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PubMed1983

Study of a family with Cerebrotendinous Xanthomatosis. No HLA linkage, but an informative recombination between HLA-B and Bf.

A large family with three children affected with the autosomal recessive disease of Cerebrotendinous Xanthomatosis (CTX) was studied for class I (HLA-A,B,C) and class II antigens (HLA-DR,D,SB), properdin factor B and glyoxalase. The extensive typing revealed an informative cross-over between HLA-B and Bf, indicating that Bf is located centromeric to the HLA-B locus and segregated in this family with HLA-D/DR. The parents in this family were first cousins and their parents were also first cousins. Three of their four haplotypes share B14, BfS, DR1, Dx and SB4 and may be identical by descent. The three affected children carried among them all four parental haplotypes, indicating that close linkage of the CTX locus to HLA is unlikely.

Adolescent↗
PubMed1983

The search for heterogeneity in insulin-dependent diabetes mellitus (IDDM): linkage studies, two-locus models, and genetic heterogeneity.

One hundred families with insulin-dependent diabetes mellitus (IDDM) were analyzed for linkage with 27 genetic markers, including HLA, properdin factor B (BF), and glyoxalase 1(GLO) on chromosome 6, and Kidd blood group (Jk) on chromosome 2. The linkage analyses were performed under several different genetic models. An approximate correction for two-locus linkage analysis was developed and applied to four markers. Two different heterogeneity tests were implemented and applied to all the markers. One, the Predivided-Sample Test, utilizes various criteria thought to be relevant to genetic heterogeneity in IDDM. The other, the Admixture Test, looks for heterogeneity without specifying a prior how the sample should be divided. Results continued to support linkage of IDDM with three chromosome 6 markers: HLA, BF, and GLO. The total lod score for Kidd blood group, under the recessive model with 20% penetrance, is 1.63--down 1.2 from the 2.83 reported by us earlier. The only other marker whose lod score exceeded 1.0 under any model was pancreatic amylase (AMY2). The two-locus correction, which involved lowering the penetrance values used in the analysis, affected estimates of theta (recombination fraction) but did not markedly change the lod scores themselves. There was little evidence for heterogeneity within any of the lod scores, under either the Predivided-Sample Test or the Admixture Test.

Adult↗
PubMed1984

Genetic heterogeneity of insulin-dependent (type I) diabetes mellitus: evidence from a study of extended haplotypes.

Two hundred subjects with insulin-dependent (type I) diabetes mellitus (IDDM) were typed for HLA-B, HLA-DR, and properdin factor B (Bf). HLA and Bf antigen and haplotype frequencies in subjects were compared with control frequencies derived from the 8th HLA Workshop. Frequencies of extended haplotypes (defined by B-Bf-DR alleles on a chromosome) were also contrasted with control frequencies. Significant positive associations between IDDM and HLA-B8, DR3, DR4, BfS, and BfF1 were confirmed, as were significant negative associations between IDDM and HLA-B7, DR2, DR5, DR7, and BfF. One haplotype (B7-BfS-DR2) exhibited significant negative association, while five haplotypes (B8-BfS-DR3, B8-BfS-DR4, B15-BfS-DR4, B18-BfF1-DR3, and B40-BfS-DR4) exhibited significant positive associations with IDDM. In this sample, 64% of all probands carried at least one of the high-risk haplotypes. In conclusion, the occurrence of five "high-risk" haplotypes associated with IDDM provides evidence for previously undocumented genetic heterogeneity and suggests that possibly more than two HLA-region genes may be involved in IDDM susceptibility.

Adolescent↗
PubMed1983

[Effects of lysozyme treatment on immune reactions in viral hepatitis. Preliminary report].

