P159 High-resolution HLA-typing can confirm diagnosis of graft versus host disease after orthotopic liver-transplantation

Abstract

Introduction Acute GVHD after orthotopic liver-transplantation (OLT) is reported to occur in ∼ 0.1% to 2% of recipients, and due to passenger lymphocytes relocating into the recipient. The diagnosis of GVHD is made on clinical and laboratory parameters. GVHD from OLT does not affect the liver, but may be apparent as skin rash, GI symptoms, and suppression of bone marrow hematopoiesis. Diarrhea and a decrease in the platelet counts may be construed as due to CMV infection. A skin rash may be inferred as an eruption due to medications or viral exanthema, and a skin biopsy may be interpreted by the pathologist as possible viral exanthema, drug eruption, or GVHD. Thus, a definitive diagnosis may be delayed. Case report Patient: 62 yo male with end-stage liver disease secondary to Hep C, without previous therapy for the Hep C. Donor: 25 yo male. Both were CMV+ and EBV+. There were no major peri-transplant complications. ∼ 4 weeks post-OLT, the patient was admitted with fever, cough, throat discomfort, and rash; and treated for suspected infection with broad-spectrum antimicrobials. ∼ 5 weeks post-OLT, pan-cytopenia had become apparent, and a skin biopsy was suspicious for GVHD. Bone marrow aspirate and biopsy revealed, extreme pancytopenia with necrosis. DNA was extracted and high-resolution (HR) HLA-typing was performed, by rSSO using OneLambda® reagents. Fusion® software was used to interpret the results. The individual pre-OLT patient and donor types were compared at the serologic equivalent and HR HLA-type, without clear indication of risk for GVHD. HR typing results from the patient’s bone marrow post-OLT indicated the presence of all four alleles, and along with the clinical features, confirmed the diagnosis of GVHD. Patient relatives were typed, and a NMDP search was initiated, but the patient succumbed before HSCT could be arranged. Conclusions DNA-Mixing studies performed in our laboratory have demonstrated that ∼ 1% contaminating DNA may interfere with typing for DRB3/4/5, ∼ 2% for DRB1, ∼ 10% for DQA1/DQB1, ∼ 20% for DPA1/DPB1, ∼ 5% for C, ∼ 10% for B, and ∼ 15% for A. Thus, 20–80% contaminating DNA seems to be required to demonstrate the presence of all four alleles, which may help confirm the diagnosis of GVHD, but as little as 1–2% could be indicative of donor cell presence.