High prevalence of antinuclear antibodies in patients following venous thromboembolism.

Background: Growing evidence suggests that activation of blood coagulation exerts protective functions during inflammation. However, it has been hypothesized that dysregulated immunothrombosis may lead to venous thromboembolism (VTE). Antinuclear antibodies (ANAs) are considered to promote the thrombotic tendency but there have been no reports on the association between ANAs and VTE.

Objectives: The objective of this study was to investigate if the presence of ANAs is associated with VTE.

Material And Methods: We enrolled 283 consecutive patients, aged 18-66 years old, following a VTE episode, and 165 age-matched healthy controls. Patients with documented autoimmune diseases (n = 56, 19.79%), including antiphospholipid syndrome (n = 48, 16.9%), were excluded. Antinuclear antibodies were determined based on immunofluorescence. The specific immunofluorescence patterns observed at serum dilution equal to or greater than 1:100 were considered as positive ANAs.

Results: The final analysis included 227 patients (aged 41.07 ±11.4, 98 males, 129 females) following provoked (n = 111) or unprovoked (n = 116) VTE. Ninety-four (42.2%) patients had positive ANAs, including 32 (33.3%) with ANAs titer ≥1:320, whereas as few as 14 (8.4%) controls had positive ANAs (p < 0.007). ANA-positive patients were more commonly diagnosed with unprovoked (n = 55; 57.4%) than provoked VTE (n = 39; 40.6%) (p = 0.03). A similar observation was made for ANAs titer ≥1: 320 (26 patients with unprovoked vs 20 patients with provoked VTE, p = 0.04). The presence of ANAs in the patient group did not correlate with age, sex, time since the VTE event, type of anticoagulation and its quality, inflammatory markers and D-dimer.

Conclusions: The prevalence of positive ANAs was 5 times higher among VTE patients than in controls. Antinuclear antibodies occur commonly in VTE and might be involved in the pathogenesis of unprovoked VTE.