Immune complexes: characteristics, clinical correlations, and interpretive approaches in the clinical laboratory

Immune-complex-mediated injury is thought to play a role in diseases such as rheumatoid arthritis, systemic lupus erythematosus, serum sickness, various infectious diseases, and malignancies. With increased appreciation of the biological and pathological significance of circulating immune complexes has come efforts to develop appropriate techniques for identifying and measuring them. Common approaches exploit such phenomena as the attachment of complement components to antigen-antibody complexes, the presence of specialized receptors for immune complexes at the surface of cells, and the ability of rheumatoid factor to bind with immune complexes. This variety of assay systems for immune complexes has yielded abstruse results in numerous human pathological conditions. Unfortunately, these results seldom correlate with one another in a given disease. Thus, use of a panel of immune complex assays has been recommended. Indirect consequences of immune complex disease may still be appraised and evaluated with some confidence in clinical medicine: measurements of C3 and C4, cryoglobulins, serum viscosity, and turbidity of serum samples. Measurement of immune complexes may be useful in diagnosis, prognosis, and therapeutic monitoring, but it is the characterization of immune complexes that holds the greatest potential for better understanding of disease mechanisms.

Immune complexes: characteristics, clinical correlations, and interpretive approaches in the clinical laboratory

Immune-complex-mediated injury is thought to play a role in diseases such as rheumatoid arthritis, systemic lupus erythematosus, serum sickness, various infectious diseases, and malignancies. With increased appreciation of the biological and pathological significance of circulating immune complexes has come efforts to develop appropriate techniques for identifying and measuring them. Common approaches exploit such phenomena as the attachment of complement components to antigen-antibody complexes, the presence of specialized receptors for immune complexes at the surface of cells, and the ability of rheumatoid factor to bind with immune complexes. This variety of assay systems for immune complexes has yielded abstruse results in numerous human pathological conditions. Unfortunately, these results seldom correlate with one another in a given disease. Thus, use of a panel of immune complex assays has been recommended. Indirect consequences of immune complex disease may still be appraised and evaluated with some confidence in clinical medicine: measurements of C3 and C4, cryoglobulins, serum viscosity, and turbidity of serum samples. Measurement of immune complexes may be useful in diagnosis, prognosis, and therapeutic monitoring, but it is the characterization of immune complexes that holds the greatest potential for better understanding of disease mechanisms.

Reversible attachment of human peripheral blood monocytes during in vitro culture

The attachment kinetics of monocytes to polystyrene surfaces from cultures of human peripheral blood mononuclear leukocytes has been determined. Initial experiments showed that the relative monocyte depletion efficiency was much higher after one hour than after twenty hours of incubation. The supernatants from samples incubated for one hour also contained fewer monocytes than did supernatants from samples incubated for twenty hours. Further studies showed that a large percentage of monocytes which initially attach during the first hour later detach. These cells retain their ability to attach to a new culture substrate and to mature into macrophages.

Thymosin administration in autoimmune disorders

Five patients with autoimmune disorders were given thymosin, fraction 5, parenterally for periods ranging from 2 to 35 mth. Four patients had systemic lupus erythematosus and the 5th had rheumatoid arthritis and Sjögren's syndrome. Treatment with thymosin was based on the hypothesis of a T-suppressor defect in these autoimmune disorders. Circulating T lymphocytes increased and remained above pretreatment levels in all patients. Assays for cytotoxicity, using mouse thymocytes and patients' sera, were positive initially and declined during the course of the treatment. In all patients, serum cytotoxicity levels were reduced to zero. There has been clinical improvement in 3 patients, and in 1, the disease has become stable. The evaluation of the 5th patient has been inconclusive. No ill effects related to the administration of thymosin were observed.

HLA type and survival in lung cancer

A significant positive association between antigens HLA Aw19 and/or HLA B5 and a disease-free survival time of one year for patients with lung cancer has been reported but not confirmed. We have HLA-typed 20 white patients with non-oat-cell bronchogenic carcinoma who have survived at least a year from the time of diagnosis. Half these patients possessed these antigens (P less than 0.08). This highly suggests that the presence of these antigens is associated with prolonged survival time. Now may be the time for performing large scale clinical trails using these antigens as stratification factors.

