title: Relative importance of IL-4 and IL-13 in lesional skin of atopic dermatitis.
abstract: BACKGROUND
  Although both interleukin-4 (IL-4) and IL-13 induce immunoglobulin E (IgE) production in vitro, the relative contribution of the two cytokines in various skin lesions of atopic dermatitis remains unclear.
  
  
  OBJECTIVE
  We examined the relative importance of IL-4 and IL-13 in lesional skin of atopic dermatitis for IgE production.
  
  
  METHODS
  The study group comprised 28 atopic dermatitis patients with serum IgE levels more than 2000 IU/ml. The expression levels of IL-4 mRNA and IL-13 mRNA versus that of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were determined using a semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) method in samples of normal-appearing skin from seven patients, very mild lesions from eight patients, subacute lesions from ten patients and lichenified lesions from ten patients with atopic dermatitis, and in samples of normal skin from six healthy control subjects.
  
  
  RESULTS
  IL-4 mRNA expression was identified in only two of the eight very mild lesions, one of the ten subacute lesions, and none of the ten lichenified lesions, whereas IL-13 mRNA expression was identified in 27 of the 28 skin lesions of atopic dermatitis. The IL-13 mRNA/GAPDH mRNA ratios (x100) in the subacute lesions (94.4+/-20.6) and lichenified lesions (71.4+/-40.4) were significantly greater than in the skin of healthy controls (13.1+/-17.7; P<0.01, P<0.05, respectively).
  
  
  CONCLUSIONS
  Upregulation of IL-13 mRNA in subacute and chronic lesions of atopic dermatitis along with scant expression of IL-4 mRNA suggest that IL-13 is a crucial cytokine in lesional skin.
authors.affiliation: Department of Dermatology, Shiga University of Medical Science, Seta Tsukinowa-cho, 520-2192 Otsu, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tazawa
authors.forename: Hisashi
authors.initials: H
authors.lastname: Sugiura
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Sugiura
authors.forename: Masami
authors.initials: M
authors.lastname: Uehara
mesh_terms: D000328:Adult; D002908:Chronic Disease; D003876:Dermatitis, Atopic / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D015870:Gene Expression / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007150:Immunohistochemistry; D018793:Interleukin-13 / Q000235:genetics*; D015847:Interleukin-4 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D012867:Skin / Q000473:pathology
chemical_list: D018793:Interleukin-13; D012333:RNA, Messenger; D015847:Interleukin-4; D007073:Immunoglobulin E