scholarly journals Follow-up investigation of antibody titers and diagnostic antibody cutoff values in patients with scrub typhus in South Korea

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Choon-Mee Kim ◽  
Dong-Min Kim ◽  
Na Ra Yun
Keyword(s):  
South Korea ◽  
Scrub Typhus ◽  
Serologic Tests ◽  
Commercial Laboratory ◽  
Cutoff Values ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Commercial Kits ◽  
A Prospective Study

Abstract Background Scrub typhus is a mite-borne infectious disease caused by Orientia tsutsugamushi. Few follow-up studies have assessed antibody titers using serologic tests from various commercial laboratories and the Korea Centers for Disease Control and Prevention (KCDC). Methods A prospective study to assess the antibody titers in patients with scrub typhus and seroprevalence in individuals undergoing health checkups was conducted using results of immunofluorescence antibody assays (IFAs) and serologic tests, used by the KCDC and commercial laboratories, respectively. The following tests were performed simultaneously: (i) indirect IFA used by the KCDC to detect immunoglobulin (Ig) M and IgG, (ii) IFA used by a commercial laboratory to detect total Ig, and (iii) antibody tests using two commercially available kits. Results When the IgM and IgG cutoff values (≥1:16 and ≥1:256, respectively) used in the IFA and the total IgG cutoff values (≥1:40) were used in prospective follow-up investigations, the antibody positivity rates of 102 patients with scrub typhus were 44.1, 35.3, and 57.6%, respectively, within 5 days of symptom onset. Among 91 individuals who recovered from scrub typhus, the follow-up IgM, IgG, and total Ig positivity rates for 13 years were 37.4% (34/91), 22.0% (20/91), and 76.9% (70/91), respectively. Among 216 individuals undergoing health checkups, the seroprevalence of IgM was 4.2% (9/216); no seroprevalence of IgG was observed. Conclusions IFAs used by the KCDC and the commercial laboratory and rapid commercial kits could not distinguish between patients who had recovered from scrub typhus and those who are currently infected with O. tsutsugamushi. In South Korea and other countries, where low antibody cutoff values are used, upward adjustments of cutoff values may be necessary.

scholarly journals 2138. Follow-up Investigation of Antibody Titers and Diagnostic Antibody Cut-Off Values in Scrub Typhus Patients in Korea

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S724-S725
Author(s):  
Dong-Min Kim ◽  
Choon-Mee Kim ◽  
Na Ra Yun
Keyword(s):  
Scrub Typhus ◽  
Health Checkup ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Commercial Kits ◽  
Antibody Tests ◽  
Immunofluorescence Antibody ◽  
Prospective Analyses ◽  
Prospective Investigation

Abstract Background Scrub typhus is a mite-borne infectious disease caused by Orientia tsutsugamushi. There have been few follow-up studies assessing antibody titers using serologic tests from various commercial labs. Methods A prospective investigation to assess antibody titers of scrub typhus patients and seroprevalence for health checkup individuals were evaluated. The antibody titers of former patients diagnosed with scrub typhus at least 1 year and a maximum of 13 years were also investigated. The following tests were performed simultaneously: (i) immunofluorescence antibody assays (IFAs) that detect immunoglobulin(Ig) M and IgG, (ii) IFA that detects total Ig by a commercial lab, (iii) antibody tests using two commercially available kits. Results In prospective analyses with cutoff values set to ≥1:16 for IgM, ≥1:256 for IgG based on the KCDC’s criteria, and ≥1:40 for total Ig. The antibody positive rates of 102 confirmed scrub typhus patients were 44%, 35.3%, and 57.6%, respectively, in the first week after symptom onset. Among 91 former patients recovered, the follow-up IgM, IgG, and total Ig positivity rates were 38.5% (35/91), 22% (20/91), and 76.9% (70/91), respectively. In overall cohort of 216 health checkup subjects, 4.2% (9/216) IgM and 0% (0/216) IgG seroprevalence was observed. Conclusion The IFA from KCDC and commercial lab, and rapid commercial kits cannot differentiate between former patients recovered from scrub typhus and current scrub typhus. In Korea and other countries where low antibody cut-off titer values have been used as criteria for diagnosing and reporting scrub typhus, upward adjustments of cut-off values may be necessary. Disclosures All authors: No reported disclosures.

scholarly journals Performance Evaluation of the Siemens SARS-CoV-2 Total Antibody and IgG Antibody Test

2021 ◽  
Author(s):  
Lisa Florin ◽  
Karel Maelegheer ◽  
Wouter Vandewal ◽  
Dirk Bernard ◽  
Johan Robbrecht
Keyword(s):  
Antibody Test ◽  
Control Group ◽  
Igg Antibody ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Polymerase Chain ◽  
Kinetics Of ◽  
Antibody Tests ◽  
Positive Controls

