Parvovirus B19 infection can induce histiocytic necrotizing lymphadenitis (Kikuchi's disease) associated with systemic lupus erythematosus.

We report three cases of systemic lupus erythematosus (SLE) associated with necrotizing histiocytic lymphadenitis (Kikuchi's disease) and immunologically proven human parvovirus B19 infection. Simultaneous occurrence of SLE and Kikuchi's disease was a characteristic of the three cases. Kikuchi's disease is an uncommon disease that usually affects young women and is characterized by painless unilateral cervical lymph-node enlargement. T-cell regions of affected lymph nodes are exclusively involved with patchy paracortical necrosis surrounded by a polymorphous cell population of histiocytes and macrophages. However, lymphadenopathy in patients with SLE may be histologically indistinguishable from Kikuchi's necrotizing lymphadenitis. The cause of Kikuchi's disease remains uncertain, although infectious agents have been proposed. A positive IgM-specific anti-human parvovirus B19 antibody test in our three cases suggests that B19 can induce a necrotizing histiocytic lymphadenitis and possibly a clinical SLE flare. High-dose (1 mg/kg/day) and medium-dose (0.5 mg/kg/day) oral prednisone was an effective treatment for constitutional and visceral symptoms of Kikuchi's and SLE diseases.