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Reference values and hematologic changes from birth to 5 years in patients with sickle cell disease. Cooperative
A K Brown1, L A Sleeper, S T Miller
1Department of Pediatrics, State University of New York Health Science Center at Brooklyn.
Insights
This study establishes hematologic reference values for infants with sickle cell disease (SCD) up to age 5. Key findings show anemia onset by 10 weeks in sickle cell anemia (SS) infants and declining splenic function.
Area of Science:
- Hematology
- Pediatric Medicine
- Genetics
Background:
- Sickle cell disease (SCD) encompasses several inherited blood disorders.
- Establishing accurate hematologic reference values is crucial for monitoring disease progression and treatment efficacy in pediatric SCD patients.
- Longitudinal data on hematologic changes from birth to age five in infants with SCD are limited.
Purpose of the Study:
- To longitudinally examine hematologic changes in infants and children with sickle cell disease from birth to five years of age.
- To establish comprehensive hematologic reference values for pediatric populations with SCD.
- To identify specific hematologic patterns associated with different SCD genotypes.
Main Methods:
- Prospective natural history study conducted across nineteen pediatric sickle cell centers in the United States.
- Enrollment of 694 infants with SCD (sickle cell anemia, sickle cell-hemoglobin C disease, and sickle-beta-thalassemia) before six months of age.
- Median follow-up duration of 4.1 years, extending through five years of age.
Main Results:
- Anemia was evident by 10 weeks in sickle cell anemia (SS) infants, associated with increased reticulocyte counts indicating hemolysis.
- Fetal hemoglobin (HbF) declined slower in SS infants compared to sickle cell-hemoglobin C (SC) infants.
- Pocked red blood cell (RBC) counts increased significantly after six months, suggesting impaired splenic function in SS infants by age one.
- SS patients with alpha-thalassemia exhibited higher hemoglobin and lower pocked RBC/reticulocyte counts post-six months compared to those without.
- SC infants showed a hematologic profile closer to normal infants, with mild anemia and slightly elevated reticulocytes and HbF.
Conclusions:
- Hematologic reference values for infants and children with SCD can be established through longitudinal studies.
- Early onset of anemia and progressive decline in splenic function are characteristic of sickle cell anemia in early childhood.
- The presence of alpha-thalassemia may modify the hematologic presentation of sickle cell anemia.
- Sickle cell-hemoglobin C disease presents with a milder hematologic profile compared to sickle cell anemia in early childhood.
Objective:
To examine hematologic changes from birth to 5 years of age and establish hematologic reference values for infants and children with sickle cell disease.
Research Design:
Prospective natural history study.
Setting:
Nineteen pediatric sickle cell centers across the United States.
Patients:
Six hundred ninety-four infants with sickle cell disease (sickle cell anemia, sickle cell-hemoglobin C disease, and sickle-beta-thalassemia) who were enrolled in the Cooperative Study of Sickle Cell Disease at younger than 6 months of age. Median follow-up time through 5 years of age was 4.1 years.
Measurements And Results:
We present longitudinal analyses of total hemoglobin concentration, percent fetal hemoglobin values, mean corpuscular volumes, total bilirubin concentration, and red blood cell (RBC), "pocked" RBC, white blood cell, platelet, and reticulocyte counts. Anemia was apparent by 10 weeks of life in infants with sickle cell anemia (SS infants). This anemia was associated with a rising reticulocyte count consistent with a hemolytic process. The reticulocyte count of SS infants increased steadily, exceeding 12% at 5 years of age. The fetal hemoglobin concentration of SS infants declined more slowly than that of infants with sickle cell hemoglobin C disease (SC infants). Pocked RBC counts rose sharply after 6 months of age, and by 1 year, 28% of SS infants had abnormal counts, above 3.5%, indicating poor splenic function. At 3 years of age, 78% of SS patients and 32% of SC patients had abnormal pocked RBC counts. The SS patients with concurrent alpha-thalassemia had, after 6 months of age and throughout early childhood, a slightly higher mean total hemoglobin concentration and lower mean pocked RBC and reticulocyte counts than SS patients without alpha-thalassemia. The hematologic profile of SC infants more closely resembled that of normal black infants, but there was mild anemia (10.5 g/dL) and slightly elevated mean values for reticulocytes (3%) and fetal hemoglobin (3%) during early childhood.