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Biomedical subjects

D Vergani

Publications and source records attributed to D Vergani.

At least 163 records · Page 9Linked to original sources
PubMed1989

Activation of the complement system in primary sclerosing cholangitis.

Recent evidence, including the presence of circulating immune complexes, suggests that abnormalities of humoral immunity may be important in the pathogenesis of primary sclerosing cholangitis. The aim of the present study was to determine whether activation of the complement system is present in patients with this disease, as this would be supportive evidence of a role for circulating immune complexes in primary sclerosing cholangitis. Plasma complement fragments C3d and C4d, and serum C3 and C4, their respective parent molecules, have been assayed. Both C3d and C4d were elevated in patients with primary sclerosing cholangitis compared with patients with extrahepatic obstructive cholestasis and normal controls (p less than 0.01 in all instances). C3 was elevated in both patient groups, in whom it was similar, compared with normal controls (p less than 0.001 in both cases), whereas C4 was similar in all groups. Elevated levels of circulating immune complexes were identified in 21 of 24 (88%) patients with primary sclerosing cholangitis, but in none of the normal controls. These findings support the hypothesis that in primary sclerosing cholangitis circulating immune complexes are associated with activation of complement via the classical pathway.

Adult↗
PubMed1989

Aetiology of insulin-dependent diabetes.

Two major types of diabetes are recognized, insulin dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM). In this review we discuss some of the underlying factors which play a role in the events leading to IDDM.

Blood Glucose↗
PubMed1989

Reflection of disease activity in rheumatoid arthritis by indices of activation of the classical complement pathway.

Levels of C4d, a fragment of C4 generated during activation of the classical complement pathway, were measured in the plasma of 77 patients with rheumatoid arthritis and 30 healthy subjects. Disease activity was judged according to Ritchie's articular index to be mildly active in 31 (group 1), moderately active in 29 (group 2), and severely active in 17 patients (group 3). Plasma levels of C3d, a fragment of C3, and serum levels of C4, C3, and immune complexes were also measured. The ratios C4d/C4 and C3d/C3 were calculated. The C4d/C4 and C3d/C3 ratios and the levels of circulating immune complexes correlated with the degree of disease activity without significantly departing from linear trend and discriminated between patients with different grades of disease activity. C4d, C3d, C4, and C3 also correlated with disease activity but in a non-linear relationship. A significant correlation was found between C4d and C3d, and between C4d/C4 and C3d/C3. C4d and C4d/C4 also correlated with circulating immune complexes. These results indicate that indices of C4 and C3 activation, in particular the ratios C3d/C3 and C4d/C4, provide a sensitive assessment of disease activity in rheumatoid arthritis, and confirm the major part played by the classical complement pathway in the pathogenesis of this disease.

Adult↗
PubMed1989

Double stranded DNA binding in autoimmune chronic active hepatitis and primary sclerosing cholangitis starting in childhood.

Autoimmune chronic active hepatitis (aCAH) and primary sclerosing cholangitis (PSC) are liver disorders occurring in childhood in which non-organ specific autoantibodies, such as anti-nuclear antibody (ANA) are frequently found. Antibodies to double stranded DNA (dsDNA), which are typically present in systemic lupus erythematosus (SLE), have been detected in both acute and chronic liver diseases in adults. In this study, using a radioimmunoassay technique widely employed to measure antibodies to dsDNA, we have demonstrated significantly increased levels (median and range; 11.9, 1.0-36.5 U/ml) in 21 children with aCAH compared with normal children (1.0, 0.7-2.1 U/ml; p less than 0.01). Five children with aCAH had levels in the range considered diagnostic for SLE (greater than 25 U/ml) and of these, three had ANA and two had anti-liver kidney microsomal antibody. In addition, one child had antibodies to dsDNA as detected by the Crithidia luciliae test. DNA binding in aCAH was correlated with serum aspartate-amino transferase levels (r = 0.68; p less than 0.001), suggesting a direct relationship with disease activity. In PSC, levels of antibodies to dsDNA were significantly increased compared to normal controls (median and range; 7.0, 5.6-10.2 U/ml; p less than 0.01) but were not as high as those found in aCAH.

Adolescent↗
PubMed1989

Hepatic schistosomiasis and chronic active hepatitis.

