The ACVD task force on canine atopic dermatitis (XXIV): allergen-specific immunotherapy.

Allergen-specific immunotherapy (ASIT) has been used for years to treat dogs with atopic dermatitis (AD) and humans with atopic diseases. The efficacy of ASIT has been well documented for humans with respiratory atopic diseases and stinging insect allergy, but its effectiveness seems more controversial for patients with AD. In spite of insufficient evidence derived from randomized controlled trials, multiple open studies and a large body of clinical observations suggest that ASIT is effective in controlling the clinical signs of dogs with AD. As a result of the scarcity of evidence from controlled trials, the true efficacy of ASIT, and the optimal protocols for allergen dose and frequency of injection are currently unknown. Allergen-specific immunotherapy nevertheless may be included in the treatment of canine AD because of its potential advantages and limited disadvantages compared to other forms of therapy. There is no evidence, however, for the preference of any specific treatment protocol. The predictive value of historical, clinical and immunologic features related to the efficacy of ASIT in dogs with AD are discussed in this paper. Adverse reactions, and the requirements for monitoring of patients receiving ASIT, then are reviewed and detailed. Finally, this review highlights aspects of ASIT where further research and controlled studies are needed.     

Rush allergen specific immunotherapy protocol in feline atopic dermatitis: a pilot study of four cats

Rush immunotherapy has been shown to be as safe as conventional immunotherapy in canine atopic patients. Rush immunotherapy has not been reported in the feline atopic patient. The purpose of this pilot study was to determine a safe protocol for rush immunotherapy in feline atopic patients. Four atopic cats diagnosed by history, physical examination and exclusion of appropriate differential diagnoses were included in the study. Allergens were identified via liquid phase immunoenzymatic testing (VARL: Veterinary Allergy Reference Labs, Pasadena, CA). Cats were premedicated with 1.5 mg triamcinolone orally 24 and 2 h prior to first injection and 10 mg hydroxyzine PO 24, 12 and 2 h prior to first injection. An intravenous catheter was placed prior to first injection. Allergen extracts (Greer Laboratories, Lenoir, North Carolina) were all administered subcutaneously at increasing protein nitrogen units (pnu) every 30 minutes for 5 h to maintenance dose of 15,000 pnus ml-1. Vital signs were assessed every 15 minutes. Two cats developed mild pruritus and the subsequent injection was delayed 30 minutes. No changes in either cat's vital signs were noted, nor was there any further pruritus. All four cats successfully completed rush immunotherapy. Two cats developed a dermal swelling on the dorsal neck one week later. In these four cats, this protocol appeared to be a safe regimen to reach maintenance therapy. A larger sample of feline patients is needed to determine the incidence of adverse reactions and to follow the success of ASIT based upon this method of induction.     

The future of immunotherapy for canine atopic dermatitis: a review

Allergen specific immunotherapy (ASIT) is a foundation treatment for canine atopic dermatitis (CAD), though few critical studies have documented its effectiveness as a disease‐modifying treatment in dogs. The mechanisms by which ASIT works in dogs have not been elucidated, although they are likely to parallel those known for humans. Current ASIT approaches in CAD focus on either subcutaneous or sublingual administration. Greater knowledge of major allergens in dogs, ideal dosage regimes and details of allergen admixture are likely to lead to better efficacy in CAD. Evaluation of biomarkers for successful therapy may also be of benefit. Potentially important advances in human medicine, that have yet to be explored in dogs, include use of modified allergen preparations such as allergoids, recombinant major allergens or allergen peptides; modification with adjuvants; or packaging of the above in virus‐like particles. Co‐administration of immunomodulators such as CpG oligodeoxynucleotides or specific monoclonal antibodies might direct the immune response in the desired direction while calming the “cytokine storm” of active disease. Initial trials of alternative routes of administration such as intralymphatic immunotherapy have yielded exciting results in humans, and continuing study in dogs is underway. Progress in ASIT of human food allergy may provide clues that will assist with improved diagnosis and patient management of CAD. Importantly, further study must be undertaken to clarify the conditions under which ASIT is a valuable treatment modality for dogs.     

