T-Cell immune activation in children with vertically transmitted hepatitis C virus infection.

Little is known concerning the clinical features, the histological outcome, and the effects on the maturation of immune system of children with vertically-transmitted hepatitis C virus (HCV) infection. Specifically, no data are available on the peripheral distribution of T-cell subsets. The frequency of naive and memory cells, activated T cells, and cytokine-producing T cells was analyzed in nine HCV-infected children born to HCV-positive mothers. In HCV-infected children, the distribution of naive and memory cells was not significantly altered in the CD4 subset whereas within the CD8 subset, an increase of memory and a decrease of naive cells was observed. The frequency of HLA-DR-positive and Fas-positive T cells was increased in HCV-infected children in both CD4 and CD8 subsets. The distribution of Fas-expressing T cells was directly related to that of HLA-DR cells and inversely related to the frequency of naive T cells. In regard with cytokine production we found increased levels of both CD4 and CD8 interferon-gamma (IFN-gamma)-producing cells whereas no difference in the percentage of interleukin-2 (IL-2)-producing T cells was observed. No meaningful correlation was observed between individual T cell subsets and ALT levels or HCV viral load. In conclusion, our results indicate an increased T-cell activation and a shift to a T(H)1 pattern of cytokine production in children with vertically transmitted HCV infection. The cause of this kind of immune response could reside in the persistent antigenic stimulation by chronic HCV infection.

Immunogenicity of an acellular pertussis vaccine composed of genetically inactivated pertussis toxin combined with filamentous hemagglutinin and pertactin in infants and children.

We studied the immunogenicity of an acellular pertussis vaccine composed of genetically detoxified pertussis toxin (PT-9K/129G), filamentous haemagglutinin, and a 69-kilodalton protein, pertactin, in 30 children aged 12 to 24 months and in 80 infants aged 2 to 4 months. A significant increase of the neutralizing titer and of the titers against pertussis toxin, filamentous hemagglutinin, and pertactin, as determined by enzyme-linked immunosorbent assay, was achieved after three doses of vaccine in all the children; a significant increase of these antibody titers was obtained in 100%, 96.1%, 93.5%, and 98.7% of the infants, respectively.

Acellular pertussis vaccine composed of genetically inactivated pertussis toxin: safety and immunogenicity in 12- to 24- and 2- to 4-month-old children.

To determine whether a nontoxic derivative of pertussis toxin obtained by recombinant DNA technology, PT-9K/129G, is a good candidate for a new pertussis vaccine, we examined the safety and the immunogenicity in children of a vaccine containing 15 micrograms of PT-9K/129G protein and 0.5 mg of aluminum hydroxide per dose. Fifty-three children 12 to 24 months of age and 21 infants aged 2 to 4 months were injected with two and three doses, respectively. The vaccine did not induce significant local or systemic reactions and elicited an increase of antibody titer in more than 98% of the children. The geometric mean of the toxin-neutralizing titers increased after each dose and was 85 units in children given two doses and 196 units in those given three doses. Two children who had detectable antibody levels before the first immunization had a high response (greater than 320 units) to the first vaccine dose. The findings suggest that PT-9K/129G is a promising antigen to be included in the development of acellular pertussis vaccines.

[Methemoglobinemia and acidosis during the first week of life]. / Metaemoglobinemia ed acidosi durante la prima settimana di vita.

Recently attention has been called on the possible role of acidosis in the increased methemoglobin formation in the erythrocyte of newborn infant. In the present paper the relations between acidosis and methemoglobin content in the red cells of newborns has been investigated. No significant differences between the percent of methemoglobin in the normal newborns and percent of methemoglobin in the newborns with acidosis has been found. In addition, no correlations between the base excess and percent of methemoglobin has been observed. On the contrary, two newborns with low glucose-6-phosphate dehydrogenase activity demonstrated a significantly increased methemoglobin content in their red cells. The results of our study do not confirm a key role of acidosis in the mechanism of methemoglobin formation in the neonate. It is likely than impairment of red cell metabolism should be the main factor in the formation of methemoglobin in the first days of life.

Response to B and T cell mitogens and surface markers in human fetal lymphoid tissues.

We studied the responses to phytohemagglutinin (PHA) and Staphylococcus aureus protein A (SpA), a B cell mitogen, and surface markers in the thymus, liver and spleen of 5 human fetuses ageing from 12 to 26 gestational wk and in cord blood lymhocytes of 9 newborns. Sheep rosette forming cells appeared in all 3 organs at 17 wk; mIgM+ cells were detected in liver and spleen at 24 and 17 wk respectively. SpA and PHA stimulated the cells of all the 5 liver and all the 3 spleen samples examined. Thymus cells responded to PHA as early as the 17th wk and showed a progressive increase in stimulation indexes. An unexpected observation was the response of the thymus cells of a 15-wk fetus to SpA; this finding is discussed in the text. Cord blood lymphocytes gave results comparable to those found in normal adults.

Auto-immune haemolytic anaemia in childhood: follow-up in 29 cases.

We describe 29 children with auto-immune haemolytic anaemia (AIHA). The patients could be followed up for long periods of time. The auto-antibodies, responsible for the AIHA, are described as well as the associated diseases that could be diagnosed, the clinical course and some clinical aspects of special importance. Finally, the treatment given to these patients and its results are discussed.

Maternofetal transfusion during delivery and sensitization of the newborn against the rhesus D-antigen.

The presence of maternal cells was determined in a blood sample of 86 rhesus D-negative newborns with a rhesus D-positive mother using the 'minor cell population technique' of Jones and Silver. Maternal cells were found in 43 percent of the samples, irrespective of ABO incompatibility. Anti-D antibodies were detected in 22.2 percent of serum samples from 53 children taken at 6-10 months after birth. There was no correlation between the presence of anti-D and the results of the minor cell population technique at birth. The results are discussed.