CIRCULATING IMMUNE-COMPLEXES IN SYSTEMIC LUPUS-ERYTHEMATOSUS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 29  (2) , 197-204
Abstract
Sera from 21 patients with systemic lupus erythematosus (SLE) were analyzed for the presence of circulating soluble immune complexes by a sensitive and quantitative radioimmunoassay employing radioiodinated human C1q [q fragment of complement component 1] (C1q-deviation test). In 25 normal individuals the percentage of C1q inhibition was 2.64 .+-. 4.45%. Of the SLE patients, 11 had significantly elevated values, and the mean value for the group was 20.38 .+-. 20.64%. The 7 patients with renal disease had somewhat higher levels (24.14 .+-. 18.70%) than those without kidney involvement (19.00 .+-. 21.84%), and elevated levels of antibodies to native DNA were associated with high levels of percentage of C1q inhibition. Intermediate (7S-19S) and large (> 19S) complexes were present in the sera, and digestions with DNase and RNase indicated that antibodies to DNA and RNA accounted for only some of them. Serial studies in individual patients demonstrated the association of circulating complexes with, and often preceding, falling complement levels during disease activation.