Immunoglobulin and complement deposition in skin of rheumatoid arthritis and systemic lupus erythematosus patients

Rheumatoid arthritis (RA) was differentiated from systemic lupus erythematosus (SLE) by direct immunofluorescent techniques on skin specimens, using monospecific antisera for IgG, IgM, C3, C1q, properdin, and fibrin. Of 30 patients with RA studied, 20 had dermal vessel deposits of immunoglobulins and complement components in unaffected skin without the characteristic dermal-epidermal junctional fluorescence of SLE. Of 24 SLE patients studied, 24 had granular deposits of immunoglobulins and complement components in unaffected skin at the dermal-epidermal junction.

Genetic polymorphism of C3 and serum levels of immunoglobulins, C3, C4 components of complement and C3-proactivator in four different populations of Afghanistan

The C3 phenotype distribution was studied in 4 different populations from Afghanistan. The gene frequencies of C3S allele were: Tajiks (0,8547), Pushtoons (0.8812), Hazaras (0.9036) and Osbeks (0.8530). These values were significantly higher than in European populations studied previously. No significant differences were found between the mean serum levels of C3, C4 and C3-proactivator among 4 population groups. A higher concentration of IgG, IgA and IgM was observed in Afghanistan sera than reported for Europeans.

Immunopathology of the end-stage kidney. Immunoglobulin and complement component deposition in nonimmune disease

Seventy nephrectomy specimens from patients with end-stage renal disease, four renal biopsies from patients with focal sclerosing glomerulonephropathy (FSGN) and normal renal function, and 17 control biopsies from normal renal allograft donors (Group I) were studied by immunofluorescence with respect to deposition of immunoglobulins and classic and alternative complement (C) pathway components. The end-stage kidneys were divided into three groups according to etiology: 16 patients with immune-mediated glomerulonephritis (Group II), 22 patients with congenital and/or familial renal disease (Group III), and 32 patients with systemic or primary renal disease in which an immune-mediated injury could not be established (Group IV). The pattern of immunoprotein deposition in glomeruli in Groups II, III, and IV, and in biopsies of patients with FSGN was similar: peripheral lobular, globular and/or granular, focal and segmental; it was limited to dying glomeruli or abnormal glomerular segments. A statistically significant correlation existed between the percent of properdin-containing glomeruli and the percent of glomeruli undergoing hyalinization in Groups II, III and IV (II, r=0.67; III, r=0.92; IV, r=0.78). No deposition was observed in normal or completely fibrotic glomeruli. In vitro heterologous complement fixation was demonstrated in 17/19 end-stage kidneys in a similar distribution. Early classic C components, C1q and C4, were detected in a somewhat higher frequency in Group II (14/16) than Group III (11/22) and Group IV (20/32) (Group II vs. III, P=.02 and II vs. IV, P=.07). C3 and properdin were detected in 77 to 100% of all 3 groups; in 18 patients, C3 and properdin were present without detectable C1q and C4. Immunoglobulins, primarily IgM, and components of the classic and alternative C pathways are regularly present in hyalinizing glomeruli irrespective of the etiology of the renal failure. These observations suggest that an immune process is operative in glomerular obsolescence regardless of the underlying etiology of the renal disease.

Symptoms and immunology of the Henoch-Schönlein-syndrome

The Henoch-Schönlein-syndrome, or anaphylactoid purpura, is usually a childhood disease. The progess of this syndrome in adults was observed in 4 cases at our clinic. An elevated IgA level in the serum with a normal complement value seems to be of immunological interest. By immunohistological methods fibrin and IgA could be demonstrated in skin and kidney biopsies; in glomerulae C3c was observed, occasionally accompanied by Properdin-factor-B. These findings differentiate this disease from other allergic superficial vasculitids by the detection of IgG and complement; while at the same time some similarities are indicated to the so called "Berger Nephritis" with comparable kidney findings.