Examination of serum total IgG1 concentration in atopic and non-atopic dogs

In this study, serum immunoglobulin G1 (IgG1) concentrations were examined in atopic and non-atopic dogs receiving different levels of parasite control. Significantly lower serum total IgG1 concentrations were found in non-atopic dogs receiving stringent parasite control than in atopic dogs or non-atopic dogs receiving less stringent parasite control. Examination of serum total IgG1 concentrations of atopic dogs after six months of allergen specific immunotherapy (ASIT) showed a significant increase in serum total IgG1 concentrations. It is proposed that serum total IgG1 concentrations are affected by parasitism, atopic dermatitis and ASIT.     

Equine atopic skin disease and response to allergen-specific immunotherapy: a retrospective study at the University of California-Davis (1991-2008)

This retrospective study reports on the clinical presentation of equine atopic skin disease and evaluates response to treatment with allergen-specific immunotherapy (ASIT) based on intradermal testing and/or serum testing. Computerized medical records from January 1991 to December 2008 yielded 54 horses included in the study. Presenting clinical signs (CS) included urticaria (n=28), pruritus (n=8) or both (n=18). Forty-one of 54 horses received ASIT, and response to ASIT (n=32) was evaluated via telephone survey. Eighty-four per cent (n=27) of owners reported that ASIT reduced their horse's CS; 59% (n=19) were able to manage CS by ASIT alone. Three horses (9%) were managed with ASIT in combination with doxepin and discontinued use of corticosteroids. There was no statistical significance between type of test performed and reported success of ASIT (χ(2) analysis, P=0.53). Ninety-three per cent (n=30) of owners reported use of antipruritic medications prior to starting ASIT; 57% (n=17) of these owners reported discontinuing those medications due to success of ASIT. Adverse effects were limited to swelling at the injection site, seen in 16% (n=5). Seventy-five per cent (n=24) of owners elected to discontinue ASIT after 6 months to 8 years (mean 2.2 years): 15 due to resolution of CS, six due to persistent CS, two because the horse was sold, and one due to cost. Ten owners reported no recurrence of CS after discontinuing ASIT; five had recurrence within a median of 2 years of discontinuing ASIT (range 1-12 years). Allergen-specific immunotherapy is a safe and effective way to manage equine atopic skin disease.     

Requirement for additional treatment for dogs with atopic dermatitis undergoing allergen-specific immunotherapy

Allergen-specific immunotherapy (ASIT) is one of the main treatments for atopic dermatitis in dogs, but it often requires additional treatments such as antibacterial and antifungal therapy for secondary bacterial and yeast infections, or antipruritic drugs to control the clinical signs or treat the adverse effects of the immunotherapy. Twenty-seven dogs enrolled in a study of ASIT were clinically assessed four times over a period of nine months; their requirement for treatment for secondary bacterial and yeast infections, for the administration of glucocorticoids as additional antipruritic therapy, and for the treatment of any adverse effects of the ASIT were evaluated. Twenty (74 per cent) of the dogs were treated for superficial bacterial pyoderma, 18 (66.6 per cent) required treatment for Malassezia species dermatitis on one or more occasions, eight (29.6 per cent) required treatment for otitis externa due to Malassezia species or bacteria, and eight required glucocorticoids to control their clinical signs. Five (18.5 per cent) of the dogs experienced adverse effects due to the ASIT and two required treatment with antihistamines (H1 receptor antagonists) in order to continue with the ASIT.     

