Presence of circulating immune complexes in patients with chronic lymphocytic leukaemia. Correlations between clinical and immunological features

The presence of circulating immune complexes (CIC) was evaluated in 60 untreated patients with chronic lymphocytic leukaemia with the polyethylene-glycol precipitation assay. The mean values of optical density (OD) in patients' sera was 0.161 +/- 0.121 compared with control values of 0.082 +/- 0.045 (P less than 0.001). Sera of 16 patients gave OD values higher than 0.172 (mean of controls plus 2 SD) and were considered positive for the presence of CIC. Using the new staging proposed by Binet for CLL we did not find any correlation between presence of CIC and stage of the disease. On the contrary, it was possible to correlate the presence of CIC with the stability of the disease: CIC were found in only 2 of the 22 patients (9.1%) with progressive disease but in 10 of the 30 patients (33.3%) with stable disease (P less than 0.05). CIC were present in 12 of the 38 patients in whom the only surface immunoglobulins present were IgM, but in only 1 of the 14 patients in whom both IgM and IgD were contemporaneously present on the lymphocyte surface. No correlations were found between levels of serum immunoglobulins and presence of CIC.