ILC2s: Unraveling the innate immune orchestrators in allergic inflammation

The prevalence rate of allergic diseases including asthma, atopic rhinitis (AR) and atopic dermatitis (AD) has been significantly increasing in recent decades due to environmental changes and social developments. With the study of innate lymphoid cells, the crucial role played by type 2 innate lymphoid cells (ILC2s) have been progressively unveiled in allergic diseases. ILC2s, which are a subset of innate lymphocytes initiate allergic responses. They respond swiftly during the onset of allergic reactions and produce type 2 cytokines, working in conjunction with T helper type 2 (Th2) cells to induce and sustain type 2 immune responses. The role of ILC2s represents an intriguing frontier in immunology; however, the intricate immune mechanisms of ILC2s in allergic responses remain relatively poorly understood. To gain a comphrehensive understanding of the research progress of ILC2, we summarize recent advances in ILC2s biology in pathologic allergic inflammation to inspire novel approaches for managing allergic diseases.

Translational Selenium Nanoparticles to Attenuate Allergic Dermatitis through Nrf2-Keap1-Driven Activation of Selenoproteins

Easy recurrence and strong treatment side effects significantly limit the clinical treatment of allergic dermatitis. The human trace element selenium (Se) plays essential roles in redox regulation through incorporation into selenoproteins in the form of 21st necessary amino acid selenocysteine, to participates in the pathogenesis and intervention of chronic inflammatory diseases. Therefore, based on the safe and elemental properties of Se, we construct a facile-synthesis strategy for antiallergic selenium nanoparticles (LET-SeNPs), and scale up the production by employing a spray drying method with lactose (Lac-LET-SeNPs) or maltodextrin (Mal-LET-SeNPs) as encapsulation agents realizing larger scale production and a longer storage time. As expected, these as-prepared LET-SeNPs could effectively activate the Nrf2-Keap1 signaling pathway to enhance the expression of antioxidative selenoprotein at mRNA and protein levels, then inhibit mast cell activation to achieve efficient antiallergic activity. Interestingly, LET-SeNPs undergo metabolism to seleno-amino acids to promote biosynthesis of selenoproteins, which could suppress ROS-induced cyclooxygenase-2 (COX-2) and MAPKs activation to suppress the release of histamine and inflammatory cytokines. Allergic mouse and Macaca fascicularis models further confirm that LET-SeNPs could increase the Se content and selenoprotein expression in the skin, decrease mast cells activation and inflammatory cells infiltration, and finally exhibit the high therapeutic effects on allergic dermatitis. Taken together, this study not only constructs facile large-scale synthesis of translational Se nanomedicine to break through the bottleneck problem of nanomaterials but also sheds light on its application in the intervention and treatment of allergies.

Laboratory safety evaluation of lokivetmab, a canine anti-interleukin-31 monoclonal antibody, in dogs

Lokivetmab (Cytopoint®, Zoetis) is a canine monoclonal antibody that specifically binds and neutralizes interleukin (IL)-31. Lokivetmab is approved for use in dogs for the treatment of atopic dermatitis (AD) and allergic dermatitis. The laboratory safety of lokivetmab was evaluated in 2 studies by adapting the science-based, case-by-case approach used for preclinical and early clinical safety evaluation of human biopharmaceuticals. The main objectives were to demonstrate the safety of lokivetmab in healthy laboratory Beagle dogs by using integrated clinical, morphologic, and functional evaluations. In Study 1, dogs were treated s.c. with saline or lokivetmab at 3.3 mg/kg (1X, label dose) or 10 mg/kg (3X intended dose) for 7 consecutive monthly doses, with terminal pathology and histology assessments. In Study 2, the functional immune response was demonstrated in naïve dogs using the T-cell dependent antibody response (TDAR) test with 2 different dose levels of unadjuvanted keyhole limpet hemocyanin (KLH) as the model immunogen. The primary endpoint was anti-KLH IgG antibody titer, and secondary endpoints were ex vivo IL-2 enzyme-linked immunospot (ELISpot) and peripheral blood mononuclear cell lymphoproliferation assays. Both studies included monitoring general health, periodic veterinary clinical evaluations, serial clinical pathology and toxicokinetics, and monitoring for anti-drug antibodies. In both studies, the health of dogs receiving lokivetmab was similar to controls, with no treatment-related changes uncovered. Extensive pathology evaluations of immune tissues (Study 1) revealed no lokivetmab-related morphologic changes, and in dogs treated at 10 mg/kg lokivetmab, immunization with the model antigen KLH did not impair the functional antibody or T-cell recall responses. There were no immunogenicity-related or hypersensitivity-related responses observed in either study. These studies in healthy laboratory dogs showed that lokivetmab was well-tolerated, did not produce any treatment-related effects, and had no effect on immune system morphology or its functional response. These studies also demonstrated the utility of a science-based case-by-case approach to the safety evaluation of a veterinary biopharmaceutical product.

