The present invention relates to highly active glycoproteins with specific sialylation degrees, a pharmaceutical composition for use in diagnosis or therapy comprising the glycoproteins, a method for the determination of highly active glycoproteins and of the conditions for their production, a method for producing the highly active glycoproteins, and a method for differential sialylation of secretory glycoproteins. The invention also relates to the use of the recombinantly expressed highly active glycoproteins for biological purposes and for prophylactic and/or therapeutic treatment or diagnosis of diseases, particularly bone marrow transplantation, neutropenia, cytopenia, AML and myelodysplastic syndromes, cancer, HIV and/or diseases of hematopoietic systems.
