10th European immunogenicity platform open symposium on immunogenicity of biopharmaceuticals

Therapeutic proteins and emerging gene and cell-based therapies are attractive therapeutic tools for addressing unmet medical needs or when earlier conventional treatment approaches failed. However, the development of an immune response directed against therapeutic agents is a significant concern as it occurs in a substantial number of cases across products and indications. The specific anti-drug antibodies that develop can lead to safety adverse events as well as inhibition of drug activity or accelerated clearance, both phenomena resulting in loss of treatment efficacy. The European Immunogenicity Platform (EIP) is a meeting place for experts and newcomers to the immunogenicity field, designed to stimulate discussion amongst scientists across industry and academia, encourage interactions with regulatory agencies and share knowledge and the state-of-the-art of immunogenicity sciences with the broader scientific community. Here we report on the main topics covered during the EIP 10th Open Symposium on Immunogenicity of Biopharmaceuticals held in Lisbon, 26–27 February 2019, and the 1-d training course on practical and regulatory aspects of immunogenicity held ahead of the conference. These main topics included immunogenicity testing, clinical relevance of immunogenicity, immunogenicity prediction, regulatory aspects, tolerance induction as a mean to mitigate immunogenicity and immunogenicity in the context of gene therapy.

Regional alopecia and dermatitis due to Lodderomyces elongisporus in a North American porcupine (Erethizon dorsatum)

BACKGROUND

Lodderomyces elongisporus is a yeast with a worldwide distribution that has been reported as a cause of infection in immunocompromised humans and in a dog that had been quilled by a porcupine.

OBJECTIVES

The objective of this report is to describe the clinical presentation, diagnosis and treatment of dermatitis caused by L. elongisporus in a North American porcupine (Erethizon dorsatum).

ANIMAL

One wild adult male North American porcupine from New York state, USA.

METHODS AND MATERIALS

The porcupine was presented for alopecia and scaling dermatitis over the caudal dorsum. Diagnostic testing included cytological evaluation, trichogram, bacterial and fungal culture, and histopathological examination of skin biopsies.

RESULTS

Histopathological findings from skin specimens demonstrated mild eosinophilic perivascular-to-interstitial dermatitis with superficial dermal fibrosis, mild epidermal hyperplasia with moderate-to-marked intracorneal and intrafollicular yeast. Fungal culture with matrix-assisted laser desorption/ionization confirmed L. elongisporus as the cause of the dermatitis. The porcupine was treated with a six week course of oral itraconazole with clinical resolution.

CLINICAL RELEVANCE

Infection with L. elongisporus should be included as a differential diagnosis for North American porcupines exhibiting signs of dermatitis including scaling and alopecia. This case report may be relevant for the diagnosis and treatment of porcupines with dermatitis and for animals or humans that have been quilled by a porcupine.

Looking back on 45 years of canine dermatology

In June 2018, I was honored (and flabbergasted!) to receive the Kennel Club Charitable Trust's Lifetime Achievement Award for research in the field of canine health, sponsored by Vernon and Shirley Hill of Metro Bank, and administered by the Kennel Club Charitable Trust. I entered the arena of veterinary dermatology in 1971, a graduate of the University of California, Davis. I retired from Cornell University as the James Law Professor Dermatology Emeritus in 2016. During my 45-year career in veterinary dermatology, I worked with all species, especially dogs, cats, and horses, eventually authoring or co-authoring 694 publications including 12 textbooks. For this personal view I will limit my comments to canine dermatology. I was asked to make this article 'a more reflective piece on my lifetime's work'. This is not at all comfortable for me, as my upbringing encouraged me not to 'toot my own horn'. However, 'toot' I must. Hence, indulge me as I share these very personal views on where we were, where we went, and some of my own dabblings along the way. If I fail to mention one of your favorite remembrances, I apologize. Don't let it get under your skin!

Real-world costing analysis for diffuse large B-cell lymphoma in British Columbia

Introduction

Diffuse large B-cell lymphoma (dlbcl) accounts for 30%-40% of all non-Hodgkin lymphomas. Approximately 60% of patients are cured with standard treatment. Targeted treatments are being investigated and might improve disease outcomes; however, their effect on cancer drug budgets will be significant. For the present study, we conducted an analysis of real-world costs for dlbcl patients treated in British Columbia, useful for health care system planning.

