COVID-19 and abdominal pain: a pediatric case report and a point of view in pediatric emergency medicine.

COVID-19 is to date a global pandemic that can affect all age groups; gastrointestinal symptoms are quite common in patients with COVID-19 and a new clinical entity defined as Multisystem Inflammatory Syndrome in Children (MIS-C) has been described in children and adolescents previously affected by COVID-19. Presenting symptoms of this new disease include high fever and severe abdominal pain that can mimic more common causes of abdominal pain; patients can rapidly deteriorate presenting severe cardiac dysfunction and multiorgan failure. Some fatalities due to this serious illness have been reported. We describe the case of a ten-year-old patient presenting with persistent high fever associated with continuous and worsening abdominal pain. Various hypotheses were performed during his diagnostic workup and an initial appendectomy was performed in the suspect of acute appendicitis. As his clinical picture deteriorated, the child was subsequently diagnosed and successfully treated as a case of MIS-C. The objective of this case report and brief review of abdominal pain in children throughout the age groups is to provide the emergency pediatrician with updated suggestions in diagnosing abdominal pain in children during the COVID-19 pandemic.

The skin prick test.

The skin prick test (SPT) is the most common test for the diagnosis of allergy. SPT is performed by pricking the skin, usually in the volar surface of the forearm, with a lancet through a drop of an allergen extract and is usually the first choice test in the diagnostic workup for allergic diseases because of its reliability, safety, convenience and low cost. SPT is minimally invasive and has the advantage of testing multiple allergens in 15 to 20 min. In children, SPT is far less disturbing than venipuncture and is used to obtain a sample of serum to measure specific IgE through in vitro tests. There is a good correlation (about 85-95%) between SPT and in vitro tests. Globally, SPT is an excellent diagnostic tool, with a positive predictive value ranging from 95-100%. SPTs can identify sensitivity to inhalants, foods, some drugs, occupational allergens, hymenoptera venom and latex. However, the relevance of such sensitivity to allergens should always be carefully interpreted in the light of the clinical history, because sensitization and clinical allergy may not coincide. In regards to safety, though the reports of systemic reactions, and particularly anaphylaxis, are very rare, in vitro IgE tests should be preferred if previous severe reactions emerge from the patient’s clinical history.

Is lingual tonsil a preferential target for processing sublingually administered materials?

The oral cavity is a site of pivotal importance in the immune response to foreign antigens, ensuring tolerance induction to harmless agents but reactivity to potentially noxious antigens. Tolerance or reactivity are driven by a number of secondary lymphoid organs, all belonging to the Waldeyer ring, that include adenoids, tubal, palatine and lingual tonsils. Waldeyer's ring tissues were acknowledged as implicated not only in the adaptive immune system but also in the innate immune system modulation, involving the toll-like receptors. In particular, findings from animal studies suggested that the lingual tonsil can be considered as an inductive site sampling and processing antigens to stimulate naïve T and B lymphocytes. According to a recent study showing that immunologically active or inactive materials placed under the tongue of allergic subjects rapidly reach the lingual tonsil, such a role seems likely also in humans, and warrants to be investigated in-depth for possible applications in medical treatments.

Association between pollen exposure and nasal cytokines in grass pollen-allergic children

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The evolution of allergen immunotherapy from empirical desensitization to immunological treatment.

In its century-long history, allergen immunotherapy (AIT), has shown continuous evolution in terms of the materials and the treatment schedules used, the adequate duration, and the mechanisms of action underlying its clinical efficacy. The passage from the empirical phase of AIT to the era of evidence-based medicine (EBM) was associated with achievement of the highest levels of evidence. This regarded both forms of AIT currently used, represented by subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT). In particular, SLIT tablet preparations of pharmaceutical quality provided physicians and patients a treatment whose efficacy had been confirmed with the highest level of scientific evidence and improved the credibility of AIT for the entire medical field. However, further advances are needed for AIT in terms of optimal patient selection and the required dosage, as well as the quality and composition of the allergen extracts, factors favouring compliance, and the most appropriate duration capable of maintaining the clinical benefit over time.

Allergen immunotherapy may exert an extra-anti-allergic activity in children.

