Borderline and weakly positive antibody levels against the S-protein of SARS-CoV-2 exhibit limited agreement with virus neutralization titres.

The presence of neutralizing antibodies against SARS-CoV-2 in a large number of people is - besides cellular immunity - important to overcome the SARS-CoV-2 pandemic. While determination of neutralizing antibodies via virus neutralization tests are laborious, assays to determine the antibody levels serologically are fully automated and widely available. Correlations between these methodologies were recently given by the manufacturers, however performance in samples close to the cut off value have not yet been fully validated. Thus, we analysed 22 borderline and low positive (<100 BAU/ml) samples and 9 high positive (≥ 100 BAU/ml) from infected and/or vaccinated individuals and compared the SARS-CoV-2 IgG II Quant assay (Abbott), LIAISON SARS-CoV-2 TrimericS IgG (Diasorin), Elecsys Anti-SARS-CoV-2 S (Roche), and SARS-CoV-2 IgG (Siemens) with results obtained from a virus neutralization test. Based on the cut off values given by Abbott, Diasorin, Roche, and Siemens, the positive serologic results were concordant with the virus neutralization test in 100%, 76%, 88%, and 71%, respectively, while in turn, negative ones were in agreement in 29%, 79%, 93%, and 86%, respectively. In conclusion, weakly positive, serologic results are challenging to correctly predict the presence of neutralizing antibodies. Our study suggests, that different cut off values (for positivity vs. presence of neutralizing antibodies) could improve the test's performance, but determination thereof requires more samples to be analysed.

Clinical validation of the Siemens quantitative SARS-CoV-2 spike IgG assay (sCOVG) reveals improved sensitivity and a good correlation with virus neutralization titers.

OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections cause coronavirus disease 2019 (COVID-19) and induce a specific antibody response. Serological assays detecting IgG against the receptor binding domain (RBD) of the spike (S) protein are useful to monitor the immune response after infection or vaccination. The objective of our study was to evaluate the clinical performance of the Siemens SARS-CoV-2 IgG (sCOVG) assay. METHODS: Sensitivity and specificity of the Siemens sCOVG test were evaluated on 178 patients with SARS-CoV-2-infection and 160 pre-pandemic samples in comparison with its predecessor test COV2G. Furthermore, correlation with virus neutralization titers was investigated on 134 samples of convalescent COVID-19 patients. RESULTS: Specificity of the sCOVG test was 99.4% and sensitivity was 90.5% (COV2G assay 78.7%; p<0.0001). S1-RBD antibody levels showed a good correlation with virus neutralization titers (r=0.843; p<0.0001) and an overall qualitative agreement of 98.5%. Finally, median S1-RBD IgG levels increase with age and were significantly higher in hospitalized COVID-19 patients (median levels general ward: 25.7 U/mL; intensive care: 59.5 U/mL) than in outpatients (3.8 U/mL; p<0.0001). CONCLUSIONS: Performance characteristics of the sCOVG assay have been improved compared to the predecessor test COV2G. Quantitative SARS-CoV-2 S1-RBD IgG levels could be used as a surrogate for virus neutralization capacity. Further harmonization of antibody quantification might assist to monitor the humoral immune response after COVID-19 disease or vaccination.

Rheumatologic diseases impact the risk of progression of MGUS to overt multiple myeloma.

Monoclonal gammopathy of undetermined significance (MGUS), a premalignant condition, is associated with various chronic inflammatory rheumatic diseases (RDs) and is frequently observed as an incidental finding during routine work-up. The association of MGUS and chronic RDs is well established, but the impact of RDs on the risk of transformation into overt multiple myeloma (MM) has not been evaluated so far. MGUS patients diagnosed between January 2000 and August 2016 were identified and screened for concomitant RDs. RDs were grouped into antibody (Ab)-mediated RDs and non-Ab-mediated RDs (polymyalgia rheumatica, large-vessel giant cell arteritis, spondyloarthritis, and gout). Progression to MM was defined as a categorical (yes/no) or continuous time-dependent (time to progression) variable. Of 2935 MGUS patients, 255 (9%) had a concomitant RD. MGUS patients diagnosed with non-Ab-mediated RDs had a doubled risk of progression compared with those without a concomitant RD (hazard ratio, 2.1; 95% CI, 1.1-3.9; P = .02). These data translate into a 5-year risk of progression of 4% in MGUS patients without rheumatologic comorbidity, 10% in those with concomitant non-Ab-mediated RDS, and 2% in those with Ab-mediated RDs. By using the complex risk stratification model that includes myeloma protein (M-protein) concentration, immunoglobulin type, and level of free light chain ratio as variables, patients with non-Ab-mediated RDs (n = 57) had the highest risk for progression (hazard ratio, 6.8; 95% CI, 1.5-30.7; P = .01) compared with patients with Ab-mediated RDs (n = 77). Chronic inflammatory diseases have an impact on the risk of MGUS progressing into overt MM, with a doubled risk of transformation observed in patients with non-Ab-mediated RDs. Future research can elucidate whether comorbidities such as RDs should be included in currently applied prognostic MGUS scores.