Methods

Patient records from a retrospective cohort of patients diagnosed with dlbcl in British Columbia during 2004-2013 were anonymously linked across multiple administrative data sources: systemic therapy, radiotherapy, hospitalizations, oncologist services, outpatient medications, and fee-for-service physician services. Using generalized linear modelling regression, time-dependent costs (in 2015 Canadian dollars) were estimated in 6-month intervals over a 5-year period. The inverse probability weighting method was applied to account for censored observations. Nonparametric bootstrapping was used to estimate standard errors for the mean cost at each time interval.

Results

The cohort consisted of 678 patients (5-year overall survival: 67%). Mean age at diagnosis was 64 ± 14 years; median follow-up was 3.2 years. Mean total cost of care was highest in the first 6 months after diagnosis ($29,120; 95% confidence interval: $28,986 to $29,170) and after disease progression ($18,480; 95% confidence interval: $15,187 to $24,772). Systemic therapy and hospitalization costs were the largest cost drivers. At each time interval, costs were observed to be positively skewed.

Conclusions

Our results depict real-world costs for the treatment of dlbcl patients with standard chop-r therapy. Cost-model parameters are also provided for economic modelling of dlbcl interventions.

A time-and-motion approach to micro-costing of high-throughput genomic assays

BACKGROUND

Genomic technologies are increasingly used to guide clinical decision-making in cancer control. Economic evidence about the cost-effectiveness of genomic technologies is limited, in part because of a lack of published comprehensive cost estimates. In the present micro-costing study, we used a time-and-motion approach to derive cost estimates for 3 genomic assays and processes-digital gene expression profiling (gep), fluorescence in situ hybridization (fish), and targeted capture sequencing, including bioinformatics analysis-in the context of lymphoma patient management.

METHODS

The setting for the study was the Department of Lymphoid Cancer Research laboratory at the BC Cancer Agency in Vancouver, British Columbia. Mean per-case hands-on time and resource measurements were determined from a series of direct observations of each assay. Per-case cost estimates were calculated using a bottom-up costing approach, with labour, capital and equipment, supplies and reagents, and overhead costs included.

RESULTS

The most labour-intensive assay was found to be fish at 258.2 minutes per case, followed by targeted capture sequencing (124.1 minutes per case) and digital gep (14.9 minutes per case). Based on a historical case throughput of 180 cases annually, the mean per-case cost (2014 Canadian dollars) was estimated to be $1,029.16 for targeted capture sequencing and bioinformatics analysis, $596.60 for fish, and $898.35 for digital gep with an 807-gene code set.

CONCLUSIONS

With the growing emphasis on personalized approaches to cancer management, the need for economic evaluations of high-throughput genomic assays is increasing. Through economic modelling and budget-impact analyses, the cost estimates presented here can be used to inform priority-setting decisions about the implementation of such assays in clinical practice.

Achievements, challenges and unmet needs for haemophilia patients with inhibitors: Report from a symposium in Paris, France on 20 November 2014

Over the past 20 years, there have been many advances in haemophilia treatment that have allowed patients to take greater control of their disease. However, the development of factor VIII (FVIII) inhibitors is the greatest complication of the disease and a challenge in the treatment of haemophilia making management of bleeding episodes difficult and surgical procedures very challenging. A meeting to discuss the unmet needs of haemophilia patients with inhibitors was held in Paris on 20 November 2014. Topics discussed were genetic and non-genetic risk factors for the development of inhibitors, immunological aspects of inhibitor development, FVIII products and inhibitor development, generation and functional properties of engineered antigen-specific T regulatory cells, suppression of immune responses to FVIII, prophylaxis in haemophilia patients with inhibitors, epitope mapping of FVIII inhibitors, current controversies in immune tolerance induction therapy, surgery in haemophilia patients with inhibitors and future perspectives for the treatment of haemophilia patients with inhibitors. A summary of the key points discussed is presented in this paper.

IL10 receptor is a novel therapeutic target in DLBCLs

Diffuse large B-cell lymphoma (DLBCL) is a biologically and clinically heterogeneous disease with marked genomic instability and variable response to conventional R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy. More clinically aggressive cases of DLBCLs have high level of circulating interleukin 10 (IL10) cytokine and evidence of activated intracellular STAT3 (signal transducer and activator of transcription 3) signaling. We investigated the role of IL10 and its surface receptor in supporting the neoplastic phenotype of DLBCLs. We determined that IL10RA gene is amplified in 21% and IL10RB gene in 10% of primary DLBCLs. Gene expression of IL10, IL10RA and IL10RB was markedly elevated in DLBCLs. We hypothesized that DLBCLs depend for their proliferation and survival on IL10-STAT3 signaling and that blocking the IL10 receptor (IL10R) would induce cell death. We used anti-IL10R blocking antibody, which resulted in a dose-dependent cell death in all tested activated B-cell-like subtype of DLBCL cell lines and primary DLBCLs. Response of germinal center B-cell-like subtype of DLBCL cell lines to anti-IL10R antibody varied from sensitive to resistant. Cells underwent cell cycle arrest, followed by induction of apoptosis. Cell death depended on inhibition of STAT3 and, to a lesser extent, STAT1 signaling. Anti-IL10R treatment resulted in interruption of IL10-IL10R autostimulatory loop. We thus propose that IL10R is a novel therapeutic target in DLBCLs.

