FRI100 Lipoprotein X In Graft Vs. Host Disease Affecting Liver

Abstract

Abstract Disclosure: D. Vedamurthy: None. C. Vitali: None. M. Cuchel: None. D. Soffer: None. D. Rader: None. Introduction: Lipoprotein-X (LpX) is an abnormal lipoprotein rich in phospholipid and unesterified cholesterol (UC) found in patients with cholestatic liver disease, lecithin-cholesterol acyl transferase (LCAT) deficiency, and after lipid emulsion infusion. LpX has been detected in patients with graft-versus-host disease (GVHD) of the liver. Cholestasis leads to the accumulation of bile salts and UC in the circulation, promoting the formation of LpX. This condition is often not well-recognized, partly because the detection of LpX is technically challenging and requires specialized laboratory assays. Case Description: A 66-year lady with acute myeloblastic leukemia (AML) underwent an allogeneic matched unrelated donor stem cell transplant (SCT) which was complicated by graft-versus-host disease (GVHD) affecting the liver, eyes, lungs, and skin. Past medical history includes hypertension. Family history was significant for coronary artery disease in the mother. She is a reformed smoker. Her post-transplant course was highly complicated with infections, GVHD affecting the liver, eyes, lungs, and skin, and vascular events including myocardial infarction and stroke. Laboratory testing revealed abnormal liver enzymes (ALT=268, AST=173, ALKP =402 U/L), and a markedly abnormal lipid profile (TC=500, Non-HDL-C=358, TG= 345 mg/dL). Her thyroid panel and viscosity were normal, but apolipoprotein B levels were discordantly low (77mg/dL). The ratio of ApoB: Non-HDL cholesterol was abnormally low (0.215). She was started on ezetimibe, evolocumab, and omega-3 fatty acids by her neurovascular team for cardiovascular risk reduction. A physical exam revealed a thin, frail woman with mild oral and nail GVHD changes. The rest of the exam was notable for the abdomen showing chronic patchy hyperpigmentation with sclerodermatous changes anteriorly and posteriorly. She had no significant focal neurologic deficits. Her lipid levels were improved with therapy, but TC, non-HDL-C, UC, and triglycerides levels were still elevated (TC=353, non-HDL=258, UC=163, TG=414 mg/dL), UC: TC ratio was high (0.46). FPLC separation of TRL-depleted plasma revealed the presence of LpX. LpX is not very atherogenic, and we recommended continuing current medical therapy as the serum viscosity was within normal limits. Conclusion: The presence of LpX should be suspected in the setting of GVHD accompanied by markedly elevated TC. LpX may cause hyperviscosity, which can induce end-organ ischemia. While the direct assessment of LpX is challenging and requires specialized techniques, ApoB and non-HDL-C levels are available in most clinical laboratories, and a very low ApoB: Non-HDL-C ratio in GVHD patients may indicate the presence of LpX. The treatment goal is to resolve the underlying causes of cholestasis. If hyperviscosity is present, Lp-X can be acutely treated by plasma exchange or lipoprotein apheresis. Presentation: Friday, June 16, 2023