Molecular IgE-sensitisation profiles of urban and rural children in South Africa.
Pediatr Allergy Immunol. 2020 Sep 24;:
Authors: Mittermann I, Dzoro S, Gattinger P, Botha M, Basera W, Facey-Thomas HE, Gaunt B, Genuneit J, Gray CL, Hlela C, Flicker S, Lunjani N, Mankahla A, Ramjith J, Valenta R, Levin ME
BACKGROUND: Allergens can act as disease-triggering factors in atopic dermatitis (AD) patients. The aim of the study was to elucidate the molecular IgE-sensitization profile in children with and without AD living in urban and rural areas of South Africa.
METHODS: Specific IgE-reactivity was assessed in 166 Black South African children aged 9-38 months using a comprehensive panel of micro-arrayed allergens. According to clinical characterization children fell in 4 groups, urban AD cases (n=32), urban controls (non-AD, n=40), rural cases (n=49) and rural controls (non-AD, n=45).
RESULTS: IgE-reactivity to at least one of the allergens was detected in 94% of urban and 86% of rural AD children. House dust mite (HDM) (81% urban, 74% rural AD) and animal-derived allergens (50% urban, 31% rural AD) were the most frequently recognized respiratory allergens whereas IgE to pollen allergens was almost absent. Urban AD children showed significantly higher frequency of IgE-reactivity (50%) to mouse lipocalin, Mus m 1, than rural AD children (12%). The most frequently recognized food allergens were from egg (63% urban, 43% rural AD), peanut (31% versus 41%) and soybean (22% versus 27%), whereas milk sensitization was rare. α-gal specific IgE almost exclusively occurred in rural children (AD: 14%, non-AD: 49%).
CONCLUSION: Molecular allergy diagnosis detects frequent IgE sensitization to HDM, animal but not pollen allergens and to egg, peanut and soy, but not milk allergens in African AD children. Urban AD children reacted more often to Mus m 1, whereas α-gal sensitization is more common in rural children likely due to parasite exposure.
PMID: 32969537 [PubMed - as supplied by publisher]
Hypothalamic-pituitary-adrenal axis suppression in asthma: A glucocorticoid receptor polymorphism may protect.
Pediatr Allergy Immunol. 2020 Sep 24;:
Authors: Akurugu WA, Van Heerden CJ, Mulder N, Zöllner EW
BACKGROUND: Asthmatic children on corticosteroids can develop hypothalamic-pituitary-adrenal axis suppression (HPAS). Single nucleotide polymorphisms (SNPs) rs242941 and rs1876828 of the corticotrophin-releasing hormone receptor 1 (CRHR1) gene were associated with lower stimulated cortisol (F) levels, whereas rs41423247 of the glucocorticoid receptor (NR3C1) gene was associated with higher basal F levels. The objective of the current study was to confirm whether these three SNPs are associated with HPAS in asthmatic children.
METHODS: DNA was extracted from saliva obtained from 95 asthmatic children, who had previously undergone basal F and metyrapone testing. Thirty-six children were classified as suppressed. Non-suppressed children were sub-classified according to their post-metyrapone adrenocorticotropin (PMTP ACTH) level into a middle (106-319 pg/ml) and a high (>319 pg/ml) ACTH response group. TaqMan® polymerase chain reaction assays were utilized.
RESULTS: Only rs41423247 was inversely associated with HPAS (OR = 0.27 [95% CI 0.06-0.90]). Its GC genotype was inversely associated with HPAS (log odds = - 1.28, p = 0.021). √PMTP ACTH was associated with CC (effect size = 10.85, p = 0.005) and GC genotypes (effect size = 4.06, p = 0.023). The C allele is inherited as a dominant trait (effect size = -1.31 (95% CI -2.39 - -0.33; p = 0.012). In the high ACTH response group, both genotypes affected the PMTP ACTH (effect sizes 1.41 and 15.46; p-values 0.023 and < 2x10-26 for GC and CC respectively).
CONCLUSIONS: The C allele of rs41423247 was found to be protective against HPAS. CC genotype is associated with the highest PMTP ACTH response.
PMID: 32969491 [PubMed - as supplied by publisher]
Uncovering the Immunological Properties of Isolated Lymphoid Follicles.
Allergy. 2020 Sep 23;:
Authors: Layhadi JA, Shamji MH
The intestine is the largest organ of the body and exhibits the greatest amount and diversity of immune cells. Intestinal homeostasis is tightly controlled by the gut mucosal immune network, which involves gut-associated lymphoid tissues (GALT), secretory IgA (sIgA), mucosal immune cells (i.e. T helper (Th), T follicular (Tfh) and T regulatory (Treg) cells), cytokines, chemokines and commensal bacteria, among others. Unsurprisingly, crosstalk between these cells and their local environment is crucial for the maturation and function of the immune system, and the disruption of this communication often leads to the development of immune disorders.
PMID: 32969038 [PubMed - as supplied by publisher]