Inhibitors - cellular aspects and novel approaches for tolerance

The immune response against therapeutic clotting factors VIII and IX (FVIII and FIX) is a major adverse event that can effectively thwart their effectiveness in correcting bleeding disorders. Thus, a significant number of haemophilia patients form antibodies, called inhibitors, which neutralize the procoagulant functions of therapeutic cofactors FVIII (haemophilia A) or FIX (haemophilia B). Understanding the cellular and molecular aspects of inhibitor formation is critical to designing tolerogenic therapies for clinical use. This review will focus on the basis of the immune response to FVIII, in particular, and will discuss emerging efforts to not only reduce immunogenicity but also to prevent and/or reverse inhibitor formation.

Resident lymphocytes in the dermis of the normal dorsolateral thoracic skin of alpacas

BACKGROUND

Small numbers of resident T lymphocytes are present in the dermis of normal skin of humans, cattle and sheep.

HYPOTHESIS/OBJECTIVES

We wanted to determine the prevalence, numbers and immunophenotype of lymphocytes in the dermis of healthy skin from alpacas.

ANIMALS

Skin biopsy specimens were collected from the dorsolateral thorax of 31 alpacas with normal skin.

METHODS

Skin biopsy specimens were evaluated for the prevalence and numbers of CD3+ and CD79a+ lymphocytes.

RESULTS

Resident CD3+ and CD79a+ lymphocytes were found around the superficial and deep dermal blood vessels. The CD3+ lymphocytes were more numerous than CD79a+ lymphocytes. Both CD3+ and CD79a+ lymphocytes were more numerous around superficial dermal blood vessels.

CONCLUSIONS AND CLINICAL IMPORTANCE

Resident CD3+ and CD79a+ lymphocytes are present around superficial and deep dermal blood vessels in normal skin from alpacas; hence, the presence of lymphocytes in these locations without obvious features of inflammation must be interpreted cautiously when evaluating skin biopsy specimens from alpacas with skin disease.

Scaling dermatosis in three dogs associated with abnormal sebaceous gland differentiation

BACKGROUND

Abnormal sebaceous gland differentiation, so-called 'sebaceous gland dysplasia', is a rare condition described in the dog and the cat. Although little is known about this condition, it is thought that a genetic defect causes abnormal sebaceous gland development. Clinically, this condition occurs in young cats and dogs and is characterized by variable degrees of adherent scale, hair casts, poor coat quality and hypotrichosis.

HYPOTHESIS/OBJECTIVE

Here, we describe the clinical presentation and treatment of three adult dogs with abnormal sebaceous gland differentiation.

ANIMALS

Three adult dogs presented with a keratinization defect characterized by progressive scaling, hair casts, dull, dry, brittle hair coat and hypotrichosis beginning in puppyhood to early adulthood.

METHODS

Multiple 6 mm punch skin biopsy samples were obtained from each dog. Treatments included various topical keratomodulatory agents, oral essential fatty acids and oral vitamin A.

RESULTS

Histologically, all sebaceous glands were small and composed of a mixture of irregularly clustered basal reserve cells and mature sebocytes. With therapy, two of the dogs showed moderate to marked clinical improvement in scaling, hair casts and hair coat quality.

CONCLUSIONS AND CLINICAL IMPORTANCE

Although rare, 'sebaceous gland dysplasia' should be considered in cases where a primary keratinization defect is suspected. Given that abnormal sebaceous differentiation is a structural defect of the skin, treatment must be maintained and is aimed at ameliorating the clinical signs rather than curing the disease.

