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Biomedical subjects

F B Bianchi

Publications and source records attributed to F B Bianchi.

At least 91 records · Page 5Linked to original sources
PubMed1995

IFL- and ELISA-antigliadin antibodies recognize different antigenic reactivities from those of R1-antireticulin and antiendomysial antibodies.

In order to establish whether antigliadin antibodies, detected by indirect immunofluorescence (IFL-AGA), display the same antibody reactivity as ELISA-AGA or whether they cross-react with reticulin antibodies (R1-ARA and antiendomysial--EmA), sera from 16 untreated coeliac patients were repeatedly absorbed with crude gliadin dissolved in ethanol/water solution. The comparison between antibody activities before and after absorption demonstrated that IFL-AGA and ELISA-AGA are nothing but a single antibody, as both of them completely disappeared or markedly reduced their titre after incubation with crude gliadin. Moreover, AGA reactivity differs from the reactivity of antibodies directed against reticulin, as R1-ARA and EmA titres were not affected by crude gliadin absorption. The absolute absence of cross-reactivity between IFL-AGA and R1-ARA is further confirmed by the removal of the former and persistence of the latter after gliadin absorption in the 9 sera positive for both antibodies. Sera of coeliac patients, therefore, show only two discrete antibody reactivities, one directed to gliadin and the other to reticulin components.

Adult↗
PubMed1994

IgA antibodies to jejunum. Specific immunity directed against target organ of gluten-sensitive enteropathy.

Serum IgA antibodies to jejunum (JAB) were found in 78 (96%) of 81 adults and children with untreated celiac disease. Not only did IgA JAB display a significant higher prevalence than IgA antigliadin antibodies (AGA) (72%) in untreated gluten-sensitive enteropathy, but they also allowed us to identify another three celiacs in addition to those detected by IgA antiendomysial antibodies (EmA). Like IgA EmA, IgA JAB persisted at low titer in seven (14%) of 50 celiacs tested after 12 months of gluten-free diet (GFD) despite the regrowth of jejunal villi, whereas IgA AGA disappeared in all these patients consistently with the normalization of intestinal mucosa. IgA JAB and EmA reappearance was close to 100% in the 13 celiacs studied after six months of gluten challenge, while IgA AGA reached the highest prevalence (about 70%) after one month of gluten ingestion without any increase in the following months. All disease and healthy controls were always negative for the three IgA antibodies. Our results prove that IgA JAB and EmA are the best screening tests for active (untreated and on gluten challenge) celiac disease, whereas IgA AGA should be used for monitoring the response to gluten withdrawal. IgA JAB are an expression of a specific immunity directed against the target organ of gluten-sensitive enteropathy, but, before ascribing them a role in the pathogenesis of celiac disease, it should be ascertained whether their production is a primary event leading to jejunal lesions or whether it is a secondary phenomenon due to antigen release from a previously damaged jejunal mucosa.

Adolescent↗
PubMed1994

Interferon therapy in liver/kidney microsomal antibody type 1-positive patients with chronic hepatitis C.

The association between liver/kidney microsomal antibody type 1 and adult cases of hepatitis C virus-related chronic liver disease has been firmly established. In the presence of both markers, evidence of autoimmunity (liver/kidney microsomal antibody type 1) and actual viremia (serum HCV RNA), the therapeutic dilemma arises between steroids, which are beneficial to autoimmune but deleterious to viral diseases, and interferon-alpha, which may exacerbate an autoimmune disorder. Six patients with liver/kidney microsomal antibody type 1 and serum HCV RNA were given interferon-alpha: three showed a response pattern similar to that observed in autoantibody-negative chronic hepatitis C cases; the other three developed a sharp transaminase peak, which was not followed by HCV RNA clearance. Considering the brisk flare-up of liver cell necrosis, interferon-alpha treatment proved to be dangerous in the above three liver/kidney microsomal antibody type 1/HCV RNA positive cases. Subsequent steroid administration reduced alanine aminotransferase peaks, but may be harmful in viral infections. Therapeutic alternatives are needed: they will probably include pure antivirals (exerting no immunostimulatory effects) with or without immunosuppressive drugs.

Adolescent↗
PubMed1994

Analysis of the hepatitis C virus genome in patients with anti-LKM-1 autoantibodies.

Hepatitis C virus genotypes have been characterized in 22 patients with anti-LKM-1 positive chronic hepatitis C. Following the Simmonds classification, 77% of patients were infected by hepatitis C virus genotype 1, 18% by genotype 2 and 5% by genotype 3, thus excluding the association of the autoimmune reaction with a particular viral type. Prevalences of genotype 1 and 2 were significantly different from those obtained in 79 patients with chronic hepatitis C who were negative for anti-LKM-1, as these were more rarely infected by genotype 1 and more frequently by genotype 2. Clinical findings of anti-LKM-1 positive patients were similar in all three groups. Sequence analysis of the amplified 5'UTR provided identification of peculiar and identical nucleotide substitutions in two out of four patients with genotype 2. The analysis of the secondary structure of this region showed that the observed nucleotide mutations increased the stability of the stem formed in this position.

