UCTD and SLE patients show increased levels of oxidative and DNA damage together with an altered kinetics of DSB repair

Immunological tolerance is a critical feature of the immune system; its loss might lead to an abnormal response of lymphocytes causing autoimmune diseases. One of the most important groups belonging to autoimmune disorders is the connective tissue diseases (CTD). CTD are classified among systemic rheumatic diseases and include pathologies such as systemic lupus erythematosus (SLE), and undifferentiated CTD (UCTD). In this study, we evaluated oxidative and genome damage in peripheral blood lymphocytes from patients with SLE and UCTD, further classified on the basis of disease activity and the presence/absence of a serological profile. Oxidative damage was evaluated in cell membrane using the fluorescent fatty acid analogue BODIPY 581/591 C11. The percentage of oxidised lymphocytes in both SLE and UCTD patients was higher than in the control group, and the oxidative stress correlated positively with both disease activity and autoantibody profile. The γH2AX focus assay was used to quantify the presence of spontaneous double strand breaks (DSBs), and to assess the abilities of DSBs repair system after T cells were treated with mitomycin C (MMC). Subjects with these autoimmune disorders showed a higher number of γH2AX foci than healthy controls, but no correlation with diseases activity and presence of serological profile was observed. In addition, patients displayed an altered response to MMC-induced DSBs, which led their peripheral cells to greatly increase apoptosis. Taken together our results confirmed an interplay among oxidative stress, DNA damage and impaired DNA repair, which are directly correlated to the aggressiveness and clinical progression of the diseases. We propose the evaluation of these molecular markers to better characterize SLE and UCTD, aiming to improve the treatment plan and the quality of the patients’ life.

Investigation of Epstein-Barr Virus Antibodies by Chemiluminescent Microparticle Immunoassay Method in Patients of Different Age Groups: Evaluation of Atypical Serological Profiles

Objective: Epstein-Barr virus (EBV) can cause different clinical pictures from infectious mononucleosis (IM) to malignancies such as B-cell lymphomas, Burkitt’s lymphoma, nasopharyngeal carcinoma, and Hodgkin lymphoma. VCA-IgM, VCA-IgG, EBNA-1 IgG antibodies are the most commonly used antibodies in revealing the serological profile. This study aimed to examine the serological profiles of patients with suspected EBV infection and to interpret the atypical profiles encountered. Methods: The results of VCA-IgM, VCA-IgG, and EBNA-1 IgG antibodies studied in the Microbiology Laboratory between 2017-2019 were evaluated retrospectively. EBV serological tests (VCA-IgM, VCA-IgG, and EBNA-1 IgG) were performed according to the manufacturer’s recommendations using the chemiluminescent microparticle immunoassay (CMIA) method (Architect, Abbott, Wiesbaden, Germany). Results: Of the 2486 patients evaluated, 1341 (53.9%) were male, 1145 (46.1%) were female, and the average age was determined as 16.93 ± 19.5. EBV past infection was detected in 56.65% of the cases, the acute infection was detected in 17.25%, and 21.09% did not encounter EBV. Atypical serological profile was detected in 5.01%. As an atypical profile, the most common positivity of three antibodies together (3.90%), then isolated VCA-IgG positivity (0.91%), and isolated EBNA-1 IgG positivity (0.20%) were determined. It was determined that 24.24% of the cases with an atypical profile were immunosuppressive patient. Conclusions: The rate of encountering EBV in our study is 78.91%. The atypical EBV serological profile rate was found to be 5.01%. Approximately one-fourth of the cases with an atypical profile was found to be in the patient group with immune disorders. It is thought that antibody tests are not sufficient to determine the stage of infection, especially in these patient groups, and further tests should be performed. It has been demonstrated that serological monitoring is required for the interpretation of atypical profiles. Keywords: Epstein-Barr virüs, serological tests, chemiluminescent microparticle immunoassay (CMIA), atypical serological profile

POS0749 ASSOCIATION BETWEEN IMMUNE-SEROLOGICAL PROFILE AND PULMONARY MANIFESTATIONS IN COLOMBIAN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS (LES)

