title: IL-7 mRNA is not overexpressed in mycosis fungoides and pleomorphic T-cell lymphoma and is likely to be an autocrine growth factor in vivo.
abstract: Interleukin-7 (IL-7) is thought to be a growth factor for cutaneous T-cell lymphoma (CTCL) since it has been shown that IL-7 transgenic mice develop a cutaneous disorder characterized by enhanced T-cell proliferation with progression to malignancy and that in vitro growth of Sézary cell lines is IL-7 dependent. However, no direct in vivo evidence exists for the involvement of IL-7 in the pathogenesis of CTCL. Therefore, we examined IL-7 mRNA expression in skin biopsies from patients with mycosis fungoides (MF) (n = 20) and pleomorphic T-cell lymphoma (n = 5). By semiquantitative RT-PCR, IL-7 mRNA was not detectable in any of the CTCL samples, or in normal human skin (n = 8) or in skin from patients with psoriasis (n = 7) or atopic dermatitis (n = 5). In contrast, IL-7 mRNA was detected in a biopsy from a kidney allograft transplant, in normal keratinocytes under various culture conditions and in several cell lines. Interestingly, using a highly sensitive nested PCR, IL-7 mRNA was detectable in all specimens tested, but there was no indication of IL-7 overexpression in MF then analysing lesions of patch, plaque or tumour stages. In contrast, increasing CD3 expression was found, which was most likely a consequence of the enhanced density of malignant T cells in advanced tumour stages. In summary, by the use of semiquantitative RT-PCR we were not able to detect IL-7 overexpression in MF or pleomorphic T-cell lymphoma. This indicates that IL-7 is probably not an autocrine growth factor in these CTCLs.
authors.affiliation: Department of Dermatology, University Hospital Charité, Berlin Humboldt University, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Asadullah
authors.forename: A
authors.initials: A
authors.lastname: Haeussler
authors.forename: M
authors.initials: M
authors.lastname: Friedrich
authors.forename: A
authors.initials: A
authors.lastname: Siegling
authors.forename: S
authors.initials: S
authors.lastname: Olaizola-Horn
authors.forename: U
authors.initials: U
authors.lastname: Trefzer
authors.forename: H D
authors.initials: HD
authors.lastname: Volk
authors.forename: W
authors.initials: W
authors.lastname: Sterry
mesh_terms: D000328:Adult; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D017931:DNA Primers / Q000235:genetics; D015870:Gene Expression; D006133:Growth Substances / Q000235:genetics / Q000502:physiology; D006801:Humans; D015851:Interleukin-7 / Q000235:genetics* / Q000502:physiology; D015603:Keratinocytes / Q000276:immunology / Q000378:metabolism; D016399:Lymphoma, T-Cell / Q000209:etiology / Q000235:genetics / Q000276:immunology*; D051379:Mice; D009182:Mycosis Fungoides / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D012867:Skin / Q000276:immunology / Q000378:metabolism
chemical_list: D017931:DNA Primers; D006133:Growth Substances; D015851:Interleukin-7; D012333:RNA, Messenger