Henry Sherwood Lawrence discovered that blood cells could 'transfer' antigen-specific cell-mediated immunity even after the cells had undergone lysis. This lymphocyte product is sometimes referred to as "dialyzable leukocyte extract" in the scientific literature due to being an extract from white blood cells undergoing dialysis to remove all molecules larger than ~5000 Daltons. Studies on cellular transfer factor have involved mostly animal models and small human clinical trials. These studies have demonstrated preliminary evidence of immune modulation as well as some clinical benefits in a handful of diseases, but the studies not been assessed beyond primary sources and the trials should only be considered pre-clinical.