Abnormally high levels of anti-collagen type IV IgG antibodies in the serum of patients with a clinically isolated syndrome correlate with an increased risk of conversion to MS

•Raised serum anti-collagen antibodies appear in more than half of patients with CIS.•IgM anti-collagen antibodies have no prognostic value regarding conversion to MS.•IgG anti-collagen antibodies correlate with increased risk of conversion to MS.

ObjectiveTo investigate anti-collagen-type-IV serum antibodies (ACIVAbs) levels in patients with clinically isolated syndrome (CIS), and to determine their predictive value for conversion into multiple sclerosis (MS).Material and MethodsSerum levels of IgM and IgG ACIVAbs in 40 untreated patients with CIS (13 male, mean age 34.85 ± 11.4 years, range 16–58 years) were compared to those of 27 gender- and age-matched healthy controls. ACIVAbs were quantified using ELISA. Patients were followed for 5 years by clinical examination and MRI studies.ResultsThirty two patients (80%) converted to MS (converted CIS, C-CIS group) while the rest 8 (20%) did not (non-converted CIS, NC-CIS). The C-CIS patients had significantly higher levels of IgG ACIVAb compared to NC-CIS while the IgM levels did not differ between C-CIS and NC-CIS. Conversion to MS occurred in 66% of patients with IgG ACIVAbs levels exceeding the 95th percentile found in controls. IgG ACIVAbs levels correlated positively with the serum levels of matrix metalloproteinases type 9 (r = 0.37; p = 0.003) and inversely with those of tissue inhibitor of metalloproteinases type 1 (r = −0.43; p = 0.0008).ConclusionHigh serum levels of IgG ACIVAbs in patients with CIS correlate strongly with increased risk of conversion to MS.