Evaluation of four commercial, fully automated SARS-CoV-2 antibody tests suggests a revision of the Siemens SARS-CoV-2 IgG assay.

OBJECTIVES: Serological tests detect antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the ongoing coronavirus disease-19 (COVID-19) pandemic. Independent external clinical validation of performance characteristics is of paramount importance. METHODS: Four fully automated assays, Roche Elecsys Anti-SARS-CoV-2, Abbott SARS-CoV-2 IgG, Siemens SARS-CoV-2 total (COV2T) and SARS-CoV-2 IgG (COV2G) were evaluated using 350 pre-pandemic samples and 700 samples from 245 COVID-19 patients (158 hospitalized, 87 outpatients). RESULTS: All tests showed very high diagnostic specificity. Sensitivities in samples collected at least 14 days after disease onset were slightly lower than manufacturers' claims for Roche (93.0%), Abbott (90.8%), and Siemens COV2T (90.3%), and distinctly lower for Siemens COV2G (78.8%). Concordantly negative results were enriched for immunocompromised patients. ROC curve analyses suggest a lowering of the cut-off index for the Siemens COV2G assay. Finally, the combination of two anti-SARS-CoV-2 antibody assays is feasible when considering borderline reactive results. CONCLUSIONS: Thorough on-site evaluation of commercially available serologic tests for detection of antibodies against SARS-CoV-2 remains imperative for laboratories. The potentially impaired sensitivity of the Siemens COV2G necessitates a switch to the company's newly filed SARS-CoV-2 IgG assay for follow-up studies. A combination of tests could be considered in clinical practice.

The role of cortisol in trust behavior: Results from an experimental study on healthy controls and patients with juvenile myoclonic epilepsy.

Trust is one of the foundations of human society and pervades all aspects of human live. Research on humans focused primarily on identifying the biological basis of trust behavior in healthy subjects, and this evidence hints to certain brain areas, hormones, and genetic factors to be fundamentally involved. The contribution of cortisol in trust has not yet elicited much attention in research, especially when specifically examined at basal cortisol levels. Trust has been previously studied in some neurological diseases but not in patients with epilepsy, and the influence of hormones on trust in these diseases remains yet unknown. Against this background, we designed an experimental study with a group of patients with juvenile myoclonic epilepsy and a group of healthy controls to compare trust behavior and plasma cortisol levels between the two groups. This economic game is frequently used in research to operationalize trust behavior. All participants further underwent neuropsychological assessment. Our results showed that there was no significant difference in trust behavior during the trust game, but a trend toward lower trust in patients. Furthermore, there was a significant difference in cortisol levels between groups with lower levels in patients. Interestingly, cortisol levels correlated with trust only in the patient group, but not in the control group. Future studies should specifically differentiate the effect of induced cortisol increases (e.g., acute stress) versus the effect of basal cortisol levels reflecting homeostasis or chronic stress on trust behavior and leverage the potential of comparison between patients and healthy controls.

Monoclonal gammopathy of renal significance (MGRS) increases the risk for progression to multiple myeloma: an observational study of 2935 MGUS patients.

PURPOSE: Monoclonal gammopathy of undetermined significance (MGUS) is a premalignancy preceding multiple myeloma (MM) or related disorders. In MGUS, renal impairment caused by deposition of the monoclonal immunoglobulins or free light-chains monoclonal gammopathy of renal significance (MGRS) is often associated with high morbidity and mortality. We analysed the prevalence of renal impairment, clinical features and the long-term outcome in 2935 patients with MGUS. METHODS: Between 1/2000 and 8/2016, 2935 adult patients with MGUS were identified in our database. RESULTS: In 44/2935 (1.5%) patients MGRS was diagnosed. In MGRS patients, significantly more progressions to MM were observed than in MGUS patients (18% vs. 3%; P<0.001). MGRS patients showed a higher risk for progression (HR 3.3 [1.5-7.4]) in the Cox model. Median time to progression was 23 years for MGUS and 18.8 years for MGRS patients. Corresponding progression rate was 8.8 [7.2-10.7] per 1000 patient-years (py) for MGUS patients and 30.6 [15.3-61] for the MGRS group. Risk for progression within the first year after diagnosis was 1% [0.6-1.4] in the MGUS group and 10% [4-29] among MGRS patients. CONCLUSION: The significantly higher risk for progression to MM means MGRS patients should be monitored carefully and treated in a specialized centre.

