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Biomedical subjects

D Vergani

Publications and source records attributed to D Vergani.

At least 73 records · Page 4Linked to original sources
PubMed1996

Abnormalities of CD45 isoform expression in HIV infection.

Using monoclonal antibodies against CD45, CD45RA, CD45RB, and CD45RO, the surface density of expression and proportions of different CD45 isoforms were analyzed on CD4+ and CD8+ T lymphocyte subsets in HIV+ patients and controls. Analysis of the relative specific fluorescence (RSF) of CD45 isoforms showed a significant reduction in expression of total CD45 and its isoforms, CD45RA, CD45RO, and CD45RB, on CD4+ and CD8+ lymphocyte subsets in HIV+ patients compared with controls. However, expression of phosphotyrosine in the cytoplasm of CD4+ and CD8+ lymphocytes did not differ significantly between HIV+ patients and controls. Percentages of "naive" CD45RA+RO- CD4+ and CD8+ lymphocytes were lower than control values in all HIV+ patients (P < 0.001). Compared with controls, HIV+ patients had similar percentages of "memory" CD45RA-RO+ CD4+ lymphocytes but significantly higher percentages of memory CD8+ lymphocytes (P < 0.001). Percentages of memory CD8+ lymphocytes were lowest in patients with AIDS (P < 0.001). The consistent reduction in surface expression of all CD45 isoforms observed in our study may be of relevance to the impaired T cell activation characteristic of HIV infection. Also, our results argue against the selective depletion of memory CD4+ lymphocytes in HIV-induced disease.

Adult↗
PubMed1996

Elevated serum levels of macrophage-derived cytokines precede and accompany the onset of IDDM.

To determine whether cytokines could have a role in the development of insulin-dependent diabetes mellitus (IDDM), we measured serum levels of cytokines derived from T helper 1 (interleukin-2 and interferon-gamma), T helper 2 (interleukin-4 and interleukin-10) lymphocytes and macrophages (tumour necrosis factor-alpha, interleukin-1 alpha and interleukin-1 beta) in patients before and after the onset of IDDM. Recently diagnosed IDDM patients had significantly higher levels of interleukin-2, interferon-gamma, tumour necrosis factor-alpha and interleukin-1 alpha than patients with either long-standing IDDM, non-insulin-dependent diabetes (NIDDM), Graves' disease, or control subjects (p < 0.05 for all). Compared with control subjects, patients with long-standing IDDM and those with NIDDM had higher interleukin-2 and tumour necrosis factor-alpha levels (p < 0.01 for all). Interleukin-4 and interleukin-10 were detectable in sera of patients with Graves' disease only, while interleukin-1 beta was not detectable in the serum of any control or test subject. To investigate whether high cytokine levels precede the onset of IDDM, we studied 28 non-diabetic identical co-twins of patients with IDDM, followed-up prospectively for up to 6 years after the diagnosis of the index. Levels of tumour necrosis factor-alpha and interleukin-1 alpha were elevated above the normal range more frequently in the eight twins who developed diabetes than in those 20 who did not (p < 0.005). Analysis of T helper 1 and T helper 2 profiles of the twin groups did not reveal a clear difference between prediabetic twins and twins remaining non-diabetic. These results support the notion that T helper 1 lymphocytes may play a role in the development of IDDM. This is associated with release of macrophage-derived cytokines, which is also a feature of the prediabetic period. The lack of evidence of a dominant T helper 1 profile of cytokine release before diabetes onset suggests that additional events, activating this arm of the cellular immune response, are required in the immediate prediabetic period.

Autoantibodies↗
PubMed1996

Peripheral blood and intrahepatic subsets of T lymphocyte activation and function in liver allograft rejection and drug-induced tolerance in rats.

