Efficacy of Intravenous Immunoglobulin in Patients With Hemorrhagic Fever With Renal Syndrome: a Prospective Study

Inclusion Criteria: The patients must meet all of the following criteria: * Age ≥ 18 years, regardless of gender; * Within 5 days of onset, hospitalized patients diagnosed with epidemic hemorrhagic fever (hemorrhagic fever with renal syndrome) must have at least one of the following laboratory test results: 1. Positive for serum specific IgM(immunoglobulin M) antibodies; 2. Or detect hantavirus RNA(ribonucleic acid) from patient specimens; 3. Or the serum specific IgG(immunoglobulin G) antibody titer in the recovery phase is more than four times higher than that in the acute phase; 4. Or hantavirus can be isolated from patient specimens. * Meet any of the following criteria: 1\. Severe illness: meet any of the following criteria: (i) Platelet count 20-50×10\^9/L; (ii) White blood cell count 15-30×10\^9/L. 2. Critical illness: meet any of the following criteria: (i) Platelet count\<20×10\^9/L; (ii) White blood cell count\>30×10\^9/L. * Volunteer to join this study and be able to sign or have a written informed consent form signed by a legal representative. Exclusion Criteria: Exclude patients who meet any of the following criteria: * Patients with primary chronic kidney disease; * Patients with severe diabetes, hypertension, heart, lung, gastrointestinal tract, liver, autoimmune disease or nervous system disease; * Have a history of malignant tumors (including solid malignant tumors and hematological malignancies etc.); * Recent use of potentially nephrotoxic drugs; * Pregnant or potentially pregnant patients; * Patients with a history of hypersensitivity to IVIG (intravenous immunoglobulin) ; * Selective IgA(immunoglobulin A) deficiency patients with IgA antibodies; * Known or suspected immunodeficiency (human immunodeficiency virus infection, primary immunodeficiency), use of immunosuppressive drugs (glucocorticoids); * Alcoholics, drug abuse, and psychiatric patients * Other conditions which researchers deem not suitable for inclusion.