The effect of orally administered Lysozyme (2 g per diem for 6-15 days) on serum immunoglobulins, C3 complement component, its C3A properdine activator and intestinal flora was studied in 45 subjects with acute viral hepatitis. Comparison of the data before and after treatment revealed a significant decrease in IgA, IgM and C3A and an equally significant increase in C3. Coproculture tests revealed important changes in many case in which one or more pathogenetic species (Enterobacter, Proteus, Citrobacter) had completely disappeared. The mechanisms used by Lysozyme in the modulation of immunological responses during viral hepatitis are discussed. These include reduction of the enteric antigen stimulus by inhibiting the growth of bacterial flora, the blocking of anti-complement factors and the modification of antibody response.

Adolescent↗
PubMed1983

High levels of complement breakdown products in tuberculous pleural effusions.

Pleural fluids from 10 patients with tuberculous pleural effusions contained high levels of small molecular weight breakdown products of C3 (C3d) and of properdin factor B (Ba) when compared to 16 patients with effusions of neoplastic origin (P less than 0.001). The same fluids exhibited overlapping values of haemolytic factor B, classical or alternative pathway-mediated haemolytic activity and native C3. A significant correlation between Ba and lysozyme levels was found in all effusions tested (P less than 0.05). These findings suggest that activation of the complement system is an important aspect of the extensive inflammation and tissue destruction characteristic of human tuberculosis.

Complement Activation↗
PubMed1984

Serum complement changes during double-blind food challenges in children with a history of food sensitivity.

Serum levels of C3, C4, factor B, properdin, total hemolytic complement and alternative-pathway hemolytic activity were measured before and after double-blind food challenge in 23 children with impressive histories of adverse reactions to foods. The 23 subjects had 11 positive food challenges and 12 negative food challenges. Nine patients with reagin-mediated positive food challenges showed increases in all six complement assays after double-blind food challenge, while the group with negative food challenges showed decreases in five of the six assays. The difference between the two groups for complement changes after double-blind food challenge was significant only for the alternative-pathway assay. Individual subject analysis revealed markedly heterogeneous changes in direction and magnitude within both groups for all complement assays. Therefore, it is concluded that measurement of serum complement levels is not a useful test for the clinical evaluation of a patient with suspected food sensitivity.

Adolescent↗
PubMed1980

Elevation of complement components in diabetes mellitus.

The serum proteins composing the complement system play a role in defense against infection and in the generation of immune-mediated disorders. To examine this system three components of the complement system in diabetes have been measured--an element in the classic (antibody-mediated) pathway, C4; an element in the properdin (non-antibody) pathway, C3 activator; and an element common to both pathways, C3. The levels of all three are increased both in diabetics and in individuals with glucose intolerance. In the glucose intolerant subjects elevation occurred either with or without fasting hyperglycemia. The levels of all three complement components were found to be positively correlated with fasting plasma glucose in the glucose intolerant group. An increase of complement components with age was found in the overall study population, and in two individual groups. For this reason a further comparison was made between nondiabetics and diabetics on the basis of age; the diabetic complement increase was still detectable. The levels of individual complement components were correlated with each other in both diabetic and nondiabetic groups. An inverse correlation was found between C3 activator and albumin level. The elevation of all complement components was found to be unrelated to the presence or severity of diabetic microvascular sequelae. The simultaneous development of complement elevation and glucose intolerance strongly suggests a metabolic basis for the increase in its components while the lack of association of complement elevation with diabetic sequelae argues against a role for complement in the pathogenesis of diabetic microangiopathy.

Adult↗
PubMed1981

Circulating and deposited immune complexes in patients with glomerular disease: immunopathologic correlations.

