Abstract
Objectives
Serologic testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has experienced a changing landscape of available assays coupled with uncertainty surrounding ...performance characteristics. Studies are needed to directly compare multiple commercially available assays.
Methods
Residual serum samples were identified based on SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) testing, clinical test results, and collection dates. Serum samples were analyzed using assays from four different manufacturers: DiaSorin anti–SARS-CoV-2 S1/S2 IgG, EUROIMMUN anti–SARS-CoV-2 IgG ELISA, Roche Elecsys anti–SARS-CoV-2, and Siemens SARS-CoV-2 Total antibody assays.
Results
Samples from SARS-CoV-2 RT-PCR–positive patients became increasingly positive as time from symptom onset increased. For patients with latest sample 14 or more days after symptom onset, sensitivities reached 93.1% to 96.6%, 98.3%, and 96.6% for EUROIMMUN, Roche, and Siemens assays, respectively, which were superior to the DiaSorin assay at 87.7%. The specificity of Roche and Siemens assays was 100% and superior to DiaSorin and EUROIMMUN assays, which ranged from 96.1% to 97.0% and 86.3% to 96.4%, respectively.
Conclusions
Laboratories should be aware of the advantages and limitations of serology testing options for SARS-CoV-2. The specificity and sensitivity achieved by the Roche and Siemens assays would be acceptable for testing in lower-prevalence regions and have the potential of orthogonal testing advantages if used in combination.
Abstract
Objectives
Monoclonal immunoglobulins (M-proteins) that migrate in the β region on serum protein electrophoresis (SPEP) are often cloaked by this region’s normal constituents. The present ...study interrogates the utility of using both quantitative and qualitative alterations in β-region bands for detection of β-migrating M-proteins.
Methods
Consecutive SPEP cases analyzed by capillary electrophoresis were searched to identify the initial workup on 1,841 patients with increased total β regions, suspicious β-region findings resulting in reflex immunofixation (IFE), or immunosubtraction (ISUB). To augment quantitative information, separate β1 and β2 measurements were established and retrospectively used to evaluate their sensitivity for M-protein detection.
Results
We identified M-proteins in 205 (11.1%) cases, including immunoglobulin A (IgA) (54%), IgG (24%), IgM (13%), and free light chain (9%) isotypes. Of the 15 cases flagged by separate β1 and β2 measurements that were not identified by total β-region measurement, 1 progressed to myeloma. Of the 56 β-migrating M-proteins identified by qualitative features but without increase in any of the β-region measurements, 1 progressed to myeloma.
Conclusions
A combination of separate measurements for β1 and β2 regions together with detection of β-region distortions increase sensitivity for identifying β-migrating M-proteins via reflex IFE or ISUB.
Uncertainty exists whether mild COVID-19 confers immunity to reinfection. Questions also remain regarding the persistence of antibodies against SARS-CoV-2 after mild infection. We prospectively ...followed at-risk individuals with and without SARS-CoV-2 for reinfection and monitored the spike and nucleocapsid antibodies. This prospective cohort study was conducted over two visits, 3 to 6 months apart, between May 2020 and February 2021. Adults with and without COVID-19, verified by FDA EUA-approved SARS-CoV-2 RT-PCR assays, were screened for spike and nucleocapsid antibody responses using FDA EUA-approved immunoassays and for pseudoviral neutralization activity. The subjects were monitored for symptoms, exposure to COVID-19, COVID-19 testing, seroconversion, reinfection, and vaccination. A total of 653 subjects enrolled; 129 (20%) had a history of COVID-19 verified by RT-PCR at enrollment. Most had mild disease, with only three requiring hospitalization. No initially seropositive subjects experienced a subsequent COVID-19 infection during the follow-up versus 15 infections among initially seronegative subjects (infection rates of 0.00 versus 2.05 per 10,000 days at risk P = 0.0485). In all, 90% of SARS-CoV-2-positive subjects produced spike and nucleocapsid responses, and all but one of these had persistent antibody levels at follow-up. Pseudoviral neutralization activity was widespread among participants, did not decrease over time, and correlated with clinical antibody assays. Reinfection with SARS-CoV-2 was not observed among individuals with mild clinical COVID-19, while infections continued in a group without known prior infection. Spike and nucleocapsid COVID-19 antibodies were associated with almost all infections and persisted at stable levels for the study duration. IMPORTANCE This article demonstrates that people who have mild COVID-19 illnesses and produce antibodies are protected from reinfection for up to 6 months afterward. The antibodies that people produce in this situation are stable for up to 6 months as well. Clinical antibody assays correlate well with evidence of antibody-related viral neutralization activity.
Abstract
Objectives
We evaluated the effect of diabetes on sickle hemoglobin (HbS) measurement on two common clinical hemoglobin separation platforms.
Methods
We performed a method comparison between ...the Bio-Rad Variant II high-performance liquid chromatography (HPLC) and Sebia Capillarys 2 Flex Piercing capillary electrophoresis (CE) using clinical specimens from 38 patients without hemoglobin variants and 57 patients with sickle cell trait (AS) (HbA1c%, 4.1%-15.4%). We investigated the effect of intermethod Hb% differences on result interpretation by a panel of expert clinical observers.
