The quantitation of serum tocilizumab using liquid chromatography tandem-mass spectrometry(LC-MS/MS)method has not been widely applied in clinical settings because of its time-consuming and costly sample pretreatments.The present study aimed to develop a validated LC-MS/MS method for detecting serum tocilizumab by utilizing immobilized trypsin without an immunoglobulin G purification step and evaluate its applicability in the treatment of rheumatoid arthritis(RA)patients administered intrave-nously or subcutaneously with tocilizumab.The tocilizumab-derived signature peptide was deciphered using a nano-LC system coupled to a hybrid quadrupole-orbitrap mass spectrometer.The serum tocili-zumab was rapidly digested by immobilized trypsin for 30 min.The chromatographic peak of the signature peptide and that of the internal standard were separated from the serum digests for a total run time of 15 min.The calibration curve of serum tocilizumab concentration was linear with a range of 2-200 μg/mL.The intra-and inter-day accuracy and relative standard deviation(RSD)were 90.7％-109.4％and＜10％,respectively.The serum tocilizumab concentrations in the RA patients receiving intravenous and subcutaneous injections were 5.8-28.9 and 2.4-63.5 pg/mL,respectively.The serum tocilizumab concentrations using the current method positively correlated with those using the enzyme-linked immunosorbent assay,although a systematic error was observed between these methods.In conclu-sion,a validated LC-MS/MS method with minimal sample pretreatments for monitoring serum tocili-zumab concentrations in RA patients was developed.

BACKGROUND/AIMS: There is a controversy about the availability of invasive treatment for esophageal/gastric varices in patients with Child-Pugh class C (CP-C) end-stage liver cirrhosis (LC). We have evaluated the validity of invasive treatment with CP-C end-stage LC patients. METHODS: The study enrolled 51 patients with CP-C end-stage LC who had undergone invasive treatment. The treatment modalities included endoscopic variceal ligation in 22 patients, endoscopic injection sclerotherapy in 17 patients, and balloon-occluded retrograde transvenous obliteration (BRTO) in 12 patients. We have investigated the overall survival (OS) rates and risk factors that contributed to death within one year after treatment. RESULTS: The OS rate in all patients at one, three, and five years was 72.6%, 30.2%, and 15.1%, respectively. The OS rate in patients who received endoscopic treatment and the BRTO group at one, three, and five years was 67.6%, 28.2% and 14.1% and 90.0%, 36.0% and 18.0%, respectively. The average of Child-Pugh scores (CPS) from before treatment to one month after variceal treatment significantly improved from 10.53 to 10.02 (P=0.003). Three significant factors that contributed to death within one year after treatment included the presence of bleeding varices, high CPS (≥11), and high serum total bilirubin levels (≥4.0 mg/dL). CONCLUSIONS: The study demonstrated that patients with a CPS of up to 10 and less than 4.0 mg/dL of serum total bilirubin levels may not have a negative impact on prognosis after invasive treatment for esophageal/gastric varices despite their CP-C end-stage LC.
Balloon Occlusion ; Bilirubin ; Endoscopy ; Esophageal and Gastric Varices ; Hemorrhage ; Humans ; Hypertension, Portal ; Ligation ; Liver Cirrhosis ; Liver ; Prognosis ; Risk Factors ; Sclerotherapy ; Varicose Veins