Reticulocyte evaluation in α⁺‐thalassemia

Abstract

Although it is almost certain that a + -thalassemia protects against malaria, the mechanisms for that are still unknown. It has been suggested that an increased number of young circulating red blood cells in a + -thalassemic children, as a result of some degree of ineffective erythropoiesis, could be related to the high frequencies of the a + -thalassemic allele in malaria endemic areas. Reticulocyte evaluation in this condition, however, has been poorly performed so far. Our objective was to determine the reticulocyte number and maturation degree, in addition to the soluble transferrin receptor and serum erythropoietin levels, in a + -thalassemia heterozygotes, comparing them with normal a-genotype controls. One hundred twenty-one a + -thalassemia carriers (-a 3.7 /aa) and 249 controls (aa/aa), all of them with normal serum ferritin levels, were subclassified according to age (1-5, 6-10, 11-15, 16-20, and over 20 years old). Reticulocyte analyzes were carried out by flow cytometry and sTfR and s-Epo levels determined by immunonephelometry and chemiluminescence, respectively. The comparisons did not show any significant difference between thalassemics and controls regarding the reticulocyte parameters [percentages and absolute values, P = 0.2643 and 0.5421; high, medium, and low maturation degree, P = 0.2579, 0.2196, and 0.4192; RET maturity index (RMI), P = 0.2471, respectively], as well as the s-Epo levels (P = 0.5711). The sTfR concentrations were higher in the thalassemic group (P = 0.0001), but statistical significance was due only to the 1-5 and over 20 subgroups (P = 0.0082 and 0.0436, respectively). The results found here are compatible with a compensated erythropoiesis and do not confirm the hypothesis mentioned above. Am.

Erythrocyte and reticulocyte parameters in iron deficiency and thalassemia

“…The important pathophysiological role played by the deposition of globin chains in erythroid precursors, leading to apoptosis and its correlation with ineffective erythropoiesis, has been assessed in different hemoglobinopathies and thalassemias (33)(34)(35). The IRF values observed are not proportionally increased, in spite of marrow erythroid hyperplasia, but are compatible with an ineffective erythropoiesis described by these authors.…”

An Observational Study of the Effect of Hemoglobinopathy, Alpha Thalassemia and Hemoglobin E on P. Vivax Parasitemia

“… 23 This hypothesis, however, is unlikely as there is no evidence of reticulocytosis in people with α + -thalassemia heterozygous. 32 …”

Effect of α+-thalassaemia on episodes of fever due to malaria and other causes: a community-based cohort study in Tanzania

“…However, there was no strong support that thalassaemia was associated with increased parasite densities in young children, and neither did any previous study. In addition, a recent study found no evidence that reticulocyte counts were increased in individuals with α + -thalassaemia [29]. …”