Neuroimmune semaphorin 4D is necessary for optimal lung allergic inflammation

Neuroimmune semaphorin 4D (Sema4D) was found to be expressed and function in the nervous and immune systems. In the immune system, Sema4D is constitutively expressed on T cells and regulates T cell priming. In addition, it displays a stimulatory function on macrophages, DC, NK cells, and neutrophils. As all these cells are deeply involved in asthma pathology, we hypothesized that Sema4D plays a critical non-redundant regulatory role in allergic airway response. To test our hypothesis, we exposed Sema4D(-/-) and WT mice to OVA injections and challenges in the well-defined mouse model of OVA-induced experimental asthma. We observed a significant decrease in eosinophilic airway infiltration in allergen-treated Sema4D(-/-) mice relative to WT mice. This reduced allergic inflammatory response was associated with decreased BAL IL-5, IL-13, TGFβ1, IL-6, and IL-17A levels. In addition, T cell proliferation in OVA₃₂₃₋₃₃₉-restimulated Sema4D(-/-) cell cultures was downregulated. We also found increased Treg numbers in spleens of Sema4D(-/-) mice. However, airway hyperreactivity (AHR) to methacholine challenges was not affected by Sema4D deficiency in either acute or chronic experimental disease setting. Surprisingly, lung DC number and activation were not affected by Sema4D deficiency. These data provide a new insight into Sema4D biology and define Sema4D as an important regulator of Th2-driven lung pathophysiology and as a potential target for a combinatory disease immunotherapy.

Resident lymphocytes in the epidermis and adnexal epithelia of normal dorsolateral thorax of alpacas

A small population of resident T-lymphocytes is present in the normal epidermis of skin from humans, mice, sheep, and cattle. The objective of this study was to determine the prevalence of lymphocytes, CD3+ cells (T-lymphocytes) and CD79a+ cells (B-lymphocytes and plasma cells), in the epidermis and adnexal epithelia of alpacas. Skin-biopsy specimens from the normal skin of the dorsolateral thorax of 31 alpacas were examined histologically and immunohistochemically for the presence of CD3+ cells and CD79a+ cells in the epidermis and adnexal epithelia. CD3+ T-lymphocytes, but not CD79a+ cells, were present in the epidermis and adnexal epithelia. Therefore, in the absence of other signs of inflammation, the presence of lymphocytes in these structures in skin-biopsy specimens should be considered normal.

Feline dermatology at Cornell University: 1407 cases (1988–2003)

Medical records of 1407 cats with dermatologic diagnoses made at Cornell University teaching hospital from 1988 to 2003 were tabulated. We expressed the diagnoses as counts, percentages of the cats with dermatologic disease (1407) and percentages of all cats seen at the university hospital (22,135) during the same period. A total of 1887 diagnoses were made in the 1407 cats. We compared the age, sex and breed group of our cases with all those 22,135 cats in (‘1-by-c’) χ2 tests in which the hospital population was considered a standard (rather than a ‘sample’). The 10 most common dermatoses, their counts, and the proportions of dermatologic diagnoses and of the total cat population that the cats with these dermatoses represented were: allergy (298; 15.8%; 1.35%), atopic dermatitis (194; 10.3%; 0.88%), bacterial folliculitis/furunculosis (189; 10.0%; 0.85%), otodectic mange (115; 6.1%; 0.52%), flea infestation (99; 5.2%; 0.45%), feline acne (74; 3.9%; 0.33%), flea-bite allergy (70; 3.7%; 0.32%), cutaneous adverse drug reaction (56; 3.0%; 0.25%), idiopathic eosinophilic-granuloma complex (55; 2.9%; 0.25%) and abscess (51; 2.7%; 0.23%). Allergies of all types, combined, accounted for 32.7% of all the feline dermatoses. Relative to the standard of the total hospital population, cats <2 years old and females (both intact and spayed) were significantly under-represented (all P≤0.001) in the dermatologic case series. In contrast, Himalayans (compared with domestic short- or longhair, Persian, Siamese and other breeds) and males (both intact and neutered) were significantly over-represented (all P ≤0.001).

Endogenous expansion of regulatory T cells leads to long-term islet graft survival in diabetic NOD mice

Donor pancreatic lymph node cells (PLNC) protect islet transplants in Non-obese diabetic (NOD) mice. We hypothesized that induced FoxP3(+) regulatory T cells (Tregs) were required for long-term islet engraftment. NOD or NOD.NON mice were treated with ALS (antilymphocyte serum) and transplanted with NOR islets +/-PLNC (5 × 10(7) ). In vivo proliferation and expansion of FoxP3(+) Tregs was monitored in spleen and PLN from ALS- and ALS/PLNC-treated recipient mice. Anti-CD25 depletion was used to determine the necessity of Tregs for tolerance. FoxP3(+) numbers significantly increased in ALS/PLNC-treated recipients compared to ALS-treated mice. In ALS/PLNC-treated mice, recipient-derived Tregs localized to the transplanted islets, and this was associated with intact, insulin-producing β cells. Proliferation and expansion of FoxP3(+) Tregs was markedly increased in PLNC-treated mice with accepted islet grafts, but not in diabetic mice not receiving PLNC. Deletion of Tregs with anti-CD25 antibodies prevented islet graft tolerance and resulted in rejection. Adoptive transfer of Tregs to secondary NOD.scid recipients inhibited autoimmunity by cotransferred NOD effector T cells. Treg expansion induced by ALS/PLNC-treatment promoted long term islet graft survival. Strategies leading to Treg proliferation and localization to the transplant site represent a therapeutic approach to controlling recurrent autoimmunity.