T lymphocyte kinetics in liver allograft rejection were studied by measuring levels of activated (CD25+ and class II MHC+) T lymphocytes (CD5+) and T cell subsets (CD4 and CD8) in peripheral blood and the livers of allogeneic DA (RT1b) to LEW (RT1') and syngeneic LEW to LEW orthotopic rat liver transplants. Median survival was 10 days in untreated allogeneic rats (n = 17). Mean (+/- SEM) T lymphocyte class II MHC expression increased from 3.4 +/- 0.44% (day 2/3) to 4.9 +/- 1.1% (day 7) (p = 0.01). Complete sequential data were available for nine animals over the period of rejection confirming the increase in class II MHC expression (p = 0.05) and showing a decrease in CD25 expression (p = 0.05). There was a significant fall in CD4:CD8 ratio from day 2/3 to day 7 (p = 0.002). CD25 and class II MHC molecule expression and the CD4:CD8 ratio remained unchanged over the comparable period in the syngeneic LEW to LEW control model (n = 5, p > 0.3 for all comparisons). Cyclosporin A (5 mg/kg/day) was given orally for 17 days and then withdrawn to induce allograft tolerance in a further nine DA to LEW rats (median survival > 100 days). Samples taken at 2/3, 7, 17, 30, 40 and 100 days showed that T cell activation marker expression remained low during cyclosporin treatment (e.g. class II MHC expression 2.32 +/- 0.35%; CD25 expression 3.53 +/- 0.44% on day 7) but increased thereafter (e.g. class II MHC expression 8.19 +/- 0.65%. CD25 13.25 +/- 0.95% on day 100). There was a fall in CD4:CD8 ratio throughout (p < 0.001). Intrahepatic mononuclear cells were harvested from six normal livers, four allogeneic livers (at 10 days), five syngeneic livers (at 10 days) and five tolerant allografts (at 100 days). Rejecting grafts showed the highest proportion of T lymphocytes (66.8 +/- 4.0% vs 18.5 +/- 3.6% in controls, p = 0.01). T cell activation was higher in both rejecting and tolerant grafts versus normal control livers (p = 0.05 for CD25 and p < 0.01 for class II MHC expression). CD8+ lymphocytes predominated in the hepatic infiltrate in all models, although the majority of these cells were both CD5 and alpha beta T cell receptor negative. There was a higher proportion of T cells in tolerant allografts (44.5 +/- 5.2%, p < 0.01) compared with control animals. Serial changes in peripheral T lymphocyte subsets may be useful in monitoring experimental acute rejection. In peripheral blood, the increase in T cell activation and loss of CD4+ lymphocytes, along with evidence of increased intragraft infiltration by this subset implies that it has a primary role in the development of tolerance in this nodel.

Animals↗
PubMed1996

Identification of 3 beta-hydroxysteroid dehydrogenase as a novel target of steroid cell autoantibodies: association of autoantibodies with endocrine autoimmune disease.

Autoantibodies directed against steroid hormone-producing cells (SCA) detectable by immunofluorescence are typically found in a small proportion of patients with premature ovarian failure (POF) as well as in other endocrine autoimmune diseases. The SCA pattern stains cells in the outer zones of the adrenal cortex, ovary, and testis. To identify the molecular target of SCA, an adrenal complementary DNA expression library was screened using SCA-positive serum, and the steroid enzyme 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) was identified. Only 1 of 48 (2%) patients with idiopathic POF, not pre-selected for the presence of other autoimmune diseases, had SCA by immunofluorescence, whereas 10 of 48 (21%) had anti-3 beta HSD autoantibodies detectable by immunoblot using recombinant human enzyme compared with 6 of 115 (5%) control subjects (P = 0.002). Absorption of SCA-positive serum with recombinant human 3 beta HSD abolished the immunofluorescence pattern. We also examined the prevalence of anti-3 beta HSD autoantibodies in other endocrine autoimmune diseases. Two of 112 (2%) diabetic patients, but none of the thyroid or Addisonian patients, had SCA by immunofluorescence. Twenty-six (23%) diabetic subjects (P < 0.001 vs. controls), 3 of 18 thyroid patients (P > 0.05 vs. controls), and none of 4 Addisonian patients had anti-3 beta HSD autoantibodies. 3 beta HSD is the first steroid cell autoantigen defined at the molecular level to be associated with idiopathic POF occurring in the absence of other polyglandular diseases. Autoantibodies to 3 beta HSD in patients with other organ-specific autoimmune diseases indicate that the enzyme behaves as a typical target of polyendocrine autoimmunity. Anti-3 beta HSD autoantibodies in patients with POF may provide a marker of those subjects whose ovarian failure is autoimmune in origin and, as recent studies suggest, may be salvageable with glucocorticoid treatment.

