Autoimmunity to heterogeneous nuclear ribonucleoprotein A1 in psoriatic patients and correlation with disease severity

BACKGROUND AND OBJECTIVES: The heterogeneous nuclear ribonucleoprotein A1 (hnRNP-A1) has been postulated as an autoantigen of psoriasis, but correlation between serum levels of anti-hnRNP-A1 autoantibodies and the severity of disease has not been investigated. We aimed to assess the frequency of anti-hnRNP-A1 autoimmunity in patients with moderate to severe psoriasis and in healthy controls, and to determine the correlation between serum levels of anti-hnRNP-A1 autoantibodies and disease severity. PATIENTS AND METHODS: We performed a case-control study on 40 adult psoriatic patients with a PASI (Psoriasis Area and Severity Index) of > 10 and 40 healthy controls matched for age and gender. Immunoblotting was used to assess serum levels of anti-hnRNP-A1 autoantibodies. RESULTS: Anti-hnRNP-A1 autoantibodies were found in 9/40 psoriatic patients (22.5 %) but in no healthy controls. The PASI was significantly higher in anti-hnRNP-A1-positive patients than in anti-hnRNP-A1-negative patients (40.33 ± 3.24 vs 26.06 ± 9.28, p = 0.0001). In patients positive for anti-hnRNP-A1, serum levels of such autoanti-bodies were correlated with the PASI (R = 0.89, p = 0.001). CONCLUSIONS: Consistent with reports in the literature, our results suggest a role of anti-hnRNP-A1 autoimmunity in psoriasis, although probably not as the primary cause or initial/fundamental event. Unlike previously published reports, our results also suggest that anti-hnRNP-A1 autoimmunity is particularly frequent among psoriatic patients with more severe disease. Further studies are necessary with a larger number of patients.