title: Perianal Crohn's disease and hidradenitis suppurativa: a possible common immunological scenario.
abstract: BACKGROUND
  Crohn's disease (CD) and Hidradenitis suppurativa (HS) are both chronic inflammatory diseases. The pathogenesis of these diseases is multifactorial, due to the interaction of genetic and environmental factors leading to a deregulated local immune response where T lymphocytes play a major role. To the best of our knowledge, no previous study has clarified whether the pathogenetic mechanism of perianal CD and HS is the same. We therefore analyzed the cellular expression pattern and the cytokine repertoire in three patients suffering from both perianal CD and HS.
  
  
  METHODS
  We evaluated three patients affected by concurrent HS and CD with fistulizing perianal disease. Surgical specimens have been fixed and embedded in paraffin prior to sectioning for histological examination. Inflammatory tissue curettages have been recovered during intervention from perianal fistulas and HS lesions in order to analyze the phenotypic and functional characteristics of infiltrating T cells. In particular we evaluated T cells, by flow cytometry, for cytokine production profile and expression of surface markers. Moreover, analysis of the T cell repertoire was performed by means of spectratyping, in only one patient.
  
  
  RESULTS
  A higher frequency of CD4+ CD161+ T lymphocytes has been detected in CD fistulas and in HS lesions than in peripheral blood (PB) samples. In the patient in whom we derived enough cells from the three sources, we found higher frequency of CD4+ IL-17- producing cells in HS lesion and fistula lesion compared to PB. It is noteworthy that the same clonotypes were expanded in this patient in T cells derived from both HS lesion and fistula lesion.
  
  
  CONCLUSIONS
  The presence of numerous CD4+ CD161+ lymphocytes in fistula and HS lesion curettages suggests that these cells may play a pathogenic role, and candidates CD161 as a possible biological target for medical treatment.
authors.affiliation: Department of Surgery and Translational Medicine, University of Florence, Largo Brambilla 3, 50139 Florence, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Giudici
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Maggi
authors.affiliation: Department of Surgery and Translational Medicine, University of Florence, Largo Brambilla 3, 50139 Florence, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Santi
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cosmi
authors.affiliation: Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Annunziato
authors.affiliation: Department of Surgery and Translational Medicine, University of Florence, Largo Brambilla 3, 50139 Florence, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Nesi
authors.affiliation: Department of Clinical and Experimental Medicine, Second University of Naples, Naples, Italy.
authors.forename: Giusi
authors.initials: G
authors.lastname: Barra
authors.affiliation: Department of Medicine, University of Perugia, Perugia, Italy.
authors.forename: Gabrio
authors.initials: G
authors.lastname: Bassotti
authors.affiliation: Department of Clinical and Experimental Medicine, Second University of Naples, Naples, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: De Palma
authors.affiliation: Department of Surgery and Translational Medicine, University of Florence, Largo Brambilla 3, 50139 Florence, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Tonelli
keywords: Crohn’s disease; Hidradenitis suppurativa; T helper lymphocytes