Concentrations of C1q, factor B, factor D and properdin in healthy children, and the age-related presence of circulating C1r-C1s complexes

The concentrations of C1q, factor B, factor D and properdin were determined in healthy children belonging to various age groups of one through five years of age. All concentrations were found to be age-dependent, though they varied from one component to another with regard to ontogenetic pattern. Thus, the concentrations of factor B were high, and those of factor D low throughout the age range studied. C1q and properdin levels were lowest in the younger children, who also showed a fairly high incidence of C1r-C1s complexes in excess of C1q. Since the concentrations of C1q are influenced by those of IgG, the presence of C1r-C1s complexes might partly have reflected maturation of immunoglobulin synthesis during ontogeny.

A sandwich ELISA for properdin in clinical specimens

We have developed a symmetrical sandwich ELISA for measuring human properdin (P) in serum by using the globulin fraction from a commercial antiserum as the capture antibody adsorbed on the plastic. The detecting reagent was a glutaraldehyde conjugate of this Ig fraction with alkaline phosphatase. Two types of inhibition were observed in this study. First, inhibition was observed when greater than 2.5 micrograms/ml of the globulin fraction was used to coat the plates. A second type of inhibition was observed for serum dilutions less than 1/400; it was independent of the concentration of capture Ab and did not occur when purified P was assayed. The data generated with this assay could be fitted in log-log mode by a quadratic equation. The coefficient of the linear term in this equation was found to be the same for serum and purified P, within the limits of experimental error. The results for different samples run on the same plate were expressed in terms of the relative concentration of each sample required to produce an OD405 = 0.2. A sample of pooled normal human serum was run on each plate as a reference; it was assigned a titer of 100 ELISA units/ml (EU/ml). The titers of the unknown samples were expressed in terms of EU/ml by reference to this standard. For purified P, the assay could readily detect 10 ng/ml. By comparing purified P with our reference serum pool, we found that 1 EU equals 0.57 microgram. Day-to-day variation for a group of nine normal sera showed a mean difference of -0.85 EU/ml, SD 5.85 EU/ml. The mean titer for these normal sera was 78.9 EU/ml, SD 15.7 EU/ml. In three recovery experiments in which purified P was mixed with pooled normal serum, the recoveries ranged from 96 to 117%. We conclude that the sandwich ELISA constitutes an adequate immunochemical assay for human P in serum specimens.

Suboptimal C3b/C3bi deposition and defective yeast opsonization. II. Partial purification and preliminary characterization of an opsonic co-factor able to correct sera with the defect

Using a correction assay a factor essential for normal deposition of C3 fragments on zymosan was identified in fractions of serum obtained by Sephacryl S-300 gel filtration (eluting between IgG and albumin), preparative Pevikon block electrophoresis (eluting in the beta-region) and DEAE-ion-exchange chromatography (eluting immediately post IgG). Active material was also identified in a commercial preparation of transferrin. A combination of DEAE-ion-exchange chromatography and gel filtration was used to partially purify the co-factor. The factor has an approximate relative molecular mass of 70,000-80,000.

Components of the alternative pathway of complement in otitis media with effusion

An evaluation of the alternative pathway of complement was undertaken in patients with otitis media with effusion (OME). Middle ear fluid (MEF) and serum specimens were obtained from 34 patients at the time of elective myringotomy for OME. Bacterial, viral, and mycoplasma cultures were made for all specimens of the fluids. Immunochemical determinations by radial immunodiffusion were performed for C3, C5, factor B, properdin, factor H, factor I, and albumin. Each patient's recent clinical course and past history were reviewed. The results of all viral and mycoplasma cultures were negative. Three of 55 bacterial cultures were positive for type B Haemophilus influenzae. All components of the alternative pathway measured were found to be present in varying amounts in MEF. When the levels of the complement components were compared to the clinical factors studied, there were no observable differences. These data suggest that components of the alternative pathway of complement are present in OME and are not useful in predicting the clinical course or outcome of this disorder.

Correlation among complement activation, protease inhibitors, and clinical course in acute pancreatitis in man

Changes in complement levels and protease inhibitors were measured in plasma/serum and peritoneal fluid during 15 attacks of acute pancreatitis. The abnormalities found in the complement system and the protease inhibitors were most pronounced in severe attacks, especially in the peritoneal fluid. Depressed levels of C1q, C3, properdin, and factor I were found in blood on admission in severe attacks. A decrease during the first days of illness was found for C1q, C3, C4, properdin, factor I, and factor H levels in blood. There was a discrepancy between the low C1q and the high C1r and C1s levels in blood. Complexes of C1r-C1s-C1 inactivator and factor B conversion products were found, especially in the peritoneal fluid, denoting an activation of the complement system. High levels of trypsin in complex with alpha 1-protease inhibitor were found, both in blood and in peritoneal fluid, denoting the liberation of active trypsin in acute pancreatitis. The levels of the functional alpha 2-macroglobulin were low, especially in the peritoneal fluid. It is concluded that both classical and alternative complement activation take place in acute pancreatitis, starting in the peritoneal cavity. The magnitude of activation depends on the severity of the disease. Trypsin-induced activation of complement components may explain some of these changes.

