Academic literature on the topic 'Serology Longitudinal studies'

Studies reported post-COVID-19 fatigue in the general population, but not among pregnant women. Our objectives were to determine prevalence, duration, and risk factors of post-viral fatigue among pregnant women with SARS-CoV-2. This study involved 588 pregnant women with SARS-CoV-2 during pregnancy or delivery in Brazil. Three groups were investigated: G1 (n = 259, symptomatic infection during pregnancy); G2 (n = 131, positive serology at delivery); G3 (n = 198, negative serology at delivery). We applied questionnaires investigating fatigue at determined timepoints after infection for G1, and after delivery for all groups; fatigue prevalence was then determined. Cox regression was used to estimate hazard ratio (HR) and 95% CI of the risk of remaining with fatigue in G1. Overall fatigue prevalence in G1 at six weeks, three months and six months were 40.6%, 33.6%, and 27.8%, respectively. Cumulative risk of remaining with fatigue increased over time, with HR of 1.69 (95% CI: 0.89–3.20) and 2.43 (95% CI: 1.49–3.95) for women with moderate and severe symptoms, respectively. Multivariate analysis showed cough and myalgia as independent risk factors in G1. Fatigue prevalence was significantly higher in G1 compared to G2 and G3. Post-viral fatigue prevalence is higher in women infected during pregnancy; fatigue’s risk and duration increased with the severity of infection.

ELISA techniques developed for the veterinary diagnosis of Rabbit Haemorrhagic Disease (RHD) in domestic rabbits were used for studying the epidemiology of RHD in Australian wild rabbits. The combination of ELISA techniques that distinguished IgA, IgG and IgM antibody responses and a longitudinal data set, mainly based on capture-mark-recapture of rabbits, provided a reliable basis for interpreting serology and set the criteria used to classify rabbits' immunological status. Importantly, young with maternal antibodies, immune rabbits and rabbits apparently re-exposed to RHD were readily separated. Three outbreaks of RHD occurred in 1996–7. The timing of RHD outbreaks was mainly driven by recruitment of young rabbits that generally contracted RHD after they lost their maternally derived immunity. Young that lost maternal antibodies in summer were not immediately infected, apparently because transmission of RHDV slows at that time, but contracted RHD in the autumn when conditions were again suitable for disease spread.

The coronavirus disease 2019 pandemic still represents a global public health emergency, despite the availability of different types of vaccines that reduced the number of severe cases, the hospitalization rate and mortality. The Italian Vaccine Distribution Plan identified healthcare workers (HCWs) as the top-priority category to receive access to a vaccine and different studies on HCWs have been implemented to clarify the duration and kinetics of antibody response. The aim of this paper is to perform a literature review across a total of 44 studies of the serologic response to COVID-19 vaccines in HCWs in Italy and to report the results obtained in a prospective longitudinal study implemented at the Fondazione IRCCS Istituto Nazionale Tumori (INT) of Milan on 1565 HCWs. At INT we found that 99.81% of the HCWs developed an antibody response one month after the second dose. About six months after the first serology evaluation, 100% of the HCWs were still positive to the antibody, although we observed a significant decrease in its levels. Overall, our literature review results highlight a robust antibody response in most of the HCWs after the second vaccination dose. These figures are also confirmed in our institutional setting seven months after the completion of the cycle of second doses of vaccination.

SUMMARYTwo groups of patients were examined for anti-Trypanosoma cruzi antibodies by immunofluorescence and ELISA (i) inhabitants of the village and surrounding rural area of Tibu, Norte de Santander, Colombia (n = 327) and (ii) employees of the Empresa Colombiana de Petroleos (ECOPETROL, n = 849). The latter group had a lower rate of positive serology (12 as compared to 29%) but the distributions of antibody titres were very similar in the two groups. A total of 119 serum samples (37 village and 82 ECOPETROL, including 25 seronegative controls) were analysed for their ability to immunoprecipitate the 7 major polypeptides of T. cruzi trypomastigotes of Mr > 72 kDa. Although 10 sera from positive patients showed no immunoprecipitation, all of the remaining positive sera contained antibodies which reacted with the 150, 90 and 85 kDa polypeptides. When the T. cruzi immunofluorescence positive, immunoprecipitation negative sera were retested by ELISA using GP90, all were negative thus suggesting that the patients had had a misdiagnosed T. rangeli infection. The new diagnosis was confirmed by immunofluorescence and ELISA with T. rangeli epimastigotes. Longitudinal studies were carried out on 19 patients from the ECOPETROL group for up to 3–5 years. Five seropositive patients showed a change in their anti-trypomastigote immunoprecipitation profiles over this period; one by loss of a previously recognized high molecular weight band and four others by conversion from a negative to a positive immunoprecipitation profile. These latter patients presented initially with uncomplicated T. rangeli infection but then acquired a T. cruzi superinfection. These patients represent the nucleus of a group in which prospective studies will identify the effect of T. rangeli infection on the course of subsequent South American trypanosomiasis and Chagas' disease.

