ItAlian ReGistry Of pNeumoniA in immUnocompromised paTients (ARGONAUT)

Inclusion Criteria: Hospitalized patients with a confirmed diagnosis of Community-Acquired Pneumonia (CAP) characterized by at least one of the following risk factors for immunosuppression: * AIDS, * Aplastic anemia; * Asplenia; * Hematologic malignancy (e.g., lymphoma/acute or chronic myeloid leukemia/multiple myeloma); * Chemotherapy within the last 3 months; * Neutropenia defined as a white blood cell count less than 500/dL on a complete blood count; * Use of biologics (including trastuzumab and therapy for autoimmune diseases (e.g., anti-TNF α), prescribed within the last 6 months before hospital admission; * Solid organ transplant; * Bone marrow transplant; * Chronic oral steroid use (\>10 mg/day prednisone or equivalent ≥3 months before accessing the ED, or cumulative dose \> 600 mg prednisone); * Use of corticosteroid therapy with a dose ≥ 20 mg prednisone or equivalent ≥14 days or cumulative dose \> 600 mg prednisone; * Active malignancy; * Malignancy within one year of pneumonia (excluding patients with localized skin cancer or early-stage malignancy); * Lung malignancy with neutropenia/chemotherapy; * Other solid malignancy with neutropenia/chemotherapy; * Other immunodeficiency (including congenital/genetic immunosuppression and immunosuppressive therapy secondary to hematologic malignancy or solid malignancy); * Primary immunodeficiency. Exclusion Criteria: * None