Disease Description (Causes and Symptoms)

Definition summary: An immune-mediated disease in which immune cells (such as T lymphocytes) from the donor (graft) recognize the recipient’s (host’s) tissues as non-self and attack them; it mainly occurs after allogeneic hematopoietic stem cell transplantation.
Pathophysiology: Transplanted mature T cells recognize host antigens → activation and cytokine secretion → damage to target organs (skin, liver, gastrointestinal tract, lungs, etc.). Acute disease (generally ≤100 days after transplantation) and chronic disease (>100 days or features of the chronic form) are distinguished.
Main symptoms:
- Skin: erythematous rash, itching, and, in severe cases, epidermal detachment/blisters
- Liver: jaundice, elevated liver enzymes
- Gastrointestinal tract: loss of appetite, nausea and vomiting, abdominal pain, diarrhea (massive diarrhea in severe cases)
- Systemic: fever, weight loss, susceptibility to infection
- The chronic form may cause various types of chronic organ damage, including dry eyes, dry mouth, fibrosis (skin hardening), and decreased pulmonary function (bronchiolitis obliterans lesions)

Treatment Methods

Prevention (before/immediately after transplantation): donor–host compatibility (HLA matching), T-cell depletion during transfusion and transplantation (processing), and combination use of immunosuppressants after transplantation (e.g., cyclosporine/tacrolimus + methotrexate or post-transplant cyclophosphamide).
First-line treatment (acute/chronic active disease): systemic corticosteroids (e.g., prednisone or methylprednisolone; for acute disease, 1–2 mg/kg/day or an equivalent dose)
For steroid dependence or resistance (or in combination with initial treatment):
- Immunosuppressants: cyclosporine, tacrolimus, mycophenolate mofetil (MMF), etc.
- Targeted therapies: JAK inhibitors (e.g., ruxolitinib) are approved and used for acute steroid-refractory disease; drugs with an indication, such as ibrutinib and belumosudil, may be used for chronic refractory disease
- Physical/nonpharmacological treatment: Extracorporeal photopheresis (ECP) is effective for chronic GVHD, particularly abnormalities of the skin, mouth, liver, and lungs
Supportive care and prevention of complications: infection prevention (antibacterial, antifungal, and antiviral prophylaxis), nutritional support, electrolyte and fluid management, skin and oral care, pulmonary rehabilitation, etc.
Treatment goals: In acute disease, suppress inflammation and improve survival; in chronic disease, preserve organ function, alleviate symptoms, and reduce steroid dependence

Required items: a list of currently used medications (including immunosuppressants and steroids), recent test results (CBC, liver function tests, electrolytes, kidney function, and infection tests—including CMV), transplantation date and donor information (including whether HLA matching was performed), hospitalization/treatment records (including biopsy results), and a record of when symptoms began and how they have progressed (take photographs if there is a rash)
Symptom checkpoints: distribution and rate of progression of the rash (photographs), frequency and amount of diarrhea (including whether blood is present), jaundice, frequency and severity of vomiting and abdominal pain, shortness of breath and cough, and visual symptoms and dry mouth, etc.
Example questions (items for the patient to prepare before the outpatient visit):
- What are the doses of my current immunosuppressants and steroids, and what is the plan for reducing (tapering) them?
- What additional tests are needed to determine the severity of my current symptoms (rash, diarrhea, and jaundice)?

“What is the severity (grade) of this disease, and what is the prognosis according to that grade?”
“What are the major side effects of the prescribed medications (steroids or immunosuppressants), and which test items should be monitored?”
“Which vaccines or prophylactic medications should I receive to prevent infections, and when should I start receiving them?”

Regarding acute GVHD: “Which grade of acute GVHD do my current symptoms correspond to, and what is the initial steroid dose? What are the next treatment options if the disease is steroid-refractory (e.g., ruxolitinib)?”
Regarding chronic GVHD: “Are pulmonary function tests (PFTs) or CT needed to evaluate pulmonary function (obstructive lesions)? How is eligibility for treatments such as ECP (extracorporeal photopheresis) or ibrutinib determined?”

Additional Points to Note (Brief)

Because high-risk complications include infection (bacterial, viral, and fungal), liver, lung, or intestinal failure, long-term organ fibrosis, and complications related to steroids and immunosuppressants (such as osteoporosis and diabetes), regular testing and infection prevention are important.
Live vaccines must not be administered during immunosuppressive treatment, and close contacts should also be cautious about the presence of infectious diseases.