Exploring novel autoantibodies within Alzheimer's disease

Alzheimers sjukdom (AD, eng. Alzheimer’s disease) upptäcktes för 111 år sedan av Alois Alz-heimer. Idag är det den ledande orsaken till demens hos äldre, och incidencen förväntas öka med befolkningens ökande livslängd. År 2050 förutspås antalet patienter med AD nå 10 miljoner personer [1]. Det har gjorts många försök att angripa AD via dess främsta kännetäcken, såsom plack av beta-amyloid (Aβ), Aβ-oligomerer, och ansamlingar av tau-protein, kallat tau-trassel. Trots att forskning om AD bedrivits i flera årtionden är dess orsak alltjämt okänd.På sistone har det funnits ett fokus på de inflammatoriska komponenterna inom AD. Det finns en utbredd aktivering av immunförsvaret i det centrala nervsystemet hos patienter med AD, men varken dess orsak eller dess roll inom AD är känd. Däremot finns det tydliga tecken på att inflammationen är av autoimmun art. Med detta i åtanke är det tydligt att det finns ett stort behov att utröna auto-immunitetens roll inom AD. I denna forskningsstudie användes proteomik-metoder för att bestämma autoantikroppsprofilerna inom plasma och cerebrospinalvätska (CSF, eng. cerebrospinal fluid) hos AD-patienter och en frisk kontrollgrupp.I denna studie användes par av plasma- och CSF-prover från 23 friska individer och 49 patien-ter. Dessutom inkluderades 2 plasmaprover och 18 CSF-prover från patienter. En 380-faldig och en 314-faldig riktad analys gjordes med hjälp utav suspension bead array-teknologi (SBA). Varje SBA bestod av färgkodade, magnetiska mikrosfärer i suspension, med antigen immobiliserade på kulornas yta. Denna analysmetod användes för att undersöka autoantikropssprofilerna i alla prover. Resul-taten visade en ökad respons från autoantikroppar mot antigenen SLC17A6 (Solute Carrier Family 17 Member 6), MAP1A (Microtubule Associated Protein 1A), och MAP2 (Microtubule Associated Protein 2) i patiener gentemot friska individer. Dock har dessa antigen uppvisat en bred reaktivitet i tidigare, opublicerade studier. Därför behövs ytterligare forskning för att fastställa deras roll inom AD.Dessutom användes paren av plasma- och CSF-prover för att undersöka autoantikroppsprofilernas överrensstämmelse inom varje patient. Det visade sig att korrelationen följde en normalfördelning, med starkare korrelation inom antigen med starkare reaktivitet mot den motsvarande autoantikroppen. Denna studie utgör en av de första storskaliga forskningsstudierna av överrensstämmelsen mellan autoantikroppsprofilerna inom plasma och CSF.Alzheimer’s disease (AD) was discovered 111 years ago by Alois Alzheimer. Today, it is the leading cause of dementia in elderly, and incidence is expected to increase with life expectancy. By 2050, the number of a˙ected individuals is predicted to reach 10 million [1]. There have been numerous attempts to describe AD by its primary hallmarks, including amyloid plaques, amyloid beta (Aβ) oligomers, and tau tangles. However, despite several decades of intense research, the cause of AD remains unknown.Recently, there has been a focus on the inflammatory components of AD. There is an extensive activation of the immune system within the CNS of AD patients, but neither its cause nor its role in AD is known. However, there are strong indications that the inflammation has an autoimmune character. Considering this, there is an imperative need to examine autoimmunity within AD. In the present study, a proteomic approach was used to determine the autoantibody profiles within plasma and cerebrospinal fluid (CSF) within AD patients and healthy controls.Paired plasma and CSF samples from 23 healthy controls and 49 patients were included in the present study. In addition, 2 plasma samples and 18 CSF samples from patients were included (not paired). One 380-plex and one 314-plex targeted suspension bead array (SBA), each consisting of color-coded magnetic microspheres with immobilized antigens, were used to analyze autoantibody profiles in all samples. The resulting data revealed an increased autoantibody response towards anti-gens SLC17A6 (Solute Carrier Family 17 Member 6), MAP1A (Microtubule Associated Protein 1A), and MAP2 (Microtubule Associated Protein 2) in patients compared to healthy controls. However, as these antigens have displayed wide reactivities in previous, unpublished studies, they require further investigation to determine their role in AD.Furthermore, the paired CSF and plasma samples were used to investigate the correlation of autoantibody profiles within patients. The correlation was found to follow a normal distribution, with correlation being higher in antigens displaying stronger autoantibody reactivity. This work represents one of the first large-scale studies on the correlation of autoantibody profiles in plasma and CSF

