title: Hypocomplementemic urticarial vasculitis or systemic lupus erythematosus?
abstract: The 2 patients presented here showed the typical signs of hypocomplementemic urticarial vasculitis syndrome (HUVS). During follow-up, there was an inverse correlation between anti-C1q autoantibody titer and C1q antigen concentration in serum in both patients over a period of 2 years. The first patient had nephritis characterized by immune deposits in glomeruli and around the tubules. The histological findings, C1q deposits, and presence of tubuloreticular inclusions in capillary endothelial cells suggested a disease process identical to systemic lupus erythematosus (SLE). The second patient, after a lag phase of 2 years, fulfilled a fourth American College of Rheumatology criteria for SLE when she developed anti-double-stranded DNA antibodies. HUVS and SLE overlap, and the criteria for identifying HUVS as an entity distinct from SLE are lacking.
authors.affiliation: Laboratory of Immunonephrology and Clinic of Medicine B, University Hospital, Basel, Switzerland. trendelenbur@ubaclu.unibas.ch
authors.forename: M
authors.initials: M
authors.lastname: Trendelenburg
authors.forename: S
authors.initials: S
authors.lastname: Courvoisier
authors.forename: P J
authors.initials: PJ
authors.lastname: Späth
authors.forename: S
authors.initials: S
authors.lastname: Moll
authors.forename: M
authors.initials: M
authors.lastname: Mihatsch
authors.forename: P
authors.initials: P
authors.lastname: Itin
authors.forename: J A
authors.initials: JA
authors.lastname: Schifferli
mesh_terms: D000328:Adult; D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D001706:Biopsy; D015922:Complement C1q / Q000172:deficiency* / Q000276:immunology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007678:Kidney Glomerulus / Q000276:immunology / Q000473:pathology; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D008181:Lupus Nephritis / Q000175:diagnosis / Q000276:immunology / Q000473:pathology; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D018366:Vasculitis, Leukocytoclastic, Cutaneous / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology
chemical_list: D015922:Complement C1q