ABO hemolytic disease of the newborn: a unique constellation of findings in siblings and review of protective mechanisms in the fetal-maternal system.

Two siblings born 6 years apart presented with similar findings of hepatosplenomegaly, dermal hematopoiesis, hemoglobinuria, and increased platelet consumption, but only moderate anemia and normal serum bilirubin. ABO incompatibility was identified, and other causes were excluded. A review of the current understanding of mechanisms that promote and prevent antibody-mediated hemolysis in the fetus is reviewed. Due to the low ratio of observed to expected significant clinical events among ABO incompatible mother-infant pairs, and the multiplicity of mechanisms that diminish hemolysis, we speculate that severe ABO hemolytic disease of the newborn occurs when there is a specific failure in one of these preventive mechanisms.

Iron absorption in the thalassemia syndromes and its inhibition by tea.

To determine the hemoglobin concentration at which iron absorption is minimal, five subjects with thalassemia major and one with thalassemia intermedia underwent a series of iron-absorption studies. The effect of tea as an inhibitor of non-heme iron absorption was also tested. Iron absorption increased as the hemoglobin concentration decreased, although iron absorption was much higher at any given hemoglobin level in the subject with thalassemia intermedia. In the subjects with thalassemia major, iron absorption averaged 10 per cent at hemoglobin concentrations between 9 and 10 and 2.7 per cent between 11 and 13 g per deciliter. The percentage of iron absorbed could be accurately predicted from the nucleated red-cell count (r = 0.91, P less than 0.001). Tea produced a 41 to 95 per cent inhibition of iron absorption. Since patients with thalassemia intermedia may absorb a large percentage of dietary iron, inhibitors of iron absorption, such as tea, may be useful in their management.