Serum allergen‐specific immunoglobulin E in atopic and healthy cats: comparison of a rapid screening immunoassay and complete‐panel analysis

Feline and canine atopic dermatitis are thought to have a similar immunopathogenesis. As with dogs, detection of allergen‐specific IgE in cat serum merely supports a diagnosis of feline atopy based on compatible history, clinical signs and elimination of other pruritic dermatoses. In this study, a rapid screening immunoassay (Allercept^® E‐Screen 2nd Generation; Heska AG, Fribourg, Switzerland; ES2G) was compared with a complete‐panel serum allergen‐specific IgE assay (Allercept^®; Heska AG; CP) in healthy cats with no history of skin disease and in atopic cats. The latter had no diagnosis of external parasitism, infection, food hypersensitivity or other skin disease explaining their pruritus, and expressed cutaneous reaction patterns typically associated with feline allergic skin disease (head, neck or pinnal pruritus, miliary dermatitis, self‐induced alopecia, eosinophilic granuloma complex). The proportion of cats positive on either the ES2G or the CP assays was not significantly different between the atopic and healthy cat groups. There was, however, strong agreement between the results of the ES2G and CP assay; overall, the two tests were in agreement for 43 of 49 (88%) serum samples. There was also strong agreement when individual allergen groups were evaluated (agreement noted: indoor, 41 of 49 samples; grasses/weeds, 37 of 49 samples; and trees, 41 of 49 samples). These results indicate that although neither test is diagnostic for feline atopic dermatitis, the screening assay is beneficial for predicting the results of a complete‐panel serum allergen‐specific IgE assay in cats.     

CpG-ODN作为免疫耐受诱导剂的研究进展

免疫球蛋白E（immunoglobulin E,IgE）介导的过敏性疾病可以通过过敏原特异性免疫疗法（allergen-specific immunotherapy,ASIT）治疗。研究人员使用佐剂和免疫调节剂增强ASIT效果并提高其安全性。CpG-寡脱氧核苷酸（CpG-oligodeoxynucleotide,CpG-ODN）具有免疫耐受促进特性,是治疗过敏性疾病的理想免疫调节剂之一。研究发现,CpG-ODN的剂量对于通过募集浆细胞样树突状细胞（plasmacytoid dendritic cells,pDCs）促进免疫调节至关重要。低剂量CpG-ODN会引起炎症反应,高剂量CpG-ODN会引发免疫耐受。CpG-ODN对IgE介导的过敏性疾病表现出预防和治疗潜力。对CpG-ODN的种类、CpG-ODN对免疫细胞的影响以及CpG-ODN作为ASIT免疫耐受诱导剂的作用机制等方面的研究进展进行综述,以期为相关研究提供参考。     

Feline glaucoma--a comprehensive review

Cats with glaucoma typically present late in the course of disease. It is likely that glaucoma in cats is under-diagnosed due to its insidious onset and gradual progression, as well as limitations of some commonly used tonometers in this species. Treatment of glaucoma in feline patients presents a clinical challenge, particularly as glaucoma is often secondary to other disease processes in cats. In this review, we consider the clinical features, pathophysiology, and classification of the feline glaucomas and provide current evidence to direct selection of appropriate treatment strategies for feline glaucoma patients.     

Treatment of proliferative feline eosinophilic keratitis with topical 1.5% cyclosporine: 35 cases

Objective  Proliferative feline eosinophilic keratitis is a chronic keratopathy caused by a suspected immune mediated response to an unknown antigenic stimulus. The purpose of this study is to demonstrate the efficacy of topical 1.5% cyclosporine solution in proliferative feline eosinophilic keratitis.
Methods  Thirty-five cats were treated topically with 1.5% cyclosporine A between 1997 and 2007. Eosinophilic keratitis was diagnosed by clinical appearance and evidence of eosinophils and/or mast cells in corneal cytology. The patients were treated with topical cyclosporine (1.5%) twice (26 of 35, 74.3%) and three times (9 of 35, 25.7%) daily. The minimum period for follow-up was 5 months.
Results  The age of the patients ranged from 2 to 13 years with a mean age of 6.0 years. Twenty-two were neutered males, and 13 were females. The represented breeds were 30 DSH, 3 DLH, one Siamese and one Maine Coon. Cytologic examination of a corneal scrape revealed the presence of eosinophils in 34 of 35 specimens, and mast cells in 25 of 35 specimens. Improvement in the treated eyes was seen in 31 cats (88.6%). Four animals (11.4%) did not respond to the treatment with topical cyclosporine. Recurrences were seen in seven (22.6%) cases. Blepharitis was noted as an infrequent side effect.
Conclusion  Based on our findings, topical cyclosporine (1.5%) is an effective treatment of proliferative feline eosinophilic keratitis in the vast majority of cases. Recurrences were mainly associated with poor owner compliance. Chronic, often lifelong therapy with medications is thus recommended.     

