Circulating immune complexes in malignant diseases increased detection rate by simultaneous use of three assay methods

Abstract

By using three different assay methods, circulating immune complexes have been detected in 85% of sera from patients with malignant melanoma, and in 77% of sera from patients with breast cancer. These methods were a C1q-binding assay, a double-antibody conglutinin-binding ELISA, and a polyethylene glycol 6000 precipitation technique followed by quantitative determination of immunoglobulins in the redissolved precipitate. Detection rates of circulating immune complexes using any one of these methods separately ranged from 33% to 56%, indicating the presence of different types of circulating immune complexes in cancer patients' sera. The combined use of the three methods mentioned resulted in an increased diagnostic sensitivity and a doubling of the predictive value. However, tests for circulating immune complexes cannot be considered as useful parameters for early diagnosis of cancer, since the comparatively low incidence of malignancies in the population at large, together with the presence of circulating immune complexes in other, nonmalignant, diseases of considerable prevalence, appears to preclude effective application of any nonspecific method for early diagnosis of cancer in general.

Evaluation of circulating immune complexes in lymphomas and leukemias using two different assays

“…No single test meets these criteria. This may be due to variations in the composition of ICs and to differing biological and physicochemical properties of ICs [11,27,29].…”

“…Because of the heterogeneity of CICs, parallel application of methods based on different principles may be a useful approach [6,8,11,131. Collective experience in the measurement of CIC has shown that no single method is ideal in all circumstances and that valuable information can be derived from the use of two or more test systems [13,22,29].…”

“…In particular, simultaneous determination of CICs by both complement-dependent [3,16,31,35] and complement-independent assays [10,11,19] might result in more satisfactory detection rates and different composition of CIC.…”

Pathways of Complement Activation Following Intestinal Ischemia-Reperfusion in Macaque

“…The CIC was determined using the polyethylene glycol (PEG) precipitation method in a Beckman Coul ter DU 8 UV spectrophotometer (Beckman Coulter, USA) (6). In brief, 0.2 mL of serum was mixed in 1.8 mL of PEG (37.5 g/L) followed by incubation at 4 °C for 1 h and subsequent centrifugation at 600 ×g for 15 min.…”

Immunoglobulins G, A, M and circulatory immune complexes in patients with laryngeal carcinoma

“…U bolesnika sa malignim melanomom, karcinomom dojke i plu}a, leukemijama i Hodgkinovim limfomom pokazano je da je porast nivoa imunih kompleksa u serumu bolesnika povezan sa pove}anjem tumorske mase, pojavom metastaza odn. lo{om prognozom 9,10,11 . U bolesnika sa karcinomom larinksa takodje je nadjena po-ve}ana kon}entracija blokiraju}ih serumskih faktora 7,12,13 .…”