ABSTRACT
Background: The severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) is a highly contagious illness associated with a hyperactivated and dysregulated host immune humoral response. In detail, there is a cytokine storm which may take to the release of interleukin IL-6 as a critical mediator for respiratory failure, shock and multiorgan dysfunction. Such dysregulation may act as a target for therapeutics and, in this view, a blockade of IL-6 function by an anti-IL-6 receptor antibody (tocilizumab) has been described to be effective for the treatment of the inflammatory process COVID-19-related. Timing of administration of therapy was reported in literature to have a critical role in benefit for patients;thus, the aim of the present study is to compare two different methods for the IL-6 assessment: the Human IL-6 ELISA Kit (Invitrogen) and the Elecsys IL-6 (Roche). Method(s): IL-6 levels of 128 COVID-19 patients, who were consequently admitted to the Emergency and Medicine Department of AOU Careggi (Hospital in Florence -Italy ) between April and May 2020, were assessed by using the two above mentioned methods and were analysed through Passing-Bablok regression fit and Bland-Altman plot. Result(s): The analyses showed that the two methods correlate, but do not agree in terms of numeric results. In particular, further investigation were performed on the Bland-Altman results, showing that the maximum number of samples for which the differences between the two methods is close to "0" (p > 0.05) (which means a good overlap between the two methods) is 49 (p=0.07), and among them, 40 samples showed a complete agreement of results (p=0.95). These results can be attributed to the different methods' linearities: 3.1-200 pg/mL for ELISA and 1.5#5000 pg/mL for ECLIA, which could be extended to 50 000 pg/mL. Conclusion(s): Although a small percentage of data overlapping in a certain range, still a high correlation among the two methods can be found;given the overall analytical performance of the ECLIA, it can be considered more adequate for different reasons: i) it is available on a fully automated platform h24, ii) it uses of a small sample volume, iii) it is low cost and no-time consuming and iiii) the different timing for measuring IL-6 is much attractive.
ABSTRACT
The first wave of COVID-19 pandemic has disrupted almost all areas of the health care services to some extent throughout the world. The present study aimed to provide reliable data on the impact of the COVID-19 pandemic on autoimmune testing in Hungary. This work was part of a European multicentric study conducted by the European Autoimmunity Standardization Initiative (EASI). Eight Hungarian laboratories associated with an EASI member participated in the survey. Clinically relevant autoantibodies were selected as follows: anti-dsDNA, anti-MPO, anti-PR3, anti-CCP, RF, anti-CL and anti-β2 GPI (both IgG and IgM isotypes) as well as anti-tTG IgA. Monthly data on test number and the number of positive results were collected for the whole year of 2019 and 2020 for each parameter. Our results showed a mean decrease of 23% in the number of autoantibody tests in 2020 compared to 2019. The decrease was the most pronounced in April (81%) with minor differences between individual autoantibodies. With respect to the rate of positive results, a mean increase of 15.3% was observed for the same period. Again, the maximum increase was observed in April (53.7%). However, the differences in this regard were larger among the tested autoantibodies. These results support the importance of an effective strategy for the coordination of autoimmune testing in challenging situations, such as the current pandemic. In the light of the effect on delay in diagnosis and/or treatment of patients with autoimmune diseases, this strategy is highly required.
ABSTRACT
The immune system plays a pivotal role in COVID-19 infection, being responsible for the clinical manifestations and prognosis of the disease. Hyperactivation of the immune response against SARS-CoV-2 virus may result, in some cases, in the development of autoimmune disorders. In fact, a robust immune response is involved in the pathogenesis of both disease conditions. The molecular mimicry, the presence of circulating autoantibodies and the overlapping of autoimmune diseases in some patients show the potential trigger effect of SARS-CoV-2 virus on human immunity in developing autoimmune disorders. A variety of systemic or organ-specific manifestations have been reported to be associated with COVID-19, particularly: antiphospholipid antibody syndrome, Kawasaki Syndrome, Guillain-Barrè Syndrome, Miller Fisher Syndrome, idiopathic thrombocytopenic purpura, and autoimmune hemolytic anemia. However, the existing evidence, which differs according to the specific disease, is poor mainly because it is based on case reports and case series without a long-term follow-up. Since it is still unknown whether these autoimmune conditions may represent a transient phenomenon post-infection, more data are needed to thoroughly understand the relationship between COVID-19 and autoimmunity.
ABSTRACT
Diagnostic tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, named also COVID-19) infection are always more widespread and constantly evolving. The WHO provides the reverse-transcription polymerase chain reaction (RT-PCR) as laboratory testing strategy recommendation for COVID-19 performed in upper and lower respiratory specimens.SARSCoV-2 infection can also be detected indirectly through serological testing;however, systematic data on the diagnostic performance and the predictive value of these tests are still lacking. The aim of this study was to evaluate the role of serological tests and their predicitive values, in combination with RT-PCR, to support diagnosis of COVID-19. We conducted a retrospective study on 637 patients admitted to the Emergency Department and Internal Medicine Ward of S.Giuseppe Hospital (Empoli,Italy) for suspected COVID-19. All sera were first tested by rapid test for qualitative detection of anti-SARSCoV-2 IgG/IgM. Sera positive for IgG and/or IgM were subsequently tested for the quantitative detection using a chemiluminescent method. Of the 637 patients, 59 had a COVID-19 diagnosis;104 were positive for anti-SARSCoV-2 IgG/IgM antibodies by a qualitative test and 57 for the viral RNA by RT-PCR, with a concordance rate between the two tests of 24% (25/104). Moreover, 32 out of the 57 patients with positive RT-PCR were negative for anti-SARS-CoV-2 IgG/IgM antibodies by qualitative test with a concordance rate of 56.1% and, on the contrary, two COVID-19 patients were negative for RT-PCR but positive for anti-SARS-CoV-2 antibodies. Double positive tests (qualitative and quantitative) over the total number of positive results ranged from 27% to 37%, according to the single isotype or combination of antibodies used. The best odd ratio (OR) for associations of anti-SARS-CoV-2 positive tests with COVID-19 was reached by combining 3 or 4 tests (OR:12.9-22.7). Since our results showed a weaker association between SARS-CoV-2 infection and the positive single qualitative test (31-37%), compared to the double positive qualitative test or the double, triple, and quadruple qualitative and quantitative tests (63-90%), the significance of the qualitative test should be evaluated according to the isotype detected and to its combination with the quantitative test.