Effect of splenic congestion associated with hemolytic anemia on mortality of rats challenged with Haemophilus influenzae b.

The effect of splenic congestion associated with acute hemolytic anemia on susceptibility to bacterial infection was investigated in rats inoculated with Haemophilus influenzae b by intranasal (in) or intravenous (iv) challenge. The rats were made anemic by phenylhydrazine treatment and were challenged with 10(6) (in) or 5 X 10(7) (iv) H influenzae b. Forty-eight hours after in inoculation of bacteria, the number of bacteria in the blood was 10 times greater in the anemic rats with extensive splenic congestion than in controls. After iv inoculation of bacteria, a significantly (P less than 0.001) higher mortality rate was found in the anemic rats with extensive splenic congestion and fewer bacteria were present in the spleens but not the livers, as compared to normal rats. Since phenylhydrazine-induced hemolytic anemia exhibited an extensive congestion in the spleen, higher mortality rate observed in the anemic rats challenged with H influenzae b may result, in part, from decreased intravascular clearance of bacteria by the spleen.