IgE reactivity to a Cry j 3, an allergen of Japanese cedar (Cryptomeria japonica) pollen in dogs with canine atopic dermatitis

The present study investigated IgE reactivity to a new Cryptomeria japonica pollen allergen (Cry j 3) in dogs with atopic dermatitis by using a fluorometric ELISA. Serum samples from 15 dogs that showed IgE sensitivity to crude C. japonica pollen allergen by ELISA were tested for specific IgE to each allergen, individually. All 15 dogs had anti-Cry j 1 IgE, 6 (40%) had anti-Cry j 2 IgE, and 11 (73%) had anti-Cry j 3 IgE. Further, we found that these anti-Cry j 3 IgE reacted to Cry j 3 with immunoblotting analysis. These findings indicate that Cry j 3 may be a major allergen in dogs.     

In vivo and in vitro tests showing sensitization to Japanese cedar (Cryptomeria japonica) pollen allergen in atopic dogs

Using both in vivo and in vitro tests, dogs with atopic dermatitis were examined for sensitization with Japanese cedar (Cryptomeria japonica, CJ) pollen allergen. Ten dogs with clinical manifestation of atopic dermatitis were shown to be sensitized to CJ pollen based on the results of intradermal skin test and serum antigen-specific IgE test. In vitro lymphocyte stimulation test showed blastogenic response after stimulation with crude antigen of CJ pollen in all of the 5 cases examined. The peripheral leukocytes showed increased histamine release after stimulation with crude antigen of CJ pollen in 2 cases examined. These data indicate that a proportion of dogs with atopic dermatitis is sensitized to CJ pollen in a cell-mediated manner and show immediate phase reaction of type I hypersensitivity.     

Seasonal rhinitis in a cat sensitized to Japanese cedar (Cryptomeria japonica) pollen

A cat showing seasonal allergic symptoms of rhinitis was examined for reactivities to Japanese cedar (Cryptomeria japonica, CJ) pollen allergen by intradermal skin test (IDST), Prausnitz-Kustner (P-K) test, and lymphocyte blastogenic response. In IDST for 26 common allergens. the cat showed a positive reaction to CJ pollen allergen. P-K test using CJ pollen allergen also showed a positive reaction, indicating the presence of serum IgE specific to CJ pollen. In the lymphocyte blastogenic response, the stimulation index in the presence of CJ pollen allergen was 2.4. These data suggested that the seasonal rhinitis observed in the cat was caused by the sensitization to CJ pollen allergen.     

IgE-reactivity to major Japanese cedar (Cryptomeria japonica) pollen allergens (Cry j 1 and Cry j 2) by ELISA in dogs with atopic dermatitis

The present study investigated IgE-reactivity to two major Japanese cedar (Cryptomeria japonica, C. japonica) pollen allergens (Cry j 1 and Cry j 2) in dogs with atopic dermatitis by use of a fluorometric ELISA. The serum samples from 27 dogs that showed IgE-sensitivity to crude C. japonica pollen allergen by ELISA were tested for specific IgE to the two major allergens. All 27 dogs had anti-Cry j 1 IgE, and 10 (37%) had anti-Cry j 2 IgE. Inhibition of binding of dog specific IgE to crude C. japonica pollen allergen was carried out by addition of Cry j 1. When serum samples containing anti-Cry j 1 IgE but no anti-Cry j 2 IgE were incubated with Cry j 1, specific IgE binding to crude C. japonica pollen allergen was almost abolished. These findings suggest that Cry j 1 is a major allergen in dogs.     

IgE reactivity and cross-reactivity to Japanese cedar (Cryptomeria japonica) and cypress (Chamaecyparis obtusa) pollen allergens in dogs with atopic dermatitis

The natural occurrence of Japanese cedar (Cryptomeria japonica) pollinosis has been reported in dogs with atopic dermatitis. However, the reactivity to Japanese cypress (Chamaecyparis obtusa) pollen allergens in these dogs has not been reported. The present study was designed to investigate the reactivity to Japanese cypress pollen allergens in dogs sensitized to Japanese cedar pollen allergens. In 19 dogs with specific IgE to C. japonica pollen allergen, we measured the specific IgE to C. obtusa pollen allergen and examined the reactivity to the allergen by intradermal test. Of the 19 dogs, 18 had specific IgE to crude and purified major allergens (Cha o 1) of C. obtusa pollen. Most of the dogs showed a positive reaction to C. obtusa pollen allergens in the intradermal test. Allergenic cross-reactivity between Cha o 1 and Cry j 1 (a major allergen in C. japonica pollen) was observed by the ELISA inhibition method. Dogs sensitized to Japanese cedar pollen allergens demonstrate reactivity to Japanese cypress pollen allergens.     

