FUNCTIONAL ASPLENIA IN HEMOGLOBIN SC DISEASE

The incidence of functional asplenia in sickle-hemoglobin C (SC) disea se has not been defined, and the use of prophylactic penicillin to pre vent life-threatening septicemia in this disorder is controversial. Th e percentage of red blood cells with pits (pit count) is a reliable as say of splenic function in other disorders but has not been validated in hemoglobin SC disease. To address these issues, we conducted a pros pective, multicenter study of splenic function in persons with hemoglo bin SC disease. Baseline clinical data were recorded, and red blood ce ll pit counts were performed on 201 subjects, aged 6 months to 90 year s, with hemoglobin SC; 43 subjects underwent radionuclide liver-spleen scanning. Pit counts greater than 20% were associated with functional asplenia as assessed by liver-spleen scan, whereas pit counts less th an 20% were found in subjects with preserved splenic function. Pit cou nts greater than 20% were present in 0 of 59 subjects (0%) less than 4 years of age, in 19 of 86 subjects (22%) 4 to 12 years of age, and in 25 of 56 subjects (45%) greater than 12 years of age. Other subjects with hemoglobin SC, who had previously undergone surgical splenectomy, had higher pit counts (59.7% +/- 9.5%) than splenectomized subjects w ithout hemoglobinopathy (38.5% +/- 8.8%) or with sickle cell anemia (2 0.5% +/- 1.9%; P < .001). Two subjects with hemoglobin SC disease (not splenectomized), ages 14 and 15 years, with pit counts of 40.3% and 4 1.7% died from pneumococcal septicemia. These data indicate that funct ional asplenia occurs in many patients with hemoglobin SC disease, but its development is usually delayed until after 4 years of age. The pi t count is a reliable measure of splenic function in hemoglobin SC dis ease, but values indicative of functional asplenia (> 20% in our labor atory) are higher than in other disorders. The routine administration of prophylactic penicillin to infants and young children with hemoglob in SC disease may not be necessary. (C) 1995 by The American Society o f Hematology.