Background Leukaemia inhibitory factor (LIF) is a member of the IL-6 family of cytokines. It is one of the key mediators in various inflammatory processes such as acute-phase reaction, tissue damage, and infections. It was shown that serum concentrations of human LIF were higher in patients with inflammatory diseases than the noninflammatory diseases. Elevated concentration of LIF in serum has been associated with the presence of hematologic malignancy (lymphoma). Increased LIF levels in bronchoalveolar lavage have been correlated with increased markers of inflammation. Elevated concentrations of LIF have been correlated with the peripheral white blood cell count in rheumatoid arthritis patients. Isolated trials on vasculitis showed that LIF was considerable elevated in a subgroup of patients with giant cell arteritis.

Objectives In this trial we aimed to evaluate the LIF levels in patients with various vasculitic disorders who were taking immunosuppressive therapy.

Methods 23 patients with various vasculitic syndromes were included. Seven patients were male (30.4%). Mean age was 43,8±12,9. The distribution of the patients according to the type of the vasculitis: granulamotos polyangitis 3 (13%), Churge-Straus 3 (13%), systemic lupus vasculitis 5 (21.5%), temporal arteritis 1 (4.3%), Takayasu's arteritis 4 (17.4%), polyarteritis nodosa 2 (6.1%), Leukocytoclastic vasculitis 1 (4.3%). Seven patients were taking IV methylprednisolone plus IV cyclophosphamide (CYC), 4 patients were taking oral steroids and IV CYC, 3 patients were taking single agent IV CYC, and 6 patients were taking single agent oral CYC. Two patients were additionally given IV immunoglobulin.Acute phase reactants including erythrocyte sedimentation rates (ESR), C-reactive protein (CRP) were measured. Serum samples were collected in EDTA containing two tubes from the patients in the morning at 9 A.M., after twelve hour fasting. All samples were stored at −40°C until studied. LIF levels were measured by quantitative sandwich enzyme immunoassay technique by Quantikine human LIF R&D systems (Minneapolis, USA) as pg/L according to the manufacturer's instructions.

Results The median ESR and CRP levels were 7 (min-max: 2-98) mm/hour and 0,5 (0.2-15) mg/dl, respectively. The LIF levels were undetectable in all patients with vasculitis.

Conclusions LIF was previously detected in sera of a group of patients with giant cell arteritis. However, there was no correlation between the levels of circulating LIF and levels of IL-6 or CRP. Levels of LIF were not evaluated in other types of vasculitides. In this study we demonstrated that LIF levels were undetectable in patients with various vasculitic syndromes, who were taking immunosuppressive therapy. Although, LIF levels were shown to be not affected by corticosteroid therapy. LIF concentrations were also undetectable in healthy controls.

References

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Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.3663