Eleven cases treated with vitamin B12 have been presented. Eight patients with pernicious anemia in relapse responded hematologically. Two patients with mild neurologic involvement were relieved by therapy with B12 alone.
Consideration of the quantities of the crystalline vitamin required to promote maximal erythropoiesis in pernicious anemia indicates that less than about 0.75 µg. daily in doses at intervals of several days will not suffice to establish and maintain blood values as high as does adequate treatment with liver extract. Parenteral daily doses of 1.0 µg. promoted good erythropoiesis in one patient, although it appears that the maximum rate of hemopoiesis may require the initial average daily dose of approximately 3.0 µg.
The reticulocyte count is an unreliable quantitative criterion of activity or adequacy of therapy.
It is suggested that hemopoietic factors in addition to PGA and B12 may be required by some patients to obtain maximal erythrocyte levels.
Vitamin B12, as well as PGA, effects a reduction in the fecal urobilinogen output of patients with pernicious anemia. The significance of this finding is discussed.
No change in urinary excretion of pteroylglutamate or of porphyrin was detected in patients treated with vitamin B12.