Corticosteroids for PJP in Non-HIV Immunocompromised Adults

Inclusion Criteria: Age ≥ 18 years. Admission to the Intensive Care Unit (ICU). Meeting the diagnostic criteria for community-acquired pneumonia (CAP). Meeting at least one of the major diagnostic criteria for severe pneumonia: (i) Requirement for endotracheal intubation and mechanical ventilation; (ii) Septic shock requiring vasopressor therapy after adequate fluid resuscitation. Or simultaneously fulfilling three of the minor criteria: (i) Respiratory rate ≥ 30 breaths/min; (ii) PaO₂/FiO₂ ≤ 250 mmHg; (iii) Multilobar infiltrates; (iv) Altered mental status and/or disorientation; (v) Blood urea nitrogen ≥ 20 mg/dL (7.12 mmol/L); (vi) Leukopenia (white blood cell count \< 4 × 10⁹/L); (vii) Thrombocytopenia (platelet count \< 100 × 10⁹/L); (viii) Hypothermia (core temperature \< 36 °C); (ix) Hypotension (systolic blood pressure \< 90 mmHg) requiring aggressive fluid resuscitation. Confirmed PJ etiology: at least one positive nucleic acid test (PCR) or next-generation sequencing (NGS) result for Pneumocystis jirovecii in respiratory specimens (respiratory secretions, throat swabs, or bronchoalveolar lavage fluid). Severe community-acquired pneumonia (SCAP) patients admitted to the emergency department/ward/ICU due to respiratory failure within \< 72 hours. Signed informed consent. Exclusion Criteria: * Age \< 18 years. * Pregnant or breastfeeding women. * HIV infection. * No targeted PJP therapy administered or therapy not according to standard protocol. * Diagnosis of PJP \>7 days prior to MICU admission. * Use of corticosteroids for PJP prior to MICU admission. * Requirement for high-dose baseline corticosteroid therapy for other conditions (prednisone ≥ 0.5 mg/kg/day or equivalent). * Any contraindication to corticosteroid use as judged by the investigator (e.g., severe concurrent infectious disease, severe gastrointestinal bleeding). * Discharge or death within 48 hours after intervention. * Participation in other clinical studies or refusal to participate in this study.