"Idiopathic Bence-Jones proteinuria": a new characterization of an old entity.

Idiopathic Bence-Jones proteinuria (BJP) is a rare plasma cell dyscrasia, of which the clinical and biological characteristics are yet unclear. Historical data suggested that they are at higher risk of progression to multiple myeloma or other related neoplasms, while recent findings are contradictory. To address these open questions, we evaluated a series of both BJP and monoclonal gammopathy of undetermined significance (MGUS) with production of an intact immunoglobulin plus Bence-Jones proteinuria (MGUS+BJP) with long-term follow-up, regarding their clinical characteristics and progression to multiple myeloma, amyloidosis or other related B cell lymphoproliferative disorders. Two hundred and twenty-nine persons fulfilling the 2004 criteria of MGUS were included in the final analyses: 31 had BJP and 198 had MGUS+BJP. At the time of diagnosis, significantly more persons in the BJP group had renal impairment, anaemia and polyneuropathy. A more detailed analysis revealed discrepancies between the serum and urine light chain type in nine cases, reflecting clonal heterogeneity. The number of disease progressions was higher in MGUS+BJP (n = 30) when compared to BJP (n = 1), with a rate of 1.6 and 0.4 progressions per 100 person-years, respectively. In conclusion, BJP has distinct clinical characteristics and a lower risk of progression when compared to MGUS+BJP. Our data suggest that MGUS+BJP being closer to malignant transformation may be due to the higher portion of genetically heterogeneous, pre-malignant plasma cell subclones.

Cystatin C is a strong predictor of survival in patients with cirrhosis: is a cystatin C-based MELD better?

BACKGROUND/AIMS: The model of end stage liver disease (MELD) includes serum creatinine, which is a poor surrogate marker of renal function in patients with cirrhosis. Especially in women and patients with advanced disease creatinine underestimates true renal function. Our objective was to assess whether or not the substitution of creatinine by cystatin C improves the prognostic performance of the model. METHODS: The association between MELD parameters and cystatin C with survival was investigated using a Cox proportional hazards model. A cystatin C-based MELD score was calculated from the results and compared with creatinine-based MELD in terms of discrimination and calibration. RESULTS: Four hundred and twenty-nine patients were included in the study; 19% died and 12% underwent liver transplantation during a median follow-up of 602 days. In multivariate Cox regression, cystatin C was an independent predictor of 90-day mortality with a hazard ratio of 8.0 (95% CI: 2.2-29.6). The median cystatin C-based MELD was 15, the median creatinine-based MELD was 12. Calibration and discrimination for 3 month and 1 year mortality was similar between the scores (AUC > 0.85 for both scores). Gender differences in cystatin C-based MELD were less pronounced than those in the creatinine-based model, because creatinine but not cystatin C was affected by gender. CONCLUSION: Substitution of creatinine by cystatin C does not improve the predictive power of MELD.

Immunoglobulin subclass 4 for the diagnosis of immunoglobulin subclass 4-associated diseases in an unselected liver and pancreas clinic population.

AIMS: The diagnosis of autoimmune pancreatitis (AIP) and immunoglobulin subclass 4 (IgG(4) )-associated cholangitis (IAC) is based on imaging studies, serology, histology and a response to steroid therapy. The major serological finding is an elevation of the serum IgG(4) concentration. Previous studies have shown that its sensitivity is about 70% and its specificity exceeds 90% at a cut-off of 140 mg/dl in selected patient populations. The aim of the present study was to assess the performance of serum IgG(4) as a diagnostic parameter in an unselected liver and pancreas clinic population. METHODS AND RESULTS: IgG(4) was prospectively determined in 1412 patients and clinical diagnoses were recorded from a review of patient charts. The prevalence of AIP or IAC in the entire cohort was 1.1% (n= 15). The sensitivity of IgG(4) for the diagnosis of AIP and IAC was 80% and the specificity was 86% at a cut-off value of ≥135 mg/dl. The positive predictive value and the negative predictive value were 6% and 99.7%, respectively. The most common differential diagnosis in patients with elevated IgG(4) was liver cirrhosis. CONCLUSION: IgG(4) has a reasonable sensitivity and specificity in a liver and pancreas clinic population, where liver cirrhosis appears to be the most frequent differential diagnosis for elevated IgG(4) concentrations.

