Circulating Immune Complexes, Complement Activation Kinetics and Serum Sickness following Treatment with Heterologous Anti‐snake Venom Globulin

Abstract

Consecutive serum and plasma samples, from a patient receiving 100 ml polyvalent horse anti-venom globulin after a rattlesnake bite, were analyzed for circulating immune complexes (IC) and activation of complement [C] factors. IC were determined by 2 independent methods, a complement consumption assay and a C1q-binding assay. Rapidly rising levels of C-fixing circulating IC were detected as early as 4-5 days after the serum treatment and distinct IC-activity was recorded in both assays on day 8 when clinical symptoms of serum sickness were observed. The IC remained in circulation for at least 5 wk. Signs of intravascular C-activation in the form of low C3, C4 and C5 values was noted on day 1 after treatment. .hivin.B [Activated factor B] was demonstrable 3-4 days after the snake bite; this factor and C3c attained a peak around day 8, just before maximal suppression of native C3 and C4. Fourteen days after the globulin treatment C3c and .hivin.B were declining rapidly while C3 and C4 approached normal values the first 36 days after treatment. An increase in heterophilic antibodies to sheep erythrocytes was observed after treatment with anti-venom globulin.