The presence of circulating immune complexes (ICs), and alterations of serum immunoglobulins G, A, and M, properdin factor B, and C3 and C4 levels were correlated with glomerular immune deposits in 50 consecutive renal biopsy patients. Urine from 25 of these patients was also examined for ICs. Agarose gel zone electrophoresis (AGE) was used for IC screening. This method detects greater than or equal to 200 ng of IC per 1.5 microliter sample application (approximately equal to 130 micrograms/ml of serum immune complexes) and gives some indication of antigen or antibody excess in the ICs. Glomerular immune deposits were detected by immunofluorescence and electron microscopy in 72% (36/50) of these patients. Circulating and/or urinary IC were found in 69% (25/36) of patients with positive immunofluorescence and 78% (11/14) of patients with negative immunofluorescence. Five of 11 patients with circulating IC but no renal deposition presented with idiopathic crescentic glomerulonephritis (ICGN). These results indicate that IC that persist in the circulation and/or pass renal glomeruli with minimal deposition may result in tissue injury. Circulating IC in antibody excess were detected in all patients with membranous glomerulonephritis. ICs were also found in 55% of patients with IgA nephropathy. Our observations support the hypothesis of an immune complex pathogenesis for these diseases. Determination of circulating and urinary IC in patients with glomerular disease may help in clinical assessment and provide information concerning the pathogenesis of these diseases in humans.

Adolescent↗
PubMed1981

Circulating immune complexes and complement levels in hemophilic children.

Immune complexes and complement levels were assayed in sera from a group of 69 hemophilic children. Using the Raji cell radioimmune assay and the C1q binding assay, abnormally high levels of circulating immune complexes were rarely found in the group of hemophiliacs which did not differ statistically from the control population. These results do not exclude the presence of low and transient levels of immune complexes in the circulation, but indicate that hemophiliacs are not exposed to increased immune complex loads similar to those found in immune complex diseases. By contrast frequent abnormalities of the complement system were found. Complement levels were elevated in a large percentage of patients, reaching statistical significance for C3, C4, C5, Factor B and Properdin. Levels of the C3 breakdown product C3d were significantly raised suggesting intravascular complement activation. The significance of these abnormalities is discussed in relation to perfusion of Factor VIII preparations.

Adolescent↗
PubMed1982

C3 convertase of human complement: enhanced formation and stability of the enzyme generated with nickel instead of magnesium.

We demonstrate that nickel++ (Ni) can replace Mg in the formation of the C3b,Bb enzyme, and that Ni is more efficient in enzyme formation than Mg. C3b-bearing sheep erythrocytes (EC3b) were used to measure radiolabeled Factor B uptake and C3 convertase activity. Up to nine times more Factor B was specifically bound to EC3b in the presence of Ni than in the presence of Mg under identical conditions. To form one effective hemolytic site (1 Z) per EC3b cell with Ni, three times less Factor B, 12 times less Factor D, and 66 times less metal ion were required than when using Mg. The C3b,Bb formed with Ni (C3b,Bb(Ni)) had a 5 to 10 times longer half-life at different temperatures than the enzyme formed with Mg (C3b,Bb(Mg)). Native properdin stabilized C3b,Bb(Ni) to the same extent as C3b,Bb(Mg) (four to five times) and Factor H accelerated similarly the decay of both enzymes. Ni could also replace Mg in the formation of the C4b,2a enzyme. C4b,2a formation was measured by using C1 and C4b-bearing sheep erythrocytes (EAC1,4b) and native C2. To form 1 Z per EAC1,4b cell with Ni, two times less C2 and 60 times less metal ion were required than when using Mg. The half-life of the C4b,2a formed with Ni was two times longer than that formed with Mg. Decay of both C3b,Bb and C4b,2a enzymes formed either with Mg or with Ni was unaffected by EDTA. These results show that Ni is more efficient than Mg in the generation of both enzymes and suggest that Ni binds to the Mg-binding sites of the enzymes with a higher affinity than Mg.

Complement Activating Enzymes↗
PubMed1978

[Determination of the alternative complement pathway in patients with amebic liver abscess].

The activation of the alternative pathway of complement in the sera of patients with amebic liver abscess was studied. Of 11 sera examined, only six showed an activation of the alternative pathway. However, all sera showed diminished levels of complement (CH50) and C3, in spite of normal levels of C1q. The results suggest that the sera of patients with invasive amebiasis have a substance capable of activating the properdin pathway. The significance of these observations is not completely clear at the present time.

