Search

Vitamin C or ascorbic acid (AA) is implicated in many biological processes and has been proposed as a supplement for various conditions, including cancer. In this review, we discuss the effects of AA on the development and function of lymphocytes. This is important in the light of cancer treatment, as the immune system needs to regenerate following chemotherapy or stem cell transplantation, while cancer patients are often AA-deficient. We focus on lymphocytes, as these white blood cells are the slowest to restore, rendering patients susceptible to often lethal infections. T lymphocytes mediate cellular immunity and have been most extensively studied in the context of AA biology. In vitro studies demonstrate that T cell development requires AA, while AA also enhances T cell proliferation and may influence T cell function. There are limited and opposing data on the effects of AA on B lymphocytes that mediate humoral immunity. However, AA enhances the proliferation of NK cells, a group of cytotoxic innate lymphocytes. The influence of AA on natural killer (NK) cell function is less clear. In summary, an increasing body of evidence indicates that AA positively influences lymphocyte development and function. Since AA is a safe and cheap nutritional supplement, it is worthwhile to further explore its potential benefits for immune reconstitution of cancer patients treated with immunotoxic drugs. [ABSTRACT FROM AUTHOR]

After decades since the discovery of natural killer (NK) cells as potential effector cells fighting malignantly transformed and virally infected cells, little progress has been made in their clinical application. This yet unrealized therapeutic effect is presumably, at least in part, due to low numbers of functional NK cells that could be obtained from the peripheral blood relative to tumor burden. Our group hypothesized that a relatively small NK cell number to targeted malignant cells is the cause of a lack of clinical effect. We pursued obtaining large numbers of NK cells via ex vivo expansion using feeder cells that express membrane-bound IL-21. Early clinical studies demonstrate safety of administration of ex vivo expanded NK cells after transplantation using this method and suggest a therapeutic benefit in terms on decreasing relapse rate and possible control of viral infections post-transplant can be achieved. Successful application of NK cells after hematopoietic stem cell transplantation opens the possibility to effectively enhance the anti-tumor effect and decrease relapse rate post-transplant. Moreover, high doses of NK cells could prove more efficacious in enhancing anti-tumor effects, not only in hematological malignancies, with our without transplantation, but also in solid tumor oncology. [ABSTRACT FROM AUTHOR]