Intact FGF23 concentration in healthy infants, children, and adolescents, and diagnostic usefulness in patients with X-linked hypophosphatemic rickets

OBJECTIVE

FGF23 measurement may have a diagnostic role to investigate patients with phosphate disorders. However, normal values for infants, children, and adolescents have not been defined.

METHODS

In a total of 282 (males 145, females 137) healthy infants (n = 30), prepubertal (n = 147), pubertal (n = 59), and postpubertal (n = 46), and in twenty patients with X-linked hypophosphatemic rickets (XLH, age 10.2 ± 5.6 years) serum phosphate (automated analyzer), and plasma intact FGF23 (immunochemiluminescent sandwich assay, DiaSorin) concentrations were measured.

RESULTS

Intact FGF23 concentrations were higher in healthy infants than in prepubertal (P < 0.01) and postpubertal subjects (P < 0.05); pubertal subjects showed higher values (P < 0.05) than postpubertal subjects. Serum phosphate concentrations were higher (P < 0.001) in healthy infants than in prepubertal, pubertal, and postpubertal subjects. Pubertal subjects had higher (P < 0.001) serum phosphate concentrations than postpubertal subjects. Intact FGF23 and serum phosphate concentrations did not differ (P = NS) by sex, age of menarche, and time after menarche. In healthy subjects, there was no correlation between intact FGF23 and serum phosphate concentrations. Intact FGF23 concentrations were higher (P < 0.0001) in patients with XLH than in healthy subjects according to chronological age and pubertal development. In all patients, intact FGF23 concentrations were above 40 pg/mL; intact FGF23 concentrations were inversely correlated with serum phosphate concentrations (r = -0.65; P < 0.01).

CONCLUSION

In healthy subjects, chronological age and puberty were main determinants of intact FGF23 concentrations. Intact FGF23 concentrations may be a useful marker for the early diagnosis of XLH in pediatric patients.

Allergic rhinitis and COVID-19: friends or foes?

Summary

Allergic rhinitis (AR) is a common disease affecting up to 40% of the general population worldwide. In the Coronavirus 2019 (COVID-19) pandemic era, many observational studies analysing the effect of asthma and chronic obstructive pulmonary disease on the risk of developing COVID-19 were conducted, while data on AR are limited.In this paper, we review the risk of developing SARS-Cov-2 infection carried by AR patients, the outcomes of those with COVID-19 disease, and the COVID-19 influence on the allergic and nasal symptoms and the psychological status of AR patients, in both adult and paediatric populations.AR patients seem to be protected from COVID 19 infection. Even if data about the influence of AR on the severity of COVID-19 disease are still not conclusive, it seems that being an AR patient does not increase the risk of poor COVID-19 prognoses. The clinical manifestation of AR can be distinguished by COVID-19 symptoms. Treating AR adequately is also strongly recommended, especially during pandemic.

Retrospective definition of reaction risk in Italian children with peanut, hazelnut and walnut allergy through component-resolved diagnosis

BACKGROUND

Serum IgE evaluation of peanut, hazelnut and walnut allergens through the use of component-resolved diagnosis (CRD) can be more accurate than IgE against whole food to associate with severe or mild reactions.

OBJECTIVES

The aim of the study was to retrospectively define the level of reaction risk in children with peanut, hazelnut and walnut sensitization through the use of CRD.

METHODS

34 patients [n=22 males, 65%; median age eight years, interquartile range (IQR) 5.0-11.0 years] with a reported history of reactions to peanut and/or hazelnut and/or walnut had their serum analyzed for specific IgE (s-IgE) by ImmunoCAP^® and ISAC^® microarray technique.

RESULTS

In children with previous reactions to peanut, the positivity of Arah1 and Arah2 s-IgE was associated with a history of anaphylaxis to such food, while the positivity of Arah8 s-IgE were associated with mild reactions. Regarding hazelnut, the presence of positive Cora9 and, particularly, Cora14 s-IgE was associated with a history of anaphylaxis, while positive Cora1.0401 s-IgE were associated with mild reactions. Concerning walnut, the presence of positive Jug r 1, Jug r 2, Jug r 3 s-IgE was associated with a history of anaphylaxis to such food. ImmmunoCAP^® proved to be more useful in retrospectively defining the risk of hazelnut anaphylaxis, because of the possibility of measuring Cor a14 s-IgE.

CONCLUSIONS

Our data show that the use of CRD in patients with allergy to peanut, hazelnut and walnut could allow for greater accuracy in retrospectively defining the risk of anaphylactic reaction to such foods.

Diagnostic relevance of IgE sensitization profiles to eight recombinant Phleum pratense molecules

BACKGROUND

Grass pollen-related seasonal allergic rhinoconjunctivitis (SARg) is clinically heterogeneous in severity, comorbidities, and response to treatment. The component-resolved diagnostics disclosed also a high heterogeneity at molecular level. Our study aimed at analyzing the characteristics of the IgE sensitization to Phleum pratense molecules and investigating the diagnostic relevance of such molecules in childhood.

