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Biomedical subjects

A Plebani

Publications and source records attributed to A Plebani.

At least 127 records · Page 7Linked to original sources
PubMed1984

An avidin-biotin ELISA for the measurement of serum and secretory IgD.

This paper describes an improved microtiter solid-phase enzyme immunoassay for the determination of serum and secretory IgD. Use of the interaction between biotinylated anti-human IgD and horseradish peroxidase(HRP)-avidin conjugate permits quantitation of human IgD in the range of 1-64 ng/ml. IgD was detected in all samples of serum, saliva and nasal secretions of 28 normal adults. In only one subject both serum and secretory IgD were undetectable. The mean concentration of serum IgD determined by this assay is similar to that reported by other authors using radioimmunoassay. The assay described is not only rapid and inexpensive but at least as sensitive as the radioimmunoassays usually employed for quantitation of IgD.

Adult↗
PubMed1984

A new immunoperoxidase assay for Lolium perenne-specific IgE in serum based on the biotin/avidin system (BAS).

A new solid-phase immunoassay based on the biotin/avidin system (BAS) for measuring serum Lolium perenne (LP)-specific IgE antibody is described. LP-specific IgE was assayed by the BAS assay and RAST for comparison in the sera of thirty-two normal asymptomatic subjects RAST-negative for LP and of twenty-six subjects with hay fever and RAST-positive for LP. The specificity of the BAS assay for LP-specific IgE was demonstrated by absorption experiments. An overall agreement of 91% (53/58) was observed between the BAS and RAST and a high correlation (r = 0.87, P less than 0.001) was found between the LP-specific IgE determined by the two methods. The advantages of the BAS assay as compared to both the RAST and classical ELISA are discussed.

Avidin↗
PubMed1984

Activity of classical and alternative pathways of complement in preterm and small for gestational age infants.

Complement activity was compared in 50 low birth weight infants divided into appropriate and small for gestational age groups; the influence of birth weight and gestational age on complement development was also investigated. CH50 and kinetics (tH50) of both classical and alternative pathway activity of complement, C3, and Factor B levels were significantly higher in small for gestational age infants (classical pathway CH50, 630 HU/ml +/- 184 SD; CP tH50, 77 min +/- 47; aternative pathway CH50, 44.8 HU/ml +/- 11.3; AP tH50, 56 min +/- 43; C3, 73.98 mg/dl +/- 12.68; and Factor B, 13.17 mg/dl +/- 3.67) than in weight-matched appropriate for gestational age infants (CP CH50, 523 HU/ml +/- 152; CP tH50, 105 min +/- 49; AP CH50, 38.8 HU/ml +/- 13; AP tH50, 90 min +/- 53; C3, 58.14 mg/dl +/- 9.43; and Factor B, 9.32 mg/dl +/- 1.73). Complement values were lower in low birth weight infants than in adult controls (P less than 0.001 in all cases). All complement parameters were mainly correlated with gestational age; CH50 values of the classical and alternative pathways were also highly correlated with each other (r = 0.64; P less than 0.001). Low birth weight infants, especially preterm infants, have an important defect of complement activity. Complement factors increase gradually during gestation and intrauterine growth retardation does not affect complement development. Classical and alternative complement pathway activities have a similar development pattern.

Complement Activation↗
PubMed1984

Serum IgG levels and complement activity in hypogammaglobulinaemic patients under substitution therapy.

Haemolytic activity of the classical and alternative pathways of complement as well as serum levels of C1q, Factor B, Factor H, C3, C4, C3d,g and IgG were determined in 15 hypogammaglobulinaemic patients on immunoglobulin replacement therapy. Alternative pathway activity (AP) and C1q were defective in the presence of low IgG levels and normalized on achievement of normal IgG levels; for both variables the correlation with serum IgG was highly significant. Classical pathway activity (CP), C3, C4 and Factor H serum levels were normal independently of IgG levels; Factor B and C3d, g serum levels were elevated in hypogammaglobulinaemic patients regardless of IgG levels. The present report supports the hypothesis that IgG serum levels influence complement function.

Adolescent↗
PubMed1983

IgM and IgD concentrations in the serum and secretions of children with selective IgA deficiency.