Effect of lymphokine-containing sera on adenocarcinoma BW10232 and melanoma B16 in C57BL/6 mice

Lymphokine-containing sera (LKS) inhibited the growth of adenocarcinoma BW10232 and melanoma B16 in C57BL/L mice. Resistance to tumor growth was conferred by daily injections into the challenge site. The injection of LKS did not provide long-term resistance, inasmuch as termination of treatment permitted resumption of tumor growth at the primary tumor site. Whether LKS exerted a direct or indirect effect on the tumor cells to retard their was not certain.

Cellular and humoral hypersensitivity to adrenal antigen in experimental adrenalitis

A role for specific cellular, as well as humoral immunity has been suggested in experimental adrenalitis. This study was performed to seek a correlation between cellular and humoral immunity in experimental adrenalitis of the guinea pig. 34 guinea pigs (GP) were arranged into 4 experimental groups. One group (11 GP) was immunized with a single injection of 250 mg homologous adrenal antigen (HAA) in complete Freund's adjuvant (CFA). A second group (6 GP) was similarly immunized at 1 and 14 days. A third group (9 GP) received 3 such injections at 1, 14, and 21 days. The fourth group (8 control GP) received RPMI-1640 in CFA. The following were performed on all groups 10 days after the last injection: lymphocyte response to PHA and HAA; HAA-specific macrophage migration inhibition (MIF); antibody titers to HAA by hemagglutination; and histopathology of adrenal, thyroid and testis. Antibody titers reached a mean level of 500 in each of the 3 HAA-immunized groups. In the single injection group, MIF activity and response to PHA were significantly increased when compared to the other immunized groups and to controls. Histopathologic changes were seen in adrenal glands of all immunized groups, but were most remarkable in the single injection group. Progressively fewer changes were observed in double and triple immunized groups. Antibody titers and histological changes were not found in controls. Histopathology correlated better with cell-mediated immune parameters than with specific antibody titers; this suggests that cell-mediated mechanisms may be the more important factor in pathologic lesions of experimental adrenalitis.

In vitro effects of thymosin on T-cell subsets in systemic lupus erythematosus

The possible immunomodulatory influence of thymosin on lymphocytes from patients with active systemic lupus erythematosus (SLE) has been evaluated. Such patients have decreased numbers of T-suppressor (T gamma) cells and normal numbers of T-helper (T mu) cells, resulting in an abnormally low T gamma/T mu ratio. In vitro incubation of lymphocytes from active SLE patients with thymosin resulted in a normalization of the T gamma/T mu ratio. This occurred because of a decrease in T mu cells rather than an increase in T gamma cells. The normalization of T gamma/T mu ratios in vitro in the presence of thymosin is compatible with possible in vivo immunomodulatory effects of these peptides.

Lymphokine-induced changes in macrophage transmembrane electrical potentials

Intracellular electrical potentials have been measured in nonactivated and immunologically-activated macrophages obtained from the peritoneal cavities of mice. Normal macrophage potentials were established and found to become significantly more electronegative after in vitro exposure for 10 minutes to a lymphokine-containing supernatant which induced macrophage activation. This approach may reflect very early concomitants of such activation and is also useful in the study of other immunologic systems.

Correlation between macrophage intracellular electrical potentials and malignant melanoma growth in a murine model

Peritoneal macrophages were collected from mice at varying periods after transplantation of an allogeneic malignant melanoma in the hind limb. The intracellular electrical potentials of these macrophages were measured and a correlation was found to exist between tumor growth measured by size and pathological examination, and the development of large negative intracellular potentials. We propose that this change in intracellular potential is correlated with changes in the immune system and may be triggered by membrane permeability changes possibly in response to calcium ions.

Minimal care concept. An alternative for the management of arthritis

This article is a report on the initial year of operation of the Arthritis Minimal Care Unit at the University of Texas Medical Branch at Galveston. The unit provided a comprehensive program for patient with arthritis including an interdisciplinary approach to care and patient-oriented program development with emphasis on patient and family education. The results of our program showed that hospital admission time and cost could be reduced and an improved quality of care could be provided in a Minimal Care Unit as compared to the acute hospital setting.