Adolescent↗
PubMed1994

Differences in immune recognition of cytochrome P4502D6 by liver kidney microsomal (LKM) antibody in autoimmune hepatitis and chronic hepatitis C virus infection.

LKM-1 antibody, which characterizes a subtype of autoimmune hepatitis (AIH), is also found in some patients with chronic hepatitis C virus (HCV) infection. It has been suggested that HCV initiates autoimmunity through molecular mimicry, because there is partial identity between HCV and cytochrome P4502D6 (CYP2D6), the putative target of LKM-1. Whether CYP2D6 is the target of LKM-1 in HCV-related liver disease, however, is controversial. To clarify this issue, we have studied by phage plaque assay and Western blot the reactivity to recombinant CYP2D6, isolated from a human liver cDNA library, in 55 patients with LKM-1, 18 (14 females, median age 12 years) anti-HCV-negative, with classical AIH, and 37 (27 females, median age 52 years) anti-HCV-positive. Reactivity to CYP2D6 was found in 72% of the anti-HCV-negative, but only in 27% of the anti-HCV-positive patients (P < 0.001), although immunofluorescence LKM-1 titres were similar in the two groups. In addition, to investigate whether the antibody responsible for the LKM-1 fluorescent pattern also reacts with CYP2D6, we have determined the specificity of LKM-1 antibodies present in the supernatant of lymphoblastoid B cell lines obtained from two patients with LKM-1-positive AIH. An oligo/monoclonal antibody thus generated gave both the typical fluorescent pattern and reacted with CYP2D6. Our results show that whilst antibodies producing the characteristic LKM-1 fluorescent pattern can react with CYP2D6, not all LKM-1-positive sera do so, particularly if obtained from patients with chronic HCV infection. This suggests that LKM-1 in HCV infection recognizes epitopes or antigens different from those targeted in AIH.

Adolescent↗
PubMed1994

Testing for hepatitis C virus sequences in peripheral blood mononuclear cells of patients with chronic hepatitis C in the absence of serum hepatitis C virus RNA.

Hepatitis C virus (HCV) is able to replicate in peripheral blood mononuclear cells (PBMC) of HCV-infected patients. Few data are available on PBMC testing for HCV RNA in serum HCV RNA negative patients, positive for anti-HCV and with histological evidence of chronic hepatitis. Twenty such patients were studied; of these, 11 were tested during interferon alpha (IFN) treatment, at the time of serum HCV RNA clearance and ALT normalisation: only one was found to be positive for HCV sequences in PBMC. Within 3 months of IFN withdrawal all 11 patients relapsed with high ALT and recurrence of serum HCV RNA. Of nine serum HCV RNA negative patients with chronic hepatitis C who were not receiving IFN when tested (four untreated patients and five patients who had already completed IFN schedule), PBMC HCV RNA was detected in four. Evidence of active HCV replication (presence of the minus strand genome) in PBMC was also observed in two cases. Thus, five of the 20 patients without detectable serum HCV RNA turned out to be carriers of HCV sequences in PBMC. These data indicate that: 1. PBMC are an extrahepatic replication site of HCV; this is true also in the absence of serum HCV RNA; 2. the role of PBMC as a "viral reservoir" after IFN-induced serum HCV RNA clearance is questioned; 3. the absence of both serum and PBMC HCV RNA in patients under IFN is not predictive of sustained viral loss; 4. testing for PBMC viral sequences might enhance the chances of detecting HCV infection.

Adult↗
PubMed1994

Quantitation of hepatitis C virus genome molecules in plasma samples.

A competitive reverse transcription PCR (cRT-PCR)-based assay for the quantitative detection of hepatitis C virus (HCV) viremia was developed, optimized, and applied to the direct molecular analysis of clinical samples from nine patients with persistent HCV infection. As for other competitive PCR-based applications, this method consists of the reverse transcription and subsequent amplification of two RNA species in the same tube: the wild-type template (to be quantified) and a known amount of a modified synthetic template. These templates have identical primer recognition sites and very similar (but not identical) sizes, thus allowing direct detection of both template species after gel electrophoresis and ethidium bromide staining. The results obtained by this cRT-PCR application for testing clinical samples from HCV-infected patients mainly indicate that the competitive approach reaches the degree of sensitivity (fewer than 5 HCV RNA molecules per 100 microliters) necessary to evaluate viral load in all HCV-infected patients, independently of clinical conditions, and that this technique is flexible enough to quantify highly divergent levels of cell-free HCV genome copy numbers in biological samples. Interestingly, we observed a sample-to-sample variation in the loss of detectable HCV genome molecules in serum in comparison with that in plasma from the same patient, thus indicating that serum specimens, although widely used in the past few years for qualitative molecular investigation of HCV-infected patients, cannot be used to obtain reliable quantitative data on HCV viremia from these patients.

Artifacts↗
PubMed1994

Ito cell heterogeneity: desmin-negative Ito cells in normal rat liver.