Identification of major allergens of Malassezia pachydermatis in dogs with atopic dermatitis and Malassezia overgrowth

Abstract We have previously shown that both atopic and normal dogs generate an IgG response to antigens of Malassezia pachydermatis . The aim of this study was to compare IgE responses to separated proteins of M. pachydermatis in 28 atopic dogs with Malassezia dermatitis and 22 clinically normal dogs using Western immunoblotting. Six different detection systems were evaluated in order to assess sensitivity and eliminate nonspecific binding and cross-reactivity. The protocol yielding the best results utilized a monoclonal mouse antidog IgE, an alkaline phosphatase conjugated goat antimouse IgG which had been passed through a canine IgG column 3 times, a chemiluminescent substrate and a digital imaging system. Proteins of 45, 52, 56 and 63 kDa were recognized by more than 50% of the atopic dog sera and thus represented major allergens. Only a minority of normal dogs showed faint IgE binding to these proteins. The results indicate that the majority of atopic dogs with Malassezia dermatitis have a greater IgE response than normal dogs, suggesting an IgE-mediated immune response may be clinically important in the pathogenesis of the disease.     

Identification of peptides containing T-cell epitopes of Japanese cedar (Cryptomeria japonica) pollen allergen (Cry j 1) in dogs

Japanese cedar (Cryptomeria japonica, CJ) pollen has been known to cause atopic dermatitis in dogs in Japan. However, since the mechanism of the CJ antigen recognition is not well understood in dogs, it is difficult to develop effective immunotherapy for atopic dermatitis caused by sensitization to CJ pollen. In order to aim at development of a peptide immunotherapy, we tried to identify T-cell epitopes of a major allergen of CJ pollen, Cry j 1, in dogs sensitive to CJ pollen allergen. Peripheral blood mononuclear cells (PBMCs) obtained from 22 dogs experimentally sensitized to CJ pollen allergen and 5 atopic dogs sensitive to CJ pollen allergen were used for mapping of T-cell epitopes of Cry j 1 using 35 kinds of synthesized overlapping peptides of Cry j 1. Reactive peptides were identified based on the results of blastogenic responses of PBMCs against the peptides when the stimulation indices were beyond 2.0. Three reactive peptides were identical in a relatively high population of experimental dogs, which were Nos. 8 (p71-90) (41%), 10 (p91-110) (50%), and 11 (p101-120) (41%). It was considered that these synthesized peptides should contain T-cell epitopes of Cry j 1 in the dogs. However, there were no reactive peptides identical among the five atopic dogs spontaneously sensitive to CJ pollen. The population of dogs experimentally sensitized to CJ pollen antigen will be used in order to investigate effects of a peptide immunotherapy using the reactive peptides. The results in atopic dogs sensitive to CJ pollen antigen will also provide useful information on necessity to develop a tailor-made immunotherapy using reactive peptides in each dog.     

Clinical use of a ceramide-based moisturizer for treating dogs with atopic dermatitis

In humans, skin barrier dysfunction is thought to be responsible for enhanced penetration of allergens. Similar to conditions seen in humans, canine atopic dermatitis (CAD) is characterized by derangement of corneocytes and disorganization of intercellular lipids in the stratum corenum (SC) with decreased ceramide levels. This study was designed to evaluate the effects of a moisturizer containing ceramide on dogs with CAD. Dogs (n = 20, 3~8 years old) with mild to moderate clinical signs were recruited and applied a moisturizer containing ceramide for 4 weeks. Transepidermal water loss (TEWL), skin hydration, pruritus index for canine atopic dermatitis (PICAD) scores, and canine atopic dermatitis extent and severity index (CADESI) scores of all dogs were evaluated. Skin samples from five dogs were also examined with transmission electron microscopy (TEM) using ruthenium tetroxide. TEWL, PICAD, and CADESI values decreased (p < 0.05) and skin hydration increased dramatically over time (p < 0.05). Electron micrographs showed that the skin barrier of all five dogs was partially restored (p < 0.05). In conclusion, these results demonstrated that moisturizer containing ceramide was effective for treating skin barrier dysfunction and CAD symptoms.     

