This study is trying to evaluate the efficacy and safety of dose-modified Emapalumab and Ruxolitinib (E-Ru) regimens for the treatment of active hemophagocytic lymphohistiocytosis.

This clinical trial is designed to evaluate a new treatment strategy for patients with active Hemophagocytic Lymphohistiocytosis (HLH)-a rare but severe immune disorder characterized by excessive inflammation and immune system activation. HLH can be life-threatening if not treated effectively.

The study is prospective and multicenter, meaning it will be conducted at multiple hospitals and medical institutions, and patients will be followed over time to assess treatment outcomes.

We aim to test the combination of two medications:

1. Emapalumab, a monoclonal antibody that blocks interferon-gamma, a key driver of the overactive immune response seen in HLH. In this trial, it will be used at a lower-than-standard dose to reduce potential side effects.
2. Ruxolitinib, a JAK1/2 inhibitor that can reduce inflammation by interfering with immune signaling pathways. It will be administered at a higher-than-standard dose to enhance its therapeutic effects.

Inclusion Criteria:

1. Fulfillment of at least five of the eight HLH-2004 criteria for HLH;
2. Age 1-70 years old;
3. No prior chemotherapy for HLH;
4. Confirmed not pregnant and willing to use effective contraceptive measures during the study period, with the last dose of medication administered at least 12 months prior;
5. Signed informed consent prior to study participation.

Exclusion Criteria:

1. According to the New York Heart Association (NYHA) score, patients with heart disease of grade II or above (including grade II);
2. HIV-infected patients;
3. Patients with severe renal dysfunction (glomerular filtration rate <15 mL/min);
4. Patients with severe liver cirrhosis (MELD score>20);
5. Uncontrollable infections (including lung infections, intestinal infections, etc.);
6. Have serious mental illness;
7. Have a history of active tumor;
8. Participate in other clinical investigators at the same time;
9. People with central nervous system involvement;
10. Exclusion criteria related to concomitant medication.