Heterogeneity assessment of vaccine-induced effects using point-of-care surrogate neutralization test for severe acute respiratory syndrome coronavirus 2.

INTRODUCTION: Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic even after vaccination. We aimed to identify immunological heterogeneity over time in vaccinated healthcare workers using neutralization antibodies and neutralizing activity tests. METHODS: Serum samples were collected from 214 healthcare workers before vaccination (pre) and on days 22, 90, and 180 after receiving the first dose of BNT162b2 vaccine (day 0). Neutralization antibody (NAb, SARS-CoV-2 S-RBD IgM/IgG) titers and two kinds of surrogate virus neutralization tests (sVNTs) were analyzed (UMIN000043851). RESULTS: The NAb (SARS-CoV-2 S-RBD IgG) titer peaked on day 90 after vaccination (30,808.0 µg/ml ± 35,211; p < 0.0001) and declined on day 180 (11,678.0 µg/ml ± 33,770.0; p < 0.0001). The neutralizing activity also peaked on day 90 and declined with larger individual differences than those of IgG titer on day 180 (88.9% ± 15.0%, 64.8% ± 23.7%, p < 0.0001). We also found that the results of POCT-sVNT (immunochromatography) were highly correlated with those of conventional sVNT (ELISA). CONCLUSIONS: Neutralizing activity is the gold standard for vaccine efficacy evaluation. Our results using conventional sVNT showed large individual differences in neutralizing activity reduction on day 180 (64.8% ± 23.7%), suggesting an association with the difference in vaccine efficacy. POCT-sVNT is rapid and user-friendly; it might be used for triage in homes, isolation facilities, and event venues without restrictions on the medical testing environment.

Incidence and management of cystic duct perforation during endoscopic transpapillary gallbladder drainage for acute cholecystitis.

BACKGROUND AND AIM: Evidence regarding the incidence and clinical outcome of cystic duct perforation (CDP) during endoscopic transpapillary gallbladder drainage (ETGBD) is inadequate. The present study aimed to evaluate the incidence and management of CDP during ETGBD. METHODS: Between March 2011 and December 2019, 249 patients underwent initial ETGBD for acute cholecystitis. The incidence of CDP was retrospectively examined and the outcomes between the CDP and non-CDP groups were compared. RESULTS: CDP during ETGBD occurred in 23 (9.2%) of 249 patients (caused by guidewire in 15 and cannula in 8). ETGBD was successful in 10 patients following CDP. In 13 patients who failed ETGBD, 11 underwent bile duct drainage during the same session; nine patients underwent gallbladder decompression by other methods, such as percutaneous drainage. Clinical resolution for acute cholecystitis was achieved in 20 patients, and no bile peritonitis was noted. ETGBD technical success rates (45.3% vs. 91.2%, p < 0.001), ETGBD procedure times (66.5 vs. 54.8 min, p = 0.041), and hospitalization periods (24.5 vs. 18.7 days, p = 0.028) were significantly inferior in the CDP group (n = 23) compared with the non-CDP group (n = 216). There were no differences in clinical success and adverse events other than CDP between both groups. CONCLUSIONS: Cystic duct perforation reduced the ETGBD technical success rate. However, even in patients with cystic duct perforation, an improvement of acute cholecystitis was achieved by subsequent successful ETGBD or additional procedures, such as percutaneous drainage.

Assessment of hepatic steatosis and hepatic tissue blood flow by xenon computed tomography in nonalcoholic steatohepatitis.

AIM: The diagnosis of non-alcoholic steatohepatitis (NASH) can be difficult using blood tests and imaging studies. Histological diagnosis by liver biopsy remains the gold standard of NASH diagnosis. There is an urgent need to develop and validate simple, reproducible, noninvasive tests to accurately assess NASH stage and grade. We assess the usefulness of xenon computed tomography (Xe-CT), as a non-invasive method of quantitatively and visually determining hepatic tissue blood flows (TBFs), and xenon solubility (lambda value) simultaneously with TBF, in the evaluation of NASH pathophysiology. METHODS: Histological severity of fatty changes and severity of fibrosis based on Brunt's classification were determined in 38 NASH patients. We evaluated correlations between the grade of fatty changes and lambda value, and correlations between the stage of fibrosis and TBFs. RESULTS: The lambda value showed significant positive correlations with both grade of steatosis (r = 0.813, P < 0.001) and each 10% range of histological fatty infiltration (r = 0.926, P < 0.001). A significant negative correlation was seen between lambda value and the liver : spleen ratio (r = -0.835, P < 0.001). Portal venous tissue blood flow and total hepatic tissue blood flow showed significant negative correlations with the progression of fibrosis (r = -0.465, P < 0.01; r = -0.433, P < 0.01, respectively). Total hepatic tissue blood flow tended to decrease with progressing grade of steatosis. CONCLUSION: Xe-CT offers a convenient and objective method for evaluating fatty infiltration and changes in blood flow in the entire liver, and appears useful for detailed evaluation of patients with NASH.