Immunological aspects of humidifier fever

An epidemiological investigation was made of eight employees working in a defined section of an office building who complained of febrile reactions accompanied by respiratory tract symptoms and fatigue. Culture of the water from the humidifier for their section yielded strains of Pseudomonas acidovorans and an unidentified Pseudomonas species. In vitro studies showed that these strains activated the alternative pathway of the complement system in Mg-EGTA supplemented serum, as evidenced by properdin depletion and conversion of C3-proactivator (Factor B) and C3. Whereas the employees with symptoms had significantly reduced properdin values during the symptomatic phase, a slight C3 conversion and antibodies to Pseudomonas spp., staff working in another part of the building with a different ventilation system did not. It was concluded that staff with humidifier fever symptoms had been exposed to Pseudomonas spp. through the faulty ventilation system, and their symptoms were most likely a result of complement activation.

[Immunologic changes in the acute period of slight craniocerebral trauma]

The authors discuss the results of a dynamic study of the characteristics of nonspecific immune responsiveness (properdin, total protein and globulin fractions in blood plasma, C-reactive protein, and immunoglobulins G, A, and M) as well as of the index of water metabolism of the brain matter--the antidiuretic hormone (ADH) in plasma, in 259 patients with the nosological forms of a mild craniocerebral injury 145 of whom had concussion of the brain and 105 had mild contusion of the brain. Congruence of the clinical manifestations of the injury and the level of plasma ADH was recorded. The participation of the factors of nonspecific immune responsiveness in the body compensatory posttraumatic reactions and the genesis of the clinical manifestations of a mild craniocerebral injury is emphasized.

Reduction of phagocyte adherence by nephritic sera: relation to complement activation

Phagocytes isolated from either normal donors or from patients with poststreptococcal (P-SGN), lupus erythematosus (SLE-GN), or membranoproliferative (MPGN) glomerulonephritis showed normal adherence to glass (PAg) after incubation in normal human serum (NHS), but was reduced after incubation in patient serum. Low PAg was the consequence of incubation of normal phagocytes with the earliest available sera from all 22 P-SGN patients, 28 of 37 SLE-GN patients, 19 of 25 patients with MPGN type I, all 10 with types II and III, and all 5 with nephritis associated with chronic bacteremia. Low C3 and decreased PAg were related by regression analysis in sera from patients with P-SGN (P less than 0.001), SLE-GN (P less than 0.005), and MPGN (P less than 0.001) type I. In patients with P-SGN and one patient with nephritis associated with chronic bacteremia, complement levels and PAg returned to normal in parallel with clinical improvement. In vitro, PAg was reduced by NHS treated with either zymosan or bovine serum albumin (BSA)-anti-BSA complexes but neither BSA-anti-BSA complexes or zymosan, previously incubated in NHS, reduced PAg. PAg was normal in serum deficient in C4 or C5 unless treated with zymosan.

Type III membranoproliferative glomerulonephritis: long-term clinical and morphologic evaluation

Seventeen patients with Type III membranoproliferative glomerulonephritis (MPGN) have been followed for more than two years; 16 were treated with alternate day prednisone. Clinical deterioration correlated with nephrotic syndrome (NS) at diagnosis: 3 of 7 patients with NS at diagnosis developed end-stage disease. Serial biopsies in the others showed progressive disease in one, improvement in one and no change in two. Of 10 patients without NS at diagnosis, 6 have improved clinically, 2 are unchanged and 2 are worse. In serial biopsies, 6 showed improved morphology and 4 were unchanged. The results indicate that Type III MPGN will stabilize or improve in most treated patients. The absence of ultrastructural transition of a Type III glomerular lesion to another type and the presence of distinctive immunofluorescent findings and complement abnormalities confirm that Type III is a unique form of MPGN.

The clinical utility of the lupus band test

In order to determine the clinical utility of the lupus band test, the presence of dermal-epidermal junction (DEJ) deposits of IgG, IgM, IgA, C3, C4, Clq, and properdin were studied in biopsies of clinically normal deltoid area skin from 102 patients with systemic lupus erythematosus (SLE) and 151 patients with other rheumatic diseases. One or more proteins were detected at the DEJ in 72.6% (74 of 102) of patients with SLE and in 36.4% (55 of 151) of the other patients, yielding a specificity of 64% and a predictive value of 57%. The predictive value for the diagnosis of SLE was greatest with C4 (100%), properdin (91.3%), and IgA (86.2%) and lowest with IgM (59%). Specificity and predictive value increased with the number of proteins detected at the DEJ. The results suggest that more rigid criteria are required before diagnostic significance is attached to a positive result on the lupus band test.

