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Biomedical subjects

A Vierucci

Publications and source records attributed to A Vierucci.

At least 109 records · Page 6Linked to original sources
PubMed1985

Altered T cell subsets and function in polytransfused beta-thalassemia patients: correlation with sex and age at first transfusion.

Monoclonal antibodies (OKT series) have been used to investigate possible modifications of T lymphocytes and T lymphocyte subsets in 65 multiply transfused beta-thalassemia patients. No significant difference was observed in percentage and absolute number of OKT3-, OKT4-, and OKT8-positive cells when compared to controls. A subgroup of patients (10 patients, 15.3%), however, could be selected who showed a reversal of OKT4/OKT8 ratio. These patients did not differ from the others as to age, number of transfusions, frequency of splenectomy, ferritin levels, hepatitis B markers, chronic liver disease incidence, and numbers of B lymphocytes and natural killer cells. The features distinguishing this group from the remaining patients were: decreased mitogen responsiveness; early age when first transfused; high incidence of males (90%). Immunological investigation was done in 2 occasions, 1 year apart, but no significant modification was observed in these patients. These findings suggest that in beta-thalassemia patients transfusion therapy started very early in life may be responsible for persistent immunological modifications. The susceptibility to such modifications might be greater in males.

Adolescent↗
PubMed1985

Antibodies to HTLV-III and the lymphadenopathy syndrome in multitransfused beta-thalassemia patients.

Antibodies to HTLV-III have been investigated in 118 multitransfused beta-thalassemia patients. Thirteen patients (11.01%) were found to be positive; 3 of these 13 showed clinical and immunological signs of the lymphadenopathy syndrome. A retrospective study carried out on 65 sera has shown that at least 6 patients were negative 3 years before the present investigation. This is the first extensive study on HTLV-III infection in multitransfused beta-thalassemics. It suggests that these patients are at risk for the acquired immune deficiency syndrome and related diseases.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Should hepatitis B surface antigen positive mothers breast feed?

Breast fed infants may be at greater risk of mother to infant hepatitis B virus infection compared with formula fed infants. We studied 85 infants born to 84 hepatitis B surface antigen positive mothers (only two of whom were hepatitis B e positive), and who had received immunisation against hepatitis B virus. Our results indicate that breast feeding does not increase the risk of developing hepatitis B virus infection in infants born to these mothers if immunisation is carried out.

Breast Feeding↗
PubMed1985

Interference of hepatitis B virus surface antigen with natural killer cell function.

The influence of purified hepatitis B virus surface antigen (HBsAg) preparations or of supernatants derived from PLC/PRF/5 cell line (which produces HBsAg) on human natural killer (NK) activity was examined. Lymphocytes pre-incubated with HBsAg and subsequently washed showed a significant decrease in NK cytotoxicity against K-562 target cells. This effect was reversible and dose-dependent. In addition, pre-incubation with either HBsAg or PLC/PRF/5 supernatants inhibited in a reversible manner lymphocyte--K-562 conjugates and the binding of B73.1 monoclonal antibody (MoAb), which recognizes Fc receptors on NK cells. This effect was not observed with HNK-1, T3, T4, T6, T8 and T11 MoAb. HBsAg was non-toxic to lymphocytes, and ineffective with K-562 target cells. Beta-interferon did not modify HBsAg-mediated inhibition, when added either before or during the contact with HBsAg. Moreover, no modification was observed when neutrophils (at various neutrophil:lymphocyte ratios) were added, even though HBsAg is known to stimulate neutrophils to produce oxygen radicals which may modulate NK activity. We speculate that HBsAg produces these effects by reacting into receptor sites (possibly Fc receptor sites) on NK cell membrane. The overall significance of our results in relation to hepatitis and hepatocellular carcinoma is discussed.

Adult↗
PubMed1984

Changes in superoxide anion production in neutrophils from multitransfused beta-thalassemia patients: correlation with ferritin levels and liver damage.

Superoxide anion production in resting and PMA- or zymosan-stimulated neutrophils was evaluated in 21 beta-thalassemia patients. The results were correlated with ferritin values, hepatitis B virus serum markers, liver pathology, immunoglobulin levels and T-cell subsets. Superoxide anion generation from resting or PMA-stimulated neutrophils was significantly higher in patients than in controls. On the contrary, zymosan-stimulated neutrophils showed reduced superoxide anion production. Increased superoxide anion production in resting neutrophils showed a significant correlation to the values of ferritin. In addition, patients with biopsy-proven chronic liver disease showed significantly increased ferritin levels and superoxide anion production as compared to the remaining patients. No correlation was observed between superoxide anion production and the presence or the absence of hepatitis B virus serum markers, immunoglobulin levels and T-cell subsets. A possible role of interreactions between iron and oxygen radicals in determining liver damage in beta-thalassemia patients is suggested.

Adolescent↗
PubMed1984

Raised IgE levels in beta-thalassaemia: correlation with splenectomy and hepatitis B virus infection.

IgE values obtained in 117 beta-thalassaemia patients were significantly higher than in age matched normal subjects. In 31 patients (26.5%) IgE levels were above 2 s.d. of normal values for age, but the frequency of IgE with reaginic activity was lower in patients (5.1%) than in controls (11.9%). The highest values were observed in splenectomized patients who were also positive for one or more serological markers of hepatitis B virus infection. The increase of IgE levels was directly correlated with the number of years after splenectomy, and patients with biopsy proven chronic liver disease had higher IgE levels than those without evidence of liver damage. On the other hand, IgE levels were not correlated with the number of transfusions, age, IgG, IgA, IgM levels or T cell subsets and mitogen responsiveness. These results show that beta-thalassaemia patients develop elevated IgE levels to which splenectomy and hepatitis B virus infection contribute in a synergistic manner.