Alopecia areata in two black Angus cows

Adult onset progressive alopecia and leukotrichia developed in 2 registered black Angus cows, aged 6 and 7 years. Histopathologic findings in skin were prominent melanin clumping and degeneration of matrix cells with formation of giant multinucleate cells within hair bulbs, accompanied by peribulbar melanin incontinence and fibrosis and dystrophic hair shafts. Intrabulbar and peribulbar lymphocytes were cluster of differentiation (CD)3-positive T cells. Findings were characteristic of alopecia areata.

An open clinical trial on the efficacy of cetirizine hydrochloride in the management of allergic pruritus in cats

Cetirizine hydrochloride was administered orally at 5 mg/cat, q24h, to 32 cats with allergic skin disease. Pruritus was reduced in 41% (13/32) of the cats. The antipruritic effect was repeatable and sustainable. There was no significant association between patient age, disease severity, or cutaneous reaction pattern and improvement during cetirizine administration. No adverse side effects were reported.

BCL2 mutations in diffuse large B-cell lymphoma

BCL2 is deregulated in diffuse large B-cell lymphoma (DLBCL) by the t(14;18) translocation, gene amplification and/or nuclear factor-κB signaling. RNA-seq data have recently shown that BCL2 is the most highly mutated gene in germinal center B-cell (GCB) DLBCL. We have sequenced BCL2 in 298 primary DLBCL biopsies, 131 additional non-Hodgkin lymphoma biopsies, 24 DLBCL cell lines and 51 germline DNAs. We found frequent BCL2 mutations in follicular lymphoma (FL) and GCB DLBCL, but low levels of BCL2 mutations in activated B-cell DLBCL, mantle cell lymphoma, small lymphocytic leukemia and peripheral T-cell lymphoma. We found no BCL2 mutations in GC centroblasts. Many mutations were non-synonymous; they were preferentially located in the flexible loop domain, with few in BCL2-homology domains. An elevated transition/transversions ratio supports that the mutations result from somatic hypermutation. BCL2 translocations correlate with, and are likely important in acquisition of, additional BCL2 mutations in GCB DLBCL and FL. DLBCL mutations were not independently associated with survival. Although previous studies of BCL2 mutations in FL have reported mutations to result in pseudo-negative BCL2 protein expression, we find this rare in de-novo DLBCL.

The combination of an antihistamine (chlorpheniramine) and an omega-3/omega-6 fatty acid-containing product for the management of pruritic cats: Results of an open clinical trial

Chlorpheniramine maleate (2 mg/cat every 12 h orally) and a fatty acid supplement (0.5 ml/cat every 24 h orally) were administered in combination to 11 pruritic cats. Although none of the cats had responded to the two products when they were administered as single therapeutic agents, six of the cats (54%) had an excellent response to the combination. Adverse effects were not seen. Under the conditions of this study, the combination of antihistamine (chlorpheniramine) and the omega-3/omega-6 fatty acid-containing supplement exhibited a superior antipruritic effect to either product alone.

CD3+ and BLA.36+ cells do not occur in the epidermis and adnexal epithelia of normal skin from the dorsolateral trunk of cats

A small population of resident T-lymphocytes is present in the normal epidermis of humans, mice, and rats. However, resident epidermal lymphocytes have not been reported in the normal skin of the cat. Skin-biopsy specimens from the normal skin of the dorsolateral trunk from 30 cats were examined histologically and immunohistochemically for the presence of lymphocytes, CD3+ cells, and BLA.36+ cells in epidermis and adnexal epithelia. All examinations were negative. It appears that lymphocytes occur rarely, if at all, in the epidermis and adnexal epithelial of normal cat skin. Hence, the presence of lymphocytes in these structures should be considered abnormal.

