A Case of IgG4-related Mesenteritis and Ankylosing Spondylitis.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease of unknown etiology and pathogenesis, which can affect all organs. The most commonly involved organs are the pancreas, hepatobiliary system, salivary glands, orbits and lymph nodes. Rarely, the thyroid, pituitary, aorta, lung and kidney may also be involved; mesenteric involvement is rare. The association of IgG4-RD with some rheumatological diseases is observed; while there are data in the literature about rheumatoid arthritis and Sjögren syndrome, but association with ankylosing spondylitis is rare. Anti-tumor necrosis factor alpha (anti-TNFα) treatment has been tried in refractory IgG4-RD cases; but this case is of great interest in terms of progressive presentation under treatment with etanercept, an anti-TNFα agent, which is also used for the treatment. But, IgG4-related mesenteritis with ankylosing spondylitis receiving anti-TNFα therapy, which has also been tried in the treatment of IgG4 disease, has not been reported in the literature. Key Words: IgG4-related disease, Mesenteritis, Ankylosing spondylitis.