Allergic patients frequently suffer from infections. Allergen immunotherapy (AIT) usually improves respiratory symptoms, mainly in allergic rhinitis (AR). This study was aimed at evaluating the possible impact of AIT on extra-allergic outcomes in a cohort of Italian children with respiratory allergy patients. The study was performed on 77 children (43 males, mean age 10.5 years) with AR. The kind and the number of prescribed allergen extracts, type of diagnosis, severity of symptoms, and use of drugs were evaluated at baseline and after 2 year AIT. Globally 40 patients were treated with AIT, the remaining 37 children served as control. AIT-treated children had lower symptoms, drug use, and less severe extra-allergic surrogate markers of infection in comparison with children untreated with AIT. In conclusion, this study provides the first evidence that 2-year SLIT is able of exerting an adjunctive anti-allergic activity in AR children.

Which allergen extract for grass pollen immunotherapy? An in vitro study.

BACKGROUND: Grass pollen is a major cause of allergy throughout the world. The only treatment targeting the causes and not only the symptoms of allergy is specific immunotherapy (IT). A number of controlled trials demonstrated the efficacy of IT in grass pollen allergic subjects, most using extracts of multiple grasses but some using extracts of a single grass. The optimal grass extract for IT has not yet been established. METHODS: This study is aimed at investigating the IgE-binding pattern in sera from IT-naïve patients from central Italy with allergic rhinitis and/or asthma caused by grass pollen. A 5-grass extract was used (containing Dactylis glomerata, Poa pratensis, Lolium perenne, Antoxanthum odoratum and Phleum pratense) and compared to Phleum pratense alone, which is the most frequently used single grass extract, by the RAST-inhibition technique. RESULTS: The 5-grass extract showed, by RAST-inhibition, a significantly higher binding compared to the Phleum pratense extract for Antoxanthum odoratum and Poa pratensis, while the two extracts for immunotherapy showed similar binding affinity for Phleum pratense and the non-Pooideae grass, Cynodon dactylon. CONCLUSIONS: The use of a mixed-grass pollen extract seems to be the optimal choice when applying specific IT in grass pollen-allergic subjects from the Mediterranean area.

Lack of inflammatory cells in the oral mucosa of subjects undergoing sublingual immunotherapy.

The cells involved in allergic inflammation, such as mast cells, basophils, and eosinophils, have been thoroughly studied in the nose, the lungs and the skin, demonstrating an evident increase in response to the introduction of the specific allergen, while little is known in the mucosal system and particularly in the oral mucosa. We investigated such tissue by using the model of sublingual immunotherapy (SLIT), by which high doses of the specific allergen enter the mouth. Oral biopsies were carried out on seven subjects allergic to grass pollen and treated with SLIT by a grass extract. In biopsies carried out before SLIT there was a very low number of mast cells and eosinophils both in the epithelium and subepithelium layers, and insignificant changes were detected after SLIT. These findings show the lack of allergic inflammation in the oral mucosa upon contact with the specific allergen and confirm the role of the mouth as a tolerogenic site, which is conceivable considering the different attitude of the mouth, where the antigens transit to undergo digestion, in respect to the airways or the skin, where the antigen absorption is potentially dangerous.

Allergy and the gastrointestinal system.

The gastrointestinal system plays a central role in immune system homeostasis. It is the main route of contact with the external environment and is overloaded every day with external stimuli, sometimes dangerous as pathogens (bacteria, protozoa, fungi, viruses) or toxic substances, in other cases very useful as food or commensal flora. The crucial position of the gastrointestinal system is testified by the huge amount of immune cells that reside within it. Indeed, gut-associated lymphoid tissue (GALT) is the prominent part of mucosal-associated lymphoid tissue (MALT) and represents almost 70% of the entire immune system; moreover, about 80% of plasma cells [mainly immunoglobulin A (IgA)-bearing cells] reside in GALT. GALT interacts strictly with gastrointestinal functions in a dynamic manner; for instance, by increasing intestinal permeability in replay to particular stimulations, or orientating the immune response towards luminal content, allowing either tolerance or elimination/degradation of luminal antigens, or sometimes provoking damage to the intestinal mucosa, such as in coeliac disease or food allergy. The immune mechanisms implicated in these actions are very complex and belong to both innate and adaptive immunity; innate immunity supplies an immediate non-specific response that is indispensable before specific adaptive immunity, which needs 7-10 days to be efficacious, takes place. The results of their interactions depend upon different contexts in which contact with external agents occurs and may change according to different genetic settings of the hosts.