A retrospective evaluation of lomustine (CeeNU) in 32 treatment naïve cats with intermediate to large cell gastrointestinal lymphoma (2006–2013)

Multi‐drug chemotherapy protocols for feline lymphoma have demonstrated variable efficacy and tolerability. In phase I trials, lomustine has demonstrated efficacy for cats with lymphoma though its use for treatment naïve feline intermediate/large cell gastrointestinal (GI) lymphoma remains unknown. This study evaluated the efficacy and tolerability of lomustine for the treatment of feline GI lymphoma. Thirty‐two cats with histologically or cytologically confirmed intermediate/large cell GI lymphoma were evaluated retrospectively. Factors assessed included clinical signs, hematologic/biochemical parameters and use of l ‐asparaginase at induction. A response rate of 50% (16/32), with median duration of response of 302 days (range 64–1450 days), was found. Median progression‐free interval was 132 days (range 31–1450 days), with overall median survival time of 108 days (range 4–1488 days). History of hyporexia, presence of anaemia and dose of lomustine were significantly associated with progression‐free survival. Overall, lomustine is a well‐tolerated and effective treatment for feline GI lymphoma.     

DNA vaccination against Japanese cedar pollinosis in dogs suppresses type I hypersensitivity by controlling lesional mast cells

Sensitization to allergens of Japanese cedar pollen is known to cause canine atopic dermatitis as approximately 10% of atopic dogs in Japan were positive to the pollen allergen. Among the two major allergens of Japanese cedar pollen, since Cry j 1 is more important than Cry j 2 as an antigen to increase IgE in atopic dogs sensitized to Japanese cedar pollen, Cry j 1 can be a target for immunotherapy. In our study, efficacy of DNA vaccination with a plasmid containing the gene of a major allergen of Japanese cedar (Cryptomeria japnonica, CJ) pollen, Cry j 1, was examined using a dog model experimentally sensitized to CJ pollen allergen. Cry j 1 DNA plasmid and a vector plasmid (pCAGGS) were injected into six dogs and three dogs, respectively, five times with an interval of 1.5 month. After the treatment with Cry j 1 DNA plasmid, production of IgE against Cry j 1 decreased in four of the six dogs in the treatment group, whereas it increased in the three dogs of the control group. The reactivity to the pollen allergen in intradermal testing and provocation testing were obviously reduced in the treatment group, but not in the control group. The number of mast cells in alveolar area of the lung in the treatment group was smaller than that in the control group. Cry j 1 DNA plasmid was also injected into three atopic dogs sensitive to Cry j 1, resulting in improvement of clinical signs in the pollination season. These findings indicated that Cry j 1 DNA plasmid could regulate mast cell-mediated reaction against Cry j 1, which could be an alternative and effective treatment for CJ pollinosis.     

Dermatophagoides farinae-specific IgG responses in atopic dogs undergoing allergen-specific immunotherapy with aqueous vaccines