Immune Metabolism in TH2 Responses: New Opportunities to Improve Allergy Treatment - Disease-Specific Findings (Part 1)

PURPOSE OF REVIEW

Recent high-level publications have shown an intricate connection between immune effector function and the metabolic state of the respective cells. In the last years, studies have begun analyzing the metabolic changes associated with allergies. As the first part of a two-article series, this review will briefly summarize the basics of immune metabolism and then focus on the recently published studies on metabolic changes observed in allergic patients.

RECENT FINDINGS

In the last 3 years, immune-metabolic research in allergology had a clear focus on asthma with some studies also reporting findings in food allergy and atopic dermatitis. Current results suggest asthma to be associated with a shift in cellular metabolism towards increased aerobic glycolysis (Warburg metabolism), while also displaying substantial changes in fatty acid- and amino acid metabolism (depending on investigated patient collective, asthma phenotype, and disease severity). Understanding immune-metabolic changes in allergies will allow us to (I) better understand allergic disease pathology and (II) modulate immune-metabolic pathways to improve allergy treatment.

Acceptance of oclacitinib maleate (Apoquel®) chewable tablets in client-owned dogs with allergic and atopic dermatitis

Background

The oral acceptance of oclacitinib maleate (Apoquel®) chewable tablets administered twice daily for 7 days at the labeled dose range of 0.4–0.6 mg/kg was evaluated in 121 dogs treated at ten general practice veterinary clinics in the United States.

Results

Dogs that were enrolled in the study were client-owned, ranged from 1 to 14 years of age, weighed 3.7 to 60.7 kg, and required twice daily treatment with Apoquel for allergic or atopic dermatitis for 7 days. One hundred and twenty-one (121) dogs with 1673 total dose administrations successfully completed the study and were included in the data summary. Out of a total number of 1673 administrations, 1533 (91.6%) were accepted voluntarily within 5 min, 134 (8%) were consumed with assistance (with food treats or by pilling) outside of the 5 min offering time and 6 (0.4%) doses were not consumed. The per dose percent acceptance rate for the 14 offered doses showed minimal variation ranging from 89.9 to 93.3%.

Conclusions

Client-owned dogs from the general veterinary patient population that required treatment with oclacitinib found the chewable tablets to be very palatable and no aversion occurred with repeated dosing. Oclacitinib chewable tablets were well tolerated and are a palatable alternative to the film-coated tablet.

The relationship between allergic diseases and tic disorders: A systematic review and meta-analysis

This systematic review aims to 1) explore the association between tic disorders (TD) and allergic diseases (AD), 2) judge whether patients with a diagnosis of TD are prone to suffer from a specific AD, by compiling the literature and analyzing the evidence. A literature search was conducted in PubMed and Embase database on February 24, 2021. The inclusion criteria for the literature were all comparative studies that reported TD patients were diagnosed with allergic illness as well. We identified that TD is positively associated with asthma, allergic rhinitis and allergic conjunctivitis, respectively. Especially, provisional tic disorder (PTD) patients might be more likely to suffer from these three AD, although it is still difficult to accurately predict which specific AD is prone to be accompanied by a specific TD. Shared genetic and etiological factors are suggested responsible for the AD-TD association. Large prospective cohort studies in future might shed light on a deep understanding of the relationship between immune disorders and tics.

