Background Anti-RNA Polimerase III (a-RNA Pol III) antibodies are markers antibodies which are detected in sera of patients with systemic sclerosis (SSc). They are found in approximately 20% of SSc, particularly with diffuse subtype. According to literature a-RNA Pol III antibodies are strongly associated with scleroderma renal crisis (SRC). They are also correlated with higher rate of SSc-related mortality. Additionally, there are many data which reported that, a-RNA Pol III antibodies are associated with an increased risk of malignancy in patients with SSc.

Objectives The aim of the study was assess the prevalence of a-RNA Pol III antibodies in patients with systemic sclerosis and to identify differences in the picture of the disease in patients with the presence of a-RNA Pol III.

Methods The study was performed in 126 (98-female and 28-male) consecutive SSc patients treated in Department of Rheumatology. Patients fulfilled the ACR classification criteria of SSc (60 have diffuse SSc-dcSSc and 66 limited SSc – lcSSc). The subtype of SSc, incidence of internal organ involvement, the prevalence of malignancy, death and serological profile were determined in the whole data group. The study group were studied according to the presence of antibodies applying commercial test – EUROLINE Systemic Sclerosis Profile. Detection and interpretation of results was carried out electronically using the specific program Euroimmun– EUROLINEScan. Due to the presence of a-RNA Pol III antibodies, patients were divided into two groups a-RNA Pol III(+) SSc – 19 pts and a-RNA Pol III(−) SSc – 107 pts.

Results According to our data a- RNA Pol III antibodies were present in 19/126 patients with SSc (15%), including the a-RNA Pol III 11 were present in 16 and a-RNA Pol III 155 in 14. In this group of 13 (68,4%) pts had no other marker to SSc antibodies as a anticentromere, anti-topoisomerase I. Moreover, in our study group, a-RNA Pol III antibodies were more common in patients with dcSSc (p=0,049), compare to lcSSc. We also showed a significant positive association with a-RNA Pol III antibodies and occurrence of malignancy (p=0,007), SRC (p=0,001) and decreased DLCO (p=0,007). There was no relationship between the presence of a-RNA Pol III and other organ involvement, digital ulcerations or calcinosis.

Conclusions 1. Anti- a-RNA Pol III antibodies are quite common in patients with systemic sclerosis, particularly with diffuse subtype.

2. In more than 50% of patients a-RNA Pol III antibodies may be present as the sole marker to SSc antibodies.

3. In SSc a-RNA Pol III antibodies are frequently associated with malignancy occurrence, kidney and lung involvement.

Disclosure of Interest None declared