Serum Vitamin B12 Concentrations in Leukaemia and in some other Haematological Conditions

THE vitamin B, , concentrations in the serum of normal subjects, of patients with niegaloblastic anaemia due to vitamin B, , deficiency and of patients with various other diseases have been previously reported by us (Mollin and Ross, 1952, 1954). Assays of vitamin B,, were made with Euglena gracilis var. bacillaris as test organism. The total vitamin B, , concentration of the serum of 126 healthy normal subjects aged 15 to 70 years ranged from IOO to 900 wg./ml. with a mean of 362 wg./ml. Almost all the vitamin was in the combined form. The mean serum B,, concentration in each of 190 patients with pernicious anaemia in relapse was much lower than those of the normal subjects, being less than 100 !.wg./ml.; in the majority of patients it was less than 50 wg./ml. In the patients with other blood disorders the serum B,, concentrations were not significantly different from those of normal subjects. This group included some patients with acute and chronic leukaemia (Mollin and Ross, 1952). More detailed studies of the serum B,, concentrations of patients with different types of leukaemia have shown that while the concentrations in chronic lymphocytic leukaemia and in acute undifferentiated leukaemia were normal, those in chronic myelocytic leukaemia were in all cases very much higher. The mean serum B,, concentrations of patients yith certain other conditions have also been found to be significantly higher than normal. The results of our more recent observations are given in this paper, a summary of which was coniniunicated to the Fifth International Congress of Haematology, which was held in Paris in September 1954. The data now presented have been obtained from 56 patients with leukaemias of various types, 32 with polycythaemia rubra Vera, eight with myelosclcrosis, two with leukaemoid reactions, six with myelomatosis, seven with aplastic anaemia, and one with chronic agranulocytosis. Except where stated in the text, the patients were UIItreated at the time when the assays were made.