Comparison between continuous or intermittent schedules of sublingual immunotherapy for house dust mites: effects on compliance, patients satisfaction, quality of life and safety.

Sublingual immunotherapy (SLIT) is indicated in the treatment of allergic rhinitis and asthma. However, an issue scantly investigated is the patients satisfaction and the consequent compliance. This study is aimed at evaluating the possible differences of SLIT administered continuously or intermittently on several parameters: clinical efficacy, Quality of Life (QoL), satisfaction, compliance and safety. Forty allergic patients were treated for 12 months. The treatment was carried out by sublingual administration of an allergen extract of a 50% mixture of Dermatophagoides pteronyssinus and Dermatophagoides farinae at 10 and 300 IR/ml concentrations. Patients were randomly treated continuously or intermittently (i.e. 2 month treatment alternate to 2 month suspension). Both schedules were significantly effective in reducing allergic symptoms and improving QoL. Compliance and satisfaction were good in both groups. Local and systemic reactions were few, self-resolving, and mild in both schedules. Intergroup analysis did not reveal any difference between the two groups regarding these parameters. In conclusion, this preliminary study provides the evidence that also intermittent SLIT is as effective and safe as traditional continuous treatment. In addition, compliance and satisfaction are super-imposable in the two groups.

Endothelial cells and normal breast epithelial cells enhance invasion of breast carcinoma cells by CXCR-4-dependent up-regulation of urokinase-type plasminogen activator receptor (uPAR, CD87) expression.

Here we show the increase of invasion of three breast cancer cell lines (8701-BC, MDA-MB-231 and SKBR3) upon long-term co-incubation with culture medium of normal microvascular endothelial cells (MVEC) and normal breast epithelial cells (HB2). The enhancement of invasion relied on the interaction of microvascular endothelial cell and normal breast epithelial cell CXCL12 (SDF1) chemokine, whose expression by breast cancer cells was very low, with the cognate CXCR4 receptor of malignant cells, which resulted in over-expression of the urokinase-type plasminogen activator receptor (uPAR) on their surfaces. uPAR over-expression, showed by RT-PCR and Western blotting, was paralleled by increased urokinase-type plasminogen activator (uPA) partitioning on the cell surface with respect to the fluid phase, as demonstrated by zymography. Long-term interaction of SDF1 with CXCR4 stimulated sustained activation of JNK phosphorylation. Blocking antibodies to CXCR4 were able to block the endothelial/epithelial cell-dependent enhancement of invasion, as well as to inhibit SDF1-CXCR4-dependent JNK phosphorylation and uPAR over-expression of malignant cells. We suggest that acquisition of the angiogenic phenotype by breast cancer cells triggers an amplification loop, in which endothelial cells and normal breast epithelial cells of the tumour cooperate to provide facilitated routes to cell invasion and metastasis and to enhance the aggressive phenotype of cancer cells.

Lower airway inflammation before and after house dust mite nasal challenge: an age and allergen exposure-related phenomenon.

BACKGROUND: Upper and lower airways allergic disease is currently considered unitarily. Allergic inflammation in one site can extend to other sites of the respiratory tract. OBJECTIVE: To evaluate bronchial inflammation before and after allergen-specific nasal challenge (ASNC) in rhinitic and asthmatic children, considering the different levels of allergen exposure, i.e. summer (low) and winter (high). METHODS: Fourteen children with rhinitis and 15 with rhinitis and asthma, all monosensitized to mites and 10 healthy controls were studied. Nasal IgE were measured before ASNC in summer and in winter season. Nasal clinical score, eosinophil cationic protein (ECP), nasal tryptase, bronchial clinical score, FEV(1), PEF, sputum ECP, sputum tryptase and exhaled nitric oxide (eNO) were evaluated before and after ASNC in summer and winter season. RESULTS: Nasal scores significantly increased after ASNC in rhinitic and asthmatic children in both seasons. Nasal IgE were significantly higher in summer compared to winter. Bronchial symptoms, FEV(1) and PEF showed no mean differences in rhinitic and asthmatic children after ASNC, with an increase of bronchial symptoms and a decrease of FEV(1) and PEF occurring in 3/15 asthmatic children. In both groups nasal tryptase and ECP after ASNC significantly increased in summer and winter, while sputum tryptase was undetectable before or after ASNC in both groups. Sputum ECP and eNO at baseline were significantly higher in patients than in controls (summer P=0.002, winter P=0.001). Sputum ECP significantly increased after ASNC in 3/15 asthmatics in summer and in 11/15 in winter, as well as in 3/14 rhinitics in summer and in 4/14 in winter. eNO significantly increased after ASNC in 3/15 asthmatics in summer and in 10/15 in winter, and in 1/14 rhinitics in summer and in 4/14 in winter. A significant median increase of sputum ECP (P=0.0007) and eNO (P=0.0012) after ASNC in asthmatic and of eNO (P=0.013) in rhinitic children was also found in winter. CONCLUSIONS: Basal sputum ECP and eNO values, significantly higher before ASNC in rhinitic patients compared to control subjects, confirm the inflammatory link of upper and lower airways. The more frequent detection of inflammatory changes induced by ASNC in winter suggests that allergen exposure favours the transfer of nasal inflammation to lower airways.