Early life stress from allergic dermatitis causes depressive-like behaviors in adolescent male mice through neuroinflammatory priming

Allergic dermatitis (AD), associated with pruritus and itchiness, is one of the major stressful conditions early in life. AD also influences the incidence of neuropsychiatric disorders and developmental disorders through neuro-immune interactions. To the best of our knowledge, there is no report that assesses the effects of early childhood dermatitis on psychiatric disorders later in life using an animal model. Here, we developed an oxazolone (Ox)-induced AD model in the early life of male C57BL/6J mice whose ears were challenged by Ox repeatedly from postnatal days (PD) 2 to PD30. On PD30, the Ox-treated ears were remarkably thickened and showed epidermal hyperplasia coupled with increased expression of T helper 2 cytokines, interleukin (IL)-4, and IL-13 in the ear tissue. Additionally, serum immunoglobulin E levels and serum corticosterone levels were higher in the Ox-treated mice than those in the control mice. Although Ox-treated PD40 mice showed neither behavioral abnormalities nor increases in pro-inflammatory cytokine expression in the brain, this study revealed that they experienced downregulation of CD200R1 expression in the amygdala under basal conditions and that additional lipopolysaccharide (LPS) administration induced enhanced neuroinflammatory reaction as the priming effect was accompanied by an increase of Iba-1-positive microglia in the amygdala and hippocampus. Furthermore, the Ox-treated PD40 mice showed depressive-like behaviors 24 h after LPS administration, whereas the control mice did not. Interestingly, the expression of indoleamine 2,3-dioxygenase and kynurenine 3-monooxygenase, key rate-limiting enzymes of the kynurenine metabolism pathway, was upregulated in the hippocampus, prefrontal cortex, and amygdala of the Ox-treated mice 4 h after LPS administration. Based on these results, we suggest that early life stress from AD aggravates susceptibility to systemic inflammation in the adolescent brain, leading to depressive behaviors with abnormal kynurenine metabolism.

Plant Associated Irritant & Allergic Contact Dermatitis (Phytodermatitis)

With more than 350,000 plant species recognized and new species continually being identified, it is not surprising that humans contact plants or plant-containing products daily. The nearly endless list of potential exposures leaves us with a challenging task when attempting to categorize and study potential plant-related irritants and allergens. This article focused on laying a sound framework for understanding some of the more pertinent potential irritants and allergens.

An accumulation of two populations of dendritic cells in skin-draining lymph nodes in response to the expression of thymic stromal lymphopoietin in the skin

Thymic stromal lymphopoietin (TSLP) acts on dendritic cells (DCs), which prime helper T (Th) cells to become type 2 cytokine producing cells. Recently, a different set of populations of TSLP-responsive DCs has been discovered. Here, we identified two populations of CD103^loEpCAM^hi migratory DCs (fraction I and fraction II) that accumulated in skin-draining lymph nodes in response to TSLP expressed in the mouse skin. Fraction I DCs with CD11b⁺PDL2^hi expression primed naïve Th cells to differentiate into cells secreting IFN-γ, IL-17A and IL-22, while fraction II DCs with CD11b^loPDL2⁺ expression primed naïve Th cells to differentiate into cells secreting IL-4, IL-5, IL-9, IL-13 and IL-10. Fraction I DCs migrated from the skin via IL-4Rα signaling pathway, whereas fraction II DCs migrated partially via TSLPR signaling pathway. All suggest that at least two populations of CD103^loEpCAM^hi DCs with distinct functions and pathways could migrate in response to TSLP expression in the skin.

Open field study on the efficacy of fluralaner topical solution for long-term control of flea bite allergy dermatitis in client owned cats in Ile-de-France region

Background

Flea bite is considered to be the main cause of allergic dermatitis in cats. There is a need for treatments able to control clinical signs of allergic dermatitis associated with flea bite in cats.

This was an open pre-treatment versus post-treatment clinical field study. All cats included in the study presented pruritus, skin lesions or other evidence compatible with flea infestation. Skin lesions were assessed (using SCORFAD) at days 0, 28, 56 and 84 whereas pruritus severity was assessed (using PVAS) at days 0, 15, 28, 56 and 84. On day 0, The fluralaner (280 mg/ml) product (Bravecto® spot-on for cats) was supplied in pipettes containing 0.4, 0.89 and 1.79 ml for cats of 1.2–2.8 kg, > 2.8–6.25 kg and > 6.25–12.5 kg body weight, respectively. The other animals living in the same household also received fluralaner. Based on cytological examination at day 0, oral amoxicillin and clavulanic acid was prescribed for 21 days if indicated. For cats presenting intense pruritus and discomfort at day 0, oral prednisolone at 0.5 mg/kg was prescribed for 3 days.

