title: Atopic dermatitis in adults: evaluation of peripheral blood mononuclear cells proliferation response to Staphylococcus aureus enterotoxins A and B and analysis of interleukin-18 secretion.
abstract: BACKGROUND
  Atopic dermatitis (AD) is a chronic, inflammatory skin disease with a high prevalence and complex pathogenesis. The skin of AD patients is usually colonized by Staphylococcus aureus (S. aureus); its exotoxins may trigger or enhance the cutaneous inflammation. Several mediators are related to the AD immune imbalance and interleukin-18 (IL-18), an inflammatory cytokine, may play a role in the atopic skin inflammation.
  
  
  OBJECTIVE
  To evaluate peripheral blood mononuclear cells (PBMC) proliferation response to staphylococcal enterotoxins A (SEA) and B (SEB) and the levels of IL-18 in adults with AD.
  
  
  METHODS
  Thirty-eight adult patients with AD and 33 healthy controls were analysed. PBMC were stimulated with SEA and SEB, phytohemaglutinin (PHA), pokeweed (PWM), tetanus toxoid (TT) and Candida albicans (CMA). IL-18 secretion from PBMC culture supernatants and sera were measured by ELISA.
  
  
  RESULTS
  A significant inhibition of the PBMC proliferation response to SEA, PHA, TT and CMA of AD patients was detected (P < or = 0.05). Furthermore, increased levels of IL-18 were detected both in sera and non-stimulated PBMC culture supernatants from AD patients (P < or = 0.05).
  
  
  CONCLUSIONS
  A decreased PBMC proliferation response to distinct antigens and mitogens (TT, CMA, SEA and PHA) in adults with AD suggest a compromised immune profile. IL-18 secretion from AD upon stimulation was similar from controls, which may indicate a diverse mechanism of skin inflammation maintained by Staphylococcus aureus. On the other hand, augmented IL-18 secretion from AD sera and non-stimulated cell culture may enhance the immune dysfunction observed in AD, leading to constant skin inflammation.
authors.affiliation: Department of Dermatology, University of Sao Paulo, School of Medicine, CEP 05403-002, Sao Paulo, Brazil.
authors.forename: Raquel Leão
authors.initials: RL
authors.lastname: Orfali
authors.forename: Maria Notomi
authors.initials: MN
authors.lastname: Sato
authors.forename: Roberto
authors.initials: R
authors.lastname: Takaoka
authors.forename: Mayce Helena
authors.initials: MH
authors.lastname: Azor
authors.forename: Evandro Ararigbóia
authors.initials: EA
authors.lastname: Rivitti
authors.forename: Jon M
authors.initials: JM
authors.lastname: Hanifin
authors.forename: Valéria
authors.initials: V
authors.lastname: Aoki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002176:Candida albicans; D016022:Case-Control Studies; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D003876:Dermatitis, Atopic / Q000097:blood* / Q000473:pathology; D004768:Enterotoxins / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D020382:Interleukin-18 / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010835:Phytohemagglutinins / Q000494:pharmacology; D011043:Pokeweed Mitogens / Q000494:pharmacology; D012720:Severity of Illness Index; D013745:Tetanus Toxoid / Q000494:pharmacology; D055815:Young Adult
chemical_list: D004768:Enterotoxins; D020382:Interleukin-18; D010835:Phytohemagglutinins; D011043:Pokeweed Mitogens; D013745:Tetanus Toxoid; C026066:enterotoxin A, Staphylococcal; D007073:Immunoglobulin E; C031818:enterotoxin B, staphylococcal