In vitro synthesis of factor B of the alternative pathway of complement activation by mouse peritoneal macrophages

Factor B of the alternative pathway of complement activation was shown to be synthesized and secreted by unstimulated mouse peritoneal macrophages. The activity of B in the culture supernatants from macrophage monolayers was detected by consumption of C3 in reaction mixtures containing supernatant and guinea pig factors C3, D and insoluble C3b. Using a monospecific antiserum, factor B in concentrated culture supernatants was shown by immunodiffusion and immunoelectrophoresis to be identical to factor B in mouse plasma and to form a characteristic complex with cobra venom factor in the presence of D. A steady rate of factor B secretion was observed for 4 days providing the medium was changed every 24 h. Cycloheximide (0.5 mug/ml), an inhibitor of protein synthesis, caused inhibition (90%) of factor B production. Incubation of culture medium containing 14C-labeled amino acids with the macrophage monolayer resulted in incorporation of radioactivity into factor B as detected by autoradiography of precipitation lines formed with anti-B antiserum; This indicated that synthesis of factor B had occurred. In the same culture supernatants the presence of newly synthesized C3 was also demonstrated.

Measles infection. Involvement of the complement system

The complement system was examined in fifty patients with acute, apparently uncomplicated measles; forty-six were children less than 10 years old. Twenty showed evidence of pathological complement activation. In thirteen of these the pattern was consistent with activation of the classical pathway while in the other seven data suggested utilization of an alternative pathway. An additional eleven patients had isolated reduction in Clq without alteration in concentration of other components; these were excluded from the classical pathway group. No patient had detectable immune complexes or C3 splitting activity in serum; however, it is suggested that the abnormal complement patterns observed are likely to indicate the presence of circulating immune complexes in a high percentage of patients with this infection.

[Change of immunologic reactivity of the animal body under the effect of various antiblastic agents during primary immune response]

Tests staged with mice and rats demonstrated 5-fluorouracil, fluorafur, methotrexate, cyclophosphane and vinblastine capable of inhibiting to a different degree the primary immune response and the factors of nonspecific immunity. Methotrexate displays the highest activity and specificity of the immunodepressive effect. By using different doses of the drug in immunizing the animals with sheep erythrocytes and vi-antigens the factors of both specific and non-specific immunity were inhibited in all cases. With their single introduction 5-fluorouracil and fluorofur can stimulate the synthesis of humoral antibodies and have no effect on the immune response. With their multiple administration the immunological reactivity of the organism becomes depressed. The extent of changes involving non-specific factors doses not depend upon the pattern and schedule of the drug administration. Cyclophosphane and vinblastin inhibit the immune response when they are introduced 24 hours after immunization. Vinblastin had the faculty of bringing down the activity of the nonspecific immunity, whereas under the effect of cyclophosphane it did not change, except for the complement.

Complement and meningococcal infection

Serum C3 levels were measured in 211 patients with meningococcal disease. Low levels were found in 13 patients with acute meningococcaemia, and complement activation may have contributed to the peripheral circulatory collapse that was responsible for nine deaths. The complement profile of these patients suggested activation of both classical and alternative complement pathways. Patients with meningitis had a higher mean serum C3 level than controls. Serial studies in 13 serum antigen-positive patients with meningitis who subsequently developed arthritis or cutaneous vasculitis showed a transient fall in serum C3 in eight. This fall was probably due to the formation of immune complexes that were responsible for their allergic complications.

Complement system in pneumococcal infections

The properdin or alternate complement pathway may function as a heat-labile opsonin for pneumococci, and evidence has been sought for its activation in pneumococcal infections. Twenty-two patients had determinations of C1q, C4, properdin factor B, C3, and hemolytic complement during hospitalization for pneumococcal infection. Measurements were made during the first 36 h after admission on 16 patients and later during recovery on 16. The admission and recovery values were compared statistically with each other and with the levels of 15 normal individuals. The admission and recovery mean values were normal and nearly identical for C1q and C4, which are two early components of the classical pathway. The mean level of factor N, a properdin pathway component, was significantly depressed on admission, but the mean recovery value was normal. Admission levels for C3, a component of the late common pathway, were depressed, and recovery values were normal. Total hemolytic complement was decreased on admission, although the decrease was not significant for the patients with both admission and recovery determinations. The findings are consistent with the hypothesis that factor B is turned over rapidly, or consumed, early in pneumococcal infections; alternatively, persons with low baseline factor B levels may be particularly susceptible to pneumococcal infection.