Abstract Introduction : Antiplatelet antibody (APA) testing is considered an adjunct laboratory test in the diagnosis of immune thrombocytopenia (ITP). While it is not routinely obtained owing to inconsistent sensitivity and specificity in prior studies (Neunert et al, 2011), the definition of ITP used in these studies was not standardized. Additionally, potential clinical utility of this testing beyond diagnosis has been suggested, such as correlations between certain serologic patterns and response to IVIG (Peng et al, 2014). In consideration of these prior findings, we undertook a retrospective analysis of APA testing [glycoprotein-specific testing done by the commercial PakAuto assay (Immucor, Brookfield, WI), a monoclonal antibody immobilization of platelet antigens (MAIPA) assay, with all testing performed by the same laboratory] utilizing standardized ITP and Evans syndrome (ES) diagnostic criteria for patient inclusion. We examined serologic evolution over time and relation of antibody positivity to disease severity and response to therapies. Methods : Data collected for analysis included dates and results of APA testing (including disease status and platelet count at time of testing), patient demographics, and disease characteristics. Satisfaction of the 2011 American Society of Hematology (ASH) ITP diagnostic criteria were required for ITP patient inclusion and standard definitions of disease severity and response to treatment from the ASH guidelines were used in analysis. Logistic regression was used to model the probability of disease severity (non-severe, severe, or refractory) and treatment response (to corticosteroids or IVIG) based on serologic findings. Longitudinal serologic evolution in patients with multiple APA assays were analyzed. Results : A total of 214 APA assays from 115 ITP patients and 12 ES patients were collected; results from eluate testing (direct assay) only were used in analysis. Baseline patient characteristics are listed in Table 1. Of 7 possible positive test serologic patterns, only 4 were seen (Figure 1); antibodies against both GPIIb/IIIa and GPIb/IX were required for the presence of antibodies against GPIa/IIa. A multinomial logistic regression model including disease severity, age, sex, duration of disease, and platelet count at time of APA assay found a statistically significant predictive relationship between an increasing number of positive antibodies and disease severity [relative to non-severe ITP, relative risk ratio for severe ITP and refractory ITP was 1.89 (P=0.001) and 2.38 (P=0.004), respectively, per one additional positive antibody, Figure 2]. Multiple logistic regression models including antibody positivity to each platelet glycoprotein (GPIIb/IIIa, GPIb/IX, or GPIa/IIa), age, sex, disease duration and splenectomy status found a significant predictive relation between presence of anti-GPIa/IIa and non-response to corticosteroid treatment (odds ratio, 0.082, P=0.008). No significant relation was found between an antibody and non-response to IVIG. Fifty patients had multiple (2 to 5) APA assays performed over months to years. In evaluation of serologic evolution over time, all 7 patients who entered clinical remission also converted from a positive to a negative serology; 22 patients had stable serologic findings over time; 5 patients had a reduction in number of positive antibodies; and 18 patients demonstrated evidence for epitope spreading, with an increase in the number of positive antibodies (Figure 3). The sensitivity of a positive APA assay for the presence of active ITP was 91%. The sensitivity and specificity of a negative APA assay for remission in a patient with previously confirmed ITP (N=40 assays in patients with clinical remission in the study) were 88% and 91%, respectively. Conclusions : The MAIPA-based direct APA assay is sensitive for the presence of active ITP in patients satisfying 2011 ASH diagnostic criteria. To our knowledge, this is the first study demonstrating that a higher number of positive glycoprotein-specific antibodies may predict for more severe disease as defined by 2011 ASH disease severity criteria. Anti-GPIa/IIa antibodies only occur in the setting of pre-existing positivity for both anti-GPIIb/IIIa and anti-GPIb/IX antibodies, possibly due to a distinctive sequence of epitope spreading. Serologic testing typically turns negative when a patient enters clinical remission. Disclosures Al-Samkari: Agios: Consultancy. Kuter:Novartis: Consultancy; Pfizer: Consultancy; Syntimmune: Consultancy; Argenx: Consultancy; Dova Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees; ONO: Consultancy; Amgen Inc.: Consultancy; Bioverativ: Consultancy, Research Funding; Principia: Research Funding; Rigel: Consultancy, Research Funding; BMS: Research Funding; Protalex: Research Funding.