Complement Activation↗
PubMed1982

Complement-mediated inhibition of immune precipitation. I. Role of the classical and alternative pathways.

This study has examined the mechanisms involved in complement-mediated inhibition of immune precipitation using radiolabelled BSA and rabbit anti-BSA. Purified proenzyme C1 was capable of maintaining the complexes in soluble form during the first few minutes of reaction whereas immune precipitation was immediate in the presence of purified C1q or C1 + EDTA (ethylenediamine tetra-acetate). In C1q deficient serum, initial immune aggregation was followed by partial solubilization of the formed precipitate similar to that obtained with normal human serum in the presence of Mg EGTA. In C2 deficient serum precipitation occurred at a slow rate. Repletion of the deficient component (C1q or C2 respectively) restored fully inhibition of precipitation. These experiments establish a critical role for the classical pathway, in this phenomenon. By contrast the role of the alternative pathway in maintaining complexes in solution was less important; only partial and delayed precipitation occurred in sera depleted of factor D (RD) or factor B (RB). B and D restored normal complement activity to depleted sera. No precipitation was detected in a reagent depleted of properdin (RP). The mechanisms of inhibition of precipitation are therefore distinct from those responsible for solubilization of an immune precipitate, which is largely dependent on the alternative pathway.

Animals↗
PubMed1982

Alteration in plasma proteins and platelet functions with aging and cigarette smoking in healthy men.

Blood samples were obtained on four different occasions from 18 cigarette smoking and 34 non-smoking healthy men (age 40-69) and analyzed to assess age- and smoking-associated changes in plasma proteins, blood coagulation and platelet functions. Collagen-induced platelet aggregation was significantly increased with aging in non-smokers. Significant changes in chronic smokers were increases in platelet count and fibrinogen in plasma; elevation of platelet factor-3 (PF-3) activity in platelet-poor plasma (PPP); increase in serum levels of alpha 1-antitrypsin, orosomucoid, haptoglobin and properdin factor B; and shortening of the lag period of collagen-induced platelet aggregation. Filtration of PPP through Millipore filters removed PF-3 membranes. The differences in PF-3 activities in filtered plasma were no longer significant between smokers and non-smokers. Results suggest that chronic smokers have higher levels of acute phase proteins reflecting underlying inflammatory processes, and higher levels of PF-3 activity in plasma due to liberation of PF-3 membranes from platelets.

Adult↗
PubMed1980

Double immunofluorescence studies on IgA-associated immune-complexes in glomerular deposits in patients with IgA nephropathy.

A study on double immunofluorescent staining of immunoglobulins and complement in IgA-associated immune-complexes of glomerular deposits in patients with IgA nephropathy is described. The components of immune-complexes deposited in kidney tissues included IgA, IgG, IgM, IgE, C3, C3A, properdin, Clq and C4. Although the majority of the deposits consisted of IgA and C3, some deposits showed the coexistence of other classes of immunoglobulins and C3 as well as other types of complement. It was suggested that the immune-complexes deposited in the glomeruli of patients with IgA nephropathy have a polyclonal nature.

Antigen-Antibody Complex↗
PubMed1981

The intrinsic coagulation-kinin pathway, complement cascades, plasma renin-angiotensin system, and their interrelationships.

Activation of the classical complement pathway is initiated by immune complexes consisting of IgM antibody or IgG subclasses 1, 2, and 3. Binding to Clq leads to activation of C1s and digestion of C4 and C2 to yield a C3 convertase. The alternative complement pathway is initiated by complex polysaccharides as well as immune complexes of the IgA class which interact with Factors B, D, C3, and properdin to yield a stabilized C3 convertase consisting of PC3Bb. Cleavage of C3 and C5 by either pathway yields the C3a and C5a anaphylatoxins which cause histamine release from mast cells and formation of the C5b6789 attack complex causes cell lysis. Both immunologic and nonimmunologic tissue damage can initiate the surface dependent pathways of coagulation, fibrinolysis, and kinin formation. Surface bound Hageman Factor interacts with complexes of prekallikrein and HMW-kininogen as well as Factor XI and HMW-kininogen to form activated Hageman factor, kallikrein, and Factor XIa. Factor XIa continues the coagulation pathway, kallikrein and Factor XIa convert plasminogen to plasmin and kallikrein digests HMW-kininogen to yield bradykinin. The Cl inhibitor, which inactivates Cls is the major plasma inhibitor of activated Hageman factor and kallikrein. In its absence, a potentially fatal form of angioedema is seen. The inactivator of the C3a and C5a anaphylatoxins is identical to carboxypeptidase N, the major plasma inactivator of bradykinin thus demonstrating the common control mechanisms which regulate the complement and kinin-forming pathways.

