Premium
Effects of α‐thalassemia‐2 on the developmental changes of hematological values in children with sickle cell disease from georgia
Author(s) -
Felice A. E.,
McKie K. M.,
Cleek M. P.,
Marino E. M.,
Kutlar A.,
McKie V. C.
Publication year - 1987
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.2830250405
Subject(s) - mean corpuscular hemoglobin , mean corpuscular volume , thalassemia , hemoglobin , hemolysis , mean corpuscular hemoglobin concentration , medicine , hemolytic anemia , hemoglobinopathy , sickle cell anemia , alpha thalassemia , fetal hemoglobin , anemia , hematology , biology , disease , immunology , gene , genetics , genotype , pregnancy , fetus
The hematology and pathophysiology of sickle cell disease during the postnatal development of younger hemoglobin (Hb) S homozygotes (SS) could be considerably affected by a variability of α globin gene numbers. We have documented longitudinal developmental changes of hematological values and hemoglobin composition on 147 patients with SS (αα/αα), 64 with SS (‐α/αα), and 9 with SS (–α/–α) between the ages of 1 and 15 years. Non‐steady‐state data were excluded from these analyses. The number and organization of α globin genes was established by gene mapping. As anticipated, mean corpuscular volume and erythrocyte counts correlated with α globin gene numbers throughout the 15‐year age interval. On the other hand, SS children with αα/αα, –α/, –α had similar hemoglobin concentrations up to the ages of 5–10 years. Around the age of 7, the SS patients with –α/–α developed a higher Hb concentration than that of the SS (–α/αα), which in turn was higher than that of the SS (αα/αα). The emergence of this difference coincided with a developmental increase of the mean corpuscular hemoglobin concentration (MCHC) in patients with SS (αα/αα) and the decline of Hb F % under 15%. This newly observed developmental change of the MCHC could lead to increased hemolysis and anemia after the age of 5‐10 years. It occurs to a smaller extent among SS (–α/αα) or not at all among SS (–α/αα) such that these two categories of patients have less severe hemolysis and higher hemoglobin levels at older ages. Although the proportion of Hb F was independent of α globin gene numbers, the absence of Hb Bart's suggested that α‐thalassemia promotes the intracellular assembly of Hb F over Hb S tetramers. Thus, the interaction of α‐thalassemia and Hb F in young SS patients may be more complex than revealed by Hb F levels in cell lysates. Among older SS children (> 7 years) α‐thalassemia and Hb F levels exceeding 15% appear to have additive effects in diminishing the rate of hemolysis.