Domenico Celestino

CD34-positive cells in human umbilical cord blood express nerve growth factor and its specific receptor TrkA

In this study, we investigated whether hematopoietic stem cells (HSC) and progenitors present in human cord blood can express nerve growth factor (NGF)-specific receptors, TrkA and p75. Our results showed a marked expression of TrkA and NGF in cord blood CD34(+) cells. A gradient of TrkA and NGF expression exists and is highest in cord blood CD34(+) cells, reduced in cord blood mononuclear cells (MNC) and minimal in mononuclear cells isolated from adult peripheral blood. Our findings suggest that NGF may play a role in the differentiation of hematopoietic progenitors and indicate a different requirement for NGF by immune cells, depending on their state of maturity.

Basophil-bound and serum immunoglobulin E directed against Helicobacter pylori in patients with chronic gastritis.

The immunoglobulin (Ig) E immune response in patients with Helicobacter pylori-associated chronic gastritis has been evaluated. Of 26 patients with H. pylori infection, 22 (84%) tested positive for basophil-bound specific IgE (determined by the histamine release test) and 18 (69%) for serum specific IgE (determined by an enzyme-linked immunosorbent assay). In contrast, only 1 of 17 persons in whom the bacterium was not detected presented cell-bound and serum specific IgE. In the 4 histamine release test--positive but enzyme-linked immunosorbent assay--negative patients, removal of antibody from the basophil surface by acid elution showed that histamine release occurred through an IgE-dependent mechanism. When normal basophils, passively sensitized with serum from IgE-positive patients, were exposed to the H. pylori antigen, a significant release was observed, confirming the class specificity of the response. Inhibition experiments with bacteria other than H. pylori showed that the IgE antibody was specifically directed against this organism. The percentage of antigen-induced histamine release did not correlate with serum specific IgE level. However, the response of basophils to antigenic challenge was proportional to IgE-dependent cellular releasability. This finding suggests that target cell sensitivity may be the most important factor in determining the entity of biological response to the antigenic challenge. The ability of H. pylori to induce a specific IgE immune response could answer key questions regarding the mechanisms inducing gastric inflammation.

IgG subclasses in human hydatid disease : prominence of the IgG4 response

To assess the participation of the four subclasses of IgG in the humoral response to Echinococcus granulosus infection, we determined total and parasite-specific IgG1, IgG2, IgG3 and IgG4 in sera from 46 patients with hydatid disease using an enzyme-linked immunosorbent assay (ELISA). Parasite-specific IgG subclass antibodies were quantitatively measured by means of standard curves obtained by affinity chromatography. Sera from 35 healthy individuals served as controls. The total component of IgG1, IgG2, and IgG3 showed a slight increase in patients with hydatidosis in comparison to normal control subjects with no significant differences. For the IgG4 subclass, however, a marked elevation was found in the patients group (p = 0.001 by analysis of variance). IgG1 and IgG4 subclasses showed a high anti-echinococcus antibody response, whereas there was a low parasite-specific IgG2 and IgG3 response. Indeed IgG-specific antibodies were found to belong mainly to IgG1 (63%) and to IgG4 (30%) and to a lesser extent to IgG2 (5%) and IgG3 (2%). The percentage of the total serum IgG4 antibodies that were specific for hydatid antigen reached a mean level of 18%, significantly higher than that of any of the other three IgG subclasses (p < 0.001 by Students t test). Thus, the continuous antigenic stimulation of hydatidosis may result in an enhanced IgG4 subclass response.

Hepatitis C virus infection of salivary gland epithelial cells. Lack of evidence.

BACKGROUND Hepatitis C virus genome (HCV-RNA) has been detected in whole salivary gland tissue of chronically infected patients. However, contamination of the tissue by plasma or blood cells was not excluded by the previous reports. AIMS To assess whether HCV infects the salivary gland epithelial cells in patients with chronic HCV liver disease. METHODS Twenty unselected patients with chronic active hepatitis (11 cases) or active cirrhosis (nine cases) were examined. Serum and saliva samples were obtained from all patients, 12 of whom (seven, chronic active hepatitis; five, active cirrhosis) underwent salivary gland biopsy. PCR for HCV-RNA was performed on RNA extracted from serum, saliva and salivary gland epithelial cells collected by isokinetic gradient separation after trypsin digestion of whole salivary gland tissue. Saliva samples were also examined for the presence of secretory IgA anti-HCV by gel chromatography and ELISA testing. RESULTS HCV-RNA was detected in all sera with titers ranging from 5.42 x 10(5) genome equivalents/ml to 123.2 x 10(5) genome equivalents/ml. Thirteen patients were infected with genotype 1b, four patients had genotype 1a, two patients had genotype 2a and one patient was unclassifiable. Low titer HCV-RNA (<2 x 10(5) genome equivalents/ml) was detected in 3/20 saliva samples (15%) from highly viremic patients infected with 1b genotype. RNA extracted from salivary gland epithelial cells consistently tested negative for HCV-RNA. In addition, all saliva specimens tested negative for secretory-IgA (S-IgA) anti-HCV, even after a 10-fold concentration of the samples. CONCLUSIONS There was no evidence that HCV infects the salivary gland epithelial cells in our viremic patients with HCV chronic liver disease. Low level HCV-RNA in saliva is most probably due to virus spillover from blood.