The Microanatomy of Healthy Skin from Alpacas (Vicugna Pacos)

The microanatomy of healthy skin from 12 different body sites was investigated in 14 alpacas ( Vicugna pacos). The microanatomy of alpaca skin is typical of domestic animal skin in general, and closely resembles that from llamas.

CD3+ and BLA.36+ cells do not occur in the epidermis and adnexal epithelia of normal equine skin

Summary A small population of resident T lymphocytes is present in the healthy human and murine epidermis. However, resident epidermal lymphocytes have not been reported in normal skin of the horse. Skin biopsy specimens from the normal skin of 27 horses were examined histologically and immunohistochemically for the presence of lymphocytes, CD3+ cells and BLA.36+ cells in epidermis and adnexal epithelia. All examinations were negative. It appears that lymphocytes occur rarely, if at all, in the epidermis and adnexal epithelia of normal horse skin. Hence, the presence of lymphocytes in these structures should be considered abnormal.

Can we prevent immunogenicity of human protein drugs?

Monoclonal antibodies have proved to be extremely valuable additions to conventional treatment for rheumatic diseases. However, despite the general trend towards "humanisation", these drugs remain immunogenic in clinical settings, baffling drug developers. In principle, humanised and fully human monoclonal antibodies are "self" immunoglobulins and should be tolerated. In this overview, the factors that may influence this process, the nature of immunogenicity and methods to analyse and modify potential immunogenicity are discussed. Finally, novel approaches to "re-induce" immunological tolerance to these proteins, including gene therapy and the recognition of unique regulatory epitopes, are outlined.

Infiltrative lymphocytic mural folliculitis: A histopathological reaction pattern in skin-biopsy specimens from cats with allergic skin disease

This study was conducted to determine the prevalence of infiltrative lymphocytic mural folliculitis (ILMF) in skin-biopsy specimens from 354 cats with various inflammatory dermatoses and from 33 cats with normal skin. Although ILMF was present in 33/47 dermatoses evaluated, the prevalence of ILMF in allergic dermatoses (116/172 cats; 67%) was significantly greater than that in non-allergic dermatoses (61/182 cats; 33%). Cats with allergic dermatoses had a 4.1 times greater odds of having ILMF than cats with non-allergic dermatoses. ILMF was not observed in any of the normal skin specimens.

Prevalence of infiltrative lymphocytic mural folliculitis in equine inflammatory skin diseases

Infiltrative lymphocytic mural folliculitis (ILMF) is a histopathological reaction pattern reported to occur in a small number of equine inflammatory dermatoses. However, the prevalence of ILMF in a variety of equine dermatoses has not been reported. Skin biopsy specimens from 250 horses with inflammatory dermatoses and from 27 horses with physically healthy skin were therefore evaluated. ILMF was present in 82% of the diseased skin specimens examined. ILMF was not seen in physically healthy skin. It appears that ILMF is frequently seen in a wide variety of equine inflammatory dermatoses and therefore is of little diagnostic significance. However, ILMF is not seen in physically healthy equine skin and the presence of lymphocytes in equine hair follicle epithelium should therefore be considered abnormal.

Prevalence of apoptotic epidermal keratinocytes in eosinophilic dermatoses of the cat: a retrospective light-microscopic study of 145 skin-biopsy specimens

A retrospective light-microscopic study was performed on skin-biopsy specimens from 145 cats with eosinophilic inflammatory dermatoses in order to determine the prevalence of apoptotic epidermal keratinocytes (AKs), the prevalence of eosinophils in close proximity to AKs, and whether there was a difference in the prevalence of AKs or the prevalence of eosinophils in close proximity to AKs based on histopathological reaction pattern. Overall, 62/145 (43%) specimens had AKs. Of the cases in which AKs were seen, 18% had eosinophils in close proximity to the AKs. The specimens were divided into three groups based on histopathological reaction pattern: perivascular-to-interstitial, diffuse, and nodular. No difference in the prevalence of AKs was found among the three histological groups. Because the sample size containing eosinophils in close proximity to AKs was too small to compare the three histological patterns individually, nodular and non-nodular patterns were compared. No difference in the presence of eosinophils in close proximity to AKs was found in these two subsets. More AKs were present if eosinophils were in close proximity to the AKs (range 1-9 with eosinophils near compared to 0-7 without).

Prevalence, number and morphological types of multinucleated histiocytic giant cells in equine inflammatory dermatoses: a retrospective light microscopic study of skin-biopsy specimens from 362 horses

REASONS FOR PERFORMING STUDY

Multinucleated histiocytic giant cells (MHGC) are seen frequently in skin-biopsy specimens from horses with inflammatory dermatoses. However, the prevalence, number and morphological types of these cells have not been reported.

