Most patients developed both humoral and T-cell responses to KLH, suggesting immunocompetence.
Eight of 15 patients developed an Id-specific T-cell proliferative response, 8/15 increased interferon-gamma-secreting T cells and 4/15 showed an Id-positive delayed-type hypersensitivity test. Anti-Id cytotoxic T-lymphocyte precursors increased after DC vaccination in 2/2 evaluable patients. A more robust T-cell response was observed after sc DC injections and increased Id-specific T-cell proliferation was found up to 1 year after vaccination. VDJ-derived peptides were as effective as the whole protein in stimulating T-cell responses. Clinically, 7/15 patients have stable disease after a median follow-up of 26 months, one patient achieved durable partial remission after 40 months, and seven patients progressed.
In conclusion, sc injections of cryopreserved Id-pulsed DCs were safe and, in contrast with intravenous administrations, induced anti-MM T-cell responses.