The presence of desmin is used to identify Ito cells in rat liver and to evaluate the purity of separated and cultured Ito cells. Heterogeneity of the normal Ito cell population has been suggested; this could include variations in the content of cytoskeletal components. For these reasons we decided to reevaluate the use of desmin staining as a phenotypical marker of Ito cells in normal rat liver. Our approach was to combine desmin staining with identification of vitamin A (autofluorescence), lipid droplets (Sudan III), vimentin, laminin and tenascin, using cryostat sections: Immunofluorescence, double-immunofluorescence or immunoperoxidase techniques were used. All the techniques described corroborate the existence of desmin-negative Ito cells, mainly located in pericentral areas. In fact, lobular desmin-positive cells showed uneven distribution because they were more frequent in periportal than in pericentral areas. On the contrary, Ito cells identified on the basis of morphological criteria or positivity for laminin were evenly distributed. Double immunofluorescence confirmed this observation, showing nearly complete codistribution of laminin and desmin in periportal areas. Outside this area, positivity for desmin was observed only in about 50% of laminin-positive cells. Our observations suggest that desmin cannot be viewed as a phenotypical marker but rather is a differentiation marker of Ito cells, possibly indicating a specific functional state.

Animals↗
PubMed1993

Ursodeoxycholic acid for symptomatic primary biliary cirrhosis. Preliminary analysis of a double-blind multicenter trial. Italian Multicenter Group for the Study of UDCA in PBC.

The administration of ursodeoxycholic acid, a hydrophilic bile acid not hepatotoxic to humans, has been suggested for treatment of primary biliary cirrhosis to improve cholestasis and reduce hepatocellular damage. Efficacy of treatment has been studied mainly in patients with asymptomatic or early-stage disease. In January 1988, to establish the efficacy and safety of ursodeoxycholic acid in a population with more severe disease, we started a multicenter, double-blind, placebo-controlled trial in patients with symptomatic disease, that is, with pruritus or serum bilirubin exceeding 2 mg/dl. Forty-four patients were assigned to ursodeoxycholic acid, 500 mg daily (corresponding to about 8.7 mg/kg body weight in these patients), and 44 to a placebo. As planned at the beginning of the study, a preliminary analysis was performed when all patients had been followed for at least 6 months (33 patients up to 12 months). Pruritus, self-evaluated by the patients, and cholestyramine consumption, as recorded in a diary, decreased significantly (p < 0.01) in both groups. In patients who initially had abnormal levels, serum bilirubin decreased significantly (p < 0.05) in the ursodeoxycholic acid group compared to placebo. After 6 months the following were also significantly better in the ursodeoxycholic acid than in the placebo group: a composite weighted biochemical index taking into account the changes in serum bilirubin, alkaline phosphatase, gamma-GT and AST (p < 0.001); serum prealbumin (p < 0.05); IgG (p < 0.01) and IgM (p < 0.01) levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Bilirubin↗
PubMed1993

Abdominal lymphadenopathy detected by ultrasonography in HIV-1 infection: prevalence and significance.

By using abdominal ultrasonography (UlS), deep nodes were detected in 41 of 85 (48%) HIV-1 positive subjects, most of them heroin addicts, but in none of 85 healthy HIV-negative controls. Computerized tomography, performed in 10 cases of lymphadenopathy, invariably confirmed the UlS findings. Prevalence [asymptomatic carriers: 8/15 (53%); PGL patients: 8/18 (44%); ARC: 13/27 (48%); AIDS: 12/25 (48%)], number, size, and site of deep nodes were comparable among the different CDC groups. No correlation was found between abdominal and superficial lymphadenopathy. Median serum concentrations of gammaglobulins (g/dl) and IgG (mg/dl) were higher in patients with than without deep nodes (2.25 vs 1.87 and 2540 vs 1900, respectively) (p < 0.01) as well as in cases with than without superficial nodes (2.15 vs 1.80 and 2340 vs 1941, respectively) (p < 0.05). Abdominal lymphadenopathy occurred during all stages of HIV infection even in asymptomatic carriers: this should be considered in the differential diagnosis of UlS-detected deep nodes. Enlargement of either deep or superficial nodes seems to reflect a state of polyclonal B cell activation.

Abdomen↗
PubMed1993

[Autoimmunity and HCV].

Since the discovery of HCV in 1989 and the availability of reliable tests to detect HCV infection, we are aware that a number of chronic hepatitis cases, previously considered as autoimmune, are closely related to HCV. This applies particularly to adults with autoimmune hepatitis type 2 (LKM1 positive): in the Mediterranean area the vast majority of such cases are indeed anti-HCV/HCV RNA positive. Different is the case of pediatric type 2 autoimmune hepatitis patients, whose disease is HCV-free and remains still "primary". In autoimmune hepatitis type 1 (anti-nuclear and anti-action antibody positive) HCV infection seems to be confined to patient with mild-moderate disease activity, while most of the severe cases are consistently HCV-free. Autoantibody testing is relevant in detecting autoimmune hepatitis within the cryptogenic subgroup and prior to interferon treatment of HCV-related chronic hepatitis.

Autoantibodies↗