OBJECTIVE

To determine the prevalence, number and morphological types of MHGC in equine inflammatory dermatoses, and the association of these cells with specific conditions.

METHODS

Skin-biopsy specimens from 335 horses with inflammatory dermatoses and from 27 horses with normal skin were evaluated for the prevalence, number and morphological types of MHGC.

RESULTS

The prevalence and number of MHGC were greater in granulomatous dermatoses than in nongranulomatous dermatoses. Infectious and noninfectious dermatoses were not different in terms of prevalence or morphological types of MHGC. Foreign-body MHGC were the predominant type in almost all cases. MHGC were not seen in normal skin.

CONCLUSIONS

MHGC are seen in a wide variety of equine inflammatory dermatoses, especially those that are granulomatous. Number and morphological types of MHGC are of no apparent diagnostic significance.

POTENTIAL RELEVANCE

MHGC are frequently present in a wide variety of inflammatory dermatoses in the horse. Because the prevalence, number and morphological types of MHGC are of minimal diagnostic significance, special stains and tissue cultures are necessary to confirm specific diagnoses.

Frequency of apoptotic keratinocytes in the feline epidermis: a retrospective light-microscopic study of skin-biopsy specimens from 327 cats with normal skin or inflammatory dermatoses

A retrospective light-microscopic study was performed on 294 biopsy specimens of haired skin from cats with various feline inflammatory dermatoses and specimens from cats with normal skin. Conditions expected to frequently have apoptotic epidermal keratinocytes (AKs) (including erythema multiforme, systemic lupus erythematosus, thymoma-associated exfoliative dermatitis, solar dermatitis, and viral dermatopathies) were found to have significantly more AKs than other types of inflammatory dermatoses. Nevertheless, we found more than two AKs in many skin-biopsy specimens from inflammatory conditions not expected to have frequent AKs (especially those from ectoparasitic dermatoses). Only a single AK was found in 1/33 cats with normal skin.

Apparent clinical resolution of pinnal actinic keratoses and squamous cell carcinoma in a cat using topical imiquimod 5% cream

Imiquimod is a topical immune response modifier and stimulator used in humans to treat a number of cutaneous neoplasms. This case report describes a cat with actinic keratoses and squamous cell carcinoma of the pinnae. The pinnal lesions were treated with topical 5% imiquimod three times per week. Treatment was discontinued after 82 days of therapy. Twelve weeks of topical imiquimod application resulted in clinical resolution of the pinnal lesions. Although no post-treatment biopsies were performed, there was no relapse of the pinnal lesions in 5 months of clinical follow-up. Expected side effects were limited to erythema, crusting, alopecia, and mild discomfort at the sites of application during the first 3 weeks of application. These results suggest that topical imiquimod, although unproven, might be a therapeutic option or adjunct to therapy for cats with actinic keratoses and squamous cell carcinoma, especially those cats for whom surgery and radiation therapy are not an option.

Gross and cytological characteristics of normal feline anal-sac secretions

This study was conducted to characterize the gross and cytological characteristics of secretions from normal feline anal sacs. Thirty cats with no recent history of anal-sac disease were selected consecutively and their anal sacs manually expressed. The color, cell counts, or presence of solid portions of the secretions in the youngest cats (<1 year old) were not significantly different from the rest. Young cats (<1 year old) tended to more often have watery secretions. The secretions contained 13 (median) epithelial cells per 600× magnification microscopic field, basophilic background debris, and a mixture of Gram-positive cocci (83 per field; median), Gram-negative cocci (38 per field; median), and Gram-negative rods (1.8 per field; median). Most secretions had occasional neutrophils, and a minority of cats had occasional yeasts in their secretion. Erythrocytes were found only rarely. Extreme heterogeneity existed in gross color, consistency, and amount of solid material. Hence, these latter parameters would not be valid indicators of anal-sac disease.

Malassezia otitis externa in the dog: the effect of heat-fixing otic exudate for cytological analysis

This study was conducted on 32 dogs with Malassezia otitis externa to determine the effect of heat-fixing otic exudate on cytological analysis. Malassezia infection was confirmed by cytological examination of otic exudate. Otic discharge collected with cotton swabs was then rolled onto glass slides. One slide per dog was heat-fixed prior to staining; the other slide was not heat-fixed. The number of yeast in 10 oil-immersion fields (1000 x magnification) was counted for both slides from each dog. Heat-fixing did not systematically cause either increased or decreased numbers of Malassezia on cytology of otic exudate.

