Provided are methods for reducing haematocytes in an individual. The method involve administering to an individual a composition that contains recombinant a2,6-sialyltransferase (ST6Gal I). The method is suitable for prophylaxis and therapy of a condition that is positively correlated with undesirable hematopoiesis. Such conditions include autoimmune diseases, transplantation rejection, blood cancers and allergic reactions and inflammations. The invention also provides a pharmaceutical preparation that contains recombinant ST6Gal I and which is suitable for administration to an individual to reduce haematocytes in the individual, and a pharmaceutically acceptable carrier.
