High frequency of antiphospholipid antibodies in relapse of multiple sclerosis: a possible indicator of inflammatory–thrombotic processes
The exact prevalence and pathogenic role of antiphospholipid antibodies (aPL) in multiple sclerosis (MS) remain unclear. This observational laboratory-blinded study evaluated the rate of aPL positivity in healthy controls and MS patients in different disease phases to recognize their frequency and possible pathogenic meaning. Reactivity for anti-cardiolipin, anti-β2 glycoprotein I, anti-prothrombin, anti-annexin V (IgG and IgM) was studied by enzyme immunoassays in 60 healthy controls and 100 consecutive MS patients [58 relapsing–remitting (RR) patients in remission, 26 RR patients in relapse, and 16 secondary progressive patients]. The overall rate of positivity for at least one aPL was significantly higher in MS patients compared to controls (32 % vs. 7 %, respectively, p < 0.0001), and in relapsing phase compared to those remitting or secondary progressive (53.8, 20.7 and 37.5 %, respectively, p = 0.002). In the single aPL analysis, the rate of positivity was significantly higher in MS patients compared to controls for anti-prothrombin IgM (7 % vs. 0, p = 0.05), and in relapsing phase compared to remitting and secondary progressive phases for anti-β2 glycoprotein I IgM (26.9, 1.7, 6.3 %, respectively, p < 0.0001), anti-prothrombin IgM (15.4, 3.4, 6.3 %, respectively, p = 0.05) and IgG (19.2, 5.2, 0 %, respectively, p = 0.05). We showed a significant aPL increase in MS patients compared to healthy controls, particularly during disease relapse which was also associated with significantly higher values of anti-β2 glycoprotein I and anti-prothrombin. These data suggest that antiphospholipid antibody occurrence in multiple sclerosis could be related to modification of structure and function of proteins involved in the inflammatory–thrombotic processes during disease re-activation.