METHODS

We examined 1120 children (age 4-18 years) with SARg. Standardized questionnaires on atopy were acquired through informatics platform (AllergyCARD™). Skin prick tests were performed with pollen extracts. Serum IgE to airborne allergens and eight P. pratense molecules (rPhl p 1, rPhl p 2, rPhl p 4, rPhl p 5b, rPhl p 6, rPhl p 7, rPhl p 11, rPhl p 12) were tested by ImmunoCAP FEIA.

RESULTS

The analysis of IgE responses against eight P. pratense molecules showed 87 profiles. According to the number of molecules recognized by IgE, the more complex profiles were characterized by higher serum total IgE, higher grass-specific serum IgE, and higher number and degree of sensitization to pollens. The most frequent IgE sensitization profile was the monomolecular Phl p 1. Sensitization to Phl p 7 was a reliable biomarker of asthma, whereas Phl p 12 of oral allergy syndrome. Sensitization to Phl p 7 was associated with a higher severity of SARg, and complex profiles were associated with longer disease duration.

CONCLUSIONS

In a large pediatric population, the complexity of IgE sensitization profiles against P. pratense molecules is related to high atopic features although useless for predicting the clinical severity. The detection of serum IgE to Phl p 1, Phl p 7, and Phl p 12 can be used as clinical biomarkers of SARg and comorbidities. Further studies in different areas are required to test the impact of different IgE molecular profiles on AIT response.

Awareness of allergic enterocolitis among primary-care paediatricians: A web-based pilot survey

BACKGROUND

Allergic enterocolitis, also known as food protein-induced enterocolitis syndrome (FPIES), is an increasingly reported and potentially severe non-IgE mediated food allergy of the first years of life, which is often misdiagnosed due to its non-specific presenting symptoms and lack of diagnostic guidelines.

OBJECTIVE

We sought to determine the knowledge of clinical, diagnostic and therapeutic features of FPIES among Italian primary-care paediatricians.

METHODS

A 16-question anonymous web-based survey was sent via email to randomly selected primary care paediatricians working in the north of Italy.

RESULTS

There were 194 completed surveys (48.5% response rate). Among respondents, 12.4% declared full understanding of FPIES, 49% limited knowledge, 31.4% had simply heard about FPIES and 7.2% had never heard about it. When presented with clinical anecdotes, 54.1% recognised acute FPIES and 12.9% recognised all chronic FPIES, whereas 10.3% misdiagnosed FPIES as allergic proctocolitis or infantile colic. To diagnose FPIES 55.7% declared to need negative skin prick test or specific-IgE to the trigger food, whereas 56.7% considered necessary a confirmatory oral challenge. Epinephrine was considered the mainstay in treating acute FPIES by 25.8% of respondents. Only 59.8% referred out to an allergist for the long-term reintroduction of the culprit food. Overall, 20.1% reported to care children with FPIES in their practice, with cow's milk formula and fish being the most common triggers; the diagnosis was self-made by the participant in 38.5% of these cases and by an allergist in 48.7%.

CONCLUSION

There is a need for promoting awareness of FPIES to minimise delay in diagnosis and unnecessary diagnostic and therapeutic interventions.

Endotypes of pollen-food syndrome in children with seasonal allergic rhinoconjunctivitis: a molecular classification

BACKGROUND

Pollen-food syndrome (PFS) is heterogeneous with regard to triggers, severity, natural history, comorbidities, and response to treatment. Our study aimed to classify different endotypes of PFS based on IgE sensitization to panallergens.

METHODS

We examined 1271 Italian children (age 4-18 years) with seasonal allergic rhinoconjunctivitis (SAR). Foods triggering PFS were acquired by questionnaire. Skin prick tests were performed with commercial pollen extracts. IgE to panallergens Phl p 12 (profilin), Bet v 1 (PR-10), and Pru p 3 (nsLTP) were tested by ImmunoCAP FEIA. An unsupervised hierarchical agglomerative clustering method was applied within PFS population.

RESULTS

PFS was observed in 300/1271 children (24%). Cluster analysis identified five PFS endotypes linked to panallergen IgE sensitization: (i) cosensitization to ≥2 panallergens ('multi-panallergen PFS'); (ii-iv) sensitization to either profilin, or nsLTP, or PR-10 ('mono-panallergen PFS'); (v) no sensitization to panallergens ('no-panallergen PFS'). These endotypes showed peculiar characteristics: (i) 'multi-panallergen PFS': severe disease with frequent allergic comorbidities and multiple offending foods; (ii) 'profilin PFS': oral allergy syndrome (OAS) triggered by Cucurbitaceae; (iii) 'LTP PFS': living in Southern Italy, OAS triggered by hazelnut and peanut; (iv) 'PR-10 PFS': OAS triggered by Rosaceae; and (v) 'no-panallergen PFS': mild disease and OAS triggered by kiwifruit.

