However, some patients are at risk of developing P jirovecii pneumonia: Patients with HIV infection and CD4+ T cell counts < 200 / microL Organ transplant recipients Patients with hematologic cancers Patients taking corticosteroids or other immunosuppressive drugs Most patients have fever, dyspnea, and a dry, nonproductive cough that evolves over several weeks (HIV infection) or over several days (other causes of compromised cell-mediated immunity).