Serum IgG and serum and secretory IgM, IgA and IgD levels were determined in 14 children with selective IgA deficiency and in 12 age and sex matched healthy controls. IgD was determined using a highly sensitive ELISA technique. In the healthy controls serum IgG, IgA and IgM were all in the age normal range, and serum IgA was significantly higher than secretory IgA with IgA in nasal secretions being significantly higher than in saliva. In the IgA deficient children serum IgG and IgM and secretory IgM were present in higher concentrations than in the controls but the difference was statistically significant only for serum IgG and salivary IgM. IgD was detectable in the serum and secretions of all patients and all but one control subject. Like IgM, serum IgD levels were significantly higher than secretory IgD levels and IgD was present in greater concentrations in nasal secretions than in saliva both in the patients and the controls, with no difference between the two groups. Thus, the data of this study show that while serum and secretory IgM levels are elevated in children with selective IgA deficiency, serum and secretory IgD are present in normal concentrations, supporting the hypothesis of a compensatory increase in IgM but not in IgD in such patients.

Adolescent↗
PubMed1982

Different role of secretory IgA in the pathogenesis of RAST-positive and RAST-negative atopic dermatitis.

Secretory-IgA (SIgA) concentrations were determined in whole saliva, unstimulated or stimulated by lemon juice, of thirty-eight children with atopic dermatitis, which comprised three adolescents, sixteen with IgE detected by RAST to one or more common allergen and twenty-two without specific IgE by RAST. There were thirty healthy controls matched for age and sex. The mean amount of total IgE was significantly greater in the RAST-positive than in the RAST-negative group. The mean SIgA concentration in unstimulated saliva of the RAST-positive atopic dermatitis group was less than that of the RAST-negative atopic dermatitis group and control groups, through the mean concentrations of SIgA of stimulated saliva were not significantly different in the three groups. It is suggested that the pathogenesis of atopic dermatitis may differ in children with or without specific-IgE antibodies; in those who were RAST-positive deficient exclusion of allergen by the intestinal barrier contributed to the pathogenesis, but not in those who were RAST-negative.

Adolescent↗
PubMed1981

Inhibition of polymorphonuclear leukocyte-mediated cytotoxicity by hydrocortisone "in vitro".

The effect of hydrocortisone (HC) on in vitro human polymorphonuclear leukocyte cytotoxicity was studied. HC was able to inhibit reversibly and in a dose-dependent way the antibody-dependent cellular cytotoxicity (ADCC) and the phytohemagglutinin-dependent cellular cytotoxicity (PDCC). The killing defect was partially overcome by increasing the antibody or the phytohemagglutinin (PHA) concentrations on the target cells. HC inhibited the PDCC more efficiently than ADCC; in fact the inhibition was present even at 10-5 M HC levels. Higher concentrations caused a progressive reduction in both tests. Inhibition of these PMN-mediated cytotoxicities may explain, in part, bot the anti-inflammatory actions of steroids and their deleterious effects on host defenses.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1980

Ontogeny of secretory immunity: levels of secretory IgA and natural antibodies in saliva.

In 187 healthy subjects from 2 months to 27 years of age, secretory IgA and free secretory component were assayed in samples of whole saliva obtained before and after stimulation with lemon juice. Antibody titers against Escherichia coli O antigens and against rabbit erythrocytes were also dosed in unstimulated saliva. Secretory IgA, undetectable in newborns, was present in all 2-month-olds tested in both unstimulated and stimulated saliva; thereafter secretory IgA levels increased progressively, reaching adult values by 6 to 8 years in unstimulated saliva and already by 2 to 4 years in stimulated saliva. The antibody titers assessed in unstimulated saliva followed a similar pattern also reaching adult values by 6 to 8 years. On the other hand, free secretory component levels showed no significant variation with age in unstimulated saliva whereas a slight increase was observed in the first year of life in stimulated saliva.

Adolescent↗
PubMed1979

Effect of in vitro treatment with reducing drugs on structure and function of human secretory immunoglobulin A.

Samples of unstimulated whole saliva from 15 healthy children with 0.5--6 mg/100 ml of secretory IgA and from 10 healthy adults with 4--18 mg/100 ml of secretory IgA were pooled and treated in vitro with dithiothreitol and alpha-mercaptopropionylglycine. The effect of these reducing drugs on the immunochemical properties of secretory IgA was evaluated. Dithiothreitol induced depolymerization of secretory IgA and splitting of the secretory piece from the IgA molecule; furthermore it strongly reduced the titer of secretory antibodies to Escherichia coli antigens. The drug alpha-mercaptopropionylglycine apparently did not affect either the polymeric structure of secretory IgA or the titer of secretory anti-E. coli antibodies; however it induced splitting of the secretory piece. On the whole it appers that drugs with reducing properties, currently employed for liquifying mucous secretions in clinical practice, should be carefully evaluated for possible depressive side-effects on local immunity.