Background Serological testing for SARS-CoV-2 plays an important role for epidemiological studies, in aiding the diagnosis of COVID-19, and assess vaccine responses. Little is known on dynamics of SARS-CoV-2 serology in African settings. Here, we aimed to characterize the longitudinal antibody response profile to SARS-CoV-2 in Ethiopia. Methods In this prospective study, a total of 102 PCR-confirmed COVID-19 patients were enrolled. We obtained 802 plasma samples collected serially. SARS-CoV-2 antibodies were determined using four lateral flow immune-assays (LFIAs), and an electrochemiluminescent immunoassay. We determined longitudinal antibody response to SARS-CoV-2 as well as seroconversion dynamics. Results Serological positivity rate ranged between 12%-91%, depending on timing after symptom onset. There was no difference in positivity rate between severe and non-severe COVID-19 cases. The specificity ranged between 90%-97%. Agreement between different assays ranged between 84%-92%. The estimated positive predictive value (PPV) for IgM or IgG in a scenario with seroprevalence at 5% varies from 33% to 58%. Nonetheless, when the population seroprevalence increases to 25% and 50%, there is a corresponding increases in the estimated PPVs. The estimated negative-predictive value (NPV) in a low seroprevalence scenario (5%) is high (>99%). However, the estimated NPV in a high seroprevalence scenario (50%) for IgM or IgG is reduced significantly to 80% to 85%. Overall, 28/102 (27.5%) seroconverted by one or more assays tested, within a median time of 11 (IQR: 9–15) days post symptom onset. The median seroconversion time among symptomatic cases tended to be shorter when compared to asymptomatic patients [9 (IQR: 6–11) vs. 15 (IQR: 13–21) days; p = 0.002]. Overall, seroconversion reached 100% 5.5 weeks after the onset of symptoms. Notably, of the remaining 74 COVID-19 patients included in the cohort, 64 (62.8%) were positive for antibody at the time of enrollment, and 10 (9.8%) patients failed to mount a detectable antibody response by any of the assays tested during follow-up. Conclusions Longitudinal assessment of antibody response in African COVID-19 patients revealed heterogeneous responses. This underscores the need for a comprehensive evaluation of seroassays before implementation. Factors associated with failure to seroconvert needs further research.

Background: Anti-John Cunningham virus (JCV) serology has been studied with varying results concerning longitudinal changes. Objectives and methods: Results from 17 published natalizumab-treated multiple sclerosis (MS) patient cohorts were analyzed with common parameters and subsequently verified in two large independent cohorts with 722 and 499 patients from Germany and the United States. Results: Published studies and the verification showed (1) a mean of 10.80% sero-negative patients presented with sero-status change to positivity per year; (2) patients, who sero-convert to index values <0.9, convert from near the threshold and have a high probability of reverting with time; (3) patients, who convert to index values >0.9, start with low index values; (4) while JCV sero-positive patients with low index values sometimes revert to sero-negativity, patients with high index values almost never revert; and (5) the conversion rate of natalizumab-treated patients is three to four times higher than the biological conversion by age. Conclusion: JCV sero-conversion was comparable using standardized parameters and indicates influence of natalizumab on JCV immune control. Converters to low index values are probably consistently infected with JCV with varying low levels of activity, in line with their low risk to develop progressive multifocal leukoencephalopathy (PML). Patients with high index values rarely revert back to sero-negativity.

Abstract Introduction/Objective Since the start of the COVID-19 pandemic, much research has focused on the kinetics and magnitude of humoral immune response. With the advantages of monitoring real-time immunoreactions, label-free immunoassay (LFIA) is becoming a powerful tool in serology studies. We have developed LFIAs to measure SARS- CoV-2 antibody avidity and neutralization activity in a cohort of COVID-19 patients and determine if they correlate with antibody concentration. Serial serum samples collected from mild to severe COVID-19 patients were measured out to 8 months post-symptom onset to determine the durability of the neutralizing antibody response. Methods/Case Report Based on thin-film interferometry technology, we established a label-free IgG avidity assay and a label-free surrogate virus neutralization test (LF-sVNT). For measurement, sensing probes pre-coated with receptor-binding domain (RBD) of SARS-CoV-2 spike protein are applied to serum samples containing SARS-CoV-2 antibodies. The label-free IgG avidity assay measures the binding strength between RBD and IgG under urea dissociation. The LF-sVNT analyzes the binding ability of RBD to ACE2 after neutralizing RBD with antibodies. Results (if a Case Study enter NA) IgG avidity indices and neutralizing antibody titers (IC50) were determined from serum samples (n=246) from COVID-19 patients (n=113). IgG concentrations were measured using a fluorescent immunoassay. The neutralizing antibody titers showed a weak correlation with IgG concentrations and no correlation with IgG avidity indices. Over the time course up to 8 months post-symptom onset, IgG concentrations and neutralizing antibody titers presented similar trends: an initial rise, plateau and then in some cases a gradual decline after 40 days. The IgG avidity indices, in the same cases, plateaued after the initial rise. Conclusion The results demonstrated that LFIA could be used an excellent solution in the determination of SARS- CoV-2 antibody characteristics. The study found that IgG concentration and neutralizing antibody titer declined over time, while IgG avidity index remained constant after reaching a plateau. The decline of antibody neutralization activity can be attributed to the reduction in antibody quantity rather than the deterioration of antibody quality, as measured by antibody avidity.

