The eosinophilic response and haematological recovery after treatment for Plasmodium falciparum malaria

To examine a possible relationship between the immune response and haematol ogical recovery after acute falciparum malaria, we followed peripheral bloo d eosinophil counts and haemoglobin concentrations for 4 weeks after starti ng effective treatment in 70 adult Thai patients. Eosinophils are induced b y Th-2 cytokines as well as other stimuli. Eosinophil counts were elevated in only 8 (11%) of the subjects at presentation,, but were increased in 65 (93%) by day 7. Eosinophil counts then decreased markedly by day 14, follow ed by a second increase until day 28. A significant positive correlation wa s found between peak eosinophil counts on day 7 and the haemoglobin concent ration on day 28, both in 16 subjects without stool parasites (r = 0.65, P = 0.006) and in 54 patients with stool parasites (r = 0.32; P = 0.0019). Th ese results suggest that a robust eosinophilic response shortly after compl eting antimalarial therapy predicts a good recovery from malaria-associated anaemia.