IL17A and clostridium difficile infection: For further elucidation of Th1, Th2, and Th17 involvement in severe CDI, we calculated the ratio of IL-12p70/IL-10, and IL-12p70/IL-5 as a measure for Th1/Th2 response proportion, and the IL-12p70/IL-17A as a measure for Th1/Th17 response.