Fetal hemoglobin during infancy and in sickle cell adults.

BACKGROUND Fetal hemoglobin has been implicated in the modulation of sickle cell crisis though it is functional during infancy. OBJECTIVE The purpose of this study was to determine the waning time of fetal hemoglobin (HbF) and its persistence in later life. METHOD Ninety infants aged 0-12 months, admitted at hospital, were tested for their HbF levels. Adult patients numbering 690 were also examined for their sickle cell status and a sickle positive patient of SS type with HbF had her family members recruited and their sickle cell types determined. RESULTS The results revealed that HbF was highest (98%) at birth, decreasing at 5% per week till 6 months when it wane off. Ten infants aged 6-12 months had HbF persisting at a level of 10% or more. Adult patients examined showed proportions of their sickle cell types as AS forming 51%, AC 20%, SS 19%, and SC 10%. An SS adult patient with mild sickle cell crisis had an ASF father who had no crisis and a mother and brother with AS each who had severe crisis. CONCLUSION These findings suggest that HbF wanes off during infancy but persist in some adults and may modulate crisis in these adults. This has implications in sickle cell management.