Children with sickle cell anemia have an increased susceptibility to bacterial infections, especially to those caused by Streptococcus pneumoniae. We therefore conducted a multicenter, randomized, double-blind, placebo-controlled clinical trial to test whether the regular, daily administration of oral penicillin would reduce the incidence of documented septicemia due to S.pneumoniae in children with sickle cell anemia who were under the age of three years at the time of entry. The children were randomly assigned to receive either 125 mg of penicillin V potassium (105 children) or placebo (110 children) twice daily. The trial was terminated 8 months early, after an average of 15 months of follow-up, when an 84 percent reduction in the incidence of infection was observed in the group treated with penicillin, as compared with the group given placebo (13 of 110 patients vs. 2 of 105; P = 0.0025), with no deaths from pneumococcal septicemia occurring in the penicillin group but three deaths from the infection occurring in the placebo group. On the basis of these results, we conclude that children should be screened in the neonatal period for sickle cell hemoglobinopathy and that those with sickle cell anemia should receive prophylactic therapy with oral penicillin by four months of age to decrease the morbidity and mortality associated with pneumococcal septicemia.

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Microspherocytes, measuring 2-3 mum in diameter, and cells with blunted projections or triangular in shape characterized the erythrocoyte morphology in three children with congenital haemolytic anaemia. Since the erythrocyte morphology resembled that associated with thermal injury, heat-induced changes in erythrocyte morphology and membrane composition were studied. Erythrocytes developed filaments and spheroid bodies which fragmented, resulting in microspherocyte transformation. Normal cells required exposure to 49 degrees C, whereas the patients' cells fragmented at 45 degrees C. Fragmentation was also observed during incubation of patients' cells at 37 degrees C for 17h. The heat-induced transformation of the patients' cells was associated with an increase in the membrane cholesterol:phospholipid and cholesterol:protein ratios. The phospholipid:protein ratio was unchanged. This suggests that fragmentation produces a selective loss of membrane components. Splenectomy ameliorated the haemolytic process. We propose that the patients' red-cell morphology is the result of in vivo fragmentation, and that the spleen is the major site of microspherocyte and poikilocyte destruction.