Autoimmune hepatitis (AIH) is an immune-mediated inflammatory liver disease of uncertain cause, and its manifestations appear to vary by race and ethnicity. The literature on AIH in the Middle East, including Jordan, is scarce; therefore, this study aimed to determine the clinical characteristics of AIH in an understudied population. This retrospective chart review study was conducted on AIH patients who presented to Jordan University Hospital over a seven-year period (2014–2020). Retrieved data included sociodemographics, liver function tests, autoimmune serologic markers, viral hepatitis serology, findings on liver biopsies, treatment regimens, post-therapy outcomes and treatment-related complications. The total number of AIH patients included in the study was 30, divided as follows: type 1 AIH (n = 17, 56.7%), type 2 AIH (n = 2, 6.7%), seronegative AIH (n = 9, 30.0%), and two patients who had AIH-primary biliary cirrhosis overlap syndrome (6.7%). The mean age at diagnosis was 44 years (standard deviation: 17 years), with a female predominance (n = 25, 83.3%). Acute presentation was seen among 18 patients (60.0%). Mild to moderate fibrosis (F1 and F2 on METAVIR scoring system) without cirrhosis was observed among patients who underwent liver biopsies (10/19, 52.6%). The majority of patients (73.3%) were initially treated with prednisone, with azathioprine combination in 16.7% of the patients. At 6 months post initial treatment, twenty patients (66.7%) achieved biochemical remission, four patients had incomplete response, two patients failed to improve (one died during the induction of remission period due to AIH-related complications), and four patients were lost to follow-up. This study provided an updated overview of AIH in Jordan. The results showed typical female predominance, and interestingly high rates of acute presentation and seronegative disease. Future longitudinal studies are recommended to address the nature and long-term prognosis of AIH in Jordan.

Background: New data collection in established longitudinal population studies provides an opportunity for studying the risk factors and sequelae of the novel coronavirus disease 2019 (COVID-19), plus the indirect impacts of the COVID-19 pandemic on wellbeing. The Extended Cohort for E-health, Environment and DNA (EXCEED) cohort is a population-based cohort (N>11,000), recruited from 2013 in Leicester, Leicestershire and Rutland. EXCEED includes consent for electronic healthcare record (EHR) linkage, spirometry, genomic data, and questionnaire data. Methods: Between May 2020 and July 2021, a new questionnaire was deployed in EXCEED, which captured COVID-19 symptoms, general physical and mental health, plus socioeconomic and environmental factors during the pandemic. An online system was developed to invite new participants to join EXCEED, with informed consent being provided online. New and existing participants then completed the COVID-19 questionnaire online. A subset of the new questionnaire respondents were invited to participate in COVID-19 serology substudies, using home antibody testing kits. Results: In total, 3,693 participants provided COVID-19 infection status (median age 62.9 (IQR 54.7-69.2), 58.9% female). Trends of monthly incidence proportions of COVID-19 in EXCEED (self-report or symptom-predicted) approximated local and national figures. Regression analysis of 2,768 participants with linked EHR data showed no obvious monotonic relationship between number of chronic diseases (of 16 pre-specified diseases) and COVID-19 infection. There were 2,144 participants with valid results from a kit allowing differentiation between antibodies due to vaccination or infection. Of these, 8.5% had results consistent with previous COVID-19 infection, and 85.9% had evidence of COVID-19 vaccination, but without evidence of infection. Conclusions: Enriching EXCEED with a new COVID-19 questionnaire and serology data may improve understanding of the risk factors, clinical sequelae and broader impacts of the COVID-19 pandemic in the general population. Controlled access to these data for bona fide researchers is via application to the EXCEED study.