Immunomodulation and immunodeficiency

Abstract

This article briefly reviews the concepts of immunodeficiency and immunomodulation as they relate to selected skin diseases in the dog and cat. Immunodeficiency states are uncommon and may be associated with a subnormal or down-regulated immune system, including humoral deficiencies, such as IgA, and abnormal lymphocyte or neutrophil function. Establishing a causal relationship between a skin disease and presumed immunodeficient state has been difficult due to the rarity of such conditions, and the limited nature of the techniques used to characterise the immune system response. Severe combined immunodeficiency in dogs is a well characterised primary immunodeficiency state involving lymphocytes; retrovirus infection in cats may lead to an acquired immunodeficient state with some association with certain dermatological conditions although it remains unclear that infection is causally linked with disease. Immunomodulation usually implies stimulating the immune system along a beneficial pathway. Such a therapeutic approach may involve a wide variety of agents, for example intravenous immunoglobulin. There are few randomised controlled trials with veterinary patients that unequivocally demonstrate beneficial responses to immunomodulatory agents. Interferons are cytokines of major interest in human and veterinary medicine for their antiviral, anti-tumour and immunomodulatory effects. The advent of veterinary-licensed products containing recombinant interferon may enable demonstration of the efficacy of interferons for conditions such as canine papillomatosis and feline eosinophilic granuloma complex. Canine pyoderma has been treated with a number of presumed immunomodulatory agents with limited success. With more detailed knowledge of the pathogenesis of pyoderma it may be possible to develop efficacious immunomodulators.

Clinical, immunological and histopathological findings in a subpopulation of dogs with pododermatitis

“…In addition, there was no alteration in the CD4 + /CD8 + lymphocyte ratio as reported in demodicosis, 22 German Shepherd pyoderma 23 or AD (with Malassezia pachydermatis infection), 24 and none of the dogs had laboratory findings consistent with hypothyroidism. Although the above assays represent relatively crude methods for assessing cell‐mediated and humoral immune function, 25 the results generated here do not suggest a global B‐ or T‐cell defect in the dogs examined.…”

Malignant transformation of a putative eyelid papilloma to squamous cell carcinoma in a dog

“…Larger masses encompassing greater than 1/3 of the eyelid length could require removal followed by reconstructive blepharoplasty. Medical treatment of papillomatosis is directed at eliminating any immunodeficiencies, 12 correction of an endocrinopathy, 15 such as hypothyroidism or hyperadrenocorticism, if present, and stimulation of humoral and cell‐mediated immune mechanisms 15,18–21 …”

Criptococose cutânea associada à severa infestação por Sarcoptes sp. e Demodex sp. em um cão

“…A quebra da barreira epitelial pode permitir a entrada e disseminação de diferentes fungos (OUTERBRIDGE, 2006). O sistema imune do hospedeiro está envolvido na patogênese de várias doenças cutâneas (FOSTER, 2004). Nos gatos, a infecção cutânea por criptococose ocorre preferencialmente na pele da cabeça e pescoço.…”

“…Em pacientes veterinários, há evidências limitadas de uma relação causal entre uma desordem imunodefi ciente aparente e o desenvolvimento de uma doença cutânea (FOSTER, 2004). Apesar dos parâmetros que predispõem ao aparecimento de demodicose não serem completamente compreendidos, sabe-se que uma alteração na resposta imunomediada por células, como os linfócitos, é um fator relevante (SINGH et al, 2010).…”