Effect of thymosin on T-lymphocyte functions in patients with acute thermal burns

Patients with severe thermal burns demonstrate a decreased cellular immunity. The purpose of this study was to ascertain whether thymosin enhances in vitro T-lymphocyte functions in such patients. Peripheral blood lymphocytes were obtained serially from 22 burned patients and 35 health adults. In vitro lymphocyte functions were evaluated by E-rosette formation, lymphocyte culture responses to PHA, Con A, PWM, PPD, SK-SD, mumps antigen, and tetanus toxoid, and mixed lymphocyte culture reactions. These tests were performed with and without in vitro addition of thymosin. Most of the parameters examined were significantly decreased in patients during the first 2 weeks postburn. The in vitro addition of thymosin significantly restored impaired lymphocyte responses, except in mixed lymphocyte culture reactions. These results demonstrate that thymosin enhances certain in vitro T-lymphocyte functions in burned patients. They further suggest that the administration of thymosin may restore decreased cell-mediated immunity in severely burned patients.

Identification and purification of immunosuppressive activity in the urine of rats and a human patient treated with niridazole

Administration of the antischistosomal compound niridazole to mice, guinea pigs, and humans results in the suppression of several manifestations of cell-mediated immunity. Sera from animals treated with niridazole blocked the in vitro production of migration inhibitory factor (MIF) while niridazole itself was inactive, suggesting that these effects are caused by water soluble mediators. We now report that crude extracts prepared from the urine of rats and a patient receiving nirdazole, but not from pretreatment control urine, similarly suppress antigen-induced inhibition of migration of peritoneal exudate cells from sensitized guinea pigs. With immunosuppressive activity monitored by the direct MIF assay, combined solvent extraction and chromatographic techniques were used to fractionate immunosuppressive activity from the urine of niridazole-treated rats and the patient; the most active fractions, purified about 100-to 1000-fold as compared to methanol-water extracts of dried voided urine, inhibited MIF production at 0.1 to 0.01 ng/ml of assay mixture. These purified fractions also showed immunosuppressive activity by an in vivo assay wherein doses as low as 1 mug/kg injected intravenously (i.v.) into mice suppressed cell-mediated granuloma formation around Schistosoma manisoni eggs. Identically purified fractions prepared from urine of rats and the patient before they received niridazole showed no immunosuppressive activity either in the MIF or in the granuloma assay systems.

Studies on the mechanism of suppression of delayed hypersensitivity by the antischistosomal compund niridazole

Niridazole given in a single oral dose of 100 mg/kg to guinea pigs sensitized to ortho-chlorobenzoyl chloride-bovine gamma-globulin (OCB-BGG) regularly abolished delayed cutaneous reactivity. Little effect was observed, however, when cells from these animals were tested in vitro with either direct or indirect assays for migration inhibitory factor (MIF). On the other hand, sera taken from nonsensitized guinea pigs after they had received 100 mg/kg of niridazole markedly diminished antigen-induced inhibition of migration of sensitized peritoneal exudate cells in vitro. The immunosuppressive effects of such sera could not be produced by niridazole itself, thereby suggesting an effect of niridazole metabolites. This suppressive activity was readily removed from the serum by dialysis. The active serum blocked the production of MIF by sensitized lymph node cells but did not affect the action of preformed MIF on macrophages. The effect of this serum was reversible; lymph node cells incubated for 24 hr with active serum, then washed and reincubated with antigen in normal serum, produced normal amounts of MIF. These studies suggest that metabolites of niridazole, but not the parent compound itslef, suppress delayed hypersensitivity in guinea pigs and prevent MIF production by lymphocytes without affecting the macrophage response to MIF.

Two stages in lymphocyte mediator production by differential susceptibility to blockade using niridazole

Sera from guinea pigs given niridazole, an anti-schistosomal compound, have been shown to reversibly block the production of antigen-induced migration inhibitory factor by sensitized guinea pig lymph node cells. Since niridazole itself has no effect in vitro, the blockade of production of migration inhibitory factor is probably due to drug metabolites in the serum. We report here further studies on the mechanism of this drug-induced suppression of cellular hypersensitivity; the data show that niridazole active serum does not block the production of migration inhibitory factor once it has been initiated. Indeed, if niridazole active serum is added a little as 60 sec after the addition of antigen, the lymphocytes will produce migration inhibitory factor. These results suggest the presence of at least two stages in production of migration inhibitory factor after the addition of antigen to lymphocytes. The first, lasting less than 60 sec, is susceptible to blockade by niridazole active serum; the second is not. The elucidation of the mechanism of this blockade should lead to further understanding of the early events after antigen triggering of sensitized lymphocytes.