3-Hydroxysteroid Dehydrogenases↗
PubMed1996

Persistent activation of CD8+ T-cells characterizes prediabetic twins.

OBJECTIVE: Elevated circulating levels of activated CD3+ T-cells are characteristic of type I diabetes at diagnosis, and activated CD8+ (cytotoxic/suppressor) T-cells predominate in the islet infiltrate. The aim of this study was to examine the peripheral blood of prediabetic and nondiabetic identical twins of patients with type I diabetes for the presence of activated CD8+ T-cells and by comparing these groups, analyze the relationship of such cells to the development of the disease. RESEARCH DESIGN AND METHODS: In a 10-year prospective study, blood T-cell subsets (CD3+ total T-cells, CD4+ helper/inducer, and CD8+ cytotoxic/suppressor) were analyzed for evidence of activation (cell surface expression of HLA-DR, CD25) in 18 identical twins of patients with type I diabetes, 8 of whom became diabetic (prediabetic twins), while 10 remained nondiabetic after at least 8 years of follow-up and are now at low risk for type I diabetes. Fifteen healthy individuals were studied as control subjects. RESULTS: At the beginning and during the study, percentage levels of activated CD3+ HLA-DR+ T-cells were significantly elevated in prediabetic and low-risk twins compared with control subjects (P < 0.005) but remained high only in prediabetic twins (P < 0.005). Both prediabetic and low-risk twins had elevated levels of HLA-DR+ CD4+ T helper cells compared with control subjects throughout the study (P < 0.001), and these remained high in both (P < 0.001 and P < 0.05, respectively). Only prediabetic twins had elevated levels of HLA-DR+ CD8+ T-cells during the study. These were significantly higher than in control subjects (P < 0.005) and low-risk twins (P < 0.05) and remained persistently elevated to diagnosis (P < 0.001). Abnormally elevated levels of HLA-DR+ CD8+ T-cells in twins indicate a 50% risk of progression to type I diabetes by life-table analysis (P = 0.01), with a positive predictive value of 100%, sensitivity of 50%, and specificity of 100%. Elevated CD25+ T-cell levels in prediabetic and low-risk twins were less marked and less able to discriminate between the twin groups. CONCLUSIONS: These results demonstrate that prediabetes is characterized by persistent elevation of HLA-DR+ CD8+ T-cells with the same cytotoxic phenotype as cells predominating in the islet at diagnosis, suggesting that the circulating cells may have a role in the pathogenesis of islet damage.

Adolescent↗
PubMed1995

Detection of brain-reactive autoantibodies in the sera of patients with systemic lupus erythematosus and cerebral involvement.

We modified, and applied to man, an ELISA established for the detection of brain-reactive autoantibodies in a murine model of SLE. We found brain-reactive antibody levels to be significantly higher in lupus patients than in healthy subjects. The antibody levels were significantly higher in lupus patients with central nervous system involvement than in those without.

Adult↗
PubMed1995

FK506 in liver transplantation for chronic hepatitis B: in vitro studies on lymphocyte activation and virus replication.