As part of an investigation of the possible role of autoimmune mechanisms in the development of chronic active hepatitis (CAH) in schistosomiasis, sera from 25 patients (Group I) with hepatic schistosomiasis without histological features of CAH and 5 patients (Group II) with CAH and intestinal mansoniasis, but without discernible hepatic infection, were examined for the presence of the liver membrane antibody (LMA) that is reportedly associated with the autoimmune variant of CAH. All patients were HBsAg-negative. Circulating LMA was found in 17 (68%) Group I and 3 (60%) Group II patients. Low titres of various organ-non-specific autoantibodies were found in about a third of all patients but these did not correlate with the presence of LMA. There was also no correlation between LMA and antibodies to the hepatitis B core antigen (anti-HBc), found in the sera of 67% of the patients, indicating that occult or recent past hepatitis B virus infection was not a factor in LMA production. Long-term follow-up of the Group I patients should reveal whether current LMA-positivity is related to eventual development of CAH in hepatic schistosomiasis.

Adolescent↗
PubMed1989

Increased activated T-lymphocytes and normal thyrotropin receptor antibody levels in Graves' disease in long-term remission.

The involvement of the immune system in the attainment and maintenance of carbimazole-induced remission in Graves' disease is poorly understood. We have investigated levels of T-lymphocytes expressing the HLA DR marker of activation and levels of thyrotropin receptor antibody (TRAb) in patients in sustained, carbimazole-induced, long-term remission from Graves' disease (median duration of remission 29 months, range 7-64). Levels of activated T-lymphocytes were increased in patients with long-term remission compared with controls (p less than 0.05) and were no different from the high levels found in patients with active Graves' disease. In contrast, levels of TRAb were normal in patients in long-term remission but high in patients with active disease (p less than 0.01). These results show that increased activated T-lymphocytes but normal levels of antibody to the thyrotropin receptor characterize patients in carbimazole-induced long-term remission of Graves' disease suggesting that activated T-lymphocytes may be important in the maintenance of remission.

Adult↗
PubMed1989

Anti-lymphocytic antibodies in autoimmune chronic active hepatitis starting in childhood.

Anti-lymphocytic antibodies (ALA) have been described in a variety of autoimmune disorders. We have investigated the presence of ALA in autoimmune chronic active hepatitis (aCAH) starting in childhood. Using a modified Terasaki technique ALA were found in 17 of 18 patients with aCAH but in only one of 15 patients with alpha-1-anti-trypsin deficiency or Wilson's disease and three of 27 age-matched healthy controls (P less than 0.0005 for both). Sera from 12 patients with uncontrolled aCAH had significantly higher cytotoxicity values than sera from six children with inactive diseases (P less than 0.01). ALA were directed to T but not B lymphocytes and were not reactive with specific HLA antigens. No preferential killing was observed against CD4 or CD8 positive T lymphocytes. Characterization of ALA revealed them to be cold-reactive IgM. The possible role of ALA in aCAH is discussed.

Adolescent↗
PubMed1988

Antibodies to human albumin epitopes in type 1 (insulin-dependent) diabetes mellitus.

The presence of antibodies to glycosylated albumin was studied by means of a newly developed sandwich enzyme-linked immunosorbent assay in 29 long-standing Type 1 (insulin-dependent) diabetic patients with microvascular complications and in 20 normal subjects. Two types of antibody reactivity were detected. One directed against glucitol-albumin expressing G and M isotypes. The second, predominantly belonging to the IgG class, reacted with an epitope shared by non-glycosylated albumin and the ketoamine adduct of albumin glycosylation. Both types of antibodies, with affinity constant ranging from 10(4) to 10(7) (mol/l)-1 were found in normal and diabetic subjects, but higher titres were significantly more prevalent in the diabetic patients. These antibodies may represent the result of immune tolerance breakdown or, alternatively, be natural antibodies. Although their function remains to be established, their raised prevalence in Type 1 diabetes may be relevant to diabetic microvascular disease.

Adult↗
PubMed1988

Cell-mediated immunity and symptomatic diabetic autonomic neuropathy.

T lymphocytes have been implicated in the nerve damage observed in allergic experimental neuritis and in idiopathic polyneuritis. Symptomatic autonomic neuropathy in long-standing Type 1 diabetes is a rare and unexplained complication, and some preliminary evidence has suggested a pathogenetic role for the immune system. We have measured levels of activated T lymphocytes in 18 Type 1 diabetic patients with symptomatic autonomic neuropathy and in 16 matched patients with uncomplicated Type 1 diabetes. Purified T lymphocytes from peripheral blood were stained with a fluorescein-labelled monoclonal antibody directed to the activation marker HLA-DR and counted under UV microscopy. Percent DR positive T lymphocytes were significantly raised in the patients with autonomic neuropathy when compared with long-standing uncomplicated diabetic patients (8.2 +/- 4.2 vs 4.9 +/- 3.3%, p less than 0.01). This finding lends support for a role of the immune system in the development of autonomic neuropathy.