The molecular and immunologic mechanisms associated with successful allergen-specific immunotherapy (ASIT) have not been completely elucidated. The aim of this study was to characterize the changes in Dermatophagoides farinae -specific IgG in atopic dogs undergoing ASIT using aqueous vaccines. Fifteen atopic dogs with a positive skin test reaction to D. farinae were treated with aqueous vaccines for a minimum of 2 months following a standard protocol. Serum samples were collected before and during therapy and used to probe Western blots containing separated proteins of D. farinae . IgG responses were detected using a polyclonal goat anticanine IgG antibody and a chromogenic substrate 3,3'-diaminobenzidine. The blots were analysed using a semiquantitative digital image analysis system that evaluated the number and molecular weight of bands, as well as their intensity, which was related to IgG concentration. Prior to ASIT, all dogs showed allergen-specific IgG responses to various antigens of D. farinae . During ASIT, there was a significant increase in the total quantity of D. farinae -specific IgG antibodies to various antigens from the mite ( P  = 0.015). Significant increases were observed for a 98-kDa band ( P  = 0.015), likely to be Der f 15; bands with molecular weights between 50 and 70 kDa ( P  = 0.012); and bands between 30 and 45 kDa ( P  = 0.035). These findings provide support for the hypothesis that ASIT induces IgG blocking antibodies to allergens known to be relevant in canine atopic dermatitis.     

Diagnosis of congenital and adult-onset hypothyroidism in cats

Whereas hyperthyroidism is the most common endocrine disorder in the cat, hypothyroidism is the least common feline endocrine disorder. This is a the result of several factors including low index of suspicion, rarity of the naturally occurring hypothyroidism in cats, and a lack of species specific tests for endogenous TSH and antithyroglobulin antibodies. Nonetheless, hypothyroidism does occur in cats, especially in kittens and after radioactive treatment for hyperthyroidism. The clinician should become familiar with the common presentations of congenital and adult-onset hypothyroidism in cats. In addition, some of the tests specific to dogs (such as endogenous canine TSH) may be utilized to diagnose subclinical hypothyroidism in cats. Fortunately, the treatment of feline hypothyroidism with synthetic levothyroxine is both straightforward and effective.     

Evaluation of the safety of an abbreviated course of injections of allergen extracts (rush immunotherapy) for the treatment of dogs with atopic dermatitis

OBJECTIVE: To evaluate the safety of an abbreviated course of injections of allergen extracts (rush immunotherapy) for the treatment of dogs with atopic dermatitis. ANIMALS: 30 dogs with atopic dermatitis examined at a veterinary dermatology referral practice for treatment with allergen-specific immunotherapy. PROCEDURE: A catheter was placed in a vein in each dog. Dogs were constantly observed throughout the procedure. Allergen extracts were administered in increasing concentrations every 30 minutes for 6 hours to a maintenance concentration of 20,000 protein nitrogen units/ml. Epinephrine, oxygen, and emergency treatment were available as needed. RESULTS: In 22 (73%) dogs, rush immunotherapy safely replaced the prolonged induction period (15 weeks) of weekly injections that consists of increasing concentrations of allergen extract. In 7 (23%) dogs, the induction period was abbreviated to 4 weeks. Of the 8 dogs that developed problems during rush immunotherapy, increased pruritus necessitated premature cessation of rush immunotherapy in 7, and 1 developed generalized wheals. Oral administration of prednisolone (1 mg/kg of body weight) resulted in resolution of adverse effects in all 8 dogs. CONCLUSION AND CLINICAL RELEVANCE: Rush immunotherapy performed by personnel at a veterinary hospital is a safe method for treatment of dogs with atopic dermatitis.     

Use of nested polymerase chain reaction (PCR) for detection of retroviruses from formalin-fixed, paraffin-embedded uveal melanomas in cats

Thirty-six formalin-fixed, paraffin-embedded enucleated globes from cats with a diagnosis of diffuse anterior uveal melanoma were obtained. Sections of tumor were excised, deparaffinized, and subjected to nested polymerase chain reaction (PCR) to identify proviral DNA sequences from the feline leukemia virus (FeLV)–feline sarcoma virus (FeSV; 36 eyes), and the feline immunodeficiency virus (FIV; 18 eyes). All samples tested were negative for FIV DNA. Three samples were positive for FeLV–FeSV DNA. This is the first reported evidence of a possible link between naturally occurring feline anterior uveal melanoma and the presence of FeLV–FeSV DNA.     