Exploring novel autoantibodies within Alzheimer's disease

Alzheimers sjukdom (AD, eng. Alzheimer’s disease) upptäcktes för 111 år sedan av Alois Alz-heimer. Idag är det den ledande orsaken till demens hos äldre, och incidencen förväntas öka med befolkningens ökande livslängd. År 2050 förutspås antalet patienter med AD nå 10 miljoner personer [1]. Det har gjorts många försök att angripa AD via dess främsta kännetäcken, såsom plack av beta-amyloid (Aβ), Aβ-oligomerer, och ansamlingar av tau-protein, kallat tau-trassel. Trots att forskning om AD bedrivits i flera årtionden är dess orsak alltjämt okänd.På sistone har det funnits ett fokus på de inflammatoriska komponenterna inom AD. Det finns en utbredd aktivering av immunförsvaret i det centrala nervsystemet hos patienter med AD, men varken dess orsak eller dess roll inom AD är känd. Däremot finns det tydliga tecken på att inflammationen är av autoimmun art. Med detta i åtanke är det tydligt att det finns ett stort behov att utröna auto-immunitetens roll inom AD. I denna forskningsstudie användes proteomik-metoder för att bestämma autoantikroppsprofilerna inom plasma och cerebrospinalvätska (CSF, eng. cerebrospinal fluid) hos AD-patienter och en frisk kontrollgrupp.I denna studie användes par av plasma- och CSF-prover från 23 friska individer och 49 patien-ter. Dessutom inkluderades 2 plasmaprover och 18 CSF-prover från patienter. En 380-faldig och en 314-faldig riktad analys gjordes med hjälp utav suspension bead array-teknologi (SBA). Varje SBA bestod av färgkodade, magnetiska mikrosfärer i suspension, med antigen immobiliserade på kulornas yta. Denna analysmetod användes för att undersöka autoantikropssprofilerna i alla prover. Resul-taten visade en ökad respons från autoantikroppar mot antigenen SLC17A6 (Solute Carrier Family 17 Member 6), MAP1A (Microtubule Associated Protein 1A), och MAP2 (Microtubule Associated Protein 2) i patiener gentemot friska individer. Dock har dessa antigen uppvisat en bred reaktivitet i tidigare, opublicerade studier. Därför behövs ytterligare forskning för att fastställa deras roll inom AD.Dessutom användes paren av plasma- och CSF-prover för att undersöka autoantikroppsprofilernas överrensstämmelse inom varje patient. Det visade sig att korrelationen följde en normalfördelning, med starkare korrelation inom antigen med starkare reaktivitet mot den motsvarande autoantikroppen. Denna studie utgör en av de första storskaliga forskningsstudierna av överrensstämmelsen mellan autoantikroppsprofilerna inom plasma och CSF.Alzheimer’s disease (AD) was discovered 111 years ago by Alois Alzheimer. Today, it is the leading cause of dementia in elderly, and incidence is expected to increase with life expectancy. By 2050, the number of a˙ected individuals is predicted to reach 10 million [1]. There have been numerous attempts to describe AD by its primary hallmarks, including amyloid plaques, amyloid beta (Aβ) oligomers, and tau tangles. However, despite several decades of intense research, the cause of AD remains unknown.Recently, there has been a focus on the inflammatory components of AD. There is an extensive activation of the immune system within the CNS of AD patients, but neither its cause nor its role in AD is known. However, there are strong indications that the inflammation has an autoimmune character. Considering this, there is an imperative need to examine autoimmunity within AD. In the present study, a proteomic approach was used to determine the autoantibody profiles within plasma and cerebrospinal fluid (CSF) within AD patients and healthy controls.Paired plasma and CSF samples from 23 healthy controls and 49 patients were included in the present study. In addition, 2 plasma samples and 18 CSF samples from patients were included (not paired). One 380-plex and one 314-plex targeted suspension bead array (SBA), each consisting of color-coded magnetic microspheres with immobilized antigens, were used to analyze autoantibody profiles in all samples. The resulting data revealed an increased autoantibody response towards anti-gens SLC17A6 (Solute Carrier Family 17 Member 6), MAP1A (Microtubule Associated Protein 1A), and MAP2 (Microtubule Associated Protein 2) in patients compared to healthy controls. However, as these antigens have displayed wide reactivities in previous, unpublished studies, they require further investigation to determine their role in AD.Furthermore, the paired CSF and plasma samples were used to investigate the correlation of autoantibody profiles within patients. The correlation was found to follow a normal distribution, with correlation being higher in antigens displaying stronger autoantibody reactivity. This work represents one of the first large-scale studies on the correlation of autoantibody profiles in plasma and CSF

