Antibody-dependent red cell removal during P. falciparum malaria: the clearance of red cells sensitized with an IgG anti-D.

The clearance of autologous red cells sensitized with an IgG anti-D has been studied in patients during and after an attack of P. falciparum malaria, and in 11 uninfected control subjects. In most patients with P. falciparum malaria there was evidence of increased clearance of sensitized red cells, compared to controls. Clearance half-times of IgG sensitized red cells were significantly decreased (P less than 0.01) in 16 patients with acute falciparum malaria (median 21 min, range 11-53 min) compared to 11 control subjects (median 37 min, range 20-60 min). This difference was independent of the degree of IgG sensitization of red cells. In patients with acute falciparum malaria, clearance half-times were positively correlated with venous haematocrit (P less than 0.05). In 11 patients studied between 1 and 9 weeks after the attack, clearance half-times (median 17 min, range 11-56 min) were also significantly decreased compared to controls (P less than 0.01). In the majority of acute and convalescent patients, there was further evidence for early destruction of an additional substantial proportion of sensitized red cells. Our data indicate that in most patients with uncomplicated P. falciparum malaria, IgG sensitized red cells are rapidly removed from the peripheral circulation by the spleen, and that rapid clearance persists during recovery.