Adult↗
PubMed1978

Immunodeficiency in Down's syndrome. Titres of "natural" antibodies to E. coli and rabbit erythrocytes at different ages.

"Natural" antibody titres to E. coli O antigens of different serotypes and to rabbit red blood cells were determined in 86 subjects with Down's syndrome and 79 mentally retarded but chromosomally normal controls ranging in age from 10 months to 52 years. Subjects in the two groups were matched for sex, age and socio-environmental conditions. Titres of both antibodies, assessed by haemagglutination, were significantly lower in subjects with DS in the 1 to 5 year old group. E. coli antibodies transiently increased to normal values in subjects with DS during the second 5 years of life, thereafter rapidly declining to levels significantly lower than those observed in controls. The titres of antibodies to rabbit erythrocytes in subjects with Down's syndrome showed a more variable course transiently approaching normal values in the 7-10 year group and after 20 years of age. These data are interpreted as further evidence for the existence of a congenital immunodeficiency in Down's syndrome.

Adolescent↗
PubMed1978

Immunodeficiency in Down's syndrome: T-lymphocyte subset imbalance in trisomic children.

In fourteen children with Down's syndrome the percentage of circulating T-cells forming rosettes with sheep erythrocytes, either in the presence or in the absence of foetal calf serum, was significantly lower than in appropriately matched controls. In contrast the percentage of T-cells forming rosettes with human erythrocytes was significantly higher in children with Down's syndrome than in controls. These data support the hypothesis that a defective T-cell maturation is an early integral feature of Down's syndrome.

Child, Preschool↗
PubMedDate not supplied

Western blot technique in the serological evaluation of three LAV/HTLV III-infected Italian families.

In order to confirm suspected LAV/HTLV III infection, serological evaluation of patients is of utmost importance. ELISA is currently being employed on a large scale for screening, but like the immunofluorescence assay, it has a variable rate of possible non-specific positivity. On the other hand, the Western Blot (WB) technique can detect antibodies to different viral proteins. In this paper we are reporting the serological patterns of three LAV/HTLV III-infected families. In particular, their viral protein-specific antibody patterns are described. With the exception of one child, all the patients tested showed seropositivity in both ELISA and WB. In the one child mentioned above, ELISA and immunofluorescence positivity were due to non-specific binding. Two out of three children tested showed a close correlation between a severe clinical course and the absence of p25-specific IgM. In contrast, one child showing a switch from IgM to p25-specific IgG antibodies had a favorable clinical course. We observed a family in which vertical transmission of LAV/HTLV III from the mother to her neonate seems not to have happened; the child was seronegative and healthy at the age of one. At birth, this neonate had LAV/HTLV III-specific IgG corresponding to the mother's pattern, but it lacked viral-specific IgM. Its mother had transmitted the viral infection to her first child, who died of AIDS. Preliminary suggestions are made about the detection of different specific antibodies and clinical features; the utility of WB is emphasized.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Acquired immune deficiency syndrome in childhood: impaired production of interleukin-2 by HIV (LAV/HTLV III) infected patients.

The phenotype and functions of T lymphocytes and of natural killer (NK) cells have been investigated in four children and five adults from three Italian families infected with HIV (LAV/HTLV III). The results show a heterogeneous pattern of immunological derangements involving distribution of T and natural killer subsets, proliferation in response to T cell mitogens and natural killer activity. However, all infected patients tested showed a very low or absent phytohaemagglutinin induced interleukin-2 production regardless of age and clinical conditions, while concanavalin A-induced interleukin-2 production was within the normal range. The impaired interleukin-2 production in response to phytohaemagglutinin in some patients is not related to phytohaemagglutinin-induced proliferation, to clinical conditions or to a defective distribution of T cell subsets. These results suggest that, in our patients, both adults and children, HIV (LAV/HTLV III) has an "early" tropism for a subset of T cells involved in interleukin-2 production.

Acquired Immunodeficiency Syndrome↗