IL-7 mRNA is not overexpressed in mycosis fungoides and pleomorphic T-cell lymphoma and is unlikely 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.

Restoration of peripheral blood T cell repertoire complexity during remission in advanced cutaneous T cell lymphoma

“…Some variants of CTCL have also been described as Th2-type malignancies, and clonal CTCL cells have been observed to produce Th2-type cytokines [1, 6, 24]. Enhanced production of IL-18 in plasma and skin is also seen in patients with CTCL [26] and may be a potent inducer of the Th2 cytokine profile [31].…”

Cytokines and cutaneous T‐cell lymphomas

“…In summary, we could fairly exclude IL-7 overexpression in MF and pleomorphic T-cell lymphoma. This indicates that IL-7 is probably not an autocrine growth factor in these CTCLs (40).…”

The Role of Cytokines in Cutaneous T Cell Lymphoma: A Focus on the State of the Art and Possible Therapeutic Targets

“…However, there are very few works on the subject [142,144,146], and some have contrasting opinions, concluding that there is no in vivo confirmation of this correlation [46]. It is being studied as a potential immunotherapeutic drug [147], but there are no data regarding this use for CTCLs.…”