Nuove specificità nell'ambito degli Autoanticorpi Antinucleo: anticorpi anti-DFS70

In recent years, a new specificity of ANA has been described on HEp2 cells, with a fluoroscopic pattern called "Dense fine speckled" (DFS). Since the antigen associated with this fluoroscopic pattern is a protein of 70 kDa this antigen has been referred to as DFS70 and, among the 28 fluoroscopic pattern is identified by ICAP, AC-02 is the frame of reference. Recently it has been suggested a role of DFS70 in association with conditions of Thrombophilia. In a French multicentric study Marler and collaborators highlighted in IFI a frequency of anti-DFS70 equal to 11% in subjects affected by thrombotic events or obstetric complications, towards 3% found in the control population. The aim of the study was to verify, in a wide case, the association between anti-DFS70 and thrombotic events. A total of 633 sera of which 413 of patients affected by thrombotic events and 220 control sera were analysed. 116 sera of PCs with antiphosphopid antibody (APS) syndrome have been investigated; 77 sera of PZ with obstetric complications (ABO); 130 sera of pz with deep venous thrombosis; 68 sera of PZ with arterial thrombosis; 22 sera of PZ with arterial or venous thrombosis in heiric therapy. For control we have been studied: 92 sera of PZ in TAO/NAO for atrial fibrillation; 28 Sera of PZ in heiric therapy but without thrombosis; And 100 sera of donors. 12 centers participated in the collection of sera, of which 2 were involved in dosages and 1 center for data collection. The study was conducted in double blind in the two different dosing centers. Center number 1 has performed the IFI on the collected sera (HEp-2 Euroimmun). Center number 2 has performed, on the same sera, the specific research of anti-DFS70 with CLIA (Inova) method on Bioflash. The results show that: IFI DFS70 positive patients with thrombosis are only 5.5% compared to 11% indicated in the French study. In Our study, patients with thrombosis however have a double prevalence compared to controls when analyzed in IFI and triple if analyzed in CLIA. IFI has shown many unconfirmed false positives in CLIA and not even with the Immunoblot method subsequently executed and therefore we confirm that the data provided in the French study cannot be considered reliable. Only sera with double positivity for DFS70 in IFI and CLIA can be considered true positive and, despite the differences observed between the two samples (PZ with thrombosis/Controli 6/1), no statistical significance is reached.