Precipitable immune complexes in Hodgkin's disease

Sera from 28 untreated patients with Hodgkin's disease and from 120 healthy controls were investigated for the presence of circulating immune complexes using a modified 3% polyethylene glycol precipitation method with subsequent quantification of the precipitated protein. Elevated levels of precipitable protein were found in 79% (p <0. 005) of Hodgkin's disease sera. The degree of elevation was associated with disease activity including the presence of B‐symptoms. Constant and pronounced increase of precipitable protein was found in six patients with stage‐III B nodular sclerosis subtype, thus exceeding the average amount of precipitable protein in healthy controls by a factor of 3–4. The erythrocyte sedimentation rate in 20 patients correlated with the amount of precipitable protein (r = 0. 79). Additionally, partial component analysis of the precipitates was carried out by laser nephelometry. Immunoglobulins and complement components were identified as being major components of the precipitated material in sera both from patients and healthy controls, thus confirming the probability of the immune complex nature of the precipitates. Significant differences between patients and healthy controls concerned the amount of precipitable components. Elevation of precipitable IgM was found to be the most sensitive parameter (86% above X̄ + 2 sd of normal controls, p <0. 005). Increased amounts of precipitable IgG, C4, and Clq were found in 57‐46% of patients' sera. Elevation of precipitable IgA and C3c were identified less often. The results suggest the quantification of precipitable immune complexes and their components to be of value as adjuncts in determining disease activity in Hodgkin's dis‐ease.