Comparative analysis of canine dermatophytosis and superficial pemphigus for the prevalence of dermatophytes and acantholytic keratinocytes: a histopathological and clinical retrospective study

Acantholytic dermatophytosis is a rarely reported condition of dogs that clinically and histopathologically mimics superficial pemphigus (erythematosus, foliaceus). Histologically, periodic acid-Schiff (PAS) and Grocott's methenamine-silver (GMS) are often necessary to show the fungus. A retrospective histopathological study was conducted on 190 canine skin biopsy specimens: 95 each with the diagnosis of canine dermatophytosis or of superficial pemphigus. All specimens were stained with haematoxylin and eosin, PAS, and GMS. Dermatophytes were not seen in any superficial pemphigus cases. Acantholytic keratinocytes were noted in 14% of the dermatophytosis cases, none of which had clinical signs consistent with superficial pemphigus. Among cases with acantholytic keratinocytes, superficial pemphigus had significantly more acantholytic cells than dermatophytosis (P = 0.02). When comparing face and nonface cases, there was no difference in prevalence of acantholytic keratinocytes in dermatophytosis or number of acantholytic keratinocytes in superficial pemphigus. All dermatophyte cases were both GMS and PAS positive with neither stain being visually superior. No dermatophyte cases where acantholytic keratinocytes were noted had a history, clinical signs and histopathological features compatible with acantholytic dermatophytosis.

A case of multiple epitrichial sweat gland ductal carcinomas in a horse

This case report describes a rare epitrichial sweat gland ductal carcinoma in a 14-year-old horse and is the first report of multiple carcinomas of this type in horses. Although several tumours developed, mostly on the distal extremities, over a 2-year period, the horse remained otherwise healthy. Topical treatment with imiquimod was successful for many of them.

Efficacy of orbifloxacin tablets for the treatment of superficial and deep pyoderma due to Staphylococcus intermedius infection in dogs

Orbifloxacin tablets were administered orally to 23 dogs with superficial and/or deep staphylococcal pyoderma. Response to therapy was excellent in 95.6% of the dogs. Duration of therapy varied from 21 to 40 days (average 29 days) for dogs having only superficial infections, and from 25 to 150 days (average 72 days) for dogs having deep infections. Relapses occurred in 18% of the dogs within a 3-month period. One dog developed a presumed adverse cutaneous drug reaction. Under the conditions of this study, orbifloxacin was an effective, safe, and convenient antibiotic for the treatment of superficial and deep staphylococcal pyoderma in dogs.

Bacteria and fungi on the surface and within noninflamed hair follicles of skin biopsy specimens from horses with healthy skin or inflammatory dermatoses

A retrospective study using light microscopy was performed to assess the prevalence of surface and follicular bacteria and fungi in skin biopsy specimens from 247 horses with inflammatory dermatoses and from 27 horses with healthy skin. Cocci were found on the surface of specimens from 23% (95% confidence interval 18%, 29%) and 7% (95% confidence interval, 0%, 19%), respectively, of horses with skin disease and horses with healthy skin. Of the nine dermatoses with at least 10 cases in our series of horses, bacterial folliculitis had a higher prevalence of surface bacteria (57%; 95% confidence interval 34%, 81%) than the other eight (which all had a prevalence < 30%). There was a significant association between the prevalence of surface cocci and the extent of epidermal hyperkeratosis. Cocci were found in the keratin of noninflamed hair follicles in only 2% of the horses with skin disease, and in none of the horses with healthy skin. Fungal poroconidia were found on the surface of 4% of the horses with skin disease, and on none of the horses with healthy skin. Yeasts were not found.

The prevalence of apoptotic keratinocytes in equine epidermis: a retrospective light-microscopic study of skin-biopsy specimens from 253 horses with normal skin or inflammatory dermatoses

A retrospective study was performed to assess the prevalence of apoptotic epidermal keratinocytes in biopsy specimens from 226 horses with inflammatory dermatoses and from 27 normal specimens. One or more apoptotic keratinocytes were found in specimens from 28 of 226 (12%) horses with various dermatoses, and in one of 27 (4%) specimens from normal horses. The prevalence (proportion of cases with apoptotic epidermal keratinocytes) of apoptotic keratinocytes in the group composed of discoid lupus erythematosus, erythema multiforme, photodermatitis, and systemic lupus erythematosus was significantly greater (52% prevalence in these cases) than that in a grouping of all other dermatoses (prevalence 8%). There was no correlation between the number of apoptotic keratinocytes and the extent of epidermal hyperplasia or hyperkeratosis.