Lymphoid response of the burn patient

Clinical observations have long suggested immunologic compromise in burned patients. Resolution of the immune system into cooperative dual components of T-cells mediating delayed hypersensitivity and B-cells mediating antibody responses prompted the present survey of T-cell and B-cell changes after acute thermal burn injury. Adults and children sustaining extensive burn injuries were studied for up to 60 days after injury. T-cell function was assessed by lymphocyte counts, in vitro lymphocyte synthesis of RNA and DNA with and without mitogenic stimulation, and lymphocyte response and stimulatory capacities in the mixed lymphocyte culture (MLC) reaction. B-cell function was studied by quantitation of the major classes of circulating immunoglobulins. Transient lymphocytopenia, increased RNA and DNA synthesis rates by both mitogenstimulated and unstimulated lymphocytes, and impairment of lymphocyte response and stimulation in the MLC were observed early in the postburn period. These parameters tended to normalize by the third week after injury. Immunoglobulin levels, particularly IgG, were depressed significantly the first week postburn, but were normal or elevated by 60 days. These studies document both T-cell and B-cell changes postburn,which appear to be reversible with the recovery phase. A transient shift of circulating lymphocytes toward the B-cell type is suggested and early depression of immunoglobulin levels is notable. Both types of changes likely contribute to the immunologic compromise of the acutely burned patient.

Methodologic differences in values for M-proteins in serum, as measured by three techniques

Accurate and reproducible measurement of M-proteins is essential for managing patients with monocional gammopathies, but serum protein electrophoresis, radial immunodiffusion, and electroimmunodiffusion yield comparatively divergent results. We have studied these differences and their causes. Sera from cases of IgG-monoclonal gammopathy, IgA-monoclonal gammopathy, and IgM-monoclonal gammopathy were assayed by each of the three techniques. Results indicated inter-method discrepancies as great as fivefold for all proteins studied. For IgG-monoclonal gammopathy, radial immunodiffusion values were less consistently so. For IgA-monoclonal gammopathy, both radial immunodiffusion and electroimmunodiffusion gave lower results than did serum protein electrophoresis. For IgM-monoclonal gammopathy, results were variable, but values by radial immunodiffusion tended to be higher than, and electroimmunodiffusion comparable to, those for serum protein electrophoresis. The differences were not correlated with protein abundance, serum freshness, immunoglobulin class, light-chain type, ultracentrifugal characteristics, or electrophoretic mobility. Clearly, values for M-protein concentration depend on the techniques used to obtain them. We postulate that subclass differences may contribute to the diversity of radial immunodiffusion results, and that for electroimmunodiffusion the fixed electrophoretic mobility of M-proteins leads to unpredictable results. We conclude that serum protein electrophoresis is the best of the three assay techniques for M-proteins.

Idiopathic (asymptomatic) monoclonal gammopathies

Asymptomatic forms of monoclonal gammopathies (MG) are recognized with increasing frequency; their recognition and differentiation from the symptomatic forms of MG appear imperative, since the therapeutic approaches are different. Available clinical and laboratory indexes lack specificity required for useful and practical discrimination; presently, we must still rely on the timecourse monitoring of such laboratory values as hemoglobin levels, M-protein concentrations, and presence of Bence Jones proteins. Elucidation of histocompatibility A and W antigenic profiles, as well as the functions and kinetics of B-lymphocytes from such patients, appear most promising. Evidence of the causative role of extrinsic and intrinsic antigenic stimulation in MG production is increasing; segregation into two distinct concentration ranges of M-proteins in the asymptomatic and symptomatic groups suggests two control levels of the expression of immune response (Ir) genes, due to partial or complete derepression of the latent Ir gene function, reflecting "partial" (asymptomatic, benign MG) and "complete" (symptomatic, malignant MG) monoclonal immune responders.