[Systemic lupus erythematosus accompanied by cutaneous vasculitis. Comparison of molecular size of circulating immune complexes].

Systemic lupus erythematosus (SLE) is a disease caused by immune complexes (IC) and is sometimes accompanied by cutaneous vasculitis at the time of onset or in case of relapse. Usually, however, this manifestation does not newly develop after the beginning of steroid treatment. Here we report on a 16-year-old boy with SLE who developed cutaneous vasculitis 10 days after starting systemic prednisolone treatment despite improvements in clinical and laboratory parameters. We examined the molecular sizes of circulating immune complexes (CIC) through the course of the disease. At the time of admission the CIC were 7S to 19S in size. When the patient developed cutaneous vasculitis, the large component of CIC decreased and the 7S CIC became the major component. Although definitive conclusions cannot be drawn, it is suggested that the shift to the smaller size of the CIC is related to the development of cutaneous vasculitis.