Common allergens of atopic dermatitis in dogs: comparative findings based on intradermal tests

Intradermal tests were performed on 58 dogs diagnosed with atopic dermatitis from 2004~2008 at the Veterinary Medical Teaching Hospital of Konkuk University, Korea. To compare the allergen distribution observed in the present investigation to the results from other studies conducted in Korea and elsewhere, the allergens were grouped according to their kinds. There was no significant difference in gender distribution among the dogs. The most common breeds among the 58 dogs were Maltese (n = 11) and Shih-tzu (n = 11). The average age was 4.8 years. The most frequently produced a positive reaction on the intradermal tests was mold (67.3%) followed by house dust (54.5%) and house dust mites (49.1%). The present study found a low distribution of dogs allergic to various outdoor allergens compared to studies performed in other countries; this may reflect differences in living conditions for dogs living in Korea.     

Sensitization rates of causative allergens for dogs with atopic dermatitis: detection of canine allergen-specific IgE

Allergen-specific IgE serology tests became commercially available in the 1980s. Since then these tests have been widely used to diagnose and treat allergic skin diseases. However, the relationship between a positive reaction and disease occurrence has been controversial. The purpose of this study was to evaluate allergens using a serologic allergy test in dogs with atopic dermatitis (AD). Dogs clinically diagnosed with AD (n=101) were tested using an allergen-specific IgE immunoassay. Among the total 92 environmental and food allergens, house dust and house dust mites were the most common. Several allergens including airborne pollens and molds produced positive reactions, and which was considered increasing allergens relating to the climate changes. The presence of antibodies against staphylococci and Malassezia in cases of canine AD was warranted in this study. Additionally, strong (chicken, turkey, brown rice, brewer''s yeast, and soybean) and weakly (rabbit, vension, duck, and tuna) positive reactions to food allergens could be used for avoidance and limited-allergen trials.     

Serum antibodies to Malassezia yeasts in canine atopic dermatitis

Significant numbers of humans with atopic dermatitis develop Malassezia-specific IgE. Immediate skin-test reactivity to Malassezia has been demonstrated in atopic dogs. The aim of this study was to compare the serum IgG and IgE response to Malassezia in atopic dogs with and without clinical evidence of Malassezia dermatitis and/or otitis, nonatopic dogs with clinical evidence of Malassezia dermatitis and/or otitis and healthy dogs. Cytology was used to diagnose clinically significant Malassezia dermatitis and otitis. Contact plate cultures confirmed the validity of this technique. Reproducible enzyme-linked immunosorbent assays for Malassezia-specific IgG and IgE in canine serum were established. Atopic dogs had significantly higher serum IgG and IgE levels than either healthy dogs or nonatopic dogs with clinical evidence of Malassezia dermatitis and/or otitis. There was no significant difference in IgG and IgE levels between atopic dogs with and without clinical evidence of Malassezia dermatitis and/or otitis. The implications of these findings in the pathogenesis and management of canine atopic dermatitis are discussed.     

Effects of propofol-induced sedation on intradermal test reactions in dogs with atopic dermatitis

We compared the effect of propofol and saline control on intradermal test reactions in dogs with atopic dermatitis undergoing outpatient intradermal testing (IDT). Nineteen dogs were used in this clinical study. Patients were randomly allocated to receive either intravenous (IV) propofol or IV 0.9% saline, and IDT was performed on the right or left (randomized) lateral thorax. One investigator, unaware of the treatments, interpreted all IDT results. Injection sites were analysed using a subjective and objective method. A value of P or= 1+ on all dogs, significantly more positive sites were apparent during propofol sedation than during saline administration. In addition, the greater number of individual dogs experiencing more positive reactions >or= 1+ during propofol sedation was significant. When subjectively analysing reactions >or= 2+, the greater number of positive reactions and the greater number of dogs with more positive reactions observed during propofol treatment was not significantly different from the saline control. When analysed objectively, the greater number of positive reactions observed during propofol sedation was not significant. A greater number of dogs had higher subjective scores and larger objective measurements during propofol sedation compared with saline administration. In summary, propofol sedation was associated with an overall greater number of positive IDT reactions compared with the saline control. Although not always significant, this difference should be considered when choosing propofol for skin testing dogs with atopic dermatitis.     