Blood Coagulation↗
PubMed1982

Decreased chemotactic activity in activated newborn plasma.

The roles of complement levels and CFI activity in the regulation of chemotactic factor generation were evaluated in newborn and adult plasmas. Plasma samples were obtained from 19 healthy adults, 19 neonates, and 12 3-day-old infants. CFI levels were determined in all samples, chemotactic activity in 15 of the 19 adult and newborn samples, and complement levels in 10 of these 15. Compared to adult plasmas, CFI activity was higher in newborn and infant plasmas and chemotactic activity was lower. A close reciprocal relationship was shown between these two activities (r=-0.958). When corrected for the effects of CFI, the difference in chemotactic activity between newborns and adults disappeared. Mean levels of C1, C3, C4, C5, C3 to C9, CH50, factor B, and properdin were lower in newborn plasmas; however, C2 levels were higher. Partial correlations between these complement components and the chemotactic activity were of small magnitude and statistically not significant. These data suggest that higher CFI activity, rather than lower complement levels, accounts for most of the differences in chemotactic activity between newborn and adult plasma. (J Lab Clin Med 99:331, 1982.)

Adult↗
PubMed1982

Behaviour of immune complexes and the complement system in normal pregnancy and pre-eclampsia.

A quantitative study of the circulating immune complexes (IC) was carried out on women during normal pregnancy (286) and the post-partum period (20) and women with pre-eclampsia (30). Furthermore, the behaviour of the complement (C) system was followed. Results showed that IC were low in the first trimester of normal pregnancy (25.3%) and decreased in the following trimesters, whereas they were always present in pre-eclampsia. A very significant difference (p less than 0.0001) was seen when we compared the incidence of IC in normal pregnancy at the third trimester and the pre-eclamptic patients. The follow-up study of the IC, carried out on 4 pre-eclamptic women, showed an increase in the IC levels associated with the exacerbation of the pre-eclamptic picture and a decrease after delivery. The study of complement in normal pregnancy showed a decrease in C1-INH, C1s and C1q, whereas C3, C5, C9 and the properdin factor B increased during the following weeks of gestation; CH50 did not vary excepting during the 1st trimester. In the puerperium all values increased. There was no significant difference between the serum levels of the C components in the 3rd trimester of normal pregnancy and pre-eclampsia. High levels of C3d were observed in normal pregnancy at the 3rd trimester and in pre-eclampsia. The study of this split product of C3 showed that there is activation of the C system, but, since the synthesis of the C components is increased, activation could be masked. Alloantibodies and circulating IC could be the factors responsible for this activation in normal pregnancy and in pre-eclampsia, respectively.

Adult↗
PubMed1982

[Could isolated mesangial deposits of C3 be responsible of glomerular hematuric nephropathies (author's transl)].

This communication presents three cases of prolonged macroscopic hematuria in young subjects. Complementary explorations eliminated urologic or vascular causes. Renal biopsies showed minimal glomerular lesions with light microscopy, normal basement membranes in electron microscopy and mesangial deposits of C3 and properdine in immunofluorescence. Although the mesangial deposits of C3 lack specificity and the number of observations is small, it appears useful to report such cases so as to indicate their frequency and perhaps their autonomy, in glomerular hematuric nephropathies.

Adult↗