Effects of thalassaemic serum on the in vitro development of the malarial parasite Plasmodium falciparum.

Sera from thalassaemic individuals were experimentally tested for their suppressive effects on the in vitro development of asexual stages of Plasmodium falciparum. Cultures in sera collected from six patients who had classical haemoglobin H disease (alpha-thal1-alpha-thal2) and six patients who had haemoglobin H disease with haemoglobin (Hb) Constant Spring (alpha-thal1-CS) showed a significantly higher degree of inhibition of parasite multiplication than cultures of thalassaemic erythrocytes in sera from healthy individuals. Similarly, sera from 12 patients with beta-thalassaemia/haemoglobin E (beta-thal-HbE) diminished parasite development in vitro. Schizonts of P. falciparum cultured in erythrocytes from non-thalassaemic individuals containing normal Hb (alpha 2 beta 2) were also inhibited when thalassaemic serum was used in place of normal serum. The degree of inhibition was proportional to the concentration (vol/vol) of the thalassaemic serum.