Quality of life-improving effect of autologous ex vivo expanded cytotoxic and opioid-producing lymphocytes for dogs with cancers.

Activated lymphocyte therapy is one of the immunotherapies for cancer patients that is expected to prolong life without any adverse effects and maintain satisfactory quality of life (QOL). However, the objective assessment and maintenance of a standardized evaluation of QOL are not easy. We aimed to evaluate activated autologous lymphocyte therapy for cancer dogs using the characteristics of the cultured cells and QOL as perceived by owners. In in vitro experiments, peripheral blood mononuclear cells (PBMCs) collected from healthy dogs were stimulated using anti-CD3 antibody and recombinant interleukin-2 under a closed system. The number of CD4 and CD8 T lymphocytes in the cultured cells was higher than that of PBMCs (P < 0.05). Natural killer activity, proenkephalin (known as the precursor of endogenous opioids) and interferon-γ mRNA in activated lymphocytes were significantly higher than in PBMCs (P < 0.05). Met-enkephalin was detected in activated lymphocytes. QOL of 58 dogs afflicted with common types of cancers in humans increased after every administration of activated lymphocyte therapy (P < 0.05). Overall, these results indicated that activated lymphocyte therapy could have beneficial effects on QOL in dogs with cancers. This was objectively evaluated and this improvement was related to presence of opioid-producing lymphocytes.