Recurrence of hepatitis B virus (HBV) in the graft is the major problem for patients with chronic HBV infection undergoing liver transplantation, which could be potentiated by the immunosuppression. In the present study, we used lymphocytes and hepatocytes isolated from patients with chronic HBV infection to investigate in vitro the effects of FK506 with and without methylprednisolone (25 ng/mL) on mitogen-induced lymphocyte proliferation, T-cell activation marker expression, and HBV replication in human hepatocytes. Increasing concentrations of FK506 (0.1, 0.5, and 5 ng/mL) resulted in a dose-dependent inhibition of lymphocyte proliferation with a reduction of the stimulation index by 9.2%, 39.0%, and 55.1%, respectively, with no difference between 25 chronic HBV carriers and normal controls. Methylprednisolone alone had no effect but potentiated the inhibitory effect of all three FK506 concentrations, such that the stimulation index was decreased by 20%, 56.2%, and 65.7%, respectively. FK506 (0.5 ng/ mL) reduced both the percentage of interleukin-2 receptor expressing T cells and the cell surface density of this receptor by 7.1% and 8.7% (P < .01), whereas it only reduced the proportion of HLA-DR expressing T cells by 6.8%. FK506 did not change significantly the intracellular HBV DNA or the hepatic expression of hepatitis B surface antigen (HBsAg) in short-term culture of human hepatocytes, whereas methylprednisolone increased the percentage of HBsAg-positive hepatocytes in all 5 patients with active viral replication. These results indicate that the effects of FK506 on T-cell activation in chronic HBV carriers are identical to normal subjects, resulting in marked suppression of T-lymphocyte function but only modest reduction in the expression of cell surface activation markers. The drug showed no direct stimulatory effect on viral replication, suggesting that FK506 can be a useful, steroid-sparing immunosuppressive agent for liver graft recipients with chronic HBV infection.

Adult↗
PubMed1995

The value of complement activation products in the assessment of systemic lupus erythematosus flares.

Complement activation products (CAP) have been reported as sensitive markers of disease activity in systemic lupus erythematosus (SLE). We have measured seven parameters of the complement system (C3, C4, factor B, C3a, C4a, iC3b, and the terminal complement complex-TCC-) in 61 SLE patients to study their interrelationship and relative efficacy as diagnostic indicators of lupus activity. Disease activity was judged according to a clinical index (SLEDAI) to be active in 22 and inactive in 39 patients. Subjects with active SLE showed increased levels of C3a, C4a, and TCC compared with those of stable lupus and normal controls, and plasma concentrations of these CAP manifested a positive correlation with disease activity scores. However, values of factor B and iC3b did not correlate with lupus flares. Serum C3 levels were a better reflection of the degree of SLE activity than were C4 levels. The anaphylatoxins were extremely sensitive markers of disease activity but they lacked enough specificity, and iC3b was not at all informative for this purpose. On the whole, TCC concentration was the most useful parameter (77% sensitivity, 80% specificity) to monitor lupus activity, correlating the best with the activity scoring system, and thus offers a better laboratory marker of lupus severity than conventional measurements of complement.

Adolescent↗
PubMed1995

Markers of immune cell activation and disease progression. Cell activation in HIV disease.

