The present invention relates to methods for increasing the activity of the immune system and, especially, to meth-ods for increasing the activity of the immune system by modulation of endogenous ectophosphatase levels. According to a particu-larly preferred embodiment, the present invention relates to methods for the prophylaxis of mammals, and especially human mam-mals, at risk of inflammatory diseases such as mammals suffering from conditions such as surgery, digestive tract diseases, respi-ratory diseases, skin diseases, burn wounds, smoke inhalation, intoxication, severe blood loss, food poisoning, chemotherapy, ra-diation therapy, severe trauma or liver diseases, immunocompromised conditions. For this, the present invention provides Use of an ectophosphatase for the preparation of a medicament for the prophylaxis of a mammal at risk of inflammatory diseases.
