Generally, there are some risk factors for the development of PJP, including immunosuppressive therapy especially corticosteroids and chemotherapy, solid organ transplantation, low CD4+ T cell counts, neutropenia and so on.[3] As previously reported,[4,5] PJP is more severe in HIV-negative patients comparing to HIV-positive patients, as with much higher rates of intensive care unit admission and mortality. This evidence concerns the gene CD4 and pneumocystosis.