A comparison of immunoglobulin G-containing high-molecular-weight complexes isolated from children with juvenile rheumatoid arthritis and congenital human immunodeficiency virus infection

Circulating immune complexes have been described in both juvenile rheumatoid arthritis and in AIDS. We isolated high-molecular-weight complexes from plasma of children with juvenile rheumatoid arthritis and congenital human immunodeficiency virus infection by sequential gel filtration followed by affinity chromatography on protein A-Sepharose. We demonstrate that 1 mixed IgG-, IgM-, and IgA-bearing immune complexes can be found in both juvenile rheumatoid arthritis and congenital human immunodeficiency virus infection and 2) complexes isolated via affinity chromatography on protein A-Sepha-rose do not have detectable C4 but activate the classic complement pathway in vitro.