A PCSK9 inhibitor induces a transient decrease in the neutrophil-lymphocyte ratio and monocyte-lymphocyte ratio in homozygous familial hypercholesterolemia patients

Background and aims: Extremely elevated levels of low-density lipoprotein-cholesterol (LDL-C) contribute to long-term chronic systemic inflammation in homozygous familial hypercholesterolemia (HoFH) patients. The aims of this study is to describe the inflammatory profile of HoFH patients and explore the effect of a PCSK9 inhibitor (PCSK9i) on a series of inflammatory biomarkers, including the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-HDL ratio (MHR), monocyte-lymphocyte ratio (MLR) and mean platelet volume-lymphocyte ratio (MPVLR). Methods: In this prospective cohort study, 25 definitive HoFH patients on high-intensity statins plus ezetimibe were administered subcutaneous injections of 420 mg PCSK9i every 4 weeks (Q4W). The biochemical parameters and inflammatory profile were analyzed on the day before PCSK9i therapy and 3 months and 6 months after PCSK9i therapy. Results: HoFH on the maximum tolerated statin dose plus ezetimibe displayed elevated lipid and disturbed blood biomarker profiles. After 3 months of add-on PCSK9i therapy, a significant reduction in LDL-C was observed. Moreover, the percentage and count of neutrophils, monocyte counts, MPV, and two inflammatory biomarkers, the NLR and MLR, were reduced. However, at 6 months of PCSK9i treatment, the NLR and MLR returned to pre-PCSK9i treatment levels. Conclusions: PCSK9i induces a transient decrease in the NLR and MLR in HoFH patients in a lipid-lowering independent manner.