Objective:To explore the postprandial plasma low-density lipoprotein cholesterol (LDL-C) changes by various detection methods.Methods:A total of 85 subjects admitted to the Second Xiangya Hospital of Central South University from November 2017 to May 2019 were included. Serum samples were collected from fasting and the 2 nd hour and the 4 th hour after breakfast. Serum lipid levels were measured with enzymatic assays and nuclear magnetic resonance spectroscopy (NMRS), and proprotein invertase subtilisin/kexin type 9 (PCSK9) levels were measured with enzyme-linked immunosorbent assays. The differences of blood lipid components at different time points were compared by Friedman two-way rank analysis of variance and Wilcoxon signed rank test, and the correlation between PCSK9 level and lipoprotein particles was analyzed by Spearman correlation. Results:Measured by enzymatic assays, compared with the fasting state, LDL-C decreased at the 2 nd hour and the 4 th hour after the meal (2.58[2.09, 3.12], 2.47[1.92, 3.02], 2.37[1.82, 2.80] mmol/L, P<0.001). Measured by NMRS, the concentration of LDL particles (1 086[830, 1 239], 1 083[848, 1 213], 1 061[814, 1 213] nmol/L, P=0.417) did not change significantly, and cholesterol in LDL particles were 2.13 (1.56, 2.54), 2.16 (1.68, 2.50), 2.06 (1.58, 2.50) mmol/L, respectively ( P=0.047)，and postprandial cholesterol in LDL particles in the 2 nd hour and in the 4 th hour did not change significantly compared with fasting ( P>0.05). while the concentration of large LDL particles (185.2[150.6,221.6], 173.0[144.8,220.3], 178.1[144.0,233.6] nmol/L, P=0.001), and the cholesterol level in large LDL particles (0.49[0.39, 0.57], 0.47[0.38, 0.57], 0.46[0.37, 0.58]mmol/L, P<0.001) decreased after the meal. The PCSK9 level also decreased significantly after the meal (299[233, 397], 257[208, 342], 251[215, 340] ng/ml, P<0.001). There was an independent positive correlation between the decrease of PCSK9 levels and the increase of remnant cholesterol detected by MNRS after the meal ( r=0.232, P=0.035). Conclusions:The postprandial LDL-C level measured by NMRS and enzymatic assays is not consistent. The decrease of LDL-C measured by enzymatic assays is not caused by the clearance of LDL particles, but by the redistribution of cholesterol in each LDL subfraction.

Bi-specific T-cell engagers (BiTEs) show great clinical outcomes for anti-cancer purposes. However, potential cytokine release syndrome (CRS) is notorious to all BiTEs. The mechanism underlying CRS is still not fully known, even though such toxicities are considered to be cytokine release related. Assessment of CRS is a key to non-clinical de-risk programs for BiTEs therapeutic development. In the present review, possible mechanisms are discussed, especially factors contributing to CRS develop?ment. T cell activation may be just an initiation of the CRS cascade, and other cell types can greatly contribute to CRS, such as a chain reaction triggered by downstream B-cells, monocytes, and endothe?lium cells. A non-clinical de-risk program can be designed based on these components in the CRS cascade. Combination of in vitro cytokine release assay, and in vivo mouse and non-human primates studies should be reliable enough to predict and mitigate CRS risk in the clinics. Further more, a good de-risk program should be able to provide ranking for candidates for further development and provide enough confidence to select a first-in-human dose.