Results

During the study all cats, except for one (cat number 10), improved significantly. Post-treatment median SCORFAD scores at all evaluations were significantly different from the pre-treatment score on day 0 (P values < 0.002 for all three post treatment examination days) with a score reduction of 49% on day 28, 79% on day 56 and 87% on day 84. The PVAS score decreased significantly over the study period for all cats but one (cat number 10). Post-treatment median PVAS scores at all evaluations were significantly different from the pre-treatment PVAS score on day 0 (P value < 0.002 for all four post-treatment days) with a reduction of 46% on day 15, 67% on day 28, 82% on day 56 and 92% on day 84. No adverse reaction or other health issue was reported during the study.

Conclusions

A single topical treatment with fluralaner results in a significant reduction of flea bite allergic dermatitis clinical signs in cats over the subsequent 12 weeks without any additional environmental treatment.

Effects of allergen-specific immunotherapy on peripheral blood regulatory T cells and serum concentrations of cytokines and immunoglobulins in horses with allergic dermatitis

The aim of this study was to assess the effect of allergen-specific immunotherapy (ASIT) on the immunological responses of horses. Blood samples were taken from thirty-two horses with allergic dermatitis treated with ASIT and 10 healthy control horses at 0, 3, 6, 9 and 12 months to investigate the evolution of the percentage of regulatory T cells (Treg) in the peripheral blood and the serum levels of cytokines and immunoglobulins. Clinical improvement was appreciated by the majority of the horses' owners (56.6%). No effect of ASIT on CD4⁺CD25^High Treg cells was found during the one year treatment period. No differences in the percentage of CD4⁺ T cells were observed between the groups, and no effects of ASIT over time were observed. The percentage of CD25⁺ T cells was always higher in the ASIT group (17.9 ± 11.3%) than in the control group (7.3 ± 4.4%, p < 0.001). We did not detect any effect of ASIT on the serum levels of TGF-β, IL-10 and IFN-γ or on the serum concentrations of IgA and IgG4. A reduction in the serum levels of total IgE in the horses with allergic dermatitis was observed at the 6th month (p < 0.05), but increased again at the end of the study. The results indicate that immunotherapy was insufficient to induce significant changes that could indicate T cell tolerance, a shift in cytokine production to more protective Th1 cells. More studies are needed with new vaccine compositions and administration protocols to improve the immunological responses of the horses with allergic dermatitis.

Subacute oral administration of folic acid elicits anti-inflammatory response in a mouse model of allergic dermatitis

Folic acid (FA) deficiency is associated with several health problems, including megaloblastic anemia and fetal neural tube defects. Therefore, supplementation with FA is strongly recommended by governments worldwide. Recent published reports indicate that FA functions in immune system maintenance. The main objective of this study is to examine possible anti-inflammatory and antipruritic effects of FA using a mouse model of allergic dermatitis. The mouse model was developed by repetitive sensitization to the Th2-type hapten toluene-2,4-diisocyanate (TDI). During the development of allergic dermatitis, FA was orally administered to the mice at doses of 8, 160, 1000 or 10,000 μg/day for 5 weeks. The ear swelling response and scratching behavior were monitored after the TDI challenge. Serum, ear tissue and auricular lymph node samples were isolated for further analysis 24 h after the TDI challenge. The ear swelling response was reduced in a dose-dependent manner by FA administration, and a significant change was observed at a concentration of 10,000-μg/day group. Comparable results were obtained through histological evaluation and cytokine level measurement in the ear tissue samples. Oral administration of FA exhibited the inhibitory effect on T-cell infiltration and T-cell-related cytokine production in auricular lymph nodes. Scratching behavior was not altered by FA administration. The in vivo evidence was corroborated by in vitro results, which showed that FA treatment significantly interfered with T-cell proliferation in a dose-dependent manner. Our findings imply that subacute oral administration of FA elicits an anti-inflammatory response, mainly through inhibition of T-cell proliferation.

Treating insect-bite hypersensitivity in horses with active vaccination against IL-5

BACKGROUND

Insect-bite hypersensitivity is the most common allergic dermatitis in horses. Excoriated skin lesions are typical symptoms of this seasonal and refractory chronic disease. On a cellular level, the skin lesions are characterized by massive eosinophil infiltration caused by an underlying allergic response.

OBJECTIVE

To target these cells and treat disease, we developed a therapeutic vaccine against equine IL-5 (eIL-5), the master regulator of eosinophils.