Background:Pulmonary involvement is common in Systemic Lupus Erythematosus (SLE) patients with varying degrees of parenchymal, vascular, and pleural compromise. In GLADEL, pulmonary involvement was reported in 28.4% of the cohort, but its occurrence ranges between 30-90% due to diversity in populations and the methods used to define it.Objectives:To describe the immune-serological profile of a Colombian cohort of SLE patients and to establish its association with pulmonary manifestations.Methods:Retrospective analysis of observational data from the follow-up of a cohort of adult patients with SLE. We included 559 patients that fulfilled the SLICC 2012 classification criteria with at least 6 months of disease history and being treated in a rheumatology specialized medical center between 2015 and 2018. The immuno-serological profile was characterized, and pulmonary involvement was monitored for 1 year. Diagnosis of pulmonary involvement was performed with the rheumatologist report in the clinical chart. Prevalence of pulmonary manifestations and immune-serological profile was determined, and logistic regression was performed afterward adjusted by age, sex, and level of education to establish the association between pulmonary manifestations and a positive auto-antibodies profile.Results:The median age of the cohort was 45 years, 96.5% were female. Pulmonary involvement was documented in 113 patients (20.5%) at the beginning of the study. Their frequency was: pleuritis (14.3%), lupus pneumonitis (3.6%), pulmonary hypertension (3.2%), interstitial lung disease (ILD) (2.3%), pulmonary embolism (2.3%), lung fibrosis (2.14%), alveolar hemorrhage (1.4%), shrinking lung (0.2%). At 1 year of follow up. there were no statistically significant differences in the frequency of pulmonary manifestations. As for the immune-serological profile, there were positive ANA in 92%, anti-dsDNA in 53.1%, anti-B2GP IgM 15.2%, anti- B2GP IgG in 17.2%, and ENA in 97.2%; as for the ENA 41.7% had positive anti-RNP, 40.2% anti-Ro, 36.4% anti-SM and 16.5% anti-La. Low complement levels was characterized as follows: C3 53.1% and C4 29.2%. In the logistic regression adjusted by age, sex and level of education, there was an association between anti-SM and pulmonary manifestations with an adjusted OR of 1.85; 95% CI 1.13-3.01.Conclusion:An association between anti-SM positivity and pleuro-pulmonary manifestations was found. In other cohorts with a greater size, anti-La and anti-RNP have been associated with pulmonary involvement (OR 2.51; 95% CI 1.39-4.57 and OR 1.32; 95% CI 1-1.75 respectively). Anti-RNP positivity has been associated in particular with ILD, pulmonary hypertension and shrinking lung. Although these manifestations prevalence was similar in our cohort, an association with this antibody was not found (OR 1.01, 95% CI: 0.2-4.9). This could be explained by the smaller sample size. As for anti-La positivity, its prevalence in our cohort was less than what was found in the GLADEL cohort (16.5% vs 24.3% respectively). It is possible that this could explain the poor association between anti-La positivity with the presence of pulmonary manifestations in our study compared with those of the GLADEL cohort. There are data that indicates that anti-SM and anti-RNP simultaneous positivity is related mainly to pleuritis OR 1.98 (95% CI: 1.31-3); and this kind of involvement was found to be more frequent in our study. Our results suggest an association between positive anti-SM and pulmonary manifestations in Colombian patients with SLE, pleuritis in particular.References:[1]Haye Salinas MJ, Caeiro F, Saurit V et al. Pleuropulmonary involvement in patients with systemic lupus erythematosus from a Latin American inception cohort (GLADEL). Lupus. 2017;26(13):1368–77.[2]Emad Y, Gheita T, Darweesh H, Klooster P, et al. Antibodies to extractable nuclear antigens (ENAS) in systemic lupus erythematosus patients: Correlations with clinical manifestations and disease activity. Reumatismo. 2018;70(2):85–91.Disclosure of Interests:None declared

Performance of four IgM antibody assays in the diagnosis of Measles virus primary infection and cases with a serological profile indicating reinfection

Objectives: To determine the diagnostic performance of four commercially available IgM tests in the diagnosis of measles virus (MeV) primary infection and cases with a serological profile indicating reinfection. Methods: Sera from 187 patients with MeV primary infection, 30 patients with suspected reinfection (after vaccine failure) and 153 patients with rash-like symptoms after exclusion of MeV infection were retested with four IgM tests. MeV infection was verified by RT-PCR, primary and suspected reinfections were differentiated by IgG avidity and neutralization assays. Results: All IgM assays displayed significant agreement (Cohen's κ≥0.604, all p<0.001) and a higher diagnostic accuracy in primary infection than in suspected reinfection (indicated by high IgG avidity and significantly higher Anti-MeV-IgG and neutralizing titers). In the overall cohort, the area under the curves (AUC) were comparable among all tests, ranging from 0.875 to 0.931, with ranges increasing to 0.911-0.930 in the primary infection and decreasing to 0.765-0.940 in the setting of high Anti-MeV-IgG avidity, and all tests displayed high specificity (81.1-92.2%). Of note, IgM tests with the highest diagnostic accuracy had discriminatory abilities not significantly different than PCR from serum. Conclusions: Although reinfections pose a challenge for IgM testing, IgM assays remain a cornerstone in the diagnosis of MeV infections. Especially in samples with a serological profile indicating reinfections, IgM tests displayed an equal or even superior diagnostic ability as compared to PCR from serum.

Serological Profile of Children and Young Adults with at Least One SARS-CoV-2 Positive Cohabitant: An Observational Study

At the end of 2019, a new disease caused by the novel coronavirus SARS-CoV-2 appeared in Wuhan Province in China. Children seemed to be infected less frequently than adults, and family clusters seemed to play an important role in the spread of the pandemic. The aim of this study is to evaluate the serological profile of children and young adults between 4 and 16 years of age in order to assess the transmission patterns of COVID-19 between cohabitants. The subjects lived with at least one cohabitant who tested positive for the disease using a nasopharyngeal swab. To avoid contact with the disease, families were interviewed by telephone. Forty-nine children and adolescents with a mean age of 11 years were then subjected to a rapid lateral flow chromatographic test. Of them, seven (14.3%) were immunoglobulin G (IgG)-positive, and four (8.2%) were immunoglobulin M (IgM)-positive. In total, 16.3% of the tested sample had antibodies against SARS-CoV-2: this may confirm the lower vulnerability of children to COVID-19, despite the small sample size. The time from the negativization of the cohabitant until the test day may have influenced the results, especially when this timeframe is wide.