Intravenous Immunoglobulin for the Treatment of Acute Exacerbations of Idiopathic Pulmonary Fibrosis

Inclusion Criteria: 1. Patients ≥ 18 years of age 2. Patients with IPF diagnosis that fulfils ATS/ERS Consensus Criteria. 3. Patients hospitalised with a definite or suspected AE-IPF diagnosis, as defined by the international working group criteria and as ascertained by the responsible Primary Investigator. The criteria of IPF-AE are as follows: * Previous or concurrent diagnosis of IPF * Acute worsening or development of dyspnoea typically \< 1 month duration * Computed tomography with new bilateral ground-glass opacity and/or consolidation superimposed on a background pattern consistent with usual interstitial pneumonia pattern * Deterioration not fully explained by cardiac failure or fluid overload Patients who fail to meet all 4 criteria due to missing computed tomography should be considered as having "suspected Acute Exacerbation". A) If the diagnosis of IPF is not previously established, this criterion can be met by the presence of radiologic and/or histopathologic changes consistent with usual interstitial pneumonia pattern on the current evaluation. B) If no previous computed tomography is available, the qualifier "new" can be dropped from the third AE-IPF criterion. 4. Patient able to understand and sign a written informed consent form. In case of incapacity of the patient, the written informed consent form will be signed by the patients' legally authorized representative. Exclusion Criteria: 1. Patients with acute worsening due to uncontrolled heart failure or pulmonary embolism. 2. Patients with known hypersensitivity to corticosteroids, IVIG or any component of the study treatment. 3. Patients with known IgA deficiency (IgA level \<7 mg/dL)- to preclude IVIG reactions. 4. Patients without a definite diagnosis of IPF or AE-IPF based on clinical, radiological, laboratory evaluation, and multidisciplinary discussion. 5. Patients with active malignancy or currently receiving cancer treatment, except for basal cell or squamous cell skin cancer or low-risk prostate cancer (T1 or T2a stage with PSA \<10 ng/dL). These criteria are aligned with current guidelines. 6. Patients that have received treatment for \>14 days within the preceding month with \>20mg daily prednisone (or equivalent) or any treatment during the last month with immunosuppressants (e.g., cyclophosphamide, mycophenolate etc.) according to already published therapeutic protocols or \> 1 mg/kg/d from more than 7 days in the last 15 days. 7. Patients participating to another interventional clinical trial. 8. Patients with documented pregnancy or lactation. 9. Patients under tutorship or curatorship. 10. Patients deprived of liberty or under court protection. 11. Patients who refuse to participate or decline to provide written informed consent.