A randomized, double-blind, placebo-controlled trial to investigate the efficacy and safety of a Chinese herbal product (P07P) for the treatment of canine atopic dermatitis

A randomized, double-blind, placebo-controlled trial of P07P, a product derived from a traditional Chinese herbal remedy, was undertaken in 50 dogs with atopic dermatitis. Owners recorded a daily itch score for 4-14 days before treatment and during treatment. Packets of powder containing P07P or placebo were added to the food once daily for 8 weeks. Dogs were assessed for erythema, surface damage, overall coat condition and seborrhoea by the same investigator, as well as for pruritus and general demeanour, at 0 (visit 2), 28 (visit 3) and 56 (visit 4) days of treatment or at withdrawal. Investigator and owner assessments of response were recorded after 28 and 56 days of treatment or at withdrawal. The predefined primary outcome measure was the owners' assessment of response at the end of treatment. Nine of the 24 dogs (37.5%) in the P07P group but only 3 of the 23 dogs (13%) in the placebo group were considered to have improved, but this difference was not statistically significant (P = 0.09). There was a significantly higher withdrawal rate due to worsening of condition in the placebo group (P = 0.04). Mean daily itch score in the second 28-day period of the study was significantly higher than baseline in the placebo group (P = 0.01) but not in the P07P group (P = 0.30). Pruritus scores showed a significant deterioration from baseline at the final visit in the placebo group (P = 0.01) but not in the P07P group (P = 1.00). There was a significant difference between the groups in change from baseline in erythema score at visit 3 (P = 0.05). There were no significant differences (P > 0.05) in surface damage, seborrhoea, overall coat condition and general demeanour scores within or between the groups throughout the study. The product was well tolerated with no severe or serious adverse events recorded. P07P may be beneficial as a novel nonsteroidal therapy for the management of dogs with atopic dermatitis.     

Induction of Th1 immune responses to Japanese cedar pollen allergen (Cry j 1) in mice immunized with Cry j 1 conjugated with CpG oligodeoxynucleotide

We determined whether a major Japanese cedar pollen allergen (Cry j 1) conjugated with CpG oligodeoxynucleotide would enhance allergen-specific Th1 responses in mice. Cry j 1 conjugated with CpG (Cry j 1-CpG) induced IL-12 in the spleen cells of naïve mice. Cry j 1-CpG immunization of BALB/c mice suppressed anti-Cry j 1 IgE response and enhanced anti-Cry j 1 IgG_2a to subsequent Cry j 1 and alum adjuvant injection. CD4⁺T cells isolated from the spleens in mice immunized with Cry j 1-CpG produced higher IFN-γ levels than did CD4⁺T cells obtained from mice as negative controls. Our results suggested that Cry j 1-CpG immunization can induce Cry j 1-specific Th1 immune responses, thereby inhibiting IgE response to the pollen allergen.     

Characterization of the inflammatory infiltrate during IgE-mediated late phase reactions in the skin of normal and atopic dogs

In canine and human atopic patients, the intracutaneous injection of offending allergens is followed by the development of both immediate and late-phase reactions. The present study was performed to expand on the characterization and dynamics of inflammatory cell subsets during IgE-mediated late-phase reactions in canine skin. Three normal dogs and three Dermatophagoides farinae -allergic dogs were selected for this experiment. All dogs were challenged intradermally with mite allergen, purified anticanine IgE antibodies (positive control) or phosphate-buffered saline (negative control). Skin biopsies were obtained before and 6, 12 and 24 h post-injection. Sections were stained with metachromatic and eosinophil-specific histological stains. Additionally, we used an immunohistochemical method with antibodies specific for canine leukocyte antigens. This study confirmed the occurrence of a late-phase reaction in atopic skin following allergen challenge, and in normal and atopic canine skin after intradermal injection of IgE-specific antibodies. Whereas early emigrating dermal cells were composed chiefly of neutrophil and activated eosinophil granulocytes, there was an influx of αβ T-lymphocytes and dermal dendritic cells in later stages of the late-phase reactions. Because IgE-mediated late-phase reactions resemble spontaneous atopic canine skin lesions, both at macroscopic and microscopic levels, we propose the use of similar challenges to study the anti-inflammatory effects of anti-allergic drugs in a pre-clinical setting.     

Oral allergy syndrome induced by tomato in a dog with Japanese cedar (Cryptomeria japonica) pollinosis

A dog with Japanese cedar (Cryptomeria japonica, CJ) pollinosis had oral allergy syndrome (OAS) after ingesting fresh tomato. The dog showed specific IgE to both CJ and tomato allergens. As a negative control, twenty dogs without atopic dermatitis that had no exposure to tomato and no specific IgE to CJ allergen were used. They had no specific IgE to tomato allergen. Furthermore, IgE cross-reactivity was observed between CJ and tomato allergens in the dog. We found that OAS induced by tomato exists in the dog and there is a relationship between CJ and tomato allergens.     

