SAT0491 Higher Levels of anti-Borrelia IGG Associate with Arthritis in Lyme Disease at Presentation: A Northern Italy Referral Center Cohort

Background Lyme disease (LD) is a multisystemic infection caused by Borrelia burgdorferi ( Bb ) sensu lato complex, involving skin, joints, nervous system and heart. Objectives To assess clinical and serological data of patients with LD at presentation in an endemic area of Northeast Italy (Trentino), with a special focus on rheumatic manifestation. Methods We retrospectively collected clinical data of Bb seropositive patients from 2014 to 2015, tested with ELISA (Enzyme-Linked Immunosorbent Assay) IgM/IgG and Western blot (WB; IgM/IgG immunoblots). Only patients with a LD9 diagnosis confirmed by a trained physician of our center were selected. Other laboratory and instrumental tests ( Bb -PCR on synovial fluid, anti- Bb antibodies research on cerebrospinal fluid, etc.) were performed if deemed necessary by clinical judgment. Results Seventynine patients resulted seropositive for Bb , but only 54 met the inclusion criteria. Among patients with confirmed LD, 27 (50%) were female, mean age at presentation was 48±21years; children were 12.9%. The main presenting symptom was erythema migrans in 72% of cases (39/54), arthritis in 17% (9/54), flu-like symptoms in 7% (4/54), chronic atrophic acrodermatitis and cognitive dysfunction in 2% of cases (1 patient each). Among arthritis, 89% (8/9) presented with acute knee monoarthritis and one patient with hand PIP arthritis. Other concomitant or further developed manifestations were CNS involvement (2/54), cranial neuropathy (1/54), pleuropericarditis (1/54), I°grade atrioventricular block (1/54), transitory leucopenia (2/54), flu-like symptoms (12/54). All patients received antibiotic treatment: 58% doxycycline, 25% amoxicillin, 5% ceftriaxone (12% not reported). Twentysix (48%) patients remember tickborne bite, with a mean latency of 10.4±16.9 weeks. When compared to the rest of the cohort, patients presenting with arthritis were younger (48y±12 vs 56y±12; p=.04), remember tickborne bite in 22% of cases (2/9; p=ns), and had increased ESR (mm/h, 51.1±36.6 vs 24.3±20.3; p=.03) and CRP levels (mm/L, 19.6±23.3 vs 5.6±10.2; p=.01). Arthritis-presenting LD-patients had higher serum IgG antibody levels if compared to overall non-arthritis presenting LD-patients (124.0 vs 25.5; p Bb antibodies presence after the 4th week from bite (124.0 vs 29.0, p Conclusions Arthritis is the second most frequent presenting symptoms of LD (17%). Knee monoarthritis is typical, patients affected are younger and only 20% recall a tick bite. We first demonstrated higher levels of serum anti- Bb IgG antibodies in patients presenting with arthritis. This seems not directly related to a longer time from bite to disease development, since anti- Bb IgG levels of patients with arthritis remain significantly higher if selectively compared to patients without arthritis tested for antibodies after the decline of the primary immune response, after 4th week. References Guellec D et al. RMD Open. 2016 Jan 11;2(1):e000120 Stinco G et al. ScientificWorldJournal. 2014 Jan 16;2014:414505 Disclosure of Interest None declared