To determine whether an autologous dendritic cell (DC) vaccine could induce anti-tumor immune responses in patients after resection of colorectal cancer metastases and whether these responses could be enhanced by activating DCs with CD40L.

Twenty six patients who had undergone resection of colorectal metastases were treated with intranodal injections of an autologous tumor lysate and control protein (KLH) pulsed DC vaccine. Patients were randomized to receive DCs that had been either activated or not activated with CD40L. All patients were followed for a minimum of 5.5 years.

Immunization induced an autologous tumor-specific T-cell proliferative or IFNγ ELISPOT response in 15 of 24 assessable patients (63%) and a tumor specific DTH response in 61%. Patients with evidence of a vaccine induced, tumor specific T-cell proliferative or IFNγ response one week after vaccination had a markedly better recurrence free survival (RFS) at 5 years (63% vs. 18%, p=0.037) than non-responders. In contrast, no association was observed between induction of KLH-specific immune responses and RFS. CD40L maturation induced CD86 and CD83 expression on DCs but had no affect on immune responses or RFS.

Adjuvant treatment of patients after resection of colorectal metastases with an autologous tumor lysate pulsed DC vaccine induced tumor-specific immune responses in a high proportion of patients. There was an association between induction of tumor-specific immune responses and recurrence free survival. Activation of this DC vaccine with CD40L did not lead to increased immune responses.

PMID: 20884622 [PubMed - as supplied by publisher] Source: National Library of Medicine.