title: Marked hypocomplementemia and tubulointerstitial nephritis in a male patient with Sjögren's syndrome.
abstract: We report a case of marked hypocomplementemia and tubulointerstitial nephritis associated with Sjögren's syndrome (SS) in a male patient. Renal biopsy revealed tubulointerstitial nephritis but did not identify specific immune deposits of the tubulo-interstitium. After steroid therapy, the renal failure and hypocomplementemia diminished. Hypocomplementemia without cryoglobulinemia is not commonly observed in SS patients, and hypocomplementemic tubulointerstitial nephritis was strongly suspected. Hypocomplementemic tubulointerstitial nephritis is rare; only one case has been described in the literature. In our case and the previous case, the patients were elderly men, and they had some similar clinical characteristics. Idiopathic hypocomplementemic tubulointerstitial nephritis resembling our case has been reported. These facts suggest that hypocomplementemic tubulointerstitial nephritis may occur in patients with SS, and such cases may not be as rare as once thought because it might be appropriate to include them in the category of idiopathic cases. Such a syndrome should be included in the differential diagnosis of hypocomplementemia.
authors.affiliation: Third Department of Internal Medicine, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan. nao1ro-y@tokyo-med.ac.jp
authors.forename: Naoichiro
authors.initials: N
authors.lastname: Yukawa
authors.forename: Norioki
authors.initials: N
authors.lastname: Tsuboi
authors.forename: Sonosuke
authors.initials: S
authors.lastname: Yukawa
authors.forename: Haeru
authors.initials: H
authors.lastname: Hayashi
authors.forename: Taisuke
authors.initials: T
authors.lastname: Arai
authors.forename: Haruo
authors.initials: H
authors.lastname: Abe
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tahara
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Takanashi
authors.forename: Tohru
authors.initials: T
authors.lastname: Hayashi