Increased Allergic Immune Response toSarcoptes scabieiAntigens in Crusted versus Ordinary Scabies

Abstract

Scabies, a parasitic skin infestation by the burrowing "itch" mite Sarcoptes scabiei, causes significant health problems for children and adults worldwide. Crusted scabies is a particularly severe form of scabies in which mites multiply into the millions, causing extensive skin crusting. The symptoms and signs of scabies suggest host immunity to the scabies mite, but the specific resistant response in humans remains largely uncharacterized. We used 4 scabies mite recombinant proteins with sequence homology to extensively studied house dust mite allergens to investigate a differential immune response between ordinary scabies and the debilitating crusted form of the disease. Subjects with either disease form showed serum IgE against recombinant S. scabiei cysteine and serine proteases and apolipoprotein, whereas naive subjects showed minimal IgE reactivity. Significantly (P < 0.05) greater serum IgE and IgG4 binding to mite apolipoprotein occurred in subjects with crusted scabies than in those with ordinary scabies. Both subject groups showed strong proliferative responses (peripheral blood mononuclear cells) to the scabies antigens, but the crusted scabies group showed increased secretion of the Th2 cytokines interleukin 5 (IL-5) and IL-13 and decreased Th1 cytokine gamma interferon (IFN-␥) in response to the active cysteine protease. These data confirm that a nonprotective allergic response occurs in the crusted disease form and demonstrate that clinical severity is associated with differences in the type and magnitude of the antibody and cellular responses to scabies proteins. A quantitative IgE inhibition assay identified IgE immunoreactivity of scabies mite antigens distinct from that of house dust mite antigens, which is potentially important for specific scabies diagnosis and therapy.

Crusted scabies is associated with increased IL‐17 secretion by skin T cells

“…It has been suggested that a Th2-biased immune response against S. scabiei infection may account for the development of crusted scabies. Extremely high levels of IgE antibody have been reported in patients with crusted scabies, indicative of a Th2-biased immune response (5,6,15,32). However, studies in goat and sheep models suggested that high IgE levels may indicate protective immune responses (33,34), and thus high levels of IgE may therefore not be directly related to a dysregulated immune response leading to the development of crusted scabies.…”

“…It has been suggested that a Th2-biased immune response in S. scabiei infestation may account for the development of crusted scabies (6,11). Peripheral blood mononuclear cells (PBMCs) isolated from patients with crusted scabies secreted higher levels of IL-4, IL-5 and IL-13, and lower levels of IFNc, compared to those of ordinary scabies patients; levels of total and antigenspecific IgE are also higher in crusted scabies patients (12)(13)(14)(15).…”

Sarna Crostosa em Doente com Infecção VIH

“…5 A produção de IL-17 estará ainda na dependência da produção por linfócitos Tγδ e será aumentada por níveis reduzidos de IL-10 e TGF-β1 (célu-las T reguladoras). 3,4,6 Adicionalmente, existe uma migração predominante de linfócitos T CD8+ para a derme e quase ausência de linfócitos B.…”

“…Doentes com sarna crostosa apresentam níveis séricos mais elevados de IgE e IgG4 do que doentes com formas clássicas da doença. 5,7 Este switch de um predomínio de resposta imunológica baseada em linfócitos Th1 para uma resposta menos eficaz baseada em linfócitos Th2 acontece ao longo da evolução da infecção VIH, estando relacionado com a evolução para SIDA. 8 Desta forma se poderá explicar a maior prevalência de sarna crostosa na população imunodeprimida por infecção pelo VIH.…”

Evaluation of an ELISA using recombinant Ssλ20ΔB3 antigen for the serological diagnosis of Sarcoptes scabiei infestation in domestic and wild rabbits

“…The antibody response to S. scabiei infestation has been documented in human (Walton et al, 2010) and animal species (Bornstein and Zakrisson, 1993;Arlian et al, 1994Arlian et al, , 1996Bornstein et al, 1995;Little et al, 1998;Arlian and Morgan, 2000;Sarasa et al, 2010;Rodríguez-Cadenas et al, 2010). ELISA tests, based on standard whole mite extracts with multiple mite antigens, which demonstrate specific antibodies to S. scabiei in different host species such as dogs, cats, camels, pigs, chamois, and red foxes have been used as reliable simple diagnostic tools (Bornstein et al, 1996(Bornstein et al, , 2006Hollanders et al, 1997;Van der Heijden et al, 2000;Lower et al, 2001;Rambozzi et al, 2004;Malik et al, 2006).…”