METHODS

The vaccine consisted of eIL-5 covalently linked to a virus-like particle derived from cucumber mosaic virus containing the tetanus toxoid universal T-cell epitope tt830-843 (CMV_TT). Thirty-four Icelandic horses were recruited and immunized with 400 μg of eIL-5-CMV_TT formulated in PBS without adjuvant (19 horses) or PBS alone (15 horses).

RESULTS

The vaccine was well tolerated and did not reveal any safety concerns but was able to induce anti-eIL-5 autoantibody titers in 17 of 19 horses. This resulted in a statistically significant reduction in clinical lesion scores when compared with previous season levels, as well as levels in placebo-treated horses. Protection required a minimal threshold of anti-eIL-5 antibodies. Clinical improvement by disease scoring showed that 47% and 21% of vaccinated horses reached 50% and 75% improvement, respectively. In the placebo group no horse reached 75% improvement, and only 13% reached 50% improvement.

CONCLUSION

Our therapeutic vaccine inducing autoantibodies against self IL-5 brings biologics to horses, is the first successful immunotherapeutic approach targeting a chronic disease in horses, and might facilitate development of a similar vaccine against IL-5 in human subjects.

Usefulness of a topical combination of dinotefuran and pyriproxyfen for long-term control of clinical signs of allergic dermatitis in privately-owned cats in Ile-de-France region

BACKGROUND

The present study assessed the activity of a combination of dinotefuran and pyriproxyfen (Vectra® Felis) for long-term control (3 months) of allergic dermatitis (AD) in privately-owned cats under common household conditions in Ile-de-France region.

METHODS

This was an open pre-treatment vs post-treatment study. Twenty-eight client-owned cats with clinical signs of AD were enrolled in the study. They received topical application of the combination of dinotefuran and pyriproxyfen on days 0, 28, 56 and 84. Two parameters (clinical signs and pruritus severity) were used to assess the animals' condition on days 0, 28 and 84. Fleas were counted if they were observed.

RESULTS

Of the 28 cats initially enrolled, 26 were presented on day 28 and 20 for the final evaluation on day 84. A significant improvement in clinical signs and pruritus was observed in cats for which fleas and/or flea feces were detected on day 0. Globally, the post-treatment AD clinical scores on days 28 and 84 were different from that of the pre-treatment on day 0, with a reduction of 30% and 71%, respectively. For cats with fleas and/or flea feces, the reduction on days 28 and 84 was 33% and 85%, respectively. The improvement of clinical signs and pruritus was not significant in cats with no visible fleas and no flea feces at the beginning of the trial (n = 8).

CONCLUSIONS

The present study indicated that the treatment with a combination of dinotefuran and pyriproxyfen should be considered as useful in controlling fleas on cats without additional environmental treatment and useful for long-term control of clinical signs and pruritus in allergic cats.

6-Shogaol, an active compound of ginger, alleviates allergic dermatitis-like skin lesions via cytokine inhibition by activating the Nrf2 pathway

Allergic dermatitis (AD) clinically presents with skin erythematous plaques, eruption, and elevated serum IgE, and T helper cell type 2 and 1 (Th2 and Th1) cytokine levels. 6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown anti-inflammatory effects, but its inhibitory effects on AD are unknown. The aim of this study was to examine whether 6-shogaol inhibits AD-like skin lesions and their underlying mechanism in vivo and in vitro. An AD-like response was induced by tumor necrosis factor-α (TNF-α)+IFN-γ in human keratinocytes or by 2,4-dinitrochlorobenzene (DNCB) in mice. In vivo, 6-shogaol inhibited the development of DNCB-induced AD-like skin lesions and scratching behavior, and showed significant reduction in Th2/1-mediated inflammatory cytokines, IgE, TNF-α, IFN-γ, thymus and activation-regulated chemokine, IL-1, 4, 12, and 13, cyclooxygenase-2, and nitric oxide synthase levels. In vitro, 6-shogaol inhibited reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) signaling, and increased the levels of total glutathione, heme oxygenase-1, and quinone 1 via nuclear factor erythroid 2 related factor 2 (Nrf2) activation. 6-Shogaol can alleviate AD-like skin lesions by inhibiting immune mediators via regulating the ROS/MAPKs/Nrf2 signaling pathway, and may be an effective alternative therapy for AD.