Characterisation of lymphosarcomas in Australian cats using polymerase chain reaction and immunohistochemical examination

Objective To examine tumour tissue of cats with lymphosarcoma for the presence of feline leukaemia virus and feline immunodeficiency virus and analyse the immunophenotype of the tumours.
Design A retrospective study of feline lymphosarcoma cases.
Methods Formalin-fixed, paraffin-embedded tumour tissue of 14 feline lymphosarcomas was examined for the presence of feline leukaemia virus and feline immunodeficiency virus by polymerase chain reaction and immunohistochemistry. Using polyclonal and monoclonal antibodies against T and B lymphocytes, the phenotypic expression of the tumours was characterised.
Results No feline leukaemia virus antigen or proviral sequences were detected. Feline immunodeficiency virus proviral sequences were detected in two cases by polymerase chain reaction. Immunophenotyping of all 14 cases resulted in seven cases being classified as B-cell phenotype, four as T-cell phenotype, and the remaining three undetermined.
Conclusions In contrast to previous reports overseas, our results suggest that feline leukaemia virus infection appears to be an infrequent cause of lymphosarcoma in the cats that were necropsied. Feline immunodeficiency virus may have a role in lymphomagenesis. The potential role of feline immunodeficiency virus needs to be explored in more depth. Compared with most previous reports, B-cell tumours were more common than T-cell tumours in this series of cats.     

The use of immunohistochemistry and the polymerase chain reaction for detection of feline leukemia virus and feline sarcoma virus in six cases of feline ocular sarcoma

Ocular sarcoma was diagnosed by light microscopic examination in enucleated globes ( n  = 4), orbital tissue biopsy ( n  = 1) and ocular evisceration contents ( n  = 1) from six cats. To determine if feline leukemia virus (FeLV) or a replication-defective FeLV, feline sarcoma virus (FeSV), was present in these ocular sarcomas, immunohistochemistry (IHC) and polymerase chain reaction (PCR) for FeLV were utilized. Immunohistochemical staining for FeLV glycoprotein 70 (gp70) was performed on all six formalin-fixed, paraffin-embedded tumors using an avidin–biotin complex technique. DNA was extracted from each specimen and a 166 bp region of the FeLV long-terminal repeat (LTR) was amplified by PCR. All tumors were composed primarily of spindle cells; two neoplasms had PAS-positive basement membrane enveloping areas of spindle cells. All tumors involved the uvea and five of six tumors showed transcleral extension, one of which invaded the optic nerve. Immunohistochemical staining for FeLV gp 70 was negative. PCR to amplify a portion of the FeLV LTR was negative. Based on these findings of these limited number of cases, FeLV/FeSV may not play a role in the tumorigenesis of feline ocular sarcomas. However, additional tumors representing all morphological subtypes should be investigated for the presence of viral antigen and DNA. It is important to determine the etiology and pathogenesis of these malignant ocular sarcomas. If the cell of origin and pathogenesis involve ocular and lenticular injury, and FeLV/FeSV is not present, then the clinical management of cases of feline ocular trauma, uveitis and glaucoma may prevent the development of this tumor.     

E. coli Nitroreductase/CB1954: In Vitro Studies into a Potential System for Feline Cancer Gene Therapy

Investigations were carried out to identify a suitable prodrug activating system for feline gene therapy with the eventual aim of treating feline thyroid disease and feline neoplasia. The E. coli nitroreductase (NTR)/CB1954 prodrug activating system was evaluated in vitro in feline cells by transient transfection with a nitroreductase expressing construct and subsequent treatment with the prodrug CB1954. The feline cells successfully expressed E. coli nitroreductase, which was able to activate the prodrug CB1954 resulting in cytotoxicity to both transformed and adjacent cells (a bystander effect) in vitro. In the absence of nitroreductase, CB1954 was non-toxic to feline cells. In addition, the nitroreductase gene was expressed in rat thyroid cells under the control of the cell type specific feline thyroglobulin promoter. This paper demonstrates that the E. coli nitroreductase/CB1954 system may be suitable for in vivo feline gene therapy, and further investigations are warranted.