Estudio del patrón de citocinas (Th1/Th2) producido por linfocitos T periféricos y del existente en tejido tumoral de pacientes con melanoma en diferentes estadios

Objectives. The Th1 or Th2 diferentiation of T cells ac- cording to their profile of cytokine expression is of great rele- vance in the regulation of immune responses.We have determi- ned by flow cytometry the expression of selected Th1 and Th2 cytokines by activated T cells in whole blood samples (WB) from normal donors and from patients with melanoma in different cli- nical stages. Additionally, we have studied the mRNA expression of several cytokines in melanoma tissue and compared it with normal skin. Methods. WB samples from 6 normal donors and 19 patients with melanoma were activated during 4 hours with PMA+ ionomycin in the presence or absence of an inhibitor of protein se- cretion (GolgiStop). Following surface staining (CD3-Cy5+CD8- FITC), fixation and permeabilization (CytoFix-CytoPerm) cells we- re stained with PE-labelled antibodies against Th1 cytokines (IL-2, IFN-, TNF-) and Th2 citokines (IL-4, IL-10). In the second part of the study, we investigated the presence of IL-2, IFN-, TNF-, IL-4, IL-5, IL-10 messenger RNA (mRNA) in 6 biopsy specimens of melanoma and compared it with 1 nevus and 1 normal skin by a real time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) tecnique. Results. The most clear and relevant results of the flow cytometry study were related to IFN- and IL-10 production. The percenta- ge of IFN- producing cells was significantively lower in melano- ma patients, independently of the stage, than in controls. IL-10 production was significantly increased in the melanoma patients with respect to normal donors. There is also a tendency to in- crease IL-10 production in the more advanced stages of the di- seae. The quantitative RT-PCR technique performed in melano- ma specimens (primary or metastatic) showed cytokine transcripts of Th2 o Th0 subtypes. Conclusions. Our data sugget that activated lymphocytes from normal donors tend to exhibit a Th1 phenotype, while melanoma patients have a higher proportion of IL-10 producing lym-phocy- tes, a cytokine with recognized immunosuppresive properties and characteristic of the Th2 phenotype. The results obtained from the melanoma tumor support the concept of a predominance of the Th2 response in melanoma patients.