Abstract Objective In this study, the performance of 2 commercially available SARS-CoV-2 antibody assays is evaluated. Methods The Siemens SARS-CoV-2 Total (COV2T) and IgG (COV2G) antibody tests were evaluated on a Siemens Atellica IM1300 analyzer. Imprecision was assessed with the CLSI EP15 protocol using positive controls. Ninety control group specimens were analyzed for specificity, and 175 specimens from 58 patients with polymerase chain reaction–confirmed SARS-CoV-2 were measured for the sensitivity and kinetics of the antibody response. Results Within-run and total imprecision were acceptable for both assays. Both tests showed a specificity of 100%. Sensitivity earlier in the disease state was greater for the COV2T assay than for the COV2G assay, but sensitivity >14 days after onset of symptoms approached 100% for both. For all patients, antibody titers remained above the seroconversion cutoff for all follow-up specimens. Conclusion This study shows acceptable performance for both the Siemens COV2T and COV2G test, although seroconversion occurs earlier with the COV2T test.

scholarly journals Evaluation of the diagnostic accuracy of antibody assays for patients with scrub typhus

2021 ◽  
Author(s):  
Choon-Mee Kim ◽  
Dong-Min Kim ◽  
Na Ra Yun
Keyword(s):  
Scrub Typhus ◽  
Immunofluorescence Assay ◽  
Total Serum ◽  
Test Accuracy ◽  
Serum Samples ◽  
Positive Polymerase Chain Reaction ◽  
Highly Sensitive ◽  
Antibody Assays ◽  
Control And Prevention ◽  
Commercial Kits

This study was carried out to evaluate the accuracy of various antibody tests for scrub typhus, namely the indirect immunofluorescence assay (IFA) from the Korea Centers for Disease Control and Prevention (KCDC) and four commercial kits (companies A–D). The test accuracy was based on the diagnosis of scrub typhus, as defined by a positive polymerase chain reaction or culture. In total, serum samples from 97 patients with scrub typhus and 200 non-scrub typhus patients were tested. The sensitivity and specificity of each test were, respectively, as follows: for KCDC: 55.7% (95% confidence interval (CI): 45.2–65.8%) and 94.8% (95% CI: 90.4–97.3%) for IgM and 42.3% (95% CI: 32.3–52.7%) and 96.3% (95% CI: 92.6–98.5%) for IgG, with diagnostic cut-offs of ≥1:16 for IgM and ≥1:256 for IgG; for kit A: 70.1% (95% CI: 59.8–78.8%) and 74.6% (95% CI: 67.6–80.6%) for total immunoglobulins, with a cut-off of ≥1:40; for kit B: 64.3% (95% CI: 51.9–75.1%) and 94.9% (95% CI: 81.4–99.1%) for IgM and 67.1% (95% CI: 54.8–77.6%) and 74.4% (95% CI: 57.6–86.4%) for IgG; for kit C: 53.6% (95% CI: 43.2–63.7%) and 99.5% (95% CI: 96.8–100%) for IgM and 36.1% (95% CI: 26.8–46.5%) and 100% (95% CI: 97.6–100%) for IgG; and for kit D: 73.2% (95% CI: 63.1–81.4%) and 89.5% (95% CI: 84.2–93.2%) for total immunoglobulins. These results are all unsatisfactory, highlighting an urgent need for the development of more highly sensitive and specific tests.

scholarly journals Efficacy of SARS-CoV-2 vaccine in thoracic cancer patients: a prospective study supporting a third dose in patients with minimal serologic response after two vaccine doses

2021 ◽  
Author(s):  
Valerie GOUNANT ◽  
Valentine Marie FERRE ◽  
Ghassen SOUSSI ◽  
Charlotte charpentier ◽  
Heloise FLAMENT ◽  
...  
Keyword(s):  
Antibody Response ◽  
Cancer Patients ◽  
Vaccine Dose ◽  
Corticosteroid Treatment ◽  
Thoracic Cancer ◽  
Antibody Titers ◽  
Chronic Corticosteroid ◽  
A Prospective Study ◽  
Humoral Responses

Hypothesis Coronavirus disease 2019 (COVID-19) resulted in a 30% mortality rate in thoracic cancer patients. Given that cancer patients were excluded from serum anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) vaccine registration trials, it is still unknown whether they would develop a protective anti-spike antibody response following vaccination. This prospective vaccine monitoring study primarily aimed to assess humoral responses to SARS-CoV2 vaccine in thoracic cancer patients. Methods SARS-CoV2-spike antibodies were measured using Abbot ARCHITECT SARS-CoV-2 IgG immunoassay, prior to first injection of BNT162b2 mRNA vaccine, as well as at Week 4, and two-to-sixteen weeks after second vaccine dose. The factors associated with antibody response were analyzed. Results Overall, 306 patients, with a median age of 67.0 years (IQR=58-74), were vaccinated. Of these, 283 patients received two vaccine doses at 28-day intervals. After 4.7-month median follow-up, seven patients (2.3%) contracted proven symptomatic SARS-CoV-2 infection, with rapid favorable evolution. Of 269 serological results available beyond Day 14 post-second vaccine dose, 17 (6.3%) were still negative (<50 AU/mL) (arbitrary units/mL), while 34 (11%) were <300 AU/mL (12.5th percentile). In multivariate analysis, only age and chronic corticosteroid treatment were significantly associated with a lack of immunization. Thirty patients received a third vaccine dose, with only three patients showing persistent negative serology thereafter, whereas the others demonstrated clear seroconversion. Conclusion SARS-CoV2 vaccines were shown to be efficient in thoracic cancer patients, most of them being immunized after two doses. A third shot given to 11% of patients with persistent low antibody titers resulted in a 88% immunization rate.

