Effect of inherited red cell defects on growth of Plasmodium falciparum: An in vitro study

BACKGROUND & OBJECTIVES: High prevalence of certain polymorphic alleles of erythrocytes in malaria endemic area has been linked to the resistance provided by these alleles against parasitic infestations. Numerous studies undertaken to demonstrate this correlation have generated conflicting results. This study was undertaken to investigate the abilities of various polymorphic erythrocytes to support in vitro growth of Plasmodium falciparum parasites. METHODS: In this study under in vitro condition the ability of P. falciparum parasites to grow was assessed in the erythrocytes obtained from a total of 40 patients with various haemoglobinopathies, such as β-thalassaemia (β-Thal), sickle cell anaemia, erythroenzymopathy-like glucose-6-phosphate dehydrogenase deficiency and membranopathy-like hereditary spherocytosis. RESULTS: Significantly reduced in vitro invasion and growth of parasites was seen in the cultures containing abnormal erythrocytes than in control cultures containing normal erythrocytes (P< 0.05). The mean per cent parasitaemia comparison was also carried out among the three polymorphic erythrocyte groups, i.e. β-Thal, sickle cell anaemia and enzyme-membranopathies. INTERPRETATION & CONCLUSIONS: Erythroenzymopathies and membranopathies were found to provide a more hostile environment for parasites, as the least parasitaemia was observed in these erythrocytes. The present in vitro study showed that P. falciparum did not grow well and did not invade well in erythrocytes obtained from common inherited red cell disorders.