomes of SCID patients in a tertiary referral center in Iran. Methods: From January 2006 to December 2015, we performed a prospective cohort study in which initial screening and advanced immunological tests were carried out on patients suspected of having SCID. Genetic analysis was also performed to confirm the diagnosis. Results: A total of 63 patients were diagnosed with SCID (43 male [68.3%]). The median age at onset and diagnosis and diagnostic delay were 40 and 110 and 60 days respectively. A total of 49 patients (77.8%) had a history of BCG vaccination, and of these, onethird experienced BCG-associated complications. The most common clinical manifestations were pneumonia, recurrent oral candidiasis, chronic diarrhea, and failure to thrive. Of the thirteen patients who underwent hematopoietic stem cell transplantation, 8 survived and 5 died before they could receive the transplant. Most patients (34.9%) were classified as having T-B-NK+ SCID and had a mutation in the RAG2 or RAG1 gene. Conclusion: Autosomal recessive SCID is the most common type in Iranian patients. Providing high-quality training to physicians and patients’ families to reduce the diagnostic delay should be prioritized. It is also important to raise awareness of live vaccination and to expand stem cell donor registries to speed up the transplantation process (AU)

Introducción: La inmunodeficiencia combinada severa (SCID) es una grave enfermedad pediátrica que puede comprometer la vida del paciente. El artículo recoge la evaluación clínica e inmunológica, el análisis molecular y la supervivencia de los pacientes con SCID atendidos en un hospital de referencia de Irán. Métodos: Desde enero de 2006 a diciembre de 2015, se realizó un estudio prospectivo en los pacientes con SCID en el que se realizó un screening inicial junto a diferentes análisis inmunológicos. Se realizó un análisis genético para confirmar el diagnóstico. Resultados: Sesenta y tres pacientes fueron diagnosticados de SCID, cuarenta y tres (63,8%) de los mismos eran varones. La mediana de la edad de inicio de la enfermedad, diagnóstico y retraso en su diagnóstico, fueron de 40, 110 y 60 días respectivamente. Cuarenta y nueve pacientes (77,8%) recibieron vacunación con BCG y un tercio de los mismos presentó complicaciones como consecuencia de la misma. Las manifestaciones clínicas más frecuentes de estos pacientes fueron: neumonía, candidiasis oral recidivante, diarrea crónica y retraso en el crecimiento. Ocho de los treces pacientes que recibieron trasplante de progenitores hematopoyéticos, lograron sobrevivir. Los restantes pacientes fallecieron antes de poder recibir dicho trasplante. El 34,9% de los pacientes tuvieron T-B-NK+ SCID y la mayoría de los pacientes eran portadores de mutaciones en los genes RAG2 o RAG1. Conclusión: La variante autosómica recesiva de la SCID es la forma más común en los pacientes iraníes. Se debe considerar prioritario proporcionar una formación adecuada a los médicos y las familias para reducir el retraso en el diagnóstico. Es igualmente importante concienciar para evitar la vacunación con gérmenes vivos y expandir los registros de donantes de células madre para agilizar el trasplante de estos pacientes (AU)