ビタミンB₁₂欠乏性巨赤芽球性貧血の治療経過中に顕在化した真性赤血球増加症の1例

抄録

A 58 year-old male was admitted because of severe anemia in March 1987. Peripheral blood showed severe macrocytic anemia and mild leukocytosis. Remarkable megaloblastic changes were seen in bone marrow smears. Laboratory findings revealed a low level of serum vitamin B₁₂, high LDH and the presence of anti-intrinsic factor antibody. Gastrointestinal tract survey showed no abnormality. No chromosomal abnormality was seen on karyotypic analysis. After the treatment with Vit B₁₂, his peripheral blood showed the tendency to polycythemia. Hyperviscosity symptoms such as headache and slow speech appeared. Circulating red blood cell volume analysed at that time was increased to 54 ml/kg. Bone marrow aspiration showed disappearance of megaloblastic changes. The numbers of BFU-E and CFU-E were increased and endogeneous colony formation of CFU-E was detected when cultured without the addition of erythropoietin.