Prevalence of Pol d 1 Sensitization in Polistes dominula Allergy and Its Diagnostic Role in Vespid Double-Positivity.

BACKGROUND: Stings by Polistes species frequently cause allergic reactions. However, standard allergy diagnostics are often unable to differentiate between primary sensitization and cross-reactivity in case of Vespula/Polistes double-sensitization because antigen 5 is the only Polistes venom molecule currently available in diagnostics (Pol d 5). OBJECTIVE: To evaluate the frequency of phospholipase A1 in Polistes venom allergy (Pol d 1) and its diagnostic role in vespid allergy. METHODS: We performed component-resolved diagnostics in patients with vespid allergic reactions who were positive to Polistes venom. A prevalence analysis was performed and the diagnostic accuracy of Pol d 1 was evaluated to detect primary Polistes sensitization in double-sensitized patients. RESULTS: Blood samples were collected from 132 patients. Pol d 1 was present in 97% to 100% of 128 Polistes-positive patients. It was frequently involved in case of positivity to a single Polistes molecule (48% in double- and 80% in mono-sensitized patients). Furthermore, Pol d 1 was positive in 95% of Pol d 5-negative subjects. The diagnostic accuracy of Pol d 1 was good (folded type: area under the curve = 87%; 82% sensitivity and 77% specificity at the best cutoff of 5.773), and even better when used combined with the whole extract ratio (area under the curve = 99%; 91% sensitivity and 100% specificity). CONCLUSIONS: The study shows that Pol d 1 is the most frequent Polistes allergen in Italian patients. It can distinguish Polistes primary sensitizations with good diagnostic accuracy, which supports its use in clinical practice.

Diagnostic performance of an automated chemiluminescence immunoassay for SARS-CoV-2 IgG and IgM antibodies detection: A real life experience.

BACKGROUND: Recently many serological assays for detection of antibodies to SARS-COV-2 virus were introduced on the market. Aim of this study was to assess the diagnostic performance of an automated CLIA for quantitative detection of anti-SARS-CoV-2 IgM and IgG antibodies. METHODS: A total of 354 sera, 89 from consecutive patients diagnosed with COVID-19 (43 mild, 32 severe and 13 critical) and 265 from asymptomatic and negative on rRT-PCR testing healthcare workers, were evaluated for IgM and IgG anti-SARS-CoV-2 antibodies with MAGLUMI immunoassay. RESULTS: The overall sensitivity and specificity were 86.5% (95%CI: 77.6-92.8) and 98.5% (95%CI:96.2-99.6), respectively. PPV, PPN, LR+, LR- and OR were 95.1 (95%CI: 87.8-98.6), 95.6 (95%CI: 92.4-97.7), 57.3 (95%CI: 21.6-152.1), 7.3 (95%CI: 4.31-12.4) and 418.6 (95%CI: 131.2-1335.2), respectively. The levels of SARS-CoV-2 IgM and IgG antibodies were 1.22 â€‹± â€‹1.2 AU/mL and 15.86 â€‹± â€‹24.83 AU/mL, 2.86 â€‹± â€‹2.4 AU/mL and 69.3 â€‹± â€‹55.5 AU/mL, 2.47 â€‹± â€‹1.33 AU/mL and 83.9 â€‹± â€‹83.9 AU/mL in mild, severe and critical COVID-19 groups, respectively. A significant difference in antibody levels between mild and severe/critical subjects has been shown. CONCLUSIONS: The CLIA assay showed good diagnostic performance and a significant association between antibody levels and severity of the disease was found.

Antibodies to fibrillarin, PM-Scl and RNA polymerase III detected by ELISA assays in patients with systemic sclerosis.

BACKGROUND: Anti-fibrillarin (AFA), anti-RNA polymerase (anti-RNAP), and anti-PM-Scl autoantibodies are useful markers for the diagnosis of systemic sclerosis (SSc) in patients who are anti-centromere- (ACA) or anti-topoisomerase I (anti-topo I)-negative, but, until recently, the only specific method for their identification was the radio-immunoprecipitation assay. The aim of this study was to evaluate the clinical accuracy of the new enzyme-linked immunosorbent assays (ELISA) developed by Phadia for their detection. METHODS: Sera of 50 ACA and anti-topo I-negative SSc patients, and, as control group, sera of 122 patients (42 with SSc, ACA or anti-topo I-positive, 40 with systemic lupus erythematosus and 40 with rheumatoid arthritis) were studied. RESULT: Using the cutoff proposed by the manufacturer (10 AU/mL), sensitivity and specificity were: for AFA, 22% and 92.6%; for anti-RNAP, 16% and 97.5%; and for anti-PM-Scl, 8% and 98.8%, respectively. Using a cutoff corresponding to 98.8% specificity for all three antibodies, sensitivity was 10%, 14% and 8%, respectively. The combined use of these three antibody assays enabled identification of 32% of ACA- and anti-topo I-negative SSc patients. CONCLUSIONS: These new ELISA methods for AFA, anti-RNAP III and anti-PM-Scl detection have good diagnostic specificity, and may help identify a subset of SSc patients ACA and anti-topo I-negative.