The present invention relates to methods for increasing the activity of the immune system and, especially, to methods for increasing the activity of the immune system by modulation of endogenous ectophosphatase levels. According to a particularly preferred embodiment the present invention relates to methods for the prophylaxis of mammals, and especially human mammals, at risk of inflammatory diseases such as mammals suffering from conditions such as surgery, digestive tract diseases, respiratory diseases, skin diseases, burn wounds, smoke inhalation, intoxication, severe blood loss, food poisoning, chemotherapy, radiation 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.
