Serum lysozyme and vitamin B 12 binding capacity in myeloproliferative disorders.

Abstract

Summary Estimations of serum lysozyme (muramidase), total B12 binding capacity (TB12BC) and folate were performed in 122 patients: 69 with myeloproliferative disorders (39, polycythaemia rubra vera (PRV); 10, chronic granulocytic leukaemia, Ph1‐chromosome positive (CGL); 20, myelosclerosis) and 53 with other disease which affect leucocyte production or turnover (17, monocytic leukaemias; 20, megaloblastic anaemia; 15, neutropenia; and a single case of red cell aplasia progressing to a myeloproliferative disorder).The highest serum lysozyme levels were found in monocytic leukaemia. Serum lysozyme concentrations were also elevated in myelosclerosis and to a lesser extent in CGL and in PRV. High levels in PRV occurred in patients developing myelosclerosis or with active disease, resistant to treatment. Significantly higher concentrations of lysozyme were present in patients with myelosclerosis following PRV than in patients with the primary form of the disease. Patients with myeloproliferative diseases and high lysozyme concentrations tended to have low serum folate levels.Slightly raised levels were found in about 50% of patients with megaloblastic anaemia. Moderately high serum lysozyme concentrations also occurred in patients with neutropenia and hypercellular bone marrows but not in those with hypocellular marrows.TB12BC concentrationswere increased in the myeloproliferative disorders, especially in CGL and to a lesser extent in myelosclerosis and least of all in PRV. The results suggest that serum lysozyme reflects granulocyte turnover (except in monocytic leukaemia) while TB12BC (providing liver function is normal) correlates closely with the total blood (and possibly marrow and splenic) granulocyte pool. The ratio between serum lysozyme and TB12BC proved to be a useful index of the balance between granulocyte turnover and total granulocyte pool in individual patients.