Anti-endothelial antibodies and neuropsychiatric systemic lupus erythematosus.

Abstract:  The pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) has been attributed to autoantibody‐mediated neural dysfunction, vasculopathy, and coagulopathy. Several autoantibodies specificities have been reported in serum and cerebrospinal fluid of NPSLE patients (i.e., antineuronal, antiribosomal P proteins, antiglial fibrillary acidic proteins, antiphospholipid, and anti‐endothelial antibodies). We have recently demonstrated an association between serum anti‐endothelial antibodies and psychosis or depression in patients with SLE. Subsequently, by screening a cDNA library from human umbilical artery endothelial cells with serum from a SLE patient with psychosis, one positive strongly reactive clone was identified encoding the C‐terminal region (C‐ter) of Nedd5, an intracytoplasmatic protein of the septin family. Anti‐Nedd5 antibodies have been found significantly associated with psychiatric manifestations in SLE patients, strengthening the view of a possible implication of autoantibodies in the development of psychiatric disorders.

Histamine release test in the diagnosis of human hydatidosis

An evaluation of the use of the histamine release test (HRT) in the diagnosis of human hydatidosis is presented. This technique, which makes it possible to evaluate directly IgE dependent immediate hypersensitivity by measuring the histamine released from leucocytes (basophils) after antigenic challenge, was compared with the detection of serum specific IgE by the radio‐allergosorbent test (RAST), and with the determination of serum specific IgE by the enzyme‐linked immunosorbent assay (ELISA). Of the 54 patients with hydatidosis, all were positive according to HRT, 42 according to RAST and 47 according to ELISA. No false positive results were obtained by HRT in 43 patients with parasitosis other than hydatidosis, however, of these 43, 10 resulted in false positives according to RAST and five according to ELISA. It is concluded that HRT is more sensitive and more specific than RAST and ELISA.

A new serological technique, time-resolved fluoroimmunoassay (TRFIA), for the immunological diagnosis of urinary schistosomiasis

The application of a new serological method, time-resolved fluoroimmunoassay (TRFIA), is described for the diagnosis of urinary schistosomiasis. A chelate of lanthanides (europium) with a long fluorescent life-time is used as label. The intensity of fluorescence is measured after a delay selected to eliminate almost completely the background fluorescence, which decays rapidly. TRFIA was compared with an established method, enzyme linked immunosorbent assay (ELISA). Using sera from proven cases of Schistosoma haematobium infection, 98.1% of the samples were positive by TRFIA and 86.5% by ELISA. Sera from patients infected with helminths other than schistosomes produced only 1.5% of false positives with TRFIA, compared with 12.3% by ELISA. TRFIA is more sensitive and specific than ELISA.

Spontaneous in vitro Generation of Histamine Releasing Factor from Mononuclear Cells of Patients with Hydatidosis

We have shown that Echinococcus granulosus infection can induce an enhanced sensitivity of basophils to IgE-dependent stimuli. To determine whether a cytokine, histamine releasing factor, could account for it, we evaluated 35 patients with active hydatidosis, 5 patients with past E. granulosus infection, and 20 normal volunteers. The spontaneous production of a factor in vitro that provoked the release of histamine from basophils was observed by mononuclear cells from patients with active disease, but not by those from subjects with past infection or from normal individuals. The histamine releasing factor was found to activate basophils through surface-bound IgE. It is concluded that E. granulosus infection induces both generation of histamine releasing factor and production of IgE that can bind this cytokine.

The serological diagnosis of human hydatid disease by time-resolved fluoroimmunoassay

The use of a new immunoassay, time-resolved fluoroimmunoassay (TR-FIA), in the diagnosis of human hydatid disease has been evaluated. This technique, which is based on the labelling of antibodies with europium (Eu), was compared with a well-established method, the enzyme linked immunosorbent assay (ELISA). Of 102 patients with hydatid disease, 97 (95.1%) were positive according to TR-FIA and 83 (81.4%) according to ELISA. The rate of non-specificity for other parasitic infections (n = 206) was 8.7% for TR-FIA and 17.5% for ELISA. It is concluded that TR-FIA is more sensitive and more specific than ELISA in the diagnosis of human hydatid disease.

Basophil releasability in human hydatidosis.

We studied immunoglobulin E (IgE)- and non-IgE-mediated releasability in basophils from 31 patients with hydatidosis. Histamine release to non-IgE-dependent stimuli did not differ significantly between normal individuals and patients with hydatidosis. On the contrary, an increased histamine liberation was obtained by challenging basophils from hydatid patients with anti-human IgE. It is concluded that Echinococcus granulosus infection induces an enhanced sensitivity of basophils to IgE-dependent stimuli.