Biochemical classification of circulating immune complexes in human malignant melanoma and hematologic neoplasms.

Circulating immune complexes (CIC) in human cancer are known to be very heterogeneous in size and composition. In 95 staged malignant melanoma patients and 71 individuals with leukemia and lymphoma, this heterogeneity was analyzed biochemically in sera positive for CIC. CICs were measured by a multiassay system and individual complexes were isolated and analyzed by immunological and biochemical methods. Analyses of sera from 100 normal individuals, from 25 rheumatoid women, and a group of 12 laboratory staff who work with human melanoma were included for comparison. Three basic patterns of complexes were identified circulating in the sera of the cancer patients. Type I are medium-sized (17-23S), complement-fixing complexes usually occurring in combinations. The prototype in melanoma contained IgG antibody and additional glycoprotein components and bound complement by the classical pathway. In hematological malignancies four subtypes could be identified depending on whether the antibody class was IgG or IgM, the nonimmunoglobulin component was glycoprotein or protein, and whether complement fixation occurred by the classical or alternate pathway. Type II complexes were noncomplement-fixing, medium-sized complexes (15-21S), which in melanoma contained IgG antibody and additional protein components. In the hematologic malignancies two subtypes could be identified depending on whether the antibody class was IgG or IgM. Both subtypes contained a glycoprotein nonimmunoglobulin component. Both melanoma and hematologic tumors had type III heavy complexes (36-44S) which were noncomplement-fixing and contained only immunoglobulin components, either IgG-IgG or IgM-IgG. As expected the rheumatoid arthritis patients frequently had both 7S and 21-23S CICs containing IgG as well as IgM rheumatoid factor with complement fixation via the classical pathway. No CICs were detected in normal young men and women (20-30 years); a few individuals in middle age (31-50 years) had small (7-11S) CICs which bound complement by the classical pathway and contained IgG and a protein nonimmunoglobulin component. The frequency of these 7S complexes increased with advancing age, with the appearance of 23S IgG-IgG or IgM-IgG complexes. IgG antibodies from only the melanoma patients reacted with cytoplasmic components of fresh melanoma cells, except the laboratory workers where all of their isolated CIC antibodies also reacted with melanoma cells. Thus the heterogeneity of complexes in melanoma is not random, but can be classified into three basic biochemical patterns. The hematologic group provides a slightly richer variation of subtypes within this basic scheme.

Circulating immune complexes in malignant melanoma: serial studies in 130 patients.

We evaluated the ability of repeated measurements of circulating immune complexes (CIC) to predict for tumor recurrence in 130 patients with malignant melanoma. Twenty-two patients had level 2, 45 had level 3, and 51 had level 4/5, stage I disease in remission at the start of monitoring, while 12 had stage II disease. The polyethylene glycol precipitation assay was used for serial studies, based on an initial comparative evaluation with the Clq-binding and Raji assays. The study averaged 22 +/- 11 months (6-43 months) and an average of 22 +/- 5.3 assays were performed per patient (range 3-36), with a follow-up of 4 years. CIC were present in sera in recurrent, irregular 'bursts' of activity. Serial measurements doubled the incidence of CIC compared to single determinations. Only 23% of these bursts of activity were clearly related temporarily to documented recurrences, while 34% occurred with treatment events such as surgery or immunotherapy, and 42% occurred without correlation to either recurrence or treatment. CIC activity was greater and more closely related to recurrence in high-risk stage I (level 4,5) and stage II patients. Whether analyzed as positive sera or as bursts of elevated CIC activity, CIC assays predicted for recurrence at the 5% significance level. The assay was highly sensitive (97%), but with poor specificity (21%) with many false positives (79%). The assay was helpful at ruling out recurrences (95%), but poor at ruling them in (29%). The advantage was seen only in high-risk stage I and II patients, and there was no advantage to serial assays over random single determinations. Although generally, CIC in the sera of melanoma patients were found to predict for recurrence, the use of serial CIC measures monitoring of individual patients cannot be recommended.

Isolation and quantitation of serum IgE levels by high-performance immunoaffinity chromatography.

High-performance immunoaffinity chromatography on monoclonal antibodies coupled to protein A-coated glass beads is a method for the rapid isolation and quantitation of immunoglobulin E (IgE) from the serum of both adult and pediatric patients. The technique is as sensitive as most immunoassays but takes less than an hour to perform. In addition to measuring total IgE in both plasma and serum, the technique provides biologically active, affinity-isolated IgE, which can be used for other clinical and research studies.

Protein A-coated glass beads. Universal support medium for high-performance immunoaffinity chromatography.

High-performance immunoaffinity chromatography (HPIC) is a technique for the fast isolation and quantitation of both antibodies and antigens. Protein A-coated glass beads provide a stable general immobilization support for most immunoglobulin G (IgG) antibodies. In conjunction with the modern expanding repertoire of monoclonal antibodies, HPIC can be applied to the quantitation and isolation of any biological material, in an active form.

High-performance affinity chromatography: a rapid technique for the isolation and quantitation of IgG from cerebral spinal fluid.

Standard techniques for the quantitative measurement of IgG in cerebral spinal fluid take up to 24 hs. This often delays diagnosis and treatment, critical in newborn infants. A high-performance affinity chromatography (HPAC) column, containing immobilized anti-IgG antibody, produced the same or better results in 1 h. The HPAC system gave a 98% correlation with the standard techniques at the normal-abnormal IgG level, but was more accurate at the extremely low IgG level.