| • | GVH reactions occur when immunocompetent cells from a donor recognize and react against “foreign” tissue antigens in an immunocompromised host |
| • | has features common to autoimmune disorders (not surprisingly) |
| • | occurs in ~ 50% of patients receiving successful marrow allografts |
| • | the development of GVHD partially protects against tumor relapse |
acute GVHD:
| • | usually 7-30 days after bone marrow transplant |
| • | may also occur after liver transplant (containing numerous immunocompetent lymphocytes) |
| • | the skin is the earliest and most frequent target organ |
| • | hepatitis (increased bili and alkaline phosphatase) and bloody diarrhea due to enteritis are other features |
clinical stages:
| • | stage I – (<25% surface area) mild fever and maculopapular rash on face, hands, and feet spreads centripetal |
| • | stage II – (>25% surface area) perifollicular erythema on trunk, especially back, becomes confluent |
| • | stage III – erythroderma |
| • | stage IV – vesicles and bullae; subepidermal with a necrotic roof (resembles TEN) |
| • | clinical ddx: drug hypersensitivity eruption, viral exanthem, Grover’s disease, or TEN (confident differentiation between stage 4 acute GVHD and TEN is generally not possible) |
| • | red, tender palms: acral erythema, neutrophilic eccrine hidradenitis |
| • | histopathology is simply incapable of differentiating |
| • | explanation: their pathophysiology is mediated by the same cell (T-lymphocyte) and they share entirely overlapping phenotypes |
| • | since GVHD can almost never be safely ruled out, and because it can progress rapidly over a few days to cause severe inflammatory damage to the skin, liver, and gut (which is irreversible and sometimes fatal), one must always presume GVHD and increase the immunosuppression (with prednisone being more effective than cyclosporine to treat acute flare) |
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| • | changes of an interface dermatitis are observed in all phases of GVHD |
| • | extension of lymphocytes into the epidermis is common |
| • | basal vacuolar alteration |
| • | necrosis of epidermal cells |
| • | satellite cell necrosis: (= the direct apposition of a lymphocyte to a necrotic keratinocyte) characteristic but may be observed in many types of interface dermatitis in which cell death is mediated by lymphocytes |
| • | when biopsied early, the histopathology is not fully manifest and the changes are non-specific (ddx: drug eruption, eruption of lymphocyte recovery, viral exanthem) |
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chronic GVHD:
| • | principally involves the skin and liver |
| • | usually, but not always, follows acute GVHD |
| • | a slowly progressive, erythematous rash on face, palms and soles becomes lichenoid with changes resembling LP in the oral mucosa |
| • | later, scleroderma-like changes occur |
| • | the condition resembles systemic sclerosis, with tightening of the skin of the face, hands, and feet |
| • | esophageal changes and subcutaneous calcification may occur |
treatment:
| • | incidence of acute GVHD has been reduced by the prophylactic use of cyclosporine and prednisone |
| • | also of value symptomatically once the disease is established |
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