Abstract
Familial lecithin-cholesterol acyltransferase (LCAT) deficiency with a primary LCAT gene mutation results in various conditions, including corneal opacity, anemia, kidney disease, and low high-density lipoprotein (HDL) levels. In recent years, secondary LCAT deficiency with nearly identical symptoms has been identified as a rare case of immune-mediated acquired LCAT deficiency caused by LCAT autoantibodies. In limited cases, prednisolone treatment is required for severe conditions and has been shown to favorably modulate LCAT autoantibodies and restore LCAT activity, resulting in improved HDL-cholesterol (HDL-C) levels, renal dysfunction, and other complications. However, there is little detailed information regarding LCAT activity, lipid changes, and renal dysfunction after the initiation of prednisorone treatment. In the present study, in addition to the effects on LCAT activity, lipids, and proteinuria, we for the first time monitored the HDL cholesterol efflux capacity (CEC), an important anti-atherosclerotic HDL function, during the first month of treatment in a patient with this disease. We found that the LCAT activity, HDL-C concentration, and HDL CEC increased from undetectable or low values to normal ranges during this period, as did proteinuria. Specifically, the HDL CEC and LCAT activity recovered faster than the HDL-C levels. Based on these findings, the effects of prednisolone treatment on LCAT and HDL CEC activities prior to HDL-C levels suggest that normal HDL-C levels may not be essential as a treatment target in immune-mediated acquired LCAT deficiency patients who require treatment.