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The need of a maintenance BCG therapy is suggested by the inability of intravesical bcg to promote a long-term systemic immune t-cell activation

par Zlotta, Alexandre
Référence British journal of urology, 80, SUPPL. 2, page (37)
Publication Publié, 1997

Article révisé par les pairs

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Résumé :

Recent studies have pointed out that clinical results obtained with maintenance therapy with BCG are superior to a single six week BCG intravesical instillations regimen in the prevention of superficial bladder tumor recurrence (TCC). We have investigated whether a single BCG course was able to induce a long-term increase in systemic cellular proliferative response against several BCG antigens. The evolution of the lymphoproliferative response, Interleukin-2 (IL-2) and Interferon γ (IFN-γ) production against BCG culture filtrate (CF), tuberculin (PPD), and whole BCG bacilli was tested before, after 6 weekly intravesical BCG instillations and at six month follow-up in 29 patients with superficial TCC. Lyinphoproliferation and IL-2 production were measured by means of a tritiated thymidinc incorporation test and expressed in cpm. IFN-γ was measured by means of a cytopathic effect reduction assay. A major increase in the lymphoproliferative response against CF, PPD and whole BCG was observed in respectively 79%, 69% and 48% of the patients after a single BCG course as compared to pre-BCG values. Increase in IL-2 and IFN production against these antigens was in a comparable range. At six month follow-up, lymphoprolifcration against all antigens returned to pre-BCG values in all patients. In 13 patients that received a supplementary BCG course because of tumor recurrence during follow-up, a novel increase in lymphoproliferation and cytokine production against the different antigens tested was observed in 52 to 73% of cases. A single course of six weekly BCG intravesical instillations is unable to induce a sustained systemic cellular immune activation (6 months) against several BCG antigens. Reactivation of the immune lymphoproliferative response is observed in a significant percentage of patients when a second BCG course is administered. The need of a maintenance therapy with BCG could be related to the absence of a long term immune activation.