Paclitaxel and immune system.

Chemotherapy remains the mainstay of treatment for both early stage as well as metastatic tumors. Paclitaxel (PTX), a novel anticancer drug, is a prominent taxane which is active against a broad range of tumors that are generally considered to be refractory to conventional chemotherapy, with benefits gained in terms of overall survival and disease-free survival. PTX is initially characterized as a mitotic inhibitor, and its anti-neoplastic effect is derived from binding to tubulin and excessive microtubule stabilization. Interestingly, drugs traditionally used for tumor cytoreduction, can exert both positive and negative effects on the host's immune system. PTX also exerts effects on the immune system and displays immunomodulatory traits. For example, PTX is immunostimulatory against tumors and also regulates lymphocyte activation suggesting that apart from promoting inhibition in cell division, it also has some other features and mechanisms which need to be taken into account. The present article reviews the clinical and experimental findings with regard to the effects of PTX on the immune cells including macrophages, dendritic cells (DCs), natural killer (NK) cells, and T and B lymphocytes together with its clinical applications in autoimmune disorders and organ transplantation which reflect greater therapeutic application of PTX beyond tumor chemotherapy.