CONCLUSIONS

In a Mediterranean country characterized by multiple pollen exposures, PFS is a complex and frequent complication of childhood SAR, with five distinct endotypes marked by peculiar profiles of IgE sensitization to panallergens. Prospective studies in cohorts of patients with PFS are now required to test whether this novel classification may be useful for diagnostic and therapeutic purposes in the clinical practice.

Immunoglobulin G in IgE-mediated allergy and allergen-specific immunotherapy

Allergen-specific IgG antibodies play a significant role in allergen-specific tolerance, either naturally induced or generated by specific immunotherapy. Nevertheless, the underlying mechanisms are still debated, and allergen-specific IgG determinations are not recommended as a diagnostic tool in IgE-mediated allergy. This review summarizes the latest findings on the immunological and diagnostic role of IgG antibodies in respiratory and food allergies, and during allergen-specific immunotherapy.

Unusual shift from IgE-mediated milk allergy to food protein-induced enterocolitis syndrome

Food protein-induced enterocolitis syndrome (FPIES) is a potentially severe non-IgE-mediated food allergy usually caused by cow's milk or soy, and more rarely by solid foods such as rice, oats, barley, chicken, turkey, egg white, green peas and peanuts. In children with FPIES, the presence of specific IgE antibodies to the causative food, either at presentation or during follow-up, defines an "atypical form" of FPIES characterized by a lesser probability of developing tolerance and a potential progression to typical IgE-mediated hypersensitivity. Although it is uncommon, the shift from non-IgE-mediated milk-protein induced enterocolitis syndrome to IgE-mediated milk allergy has recently been described. We report the first case, to our knowledge, of a shift from IgE-mediated cow's milk allergy to pure non-IgE-mediated FPIES, in a 4-month-old male infant.

Severe anaphylaxis to sheep's milk cheese in a child desensitized to cow's milk through specific oral tolerance induction

Specific oral tolerance induction to food (SOTI) is a new promising treatmentfor persistent IgE-mediatedfood allergy. Our paper reports a case of a 5-year-old girl with cow's milk allergy, who developed severe anaphylaxis after the ingestion of a croissant containing sheep's milk ricotta cheese, even though she had been previously desensitized to cow's milk through SOTI. The sheep's milk specific allergen causing the severe allergic reaction (a derivative of alpha-casein of 54,1kDa) was identified by SDS-PAGE and immunoblotting. We conclude that SOTI is a species-specific procedure and the induced tolerance to cow's milk doesn't necessarily provide protection against milk of other mammals. Therefore, children desensitized to cow's milk through SOTI should strictly avoid the intake of milk of other mammals, until tolerance to those kinds of milk is documented by an oral food challenge.

High prevalence of capillary abnormalities in patients with diabetes and association with retinopathy

AIMS

To investigate the presence of capillary abnormalities in patients with Type 1 and Type 2 diabetes using nailfold videocapillaroscopy and to evaluate the possible correlation with the typical diabetes mellitus microangiopathic lesions detectable in retinal blood vessels.

METHODS

Forty-nine patients with diabetes mellitus (21 with Type 1 and 28 with Type 2 diabetes) and 39 subjects without diabetes were enrolled. Ophthalmoscopy was performed on all patients and was followed by retinal fluorangiography when indicated. Subjects underwent nailfold videocapillaroscopy to evaluate density, length, morphology and distribution of capillary loops, presence of ectasia, microbleedings and blood flow modifications. A score (0-3) was applied to quantify features of nailfold videocapillaroscopy.

RESULTS

Subjects with diabetes showed a significantly increased (P = 0.0001) nailfold videocapillaroscopy score and significantly greater alterations of capillary length (P = 0.004), distribution (P = 0.02), morphology (P = 0.0001), density (P = 0.02) and flux (P = 0.004), as well as presence of ectasic loops (P = 0.009) and of oedema/exudates (P = 0.03) compared with control subjects. In addition, patients with Type 1 diabetes had a significantly higher score (P = 0.01) and greater morphologic alterations (P = 0.03) compared with subjects with Type 2 diabetes. Nailfold videocapillaroscopy score also showed a positive correlation with retinopathy, detected by both ophthalmoscopy (P = 0.0001) and fluorangiography (P = 0.02), independently from sex, age, type of diabetes and all potential confounders. Moreover, nailfold videocapillaroscopy was capable of identifying alterations in almost 50% of patients with diabetes without retinopathy.

CONCLUSIONS

A high prevalence of nailfold capillary changes is detected in patients with diabetes using nailfold videocapillaroscopy. These abnormalities tightly correlate with retinal damage and may be expression of a generalized microvessel involvement in both Type 1 and Type 2 diabetes.