The spectrum of infections in patients with leukemia continues to change. During the past 8 years there has been a significant increase in infections due to fungi and other organisms with a lower order of pathogenicity and a natural resistance to commonly employed antibiotics. Pseudomonas infections constitute the most important bacterial problem. Serious staphylococcal infections have been markedly reduced by the synthetic, penicillinase-resistant penicillins. The reasons for the shifting patterns of infection are considered.
Several approaches to the treatment of the above infections through improving or replacing host defense mechanisms are considered. Granulocyte transfusions are effective in the management of Pseudomonas septicemia and significantly reduce the mortality of that disease. The host-defense deficits responsible for the frequency of fungus infections are considered. It is proposed that this deficit relates primarily to failure of lymphocyte function.