Topically applied manganese-porphyrins BMX-001 and BMX-010 display a significant anti-inflammatory response in a mouse model of allergic dermatitis

In this study, we topically administered two antioxidant compounds, the manganese-porphyrin-derivatives BMX-001 and BMX-010, in a mouse model of allergic dermatitis and compared the efficacy for reduction of itch and inflammation. In vitro effects of BMX-001 and BMX-010 on keratinocytes, bone marrow derived dendritic cells (BMDCs) and T-cells were initially analysed. For assessment of scratching behaviour, BMX-001 and BMX-010 (0.01 and 0.1 %) were topically applied 16 h and/or 1 h before compound 48/80 or toluene-2,4,-diisocyanate (TDI) challenge in a TDI induced mouse dermatitis model. Additionally, assessment of allergic skin inflammation was performed in a similar manner in the TDI model. Post-treatment ear thickness was measured 24 h after TDI challenge and compared to basal values. The mice were sacrificed and the ear auricle was removed for further analysis. In vitro, both BMX substances significantly inhibited cytokine production of keratinocytes as well as of BMDC and T-cell proliferation. Topical treatment with BMX cream resulted in a significant decrease in scratching behaviour in the compound 48/80 model, but not in the TDI model. Mice treated with BMX-001 and BMX-010 showed a moderate dose dependent decrease in ear thickness, and interestingly, the concentration of the cytokines IL-1β and IL-4 in inflamed skin was reduced by 80-90 % by all treatment options. These first results suggest the potential benefit of a BMX-001 and BMX-010 cream for the treatment of allergic-inflammatory skin diseases.

Histamine and Histamine Receptors in Allergic Dermatitis

In this chapter we will first introduce the pathophysiological process of several skin diseases including allergic dermatitis, a common skin disease, including chronic allergic contact dermatitis (CACD), and atopic dermatitis (AD). In CACD and AD patients, repeated skin exposure to antigens contributes to the development of chronic eczematous lesions. Repeated application of haptens on mice allows emulation of the development of CACD in humans. Further, we will focus on H1, H2, and H4 histamine receptors and their effects on CACD and AD. Histamine-deficient mice, with a knockout histidine decarboxylase (HDC) gene, were used to investigate the role of histamine in CACD and AD. Histamine induces infiltration of inflammatory cells, including mast cells and eosinophils, and elevates Th2 cytokine levels in CACD. Histamine promotes the development of eczematous lesions, elevates IgE serum levels, and induces scratching behavior in CACD. The administration of H1 or H4 receptor antagonists was effective to ameliorate these symptoms in murine CACD models. The combination of H1 and H4 receptor antagonists is a potential therapeutic target for chronic inflammatory skin diseases such as CACD and AD, since combined therapy proved to be more effective than monotherapy.

[Immunoallergic skin manifestations associated with new pets: three cases]

BACKGROUND

The number of household pets increased greatly during the twentieth century, with numbers of new pets (NP, i.e. any pets other than cats and dogs) rising especially sharply over the last decade.

PATIENTS AND METHODS

We first of all report the case of a female patient with eczema lesions on areas skin coming into contact with a ferret, with removal of the animal resulting in wound healing, followed by two patients presenting atypical polymorphous erythema reactions induced by dermatophytes present in their pet rat.

DISCUSSION

While the most common allergies are respiratory, allergic skin reactions, both immediate and delayed, may also result from contact with these new allergens. The animal itself or its environment may be the cause.

[New pets, allergens and allergic dermatitis]

The number of household pets increased greatly during the twentieth century, with the numbers of new pets (NP, i.e. any pet other than cats and dogs) rising especially sharply over the last decade. Contact with such animals, whose owners do not always know how to look after them properly, expose the population to new risks such as trauma, infection and allergy. While the most common allergies are respiratory, allergic skin reactions, both immediate and delayed, may also result from contact with these new allergens. The animal itself or its environment may be the cause. Herein, we review NPs and reports of allergic dermatitis associated with them.

An unusual complication of late onset allergic contact dermatitis to povidone iodine in oral & maxillofacial surgery - a report of 2 cases

BACKGROUND

Povidone iodine (PVP-I) is a chemical complex of polyvinylpyrrolidone (also known as povidone or PVP) and elemental iodine. Iodine containing compounds are widely and commonly used as antiseptics and disinfectants. They are available in various forms like aqueous solution, tincture, aerosol, ointment, or foam. Skin irritation to them is due to the oxidative effects of iodine. Because of the low free iodine concentration in povidone-iodine, skin irritation is less frequent from short contact (1).

