Background Systemic lupus erythematosus (SLE) is one of the most common autoimmune disorders in women during their childbearing years. Familial Mediterranean fever (FMF) is an autoinflammatory disease that is characterized by recurrent attacks of fever, arthritis, serositis and skin rash. An increased prevalence of systemic autoimmune diseases has been reported in FMF. Only several reports of SLE and FMF co-occurrence have been published.

Objectives The objective of this study was to validate the possible association between FMF and SLE and determine specifies of duration of both diseases in case of their co-existence.

Methods The study enrolled 3 groups. The first one included 23 patients with SLE with concomitant FMF, II group included 23 FMF patients and the III group -23 patients with SLE. FMF was established by genetic investigation of MEFV gene. All patients with SLE fulfilled diagnostic criteria of SLE by ACR. Methods of investigation were followings: anamnesis, physical examination, SLE activity estimation by SLEDAI index, results of laboratory analysis.

Results In 3 groups female were 21 (91.3%), male – 2 (8.7%). Mean age of patients in I group was 37.4±2.5 years, in II group - 36.4±2.5 and in III group – 35.6±2.6 years. The beginning of FMF was in earlier ages in patients with only FMF than in cases of association with SLE. Age of SLE onset was similar in I and III groups. We studied the difference of clinical symptoms of both diseases SLE and FMF between groups. Clinical manifestations of FMF were described between I and II groups and clinical symptoms of SLE between I and III groups. In the I group FMF attacks frequency and duration were significant less than in II group. The activity of SLE estimated by SLEDAI index was significant lower than in SLE without FMF. SLE co-occurring with FMF had mild duration than classic lupus according to both clinical and laboratory findings including serological markers of SLE -ANA, anti-dsDNA and circulated immune complexes. Low dose medication (prednisone, pulse – therapy i.e. i/v injection of 1000 mg methylprednisone during 3 days or combined pulse-therapy with methylprednisone and immunosuppressors) was required to achieve control of lupus signs and symptoms. The prevalent mutation was M694V - 44.6%; V726A composed 21.7%, M680I-9.8%. Most common variations with M694V were followings: M694V/M694V, M694V/V726A, M694V/N.

Conclusions A remarkable overlap was highlighted between familial Mediterranean fever and systemic lupus erythematosus: both diseases have such common features as arthralgia, myalgia, arthritis, fever, skin involvement, serositis, hepato-splenomegaly and renal involvement. It is likely, that the moderation in disease phenotype and peculiar disease characteristics observed in patients with both SLE and FMF are related to MEFV. MEFV mutations appear to modify SLE phenotype.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.3549