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

Abstract

Scabies is an ectoparasitic infestation by the mite Sarcoptes scabiei. Although commonly self-limiting, a fraction of patients develop severely debilitating crusted scabies. The immune mechanisms underlying the development of crusted scabies are unclear, and undertaking longitudinal infection studies in humans is difficult. We utilized a porcine model to compare cellular immune responses in peripheral blood and skin of pigs with different clinical manifestations of scabies (n = 12), and in uninfected controls (n = 6). Although clinical symptoms were not evident until at least 4 weeks post-infestation, the numbers of peripheral IFNγ-secreting CD4(+) T cells and γδ T cells increased in infected pigs from week 1 post-infestation. γδ T cells remained increased in the blood at week 15 post-infestation. At week 15, skin cell infiltrates from pigs with crusted scabies had significantly higher CD8(+) T cell, γδ T cell and IL-17(+) cell numbers than those with ordinary scabies. Peripheral IL-17 levels were not increased, suggesting that localized skin IL-17-secreting T cells may play a critical role in the pathogenesis of crusted scabies development. Given the potential of anti-IL-17 immunotherapy demonstrated for other inflammatory skin diseases, this study may provide a novel therapeutic avenue for patients with recurrent crusted scabies.

Increased risk of psoriasis following scabies infection: A nationwide population‐based matched‐cohort study

“…These important findings regarding inflammatory cytokines are summarized in Table . Similarly, immune‐mediated inflammatory processes after a S. scabiei exposure have also been previously reported . It seems that elevated levels of IL‐2, IL‐4, IL‐6, IL‐17 and IFN‐γ have been demonstrated in both scabies and psoriasis in most previous studies (Table ).…”

“…Specifically, a Th17 cell‐mediated inflammatory pathway with production of IL‐17 plays an important role in human immunopathology. Elevated IL‐17 levels are found in both scabies and psoriatic patients . Cytokine interactions in psoriasis have been reported to activate signal transducer and activator of transcription (STAT)1, STAT3 and nuclear factor‐κB transcription factors .…”

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. 4,7 Níveis elevados de mastócitos teciduais têm também sido reportados.…”

“…3,4,6 Adicionalmente, existe uma migração predominante de linfócitos T CD8+ para a derme e quase ausência de linfócitos B. 4,7 Níveis elevados de mastócitos teciduais têm também sido reportados. Doentes com sarna crostosa apresentam níveis séricos mais elevados de IgE e IgG4 do que doentes com formas clássicas da doença.…”

Th1/Th2 immune responses and oxidative stress in caprine flea allergy dermatitis

“…The recently described pro‐inflammatory Th17 CD4 + T‐lymphocytes producing IL‐17, IL‐21 and IL‐22 were involved in autoimmune diseases and elimination of extracellular pathogens . The key role of Th2 and Th17 cytokines in determining severity of ectoparasitic diseases like scabies has been reported recently …”