A thorough battery of immunology endpoints was examined in mice administered patulin daily by gavage for 28 days at doses of 0.08 to 2.56 mg patulin/kg b.w. [97]. These doses were calculated to be approximately equivalent to estimated human exposure levels. Changes in immune cell numbers included depressed peripheral blood leukocytes and lymphocytes numbers (observed at 1.28 and 2.56 mg toxin/kg b.w./day), an increased number of splenic monocytes and Natural Killer cells (from 0.08 mg toxin/ kg b.w./day), an increased number of cytotoxic T lymphocytes (at 2.56 mg patulin/kg b.w./day) and changes in the percentage of immunoglobulin (Ig)+, CD3+, CD4+/CD8− and CD4−/CD8+ lymphocytes in the spleen. These changes in cell number did not reflect functional changes. There were no measurable changes in immune function in patulin-treated mice using the following endpoints: antibody response to sheep red blood cells (SRBC), mixed leukocyte responses and Natural Killer cell functions. The authors concluded that exposure to patulin, at levels consistent with potential human exposure in food would not be likely to alter immune responses