scholarly journals Longitudinal Serological Analysis and Neutralizing Antibody Levels in Coronavirus Disease 2019 Convalescent Patients

2020 ◽  
Author(s):  
Frauke Muecksch ◽  
Helen Wise ◽  
Becky Batchelor ◽  
Maria Squires ◽  
Elizabeth Semple ◽  
...  
Keyword(s):  
Neutralizing Antibody ◽  
Neutralization Titer ◽  
Serological Assay ◽  
Antibody Assays ◽  
Antibody Titers ◽  
Binding Antibody ◽  
Antibody Levels ◽  
Prior Infection ◽  
Commercial Platform

Abstract Background Understanding the longitudinal trajectory of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies is crucial for diagnosis of prior infection and predicting future immunity. Methods We conducted a longitudinal analysis of coronavirus disease 2019 convalescent patients, with neutralizing antibody assays and SARS-CoV-2 serological assay platforms using SARS-CoV-2 spike (S) or nucleocapsid (N) antigens. Results Sensitivities of serological assays in diagnosing prior SARS-CoV-2 infection changed with time. One widely used commercial platform that had an initial sensitivity of &gt;95% declined to 71% at 81–100 days after diagnosis. The trajectories of median binding antibody titers measured over approximately 3–4 months were not dependent on the use of SARS-CoV-2 N or S proteins as antigen. The median neutralization titer decreased by approximately 45% per month. Each serological assay gave quantitative antibody titers that were correlated with SARS-CoV-2 neutralization titers, but S-based serological assay measurements better predicted neutralization potency. Correlation between S-binding and neutralization titers deteriorated with time, and decreases in neutralization titers were not predicted by changes in S-binding antibody titers. Conclusions Different SARS-CoV-2 serological assays are more or less well suited for surveillance versus prediction of serum neutralization potency. Extended follow-up should facilitate the establishment of appropriate serological correlates of protection against SARS-CoV-2 reinfection.

Short-Term Ultramicronized Palmitoylethanolamide Therapy in Patients with Myasthenia Gravis: a Pilot Study to Possible Future Implications of Treatment

2019 ◽  
Vol 18 (3) ◽  
pp. 232-238 ◽  
Author(s):  
Emanuela Onesti ◽  
Vittorio Frasca ◽  
Marco Ceccanti ◽  
Giorgio Tartaglia ◽  
Maria Cristina Gori ◽  
...  
Keyword(s):  
Pilot Study ◽  
Myasthenia Gravis ◽  
Repetitive Nerve Stimulation ◽  
Beneficial Effects ◽  
Antibody Titers ◽  
The Stability ◽  
Ultramicronized Palmitoylethanolamide ◽  
Open Pilot

Background: The cannabinoid system may be involved in the humoral mechanisms at the neuromuscular junction. Ultramicronized-palmitoylethanolamide (μm-PEA) has recently been shown to reduce the desensitization of Acetylcholine (ACh)-evoked currents in denervated patients modifying the stability of ACh receptor (AChR) function. <p> Objective: To analyze the possible beneficial effects of μm-PEA in patients with myasthenia gravis (MG) on muscular fatigue and neurophysiological changes. <p> Method: The duration of this open pilot study, which included an intra-individual control, was three weeks. Each patient was assigned to a 1-week treatment period with μm-PEA 600 mg twice a day. A neurophysiological examination based on repetitive nerve stimulation (RNS) of the masseteric and the axillary nerves was performed, and the quantitative MG (QMG) score was calculated in 22 MG patients every week in a three-week follow-up period. AChR antibody titer was investigated to analyze a possible immunomodulatory effect of PEA in MG patients. <p> Results: PEA had a significant effect on the QMG score (p=0.03418) and on RNS of the masseteric nerve (p=0.01763), thus indicating that PEA reduces the level of disability and decremental muscle response. Antibody titers did not change significantly after treatment. <p> Conclusion: According to our observations, μm-PEA as an add-on therapy could improve muscular response to fatigue in MG. The possible modulation of AChR currents as a means of eliciting a direct effect from PEA on the conformation of ACh receptors should be investigated. The co-role of cytokines also warrants an analysis. Given the rapidity and reversibility of the response, we suppose that PEA acts directly on AChR, though further studies are needed to confirm this hypothesis.

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