Comparison of efficacy, safety and immunologic effects of subcutaneous and sublingual immunotherapy in birch pollinosis: a randomized study.

BACKGROUND: Sublingual immunotherapy (SLIT) is currently considered a valid option to subcutaneous immunotherapy (SCIT), but only a few studies made a direct comparison of their effectiveness. The aim of this study was to compare the clinical and immunological effects of SCIT and SLIT in pollinosis induced by Betulaceae. METHODS: Forty-seven adult patients were randomized to receive SCIT or SLIT, performed by Betulaceae (alder, birch, and hazel) extracts from Stallergenes (Antony, France) standardized in index of reactivity (IR) with the treatment schedules proposed by the producer. The clinical effects were established by symptom-medication scores recorded during the month of March. Side effects were reported directly by the physicians for SCIT and were registered in diary cards by the patients for SLIT. Immunologic evaluation was done by measuring specific IgE and IgG4 to Bet v 1. RESULTS: Thirty-four patients (19 for SCIT and 15 for SLIT) completed the registration of symptoms and drug consumption during pollen period of Betulaceae. Mean cumulative doses of respectively 50.65 IR by SCIT and 4653.1 IR by SLIT were administered, with a SLIT/SCIT ratio of 92. There was no significant difference in mean symptom-medication score between SCIT and SLIT. Systemic reactions occurred in 16% of SCIT treated but in none of SLIT treated. As to immunologic evaluation, Bet v 1 specific IgE did not rise after the pollen season in SCIT treated, while increased non significantly in SLIT treated. Bet v 1 specific IgG4 increased in both treatment, buy only the increase with SCIT was significant (p = 0.001). CONCLUSION: SLIT and SCIT with a ratio of about 100 are equally effective in controlling rhinoconjunctivitis caused by tree pollen allergy. SLIT is safer than SCIT, but does not show the same immunologic effects on serum specific IgE and lgG4 antibodies.

Sublingual immunotherapy: from safety to mechanism of action.

Allergen specific immunotherapy is an important option for the treatment of respiratory allergy and its clinical efficacy has been clearly demonstrated by several studies. However, the injective route of administration and the possibility of severe side effects has limited its use in children and led to the introduction of new forms of administration. Sublingual immunotherapy (SLIT) has proven to be an effective and safe treatment for respiratory allergy. However, its mechanism of action is still debated. Pharmacokinetic studies showed that, differently from nasal mucosa, allergen extracts administered by SLIT are not immediately adsorbed but are long retained before being drained to local lymph nodes. This difference may be responsible of the absence of severe side effects and instead of short-lasting local symptoms. Studies by biopsies of the oral mucosa should greatly help in defining the presence and the role of cells involved in the mechanisms of oral tolerance.

Dose dependence of efficacy but not of safety in sublingual immunotherapy.