CASE

We report two cases, both with no history of allergy to any drugs, who developed an allergic reaction 24 hours after the usage of povidone iodine as a pre-operative antiseptic to prepare (scrub) the lower third of face before surgical removal of third molars. This case report was granted an exemption by the ethical committee of our institution review board. The Helsinki declaration doesn't apply to this case presentation.

CONCLUSIONS

PVP-1 is the most commonly used antiseptic scrubbing solution prior to most surgeries. However, allergic contact dermatitis due to PVP-I has not been extensively documented or reported and hence under evaluated, compared to other commonly encountered allergens. There is almost general agreement to the proposition that PVP-I is a very rare sensitizer (2,3) though there are some conflicting reports on the matter. However, sometimes when prolonged skin contact with PVP-I occurs when used as a pre-operative antiseptic agent, it can cause allergic dermatitis (4,5). Does this finding make pre-operative testing for allergies to PVP-1 necessary in all patients? A point to ponder.

The relationship between bifidobacteria and allergic asthma and/or allergic dermatitis: a prospective study of 0-3 years-old children in Turkey

Bifidobacteria are beneficial bacteria for humans. These bacteria are particularly effective at protecting against infectious diseases and modulating the immune response. It was shown that in newborns, the fecal distribution of the colonizing Bifidobacterium species influences the prevalence of allergic diseases. This study aimed to compare the faecal Bifidobacterium species of allergic children to those of healthy children to detect species level differences in faecal distribution. Stool samples were obtained from 99 children between 0 and 3 years of age whose clinical symptoms and laboratory reports were compatible with atopic dermatitis and allergic asthma. Samples were also obtained from 102 healthy children who were similar to the case group with respect to age and sex. Bifidobacteria were isolated by culture and identified at the genus level by API 20 A. In addition, 7 unique species-specific primers were used for the molecular characterization of bifidobacteria. The McNemar test was used for statistical analyses, and p < 0.05 was accepted as significant. Bifidobacterium longum was detected in 11 (11.1%) of the allergic children and in 31 (30.3%) of the healthy children. Statistical analysis revealed a significant difference in the prevalence of B. longum between these two groups (X(2): 11.2, p < 0.001). However, no significant differences in the prevalence of other Bifidobacterium species were found between faecal samples from healthy and allergic children. (p > 0.05). The significant difference in the isolation of B. longum from our study groups suggests that this species favors the host by preventing the development of asthma and allergic dermatitis. Based on these results, we propose that the production of probiotics in accordance with country-specific Bifidobacterium species densities would improve public health. Thus, country-specific prospective case-control studies that collect broad data sets are needed.

A study for characterization of IgE-mediated cutaneous immediate and late-phase reactions in non-allergic domestic cats

Immunoglobulin-E (IgE) mediated reactions can be induced by intradermal injection of anti-IgE antibodies in both humans and dogs. These reactions grossly and histologically mimic changes seen in naturally occurring allergic dermatitis in these species. Similar studies have not been conducted in the cat. Purified polyclonal rabbit-origin IgG specific for canine IgE (anti-IgE) and rabbit immunoglobulin G (IgG) were injected intradermally in 7 non-allergic laboratory colony cats. Wheal measurements were obtained and biopsies collected before injection and at injection sites after 20 min, 6, 24, and 48 h. Injection of anti-IgE induced an immediate wheal response which was significantly larger than that seen after injection of rabbit IgG. Anti-IgE injected skin was also significantly thicker than IgG-injected skin. This corresponded with a significant increase in number of visibly degranulated mast cells in anti-IgE samples when compared to IgG samples. Injection of anti-IgE was associated with the rapid recruitment of inflammatory cells to the injected dermis. The number of inflammatory cells and mononuclear cells were significantly elevated after the injection of anti-IgE when compared to IgG-injected skin. Both eosinophils and neutrophils were significantly increased in anti-IgE samples relative to IgG, although neutrophils were only transiently increased. The high eosinophil and relatively low neutrophil cell counts in these samples were consistent with previously documented histologic features of naturally occurring feline allergic skin disease. Immunohistochemistry identified a significantly overall increased CD1a(+) cells after the intradermal injection of anti-IgE when compared to IgG and non-injected skin. CD3(+), CD8(+) and CD4(+) were also significantly increased overall in anti-IgE injected skin relative to IgG injected skin. These data document the gross and cellular response to injection of anti-IgE in the skin of healthy, non-allergic cats and support a possible role for IgE in the development of feline allergic dermatitis.