The effects of capsaicin topical therapy in dogs with atopic dermatitis: a randomized,double-blinded,placebo-controlled,cross-over clinical trial

Abstract The efficacy of twice daily topical application of capsaicin (0.025%) for the management of pruritus in dogs with atopic dermatitis (AD) was evaluated in double-blinded, placebo-controlled study. Twelve dogs with AD were randomly assigned to either 0.025% capsaicin or vehicle lotion applied twice daily for 6 weeks. After a 4-week wash-out period, treatments were switched. Significant improvement was reported by owners ( P  = 0.0006), but not by investigators. Owners noted temporary worsening of pruritus after the first week of capsaicin therapy. Overall capsaicin was well tolerated. Substance P (SP) concentrations in the skin did not correlate with the severity of the pruritus and did not change significantly over time and between treatments. Lesional skin had less SP than nonlesional skin ( P  = 0.03). These observations suggest that topical capsaicin should be further evaluated as an adjunctive antipruritic agent in dogs with AD.     

Intradermal skin test reactivity to histamine and substance P is blunted in dogs with atopic dermatitis

Skin reactivity to intradermal injections (0.1, 0.5 and 1 nm ) of substance P (SP) was evaluated in 20 clinically normal dogs and 20 dogs with atopic dermatitis (AD). Saline and histamine were used as negative and positive controls, respectively. Wheal diameters were measured. Reactions were evaluated for erythema and induration and a subjective score, on a scale from 0 to 4+, was given. Evaluations were performed at 3, 5, 10, 15 and 30 min after the injections. Wheal diameters for histamine and SP injections were significantly smaller in dogs with AD compared with clinically normal dogs. In both groups, reactions to the various concentrations of SP were not significantly different from each other and were always smaller than histamine reactions. Erythema was not seen with SP injections. In addition, subjective scores for SP injections were significantly lower in dogs with AD compared with controls. The results of this study are similar to those reported in human medicine, where a role for SP in AD is proposed and desensitization of receptors to both SP and histamine is hypothesized. Further studies are needed to investigate the role of SP in the pathogenesis of canine AD.     

Canine atopic dermatitis: a retrospective study of 169 cases examined at the University of California, Davis, 1992-1998. Part II. Response to hyposensitization

One hundred and sixty-nine dogs were diagnosed with atopic dermatitis, and treated with hyposensitization for at least 1 year based on the results of either intradermal skin tests (IDST) or enzyme-linked immunosorbant serum assays (ELISA). Excellent (i.e. hyposensitization alone controlled clinical signs), good (> 50% improvement), moderate (< 50% improvement) and no (clinical signs were unchanged) responses were seen in 19.5, 32.5, 20.1 and 27.8%, respectively. Age of onset, age when treatment was initiated or the duration of clinical signs had no influence on response to hyposensitization. Dogs having concurrent flea allergy dermatitis were statistically more likely to respond better than dogs with concurrent food allergies. Although not statistically significant, there were trends for Golden Retriever and male dogs to respond better than other breeds and female dogs, respectively. Dogs having more than 21 positive reactions in allergy tests and treated with more than 21 allergens had lower response scores, and a longer time course before achieving beneficial response. Lower response scores were seen in dogs having positive reactions to cultivated plants, grasses, trees or insects. There was no difference in response to hyposensitization whether based on IDST or ELISA results.     

Investigation on the clinical efficacy and safety of 0.1% tacrolimus ointment (Protopic) in canine atopic dermatitis: a randomized, double-blinded, placebo-controlled, cross-over study

Topical tacrolimus is successfully used in people with atopic dermatitis. Preliminary studies in dogs with atopic dermatitis using tacrolimus in a compounded lotion formulation indicated that tacrolimus significantly decreased erythema and pruritus according to investigator, but no significant improvement was reported by the dog owners. The objectives of this study were to evaluate the clinical efficacy and safety of the commercially available 0.1% tacrolimus ointment (Protopic) in dogs with atopic dermatitis. The study was designed as a double-blinded, placebo-controlled, cross-over study. Selected dogs were allocated to either tacrolimus or placebo for 4 weeks. After 4 weeks there was a wash-out period of 2 weeks and treatments were switched. Twelve dogs completed the study. Clinical signs were scored. Blood samples were collected for complete blood count, chemistry panels and tacrolimus levels at week 0 and 4 of each treatment. Tacrolimus ointment significantly decreased severity of symptoms for both owners and investigators at the end of the trial. When the same dogs received the placebo, there were no differences between week 0 and week 4 scores. Dogs with localized disease responded better than dogs with generalized disease. Tacrolimus was detected in the blood of animals receiving the active ingredient. Levels were below the level of toxicity and no adverse effects were reported in any of the dogs. No changes in complete blood count and chemistry parameters were detected between groups or within groups. In conclusion, tacrolimus appears to be a safe alternative treatment in dogs with atopic dermatitis, especially in those with localized disease.