Tolerability of N-chlorotaurine in the bovine mammary gland.

N-Chlorotaurine (NCT) is a promising endogenous agent for topical treatment of infections. We tested the tolerability and pharmakokinetics of NCT in the bovine mammary glands in a phase 1 study. Three concentrations of NCT in water (0.1%, 1.0%, 2.0%) were administered intramammarily in each of two cows. Into two quarters of the udder 100 ml NCT was injected into each twice daily for 5 d, while 0.9% NaCl was injected into the other two quarters in a randomized and blinded manner. Samples of milk were taken to determine the number of leucocytes and the activity of NCT, and samples of urine and blood to determine the taurine and chloride concentration. Chloride concentrations in serum samples were determined by an ISE-Unit of a Modular-System of the Roche Diagnostics company. The udder was monitored clinically for signs of inflammation. Oxidative activity could be detected in the milk after single irrigations for 15 min (0.1% NCT) and for maximally 5 h (1% and 2% NCT), respectively. On day 2, leucocytes increased to 4 x 10(6)/ml in the NCT group, while they remained 1 x 10(6)/ml in the saline group. However, on days 3-5 they increased to (5-7) x 10(6) in both the NCT and control group without any statistical difference. One day after the end of dosing the number decreased significantly and reached the baseline (<1 x 10(6)/ml) on day 10. The decrease was similar in both groups. Except for sporadic slight induration of single quarters in both groups and slight reduction of milk performance no disorders occurred. Taurine levels in blood and urine did not change. Irrigation of the bovine mammary gland with both NCT and saline caused a transient increase of leucocytes in the milk, but no severe side effects. The absence of residues and decay products may be a great advantage of NCT over other antimicrobial agents.

C-reactive protein plasma levels but not factor VII activity predict clinical outcome in patients undergoing elective coronary intervention.

BACKGROUND: Both vascular inflammation as determined by C-reactive protein (CRP) and extrinsic coagulation as measured by factor VII activity (F VII) may predict clinical restenosis rate in patients with stable angina pectoris undergoing elective percutaneous coronary intervention (PCI). HYPOTHESIS: The primary objective of this study was to investigate the associations between baseline CRP levels, F VII activity, and restenosis rate after elective PCI in a 6-month follow-up period. METHODS: This prospective study included 81 patients aged > or = 19 years undergoing PCI for angiographically significant (> or = 70%) stenosis, with or without stenting, and 49 controls. Factor VII activity and CRP were measured in samples collected at angiography and 16-24 h post procedure after overnight fast. Successful PCI was defined as final diameter of < 50% with TIMI 3 flow and no complication within 1 h. After 6 months all patients who had undergone PCI were evaluated via a standardized questionnaire. Clinical restenosis was defined as the occurrence of a major adverse coronary events (MACE), within the follow-up period. RESULTS: Diagnostic angiography led to a significant increase in CRP levels after 16-20 h in patients with discrete CAD (n = 22) but not in patients without any signs of coronary atherosclerosis (n = 27). During a 6-month follow-up after PCI, 17 of 81 (21%) patients developed MACE. Tertiles of CRP levels independently predicted clinical restenosis, as it developed in 33.3% of patients with the highest CRP levels (0.7-4.8 mg/dl), in 16.6% of patients with second tertile CRP levels (0.23-0.69 mg/dl), and in 7.4% of patients with lowest tertile CRP levels (0.0-0.22 mg/dl). There was a significant difference in the restenosis rate between patients from the first and the third tertiles (p = 0.018). Successful PCI was associated with a significant decrease of mean CRP levels after 6 months, whereas PCI in patients suffering from MACE led to no change in CRP levels. There was no association between factor VII activity and clinical outcome after PCI, and F VII activity did not change over a 6-month period. CONCLUSIONS: In patients with stable angina pectoris undergoing elective PCI, increased preprocedural and 6-month follow-up CRP plasma levels are associated with clinical restenosis. Factor VII plasma activity lacks such correlations.