Evaluation of serum sialyl Lewisx-i in hematologic disorders.

Sialyl Lewisx-i (SLX) was found in more than 40% of patients with acute leukemia or chronic myelogenous leukemia, and in about 20% of those with myelodysplastic syndrome or malignant lymphoma. This tumor marker was absent in all patients with polycythemia vera, essential thrombocythemia, primary myelofibrosis, chronic lymphatic leukemia, multiple myeloma, and those with acute leukemia or malignant lymphoma in remission. The marker was found in 8% and of the patients with idiopathic thrombocytopenic purpura and 33% of those with autoimmune hemolytic anemia but in no patient with aplastic anemia or megaloblastic anemia. Immunostaining with SLX antibody showed that tumor cells of the patients with high levels of serum SLX were producing the SLX antigen. The detection of this marker in the serum is thought to be useful not only in the diagnosis but also in the observation of the recurrence of the diseases.