Polycythemia Rubra Vera With Pernicious Anemia Some Observations on Vitamin B₁₂ Metabolism

A patient with polycythemia rubra vera developed symptoms and signs of pernicious anemia three years after institution of therapy for the polycythemia. This is the first satisfactorily documented report of this sequence. Strict criteria utilized make both diagnoses unequivocal. Autoantibody studies, the first performed in such a patient, show the presence of parietal cell and intrinsic factor autoantibodies but no antibodies to other tissues. Vitamin B₁₂ requirements have been excessive despite high or high normal serum levels and extreme marrow sensitivity to withdrawal of the Vitamin is evident in the presence of these high serum levels. Studies on Vitamin B₁₂ binding proteins showed an elevation in α binding globulin with reversal of the α to β ratio. It is suggested that this protein is physiologically abnormal. The literature is briefly reviewed regarding the pathogenesis of the two disorders with the conclusion that their appearance in the one patient represents purely a chance phenomenon.