To analyze the role of the IL-4Rα during cryptococcosis in the initial period of infection we inoculated WT and IL-4Rα−/− mice with 500 colony forming units (CFU) of the highly virulent C. neoformans strain 1841 (isolated from a HIV/AIDS patient with cryptococcal meningitis [14]) and analyzed the animals starting at 7 days post infectionem (dpi). This evidence concerns the gene IL4R and infection.