%0 Case Reports
%T An overlapping case of IgG4-related disease and systemic lupus erythematosus treated with belimumab: a case-based review.
%A Iwamoto M
%A Asashima H
%A Sugita T
%A Kawashima F
%A Sugita N
%A Rai A
%A Kuroda Y
%A Kawashima A
%A Tabuchi D
%A Akao S
%A Sato R
%A Nishiyama T
%A Toko H
%A Honda F
%A Ohyama A
%A Kitada A
%A Abe S
%A Miki H
%A Hagiwara S
%A Kondo Y
%A Tsuboi H
%A Matsumoto I
%J Rheumatol Int
%V 44
%N 3
%D 2024 Mar 3
%M 38170205
%F 3.58
%R 10.1007/s00296-023-05510-3
%X IgG4-related disease (IgG4-RD) is a systemic condition in which IgG4+ plasma cell infiltration and fibrosis cause organ swelling and lead to diverse clinical manifestations. Although IgG4-RD typically responds to glucocorticoids (GCs), relapse during tapering occurs and an early GC-sparing approach might therefore be beneficial. Systemic lupus erythematosus (SLE) is a chronic inflammatory disease with multiple symptoms that is also treated with GCs as a first-line therapy. Recently, belimumab, a recombinant human IgG-1λ monoclonal antibody that inhibits B-cell activating factor, was approved, but reports of use for IgG4-RD are scarce. Here, we present a rare case of IgG4-RD complicated with SLE which was successfully treated with belimumab. A 67-year-old man was diagnosed with IgG4-RD based on a high serum IgG4 level and histopathological findings. Furthermore, he had pericardial effusion on echocardiography, and laboratory tests revealed thrombocytopenia, autoimmune hemolysis, positive anti-nuclear antibodies, positive anti-DNA antibodies, and hypocomplementemia. These data led to an SLE diagnosis. Treatment was started with prednisolone at 40 mg/day, plus hydroxychloroquine, which initially improved both the SLE and IgG4-RD symptoms. During the GC tapering, belimumab was added and clinical symptoms resolved completely. Our case and the literature review summarize reported rare overlapping cases of IgG4-RD and SLE and suggest that belimumab is a promising candidate for the treatment of IgG4-RD.