An evaluation of a FluoroSpot assay as a diagnostic tool to determine SARS-CoV-2 specific T cell responses

Numerous assays evaluating serological and cellular responses have been developed to characterize immune responses against SARS-CoV-2. Serological assays are both cost- and time-effective compared to cellular assays, but cellular immune responses may provide a diagnostic value to determine previous SARS-CoV-2 infection in seronegative individuals. However, potential cross-reactive T cell responses stemming from prior encounters with human coronaviruses (HCoVs) may affect assay specificity. In this study, we evaluated the specificity and sensitivity of a SARS-CoV-2 IFN-gamma Release Assay (IGRA) based on the FluoroSpot method employing commercially available SARS-CoV-2-specific peptide pools, as well as an in-house designed SARS-CoV-2 peptide pool restricted to 5 amino acid stretches or less aligning with endemic HCoVs. Blood samples were obtained from healthcare workers (HCW) 5-6 months post SARS-CoV-2 spike (S) IgG and nucleocapsid (N) IgG dual seroconversion (n = 187) and HCW who had been S IgG and N IgG dual seronegative at repeated occasions, including the current sampling time point (n = 102). In addition, samples were obtained 4 to 5 months post infection from 55 polymerase chain reaction (PCR)-confirmed COVID-19 patients. Assay specificity and sensitivity were calculated with serology as a reference standard for HCW. The in-house generated peptide pool displayed a specificity of 96.1%, while the commercially available peptide pools displayed specificities of 80.4% and 85.3%, respectively. Sensitivity was higher in a cohort of previously hospitalized COVID-19 patients (96.4% and 84.0% for the commercially available peptide pools and 92.7% for the in-house generated peptide pool) compared to the HCW cohort (92.0% and 66.8% for the commercially available peptide pools and 76.0% for the in-house generated peptide pool). Based on these findings, the individual diagnostic value of T cell immune responses against SARS-CoV-2 currently appears to be limited but remain an important research tool ahead

SARS-CoV-2 exposure, symptoms and seroprevalence in healthcare workers in Sweden

SARS-CoV-2 may pose an occupational health risk to healthcare workers. Here, we report the seroprevalence of SARS-CoV-2 antibodies, self-reported symptoms and occupational exposure to SARS-CoV-2 among healthcare workers at a large acute care hospital in Sweden. The seroprevalence of IgG antibodies against SARS-CoV-2 was 19.1% among the 2149 healthcare workers recruited between April 14th and May 8th 2020, which was higher than the reported regional seroprevalence during the same time period. Symptoms associated with seroprevalence were anosmia (odds ratio (OR) 28.4, 95% CI 20.6-39.5) and ageusia (OR 19.2, 95% CI 14.3-26.1). Seroprevalence was also associated with patient contact (OR 2.9, 95% CI 1.9-4.5) and covid-19 patient contact (OR 3.3, 95% CI 2.2-5.3). These findings imply an occupational risk for SARS-CoV-2 infection among healthcare workers. Continued measures are warranted to assure healthcare workers safety and reduce transmission from healthcare workers to patients and to the community. Healthcare workers may be at higher risk of SARS-CoV-2 infection than the general population. Here, the authors report 19% seroprevalence of SARS-CoV-2 antibodies among 2,149 employees in a Swedish hospital. Seroprevalence was associated with patient contact and higher than the seroprevalence in the community in same time period

SARS-CoV-2 induces a durable and antigen specific humoral immunity after asymptomatic to mild COVID-19 infection