Immunofixation. I. General principles and application to agarose gel electrophoresis

Immunofixation offers the worker an economical means of physically locating a protein in an electrophoretic strip and is ideally suited to forensic medicine, genetic studies, or research. The method is as simple and economical as the commonly used one- or two-dimensional immunoelectrophoresis, yet yields considerably more information.

Effect of proteolytic digestion on the structure and function of human properdin

Human properdin (P) was found to be sensitive to the action of trypsin, chymotrypsin, pepsin, and Streptomycetes caesipitosus protease. Incubation of P with these enzymes resulted in loss of its functional activity and the production of antigenically deficient components compared to untreated P. Upon incubation with trypin, P was initially cleaved into a minor fragment and a major fragment. Further degradation ot the fragments occurred with prolongation of inculation time. The minor fragment was highly susceptible to further proteolysis compared to the major fragment which contained the carbohydrate moiety of the molecule. SDS-polyacrylamide gel electrophoretic analysis of trypsin-digested P suggested that the subunit polypeptide chains were initially cleaved at similar points to produce the major and minor fragments. The sedimentation velocity of the major fragment was higher than that of the intact molecule. The implications of these observations of the configuration of P are discussed.

Intraarticular activation of the complement system in patients with juvenile rheumatoid arthritis

Analyses of CH50, complement components, properdin factors, and kininogen in synovial fluid of patients with juvenile rheumatoid arthritis revealed evidence of activation of the classic complement pathway in all clinical subgroups. Juveniles with the adult pattern of disease had the greatest incidence of complement abnormalities. Evaluation of individual components by both activity determination and protein measurement showed decreased synovial fluid specific functional activity (activity per microgram protein) to the more marked in synovial fluids with profound depressions of complement activity. These findings provide further evidence that nonfunctional, antigenically intact component protein may remain after complement activation. Radial immunodiffusion measurements of properdin factors and kininogen failed to support their involvement in joint inflammation. Serum complement component measurements by activity but not protein concentration correlated with other parameters or inflammation. Four patients had isolated depressions of serum C2 activity. Immunoglobulin levels, particularly IgA, correlated with some complement measurements and with the sedimentation rate.

[Evaluation of the changes of natural resistance in patients with diffuse peritonitis]

A suppression of humoral and cell mechanisms of natural nonspecific resistance was found in patients with diffuse peritonitis. A considerable degranulation of basophilic leucocytes was indicated by the direct Shelley reaction, that evidences alterations in the functional state of these cells. Postoperatively, there is a break in restoration of the activity of properdine and its cofactors, and a considerable suppression of the phagocytic capacity of microphages is noted, that leads inevitably to a reduction of immune reactivity.

Recurrence of membranoproliferative glomerulonephritis following kidney transplantation. Serum complement component studies

Sixteen patients with membranoproliferative glomerulonephritis who required kidney transplantation because of renal failure were evaluated for evidence of recurrence of the original disease by serologic and morphologic studies. Of the 12 patients with transplant tissue available for study, seven showed membranoproliferative glomerulonephritis by light morphology. Four of these seven also had hypocomplementemia, and this hypocomplementemia was characterized by decreased serum CH50, C3 beta1A or C3-C9 but norma serum C1, C4 and C2 by hemolytic assay. Immunofluorescent microscopy demonstrated more intense glomerular deposition of C3 and properdin in the hypocomplementemic patients. Ultrastructural studies demonstrated intramembranous deposits typical of dense deposit disease in one patient who also had marked hypocomplementemia. One patient who had two transplant biopsies and persistent hypocomplementemia showed progression from predominantly mesangial glomerular changes to both capillary wall and mesangial abnormalities. This study has shown a high rate of recurrence of membranoproliferative glomerulonephritis in the transplanted kidneys. A high death rate was noted in persistently hypocomplementemic patients. The serum C profile in hypcomplementemic patients who received translants was similar to that seen before transplantation, but the signficance of this finding remains unknown.