[Prevention of parasitic infections (excluding toxoplasmosis) in immunocompromised patients]

Immunocompromised patients, notably those with cell mediated immunity deficiency, are at risk for severe and life-threatening parasitic infections. Severity and frequency of Pneumocystis carinii pneumonia have led to systematically initiate prophylaxis for high-risk patients such as patients with HIV infection, hemopathy or renal transplants. Cotrimoxazole has shown the best efficacy both in primary and secondary prophylaxis. Side effects, notably skin rash, constitute the major limiting factor of cotrimoxazole therapy. However, its efficacy in preventing cerebral toxoplasmosis and to a lesser extent bacterial infections, makes cotrimoxazole the drug of choice for HIV-positive patients in this direction. Aerosolized pentamidine is probably the best alternative considering its similar results in primary prophylaxis for patients with a CD4 count > or = 100/mm3. Dapsone, associated with pyrimethamine for toxoplasmosis prevention, and atovaquone represent other possible alternatives. Such a prevention is absolutely necessary for HIV patients with a previous history of pneumocystosis or with less than 200 CD4/mm3. Moreover, children with SCID or acute leukemia as well as patients with renal or heart-lung transplantation would benefit from pneumocystosis prophylaxis. The frequency of relapses of visceral leishmaniasis also justifies a secondary prophylaxis. Because of its efficacy on P. carinii, intravenous pentamidine could be considered the drug of choice. However preliminary studies have indicated the value of liposomal amphotericin B (1 mg/kg twice a month) in this setting. Finally, cryptosporidiosis and microsporidiosis would benefit from secondary prophylaxis. However, since first line therapy is not well established, further studies are needed to precisely determine which drug could be of value.