GPT and B-cell chronic lymphocytic leukemia: Winkler et al. studied 11 patients that underwent rituximab treatment for fludarabine-resistant recurrent CLL/ NHL and reported that serum concentrations of liver enzymes, including ALT, AST, and GGT, increased to levels that exceeded the normal range by a factor greater than 5, whereas the concentration of ALP, and direct and indirect bilirubin remained stable throughout antibody treatment [7].