Adolescent↗
PubMed1984

T lymphocytes in children with recurrent respiratory infections: effect of the use of thymostimulin on the alterations of T-cell subsets.

OKT3-, OKT4- and OKT8-positive cells were estimated in 303 children with recurrent respiratory infections. The patients (selected by a score method) had experienced 13 or more infections a year. Modifications in T-cell subsets were observed in 154 patients (50.8%). Decreased OKT3- and OKT4-positive cells were present in 80 children (26.4%), while 74 patients (24.4%) showed normal values of OKT3-positive cells but decreased OKT4- and increased OKT8-positive cells. An attempt at treatment with thymostimulin was undertaken in a group of randomly chosen children with modifications in T-cell subsets. The use of thymostimulin induced the treated children more readily than the untreated ones to show improvement in both the score for respiratory infections and the distribution of T-cell subsets.

Antibodies, Monoclonal↗
PubMed1983

A mechanism for liver cell injury in viral hepatitis: effects of hepatitis B virus on neutrophil function in vitro and in children with chronic active hepatitis.

Neutrophil function was studied by nitroblue tetrazolium (NBT) reduction, superoxide anion (O2-) production, chemotaxis, and bactericidal activity in 9 children with HBsAg-positive chronic active hepatitis (CAH). NBT reduction and O2- production were higher in resting neutrophils from the children with CAH than from the controls, but the production of O2- was depressed after stimulation with zymosan. No defect was observed in both random and direct locomotion, whereas a significant decrease was present in bactericidal activity. To evaluate the role of virus components, purified preparations of HBsAg and HBcAg were added to neutrophils from normal children. The incubation with such products induced in vitro the same modifications that were observed in the neutrophils from children with CAH. In addition, defects in phagocytosis and killing of Candida albicans as well as in chemotaxis were demonstrated. The production of O2- was reduced in the neutrophils, stimulated by zymosan and previously opsonized with HBsAg-positive serum.

Adolescent↗
PubMed1983

Usefulness of monoclonal antibodies in the diagnosis and monitoring of patients with primary immunodeficiencies: combined experience in three clinical immunology centers.

Circulating levels of T-cell subsets and NK cells were determined in 78 patients with primary immunodeficiencies, 35 children with recurrent respiratory infections, and healthy age-matched controls. Normal T cell and natural killer (NK) cell values were observed in individuals with immunoglobulin A (IgA) deficiency and X-linked agammaglobulinemia, while reduced OKT4/OKT8 cell ratios and low levels of 5/9+ T helper cells were found in approximately 60% of patients with common variable immunodeficiency. Infants with severe combined immunodeficiency (SCID) and lymphopenia had virtually no cells expressing T-cell or NK-cell surface antigens, but had normal numbers of monocytes and other types of blood cells. Infants with DiGeorge syndrome, other primary T-cell defects, or SCID with B cells had few or no circulating cells of mature T helper-suppressor phenotypes, but had normal numbers of NK cells (HNK-1+) and NK function. These results support the idea of a common stem cell precursor for T, B, and NK cells, each of which follows a separate pathway of differentiation. Profound alterations were observed in the distribution and function of T-cell subsets in ataxia-telangiectasia patients who were previously shown to have thymic dysplasia. A significant reduction in the frequencies of OKT3+ and OKT4+ cells was observed in children with frequent respiratory infections during infancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Agammaglobulinemia↗
PubMed1983

Imbalance in T-cell subsets of five children with congenital agammaglobulinemia and its effect on "in vitro" immunoglobulin synthesis.

OKT3, OKT4 and OKT8 monoclonal antibodies have been used to assess the number of total T cells and of some T-cell subpopulations in five children with Congenital Agammaglobulinemia. A significant increase in OKT8+ cells and parallel decrease in OKT4+ cells were observed in all patients, both as percentages and absolute numbers. by contrast there was no significant difference in the number of total T cells (OKT3+) and OKT3+ OKT4- OKT8- cells between patients and controls. Determinations were made of the synthesis of IgG and IgM by normal B cells cultured with T lymphocytes from patients stimulated by pokeweed mitogen. In all cases a significant decrease in Ig synthesis was observed. These results may be consistent with imbalance in the T regulatory subsets. However, a similar imbalance was observed in a healthy father of one patient, who had no other immunological defect. A normal distribution of T-cell subsets was observed in all the other relatives examined.

Agammaglobulinemia↗
PubMed1983

Neutrophyl function in children with chondrodystrophia calcificans congenita: evidence for defective chemotaxis.

Some neutrophil functions (superoxide anion production, bactericidal activity and chemotaxis) have been examined in four children with Chondrodystrophia Calcificans Congenita. Superoxide anion production and bactericidal activity were in the normal range, but a defect in cellular chemotaxis has been proved. This finding account for predisposition to infection which is frequently present in these patients, and may include this disease among those syndromes in which a deficiency of the immune system is associated with growth failure.

Blood Bactericidal Activity↗
PubMed1981

[Granulocytic function in children with selective IGA deficiency and recurrent infections: demonstration of altered chemotaxis].

Some parameters of neutrophil function (NBT reduction, bactericidal activity, chemotaxis) have been examined in 15 children with selective IgA deficiency and recurrent infections of respiratory and/or intestinal tract. In no case a defect in NBT reduction was observed. Mean results of bactericidal activity were normal, but in one child bacterial killing was lower than 2 SD of normal values. In 7 out 12 of patients a severe defect in cellular chemotaxis was proved, and in 1 a poor chemotactic activity of the serum was observed. Correlations between the defect in neutrophil chemotaxis and selective IgA deficiency are discussed.

Blood Bactericidal Activity↗