Immune cell activation is a feature of infection with the human immunodeficiency virus (HIV). Here we report our studies on a cohort of over 400 patients with HIV infection studied cross-sectionally and longitudinally to examine the relationship between markers of immune cell activation and disease progression. To examine disease progression, 340 patients with HIV infection but without AIDS were followed for a total of 574 patient years, during which 56 developed AIDS. In our first study, 157 patients in CDC groups II-IV were examined cross-sectionally for in vivo expression of the activation markers HLA-DR and CD25 on CD3, CD4 and CD8 T cells. Levels of CD3+ HLA-DR+ T cells are high in HIV infection and show a significant negative correlation with CD4 counts (r = 0.52; p < 0.001). The appearance of HLA-DR+ CD3+ T cells is an early feature of asymptomatic HIV+ patients, with a greater proportion (82%) showing abnormally high levels of these than abnormally low levels of CD4 (52%; p < 0.001). Examining activation of the CD4 subset specifically is likely to be of greater interest, given that this cell is the viral target. Indeed, we found that in the cross-sectional study, levels of HLA-DR+ and CD25+ CD4 lymphocytes show a step-wise linear increase with increasing disease severity (significant test for linear trend; p < 0.001). In our previous studies, only declining CD4 count has shown such a significant linear trend. These data suggest that measuring activated CD4+ T cells in the periphery may be a powerful predictive tool. In our second study, we examined the expression of other markers acquired (CD45R0) and lost (CD45RA) following activation of naïve T cells. Examining expression of these on CD4 and CD8 cells cross-sectionally in 71 HIV+ patients, we found abnormalities in percentage levels of CD45RA+ and CD45R0+ populations, none of which showed any relationship to disease severity. Intriguingly, however, we noted that the surface density of both CD45RA and CD45R0 molecules on CD4 and CD8 cells was markedly and significantly reduced at all stages of HIV infection (eg relative specific fluorescence reduced by up to 50%; p < 0.001). This abnormality was confirmed in studies using antibodies to a common epitope on all CD45 isoforms (pan-CD45) and to the CD45RB isoform. Finally, returning to the question of immune cell markers of activation and disease progression, we have examined some of the best documented markers in our longitudinal study.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Circulating levels of mannose binding protein in human immunodeficiency virus infection.

Mannose binding protein (MBP) is a serum lectin which, upon binding to a carbohydrate extremity, acquires the ability to activate the classical complement pathway. MBP binds human immunodeficiency virus (HIV) in vitro via glycans on gp120 and thus, it may play a defensive role in HIV infection and contribute to virus clearance through the activation of complement associated with this condition. We measured serum MBP and activation indices of the classical complement pathway (plasma C4d and C3d) in HIV-seropositive patients at different stages of disease severity, and in normal subjects. MBP was higher in HIV patients as a whole and in each Centers for Disease Control (CDC) group than controls (P<0.01). MBP was not significantly different between CDC groups and and did not significantly correlate either with CD4-positive lymphocytes, neopterin or beta2-microglobulin or with C4d and C3d. The possibility that MBP plays a defensive role in HIV infection cannot be excluded, but, it it is, it does not appear to act by recruiting complement for vital elimination.

Adult↗
PubMed1995

Significance of extractable nuclear antigens in childhood autoimmune liver disease.

Antinuclear antibody (ANA) is found in connective tissue disorders and in autoimmune liver disease. While ANA-positive connective tissue disorders are subdivided according to possession of specific antibodies to extractable nuclear antigens (ENA) (anti-ribonucleoprotein (anti-RNP), anti-Smith (anti-Sm), anti-Ro, anti-La), little is known about the presence and significance of ENA in autoimmune liver disease. To investigate this, we have tested 35 children with autoimmune hepatitis (AIH) (19 ANA and/or smooth muscle antibody-positive (ANA/SMA+ve); 16 liver kidney microsomal 1-positive (LKM-1 + ve)) and 14 with ANA/SMA+ve autoimmune sclerosing cholangitis (ASC), using both double dimension immunodiffusion and ELISAs. Eighty children with non-autoimmune liver disease (20 alpha 1-antitrypsin deficiency, 20 Wilson's disease, 20 Alagille's syndrome and 20 chronic hepatitis B virus infection) and 20 healthy controls were also tested. ENA were detected in seven (20%) patients with AIH: two ANA-positive, one SMA-positive and four LKM-1-positive. Three were positive for anti-Sm, two for anti-La, one for anti-Sm/anti-La and one for anti-Sm/anti-La/anti-Ro. ENA-positive had more severe liver disease than ENA-negative patients (P < 0.03). ENA were not detected in ASC, non-autoimmune liver diseases and controls. Our results indicate that ENA reactivity, including anti-Sm and anti-La, characteristic of systemic lupus erythematosus and Sjögren's syndrome, respectively, are present in some patients with AIH even in the absence of ANA, and may characterize a particularly severe form of the disease.

Adolescent↗