Hemoglobin and Red Blood Cells Versus Malaria

The plasmodial parasites that cause malaria put themselves largely outside the reach of the immune system by sequestering themselves in red cells, liver cells, and sometimes cells in the spleen and bone marrow. That has forced a different kind of defense strategy over the millennia: evolutionary changes in the genetic programming of hemoglobin and red cells. Mutations are common in those with ancestral ties to the malaria belt extending from sub-Saharan Africa eastward through the Middle East to Southeast Asia. Mutations are present in a quarter of all people living today. But those mutations have their own adverse effects. The spectrum of abnormalities include the thalassemias (imbalanced production of α and β globin subunits) and the hemoglobin variants (abnormal β globin subunits, especially the sickle mutation), and red cell glucose-6-phosphate dehydrogenase deficiency and red cell membrane antigen abnormalities.