Current SARS-CoV-2 serological assays generate discrepant results, and the longitudinal characteristics of antibodies targeting various antigens after asymptomatic to mild COVID-19 are yet to be established. This longitudinal cohort study including 1965 healthcare workers, of which 381 participants exhibited antibodies against the SARS-CoV-2 spike antigen at study inclusion, reveal that these antibodies remain detectable in most participants, 96%, at least four months post infection, despite having had no or mild symptoms. Virus neutralization capacity was confirmed by microneutralization assay in 91% of study participants at least four months post infection. Contrary to antibodies targeting the spike protein, antibodies against the nucleocapsid protein were only detected in 80% of previously anti-nucleocapsid IgG positive healthcare workers. Both anti-spike and anti-nucleocapsid IgG levels were significantly higher in previously hospitalized COVID-19 patients four months post infection than in healthcare workers four months post infection (p = 2*10(-23) and 2*10(-13) respectively). Although the magnitude of humoral response was associated with disease severity, our findings support a durable and functional humoral response after SARS-CoV-2 infection even after no or mild symptoms. We further demonstrate differences in antibody kinetics depending on the antigen, arguing against the use of the nucleocapsid protein as target antigen in population-based SARS-CoV-2 serological surveys

Robust humoral and cellular immune responses and low risk for reinfection at least 8 months following asymptomatic to mild COVID-19

Background: Emerging data support detectable immune responses for months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination, but it is not yet established to what degree and for how long protection against reinfection lasts. Methods: We investigated SARS-CoV-2-specific humoral and cellular immune responses more than 8 months post-asymptomatic, mild and severe infection in a cohort of 1884 healthcare workers (HCW) and 51 hospitalized COVID-19 patients. Possible protection against SARS-CoV-2 reinfection was analyzed by a weekly 3-month polymerase chain reaction (PCR) screening of 252 HCW that had seroconverted 7 months prior to start of screening and 48 HCW that had remained seronegative at multiple time points. Results: All COVID-19 patients and 96% (355/370) of HCW who were anti-spike IgG positive at inclusion remained anti-spike IgG positive at the 8-month follow-up. Circulating SARS-CoV-2-specific memory T cell responses were detected in 88% (45/51) of COVID-19 patients and in 63% (233/370) of seropositive HCW. The cumulative incidence of PCR-confirmed SARS-CoV-2 infection was 1% (3/252) among anti-spike IgG positive HCW (0.13 cases per 100 weeks at risk) compared to 23% (11/48) among anti-spike IgG negative HCW (2.78 cases per 100 weeks at risk), resulting in a protective effect of 95.2% (95% CI 81.9%-99.1%). Conclusions: The vast majority of anti-spike IgG positive individuals remain anti-spike IgG positive for at least 8 months regardless of initial COVID-19 disease severity. The presence of anti-spike IgG antibodies is associated with a substantially reduced risk of reinfection up to 9 months following asymptomatic to mild COVID-19

Systematic evaluation of SARS-CoV-2 antigens enables a highly specific and sensitive multiplex serological COVID-19 assay

Objective: The COVID-19 pandemic poses an immense need for accurate, sensitive and high-throughput clinical tests, and serological assays are needed for both overarching epidemiological studies and evaluating vaccines. Here, we present the development and validation of a high-throughput multiplex bead-based serological assay. Methods: More than 100 representations of SARS-CoV-2 proteins were included for initial evaluation, including antigens produced in bacterial and mammalian hosts as well as synthetic peptides. The five best-performing antigens, three representing the spike glycoprotein and two representing the nucleocapsid protein, were further evaluated for detection of IgG antibodies in samples from 331 COVID-19 patients and convalescents, and in 2090 negative controls sampled before 2020. Results: Three antigens were finally selected, represented by a soluble trimeric form and the S1-domain of the spike glycoprotein as well as by the C-terminal domain of the nucleocapsid. The sensitivity for these three antigens individually was found to be 99.7%, 99.1% and 99.7%, and the specificity was found to be 98.1%, 98.7% and 95.7%. The best assay performance was although achieved when utilising two antigens in combination, enabling a sensitivity of up to 99.7% combined with a specificity of 100%. Requiring any two of the three antigens resulted in a sensitivity of 99.7% and a specificity of 99.4%. Conclusion: These observations demonstrate that a serological test based on a combination of several SARS-CoV-2 antigens enables a highly specific and sensitive multiplex serological COVID-19 assay