Adult↗
PubMed1988

IgG subclass deficiency in asthma.

Total immunoglobulin G (IgG) and subclasses were measured in serum samples from 82 children with chronic asthma, aged 1.5 to 6.3 years, and 76 controls. Concentrations of IgG1, IgG2, IgG3, and total IgG were significantly lower in asthmatic children aged 1 to 5, and IgG2 concentrations were also significantly lower in asthmatic children over 5 years of age. Twenty eight asthmatic children had at least one value in the deficient range, and 26 had IgG2 deficiency alone or in combination. Five children had IgG2 and IgA deficiency. These 28 children were significantly younger and fewer had raised IgE concentrations than the remainder. IgG subclass deficiency, which may reflect delayed maturation of the immune system, is common in young asthmatic children, and may have a role in the pathogenesis of the disease.

Asthma↗
PubMed1988

Correlation of the activation of the fourth component of complement (C4) with disease activity in systemic lupus erythematosus.

Levels of C4d, a fragment of C4 generated during activation of the classical complement pathway, were measured in the plasma of 48 patients with systemic lupus erythematosus, 11 with inactive (group 1), 23 with mildly active (group 2), 14 with moderately/severely active disease (group 3), and 30 healthy subjects. Levels of C3d, C4, and C3 were also measured and the C4d/C4 and C3d/C3 ratios calculated. C4d levels correlated with the degree of disease activity, being higher in group 3 than in group 2, in group 2 than in group 1, and in group 1 than in controls. C4d/C4 gave a similar result. Activation indices of the common complement pathway, C3d and C3d/C3, also correlated with disease activity, but in a non-linear relationship, failing to discriminate between patient groups. C4 and C3 showed no correlation with disease activity. These results indicate that indices of C4 activation, C4d and C4d/C4, provide a laboratory measure of disease activity in lupus patients, for whom an objective assessment of the severity of the disease is not readily available.

Adult↗
PubMed1988

Low serum haemolytic function of the fourth complement component (C4) in insulin dependent diabetes.

Low serum concentrations of the fourth component of complement (C4) are found in insulin dependent diabetes, and may be important in the aetiology of the disease. To ascertain whether function of C4 is also impaired both its haemolytic activity and its concentration were measured in 34 insulin dependent diabetics, 15 non-insulin dependent diabetics, 20 healthy subjects, and 12 pairs of monozygotic twins discordant for insulin dependent diabetes. C4 function was measured by a radial immune haemolytic assay, and C4 concentration by laser nephelometry. Both measurements were significantly lower in insulin dependent diabetics (C4 function: median 47%, range 4-100%; C4 concentration: 0.22 g/l, 0.10-0.38 g/l) than in non-insulin dependent diabetics (67%, 33-138%, p less than 0.01; 0.27 g/l, 0.16-0.50 g/l, p less than 0.02) and controls (74%, 33-138%, p less than 0.01; 0.27 g/l, 0.18-0.40 g/l, p less than 0.03). C4 function and concentration were lower in both diabetic (48%, 12-100%; 0.17 g/l, 0.08-0.31 g/l) and non-diabetic twins (47%, 12-100%; 0.17 g/l, 0.07-0.36 g/l) than controls (p less than 0.01; p less than 0.01). Thirteen (38%) of the insulin dependent diabetics had a reduction in either C4 function or concentration, but in only five were both features reduced. Values of function and concentration were strongly correlated in both diabetic and non-diabetic twins (r = 0.95, p less than 0.001; r = 0.92, p less than 0.001). These results show defects in C4 function and concentration in insulin dependent diabetes, which--being present in the non-diabetic co-twin of diabetics--may represent a genetic predisposition to the disease.

Adult↗
PubMed1988

Clinical application of new technique that measures C4d for assessment of activation of classical complement pathway.

A new laser nephelometric technique that measures C4d for the assessment of the activation of the classical complement pathway was developed. C4d was isolated from other larger C4 related molecules at a final concentration of polyethylene glycol of 12% and then quantitated by laser nephelometry using a commercially available antiserum, which reacts with C4d determinants. C4d standard (100%) was produced by exhaustive activation of the classical pathway in pooled normal human serum using heat aggregated human immunoglobulin. Serial dilutions of the standard provided a reference curve against which clinical samples were read. Patients with rheumatoid arthritis showed significantly higher C4d values (mean 53.8%) than controls (21.7%; p less than 0.001). The technique proved accurate, rapid, and suitable for the routine laboratory evaluation of complement activation through the classical pathway, and it may be useful in the management of those conditions in which complement activation has a pathogenic role.

Adolescent↗