Results
In diabetic specimens, HPLC undermeasured HbS% up to 7.4% vs CE, due to S1c eluting closely with A0 in HPLC. This increased concern for underlying α-thalassemia in diabetic patients with AS based on HPLC results. HPLC P2% was linearly related to HbA1c% and can be a screen for diabetic AS samples.
Conclusions
Glycosylation can interfere with HbS% measurement by HPLC. Susceptible specimens should be identified and preferentially analyzed via CE.
Objectives: Monoclonal immunoglobulins (M-proteins) that migrate in the P region on serum protein electrophoresis (SPEP) are often cloaked by this region's normal constituents. The present study ...interrogates the utility of using both quantitative and qualitative alterations in beta-region bands for detection of beta-migrating M-proteins. Methods: Consecutive SPEP cases analyzed by capillary electrophoresis were searched to identify the initial workup on 1,841 patients with increased total beta regions, suspicious beta-region findings resulting in reflex immunofixation (IFE), or immunosubtraction (ISUB). To augment quantitative information, separate beta1 and beta2 measurements were established and retrospectively used to evaluate their sensitivity for M-protein detection. Results: We identified M-proteins in 205 (11.1%) cases, including immunoglobulin A (IgA) (54%), IgG (24%), IgM (13%), and free light chain (9%) isotypes. Of the 15 cases flagged by separate beta1 and beta2 measurements that were not identified by total beta-region measurement, 1 progressed to myeloma. Of the 56 beta-migrating M-proteins identified by qualitative features but without increase in any of the beta-region measurements, 1 progressed to myeloma. Conclusions: A combination of separate measurements for beta1 and beta2 regions together with detection of beta-region distortions increase sensitivity for identifying beta-migrating M-proteins via reflex IFE or ISUB. KEY WORDS Monoclonal gammopathy; Beta region; M-protein; Capillary electrophoresis; Immunofixation; Immunosubtraction; Serum protein electrophoresis
Evidence for the extraneuronal accumulation of norepinephrine has been demonstrated to occur in macrophage (M phi), yet the physiologic role of this system remains undefined. We have assessed the ...response of murine peritoneal M phi to adrenergic antagonists. We have also defined a physiologic role of a M phi-associated pool of the nonspecific adrenergic agonist norepinephrine. We investigated the constitutive involvement of alpha-adrenergic and beta-adrenergic receptors in LPS-induced TNF-alpha production. CFA-elicited M phis were incubated with LPS (1 microgram/ml) in the presence or absence of adrenergic agonists and/or antagonists. Although stimulation of alpha-adrenergic receptors increased TNF production and gene expression, beta-adrenergic receptors decreased it. Interestingly, when adrenergic antagonists along with LPS alone were added to M phi, they generated the response opposite to that produced by their suitable agonist, suggesting a role for endogenous norepinephrine in M phi. Thus, although alpha 2-adrenergic antagonists attenuated TNF production, beta-adrenergic antagonists augmented TNF expression in a concentration-dependent manner. Norepinephrine and epinephrine were found in M phi as determined by HPLC and LPS stimulation induced a significant decrease in their content. M phis were also incubated with LPS or medium only, washed, and then challenged 12 h later with LPS. When given a second LPS stimulation, M phis were found to have an increased response to alpha 2-adrenergic agonists and decreased response to alpha 2-adrenergic antagonists. Therefore, M phi-associated norepinephrine appears to regulate LPS-induced TNF production in an autocrine fashion.
Adrenal vein sampling (AVS) is required to distinguish unilateral from bilateral aldosterone sources in primary aldosteronism (PA), and cortisol is used for AVS data interpretation, but cortisol has ...several pitfalls. In this study, we present the utility of several other steroids in PA subtyping, both during AVS, as well as in peripheral serum. We included patients with PA who underwent AVS at University of Michigan between 2012 and 2018. We used mass spectrometry to simultaneously quantify 17 steroids in adrenal veins (AV) and periphery, both at baseline and after cosyntropin administration. PA was classified as unilateral or bilateral based on a lateralization index ≥ or <4, respectively, separately for baseline and post-cosyntropin administration. Of 131 participants, AV catheterizations was deemed failed in 28 (21 %) patients (36 AVs) at baseline. Eight steroids demonstrated higher AV/periphery ratios than cortisol (
<0.01 for all); 11β-hydroxyandrostenedione, 11-deoxycortisol, and corticosterone rescued most failed baseline catheterizations. Lateralization was generally consistent when using these alternative steroids. Based on pre- and post-cosyntropin data, the remaining 103 patients were classified as: U/U, 37; B/B, 32; U/B, 20; B/U, 14. Discriminant analysis of multi-steroid panels from peripheral serum showed distinct profiles across the 4 groups, with highest aldosterone, 18-oxocortisol and 11-deoxycorticosterone in U/U patients. In conclusion, 11β-hydroxyandrostenedione and 11-deoxycortisol are superior to cortisol for AVS data interpretation. Single assay multi-steroid panels measured in peripheral serum are helpful in stratified PA subtyping and have the potential to circumvent AVS in a subset of patients with PA.
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