[Evaluation of the efficiency of the immune system after immunostimulation in patients with breast cancer]

67 patients with mammary carcinoma were submitted to an immunological control examination. This control comprised 14 tests which determined the efficacy of the immune systems, among others: activity of complement, properdin, lysozyme, and beta-lysin, the rate of immunoglobulins, and the behavior of leucergy, rosette tests, NBT, BLT, and tuberculin test. The thoroughly executed examinations did not show any significant difference between patients with active neoplasms and patients in remission stage. The analysis of the results achieved for patients in an advanced stage (TNM) only showed a significant increase (p less than 0.05) of IgG in stage III/IV. The patients were treated with CVF, levamisole (Decaris), and BCG. The observation period was twelve months. The results achieved were discussed in detail.

Complement aberrations in serum from children with otitis due to S. pneumoniae or H. influenzae

Complement components C1q, C1s, C3, C4, factor B and properdin were measured, together with C1 subcomponent complexes and Cq binding substances in acute and convalescent samples from patients with relapsing and non-relapsing otitis media due to S. pneumoniae and H. influenzae. Analysis of C1 subcomponent complexes together with the finding of low C1q levels gave evidence of a disturbed C1 function in acute OME. Furthermore, complement activation by the classical and by the alternative pathways was demonstrated. Complement aberrations were more pronounced in relapsing otitis than in non-relapsing otitis. C1q binding substances that might possibly cause the complement aberrations found were present in most of the patients.

Activation of the alternative complement pathway in ascitic fluid during spontaneous bacterial peritonitis

We studied complement and immunoglobulin profiles on the serum and ascitic fluid of a patient before and during gram-negative spontaneous bacterial peritonitis (SBP). During the infection, activation of the alternative complement pathway in ascitic fluid was manifested by a 35% reduction in functional activity and depression of both properdin and factor B concentrations to nondetectable levels. Activation of the complement cascade was also demonstrated by a 50% reduction in the C3 concentration and depression of total hemolytic complement. There was no evidence of complement activation of a functionally intact complement system in the ascitic fluid of cirrhotic patients. Complement consumption in ascitic fluid may predispose the cirrhotic to SBP.

Immunopathology of periodontal disease. II. Immunofluorescent studies on the localized immune response in periodontitis and juvenile periodontitis

Local immunologic responses were studied in eleven patients with periodontitis, ten patients with juvenile periodontitis, and ten control subjects by performing immunofluorescence on gingival biopsies. F(ab')2 monospecific conjugates to human IgG, IgM, IgA, IgD, and kappa and lambda light chains were used as well as monospecific conjugates to human IgE and properdin. Biopsies from patients with juvenile periodontitis displayed a more intensified immunologic response as evidenced by increases of (I) positive cells stained with a F(ab')2 antihuman immunoglobulin conjugate; (2) IgG, IgM, and kappa and lambda containing cells; (3) extracellular fluorescence of IgG, IgM, IgA, and kappa and lambda light chains; and (4) properdin deposition. Neither IgD nor IgE conjugates reacted significantly with biopsies from the three patient groups. These findings support our previous conclusion that immunologic responses in periodontitis and juvenile periodontitis appear qualitatively similar, but that patients with juvenile periodontitis exhibit a more intense immune response.

In vitro complement activation by intercellular antibodies

By in vitro complement immunofluorescence, 6 sera from pemphigus with intercellular antibodies were tested for their capability to fix C1q, C4, C3, and properdin. All 6 serum samples yielded positive reaction for C3 staining. Three serum samples gave positive staining for C1q, 5 serum samples for C4, and 3 serum samples for properdin, respectively. Substitution of C2 deficient serum as a complement source inhibited C3 and properdin staining but not positive C1q and C4 staining. These results are best explained by the concept that complement activation in vitro by intercellular antibodies occurs via the classical pathway followed by assembly of the C3 amplification mechanism.

In vitro alternative pathway activation of complement by the brush border of proximal tubules of normal rat kidney

The purpose of this study was to investigate which structures of the nephron, if any, are capable of directly activating the complement (C) system. To this end, two sets of experiments were performed. First, activation of C was assessed on sections of frozen kidney tissue, using the indirect immunofluorescence technique for the demonstration of C fixation. Second, glomerular or tubular fractions of kidney were incubated with normal fresh serum, and subsequent C consumption was measured. The data obtained support the interpretation that the brush border of proximal tubules activates the alternative pathway of the C system. This phenomenon may have pathogenic significance in conditions of aselective proteinuria.

Aluminum-containing dense deposits of the glomerular basement membrane: identification by energy dispersive X-ray analysis

Heavy metals, including gold, mercury, lead, bismuth, and cadmium, have the potential to cause renal disease. With the development of X-ray microanalysis, these heavy metals can now be identified in tissue deposits. This report describes a case of renal failure, probably related to dysproteinemia, in which granular, electron-opaque dense deposits were present in the glomerular basement membranes. Energy dispersive X-ray analysis demonstrated that these dense deposits contained aluminum. An analysis of this patient's history in relation to the current knowledge of aluminum metabolism suggests that the aluminum deposition occurred secondary to previous glomerular injury. This case emphasizes the need to utilize heavy metal identification technology whenever granular, electron-opaque dense deposits are identified and represents, to our knowledge, the first study to document aluminum deposits within the glomerular basement membrane of humans.