Sublingual immunotherapy (SLIT) currently represents, as indicated by meta-analysis of its efficacy and safety, a valid option to the generally used traditional subcutaneous immunotherapy (SCIT) for treating respiratory allergy. Regarding efficacy, recent studies demonstrated that, similar to what has already been observed in SCIT as well as in experimental and clinical studies about the magnitudo of allergen exposure, the effectiveness on both clinical symptoms and immunologic changes depends on the amount of allergen administered during treatment. In addition, in vitro studies addressed with the role of dendritic cells, currently considered to be of pivotal importance in orienting toward tolerance the immune response to allergens, showed that the internalisation of allergen molecules, which is followed by tolerogenic presentation to T cells, depends on the amount of allergen. However, such dose dependence is not apparent concerning the safety. In fact, the comparison of studies respectively conducted with high and low allergen doses did not show differences in the rate of systemic reactions, which in any case never had the presentation of anaphylaxis, and instead a significant difference in the rate of local reactions, following the oral and gastrointestinal contact with the allergen extract, in favour of high dose studies.

Sublingual reactivity to rBET V1 and rPHL P1 in patients with oral allergy syndrome.

Oral Allergy Syndrome (OAS) in patients with pollen-induced rhinoconjunctivitis is caused by specific IgE recognizing cross-reacting epitopes of fruits and plants, which were clearly shown in vitro, but failed to be demonstrated in vivo by cross-challenges in the target organs. Considering the hypothesis of degradation of such epitopes in natural extracts, challenges with recombinant pollen allergens were done to evaluate the reactivity of the oral mucosa in OAS patients. Seventeen patients with OAS and rhinitis from birch (10) and grass pollen (7) and 10 non-atopic controls were studied by skin prick tests (SPT), allergen specific nasal challenges (ASNC) and allergen specific sublingual challenges (ASSC) with birch and timothy extracts and with rBet v1 and rPhl p1 at increasing concentrations from 1 to 1000 mcg/ml. None of the healthy subjects in the control group had any positive test for birch and timothy extracts or for recombinant allergens. In the OAS group the following results were observed: SPTs with recombinant allergens were positive in all patients, mostly at 10 mcg/ml concentration; ASNC with rBet v1 were positive in all patients, mostly at 100 mcg/ml; ASSC with natural pollen extracts were positive in only 2 of 17 patients, but in 15 of 17 with rBet v1 and rPhl p1, mostly at 500 mcg/ml and 1000 mcg/ml. ASSC with rBet v1 and rPhl p1 were positive with a mean concentration of 677 and 533 mcg/ml, respectively. The results of sublingual challenges with rBet v1 and rPhl p1 showed the in vivo cross-reactivity between pollens and foods in patients with OAS, but high concentrations of the recombinant allergens were needed to reproduce oral symptoms, thus explaining the failure of challenges performed with natural extracts, which have concentrations of major allergens lower than 50 mcg/ml. This indicates that sublingual mucosa is much less reactive to allergens than other surfaces, such as skin and nasal mucosa, probably because of its anatomic and immunologic peculiarity.

Three-year follow-up of clinical and inflammation parameters in children monosensitized to mites undergoing sub-lingual immunotherapy.

Parallel follow-up of clinical and inflammatory markers during sub-lingual immunotherapy (SLIT) is highly beneficial. Twenty-four children (age 4-16) monosensitized to house dust mite were randomized to receive either active or placebo SLIT for 1 yr in a double-blind placebo controlled design (Marcucci et al., Allergy 2003: 58: 657-62). Thereafter, for 2 yr they all received active treatment. Symptom scores for rhinitis, asthma, and drug usage were daily recorded. Eosinophil cationic protein (ECP) and tryptase in sputum and nasal secretions, serum and nasal mite-specific immunoglobulin E (IgE) were recorded before treatment and at 10-12 months intervals. Nasal ECP and nasal tryptase after specific nasal provocation tests were significantly reduced as compared to baseline values (p = 0.0043 and 0.0195, respectively) in the third year of active treatment. None of the other inflammatory parameters was increased. In placebo treated patients all these parameters tended to decrease only after switching to active treatment. Clinical scores did not improve in treated vs. placebo patients in the double-blind placebo-controlled phase of the study. In both cohorts a clinical benefit was observed as intra-group score reduction as compared to baseline. A significant difference was reached in patients treated for 2 yr for rhinitis and asthma (p = 0.0009 and 0.0019, respectively) but not for drug usage and in patients treated for 3 yr for rhinitis, asthma, and drug usage (p = 0.0105, 0.0048, and 0.02, respectively). SLIT in children monosensitized to mites reverted the spontaneous increase in nasal IgE and in local parameters of allergic inflammation. These outcomes were followed by a consolidated clinical improvement in the second and third year of treatment.