Human aging is associated with immunosenescence, a process characterized by alterations in numerical and functional features of immune system components. Dendritic cells (DCs) are the main antigen-presenting cells, playing a pivotal role in adaptive and innate immunity. Therefore, we investigated the distribution of human circulating DCs throughout the life, in order to contribute to the knowledge of the physiological background underlying the aging of immune system. Cytofluorimetric analysis of peripheral blood samples by all-aged healthy population showed a significant decrease of circulating DCs and of their two main subsets among age. This reduction was limited to the plasmacytoid cell subtype when young and old subjects were analyzed separately. The analysis of circulating Treg cell number in a cohort of the subjects showed a significant reduction with increasing age and a positive significant correlation to myeloid or plasmacytoid absolute numbers. In conclusion, this work provides a large set of data of normal reference values of peripheral blood dendritic cells in healthy population suitable for comparative clinical studies concerning pathological immune dysfunctions.

No abstract

Systemic B. henselae infection represents an important cause of inflammatory hypoechogenic hepatosplenic lesions in children. Serology provides rapid diagnosis, avoiding multiple and invasive investigations. Hepatosplenic involvement can be found even in children with typical cat-scratch disease without apparent systemic manifestations. The frequency of liver and/or splenic involvement in cat-scratch disease is probably underestimated.

We studied the effects of everolimus on the erythroid differentiation of human leukaemic K562 cells and on the cultures of erythroid progenitors derived from the peripheral blood of β-thalassaemia patients. A quantitative real-time reverse-transcription polymerase chain reaction assay was employed for the quantification of the accumulation of globin mRNAs. The results obtained demonstrate that everolimus is a potent inducer of the erythroid differentiation of K562 cells. Erythroid induction is associated with an increase in α- and γ-globin mRNAs. In erythroid precursor cells from 4 β-thalassaemia patients, everolimus stimulated a preferential increase (ranging from 1.8- to 7.2-fold) in γ-globin mRNA. Only minor effects were observed on the expression of α-globin genes. These results, in our opinion, are of interest as this compound is already employed in clinical trials as an anti-rejection agent following kidney transplantation. These data suggest that everolimus warrants further evaluation as a potential therapeutic drug in the treatment of β-thalassaemia.

Few data are available on the seroprevalence of antibodies to Bartonella henselae among children. We retrospectively evaluated the presence of immunoglobulin G and M class antibodies to B. henselae in 508 children living in central Italy who were apparently free of any features suggesting B. henselae infection. We found that B. henselae infection is common among children in central Italy, occurs early in life, is in most cases asymptomatic, and resolves spontaneously.

Abnormalities in the immune system and zinc homeostasis in patients with β-thalassemia major (TM) have been reported. Since zinc ion is essential for the efficiency of the immune system and is required to induce biological activity to thymulin (Zn-FTS), a biochemically defined thymic hormone, we investigated the plasma levels of zinc and both active thymulin (Zn-FTS) and total zinc saturable thymulin (Zn-FTS+FTS) in 18 patients with TM aged between 2 and 31 years and 22 normal controls of the same age. Inhibitory molecules anti-thymulin and the distribution of lymphocyte subsets were also analyzed. Patients with TM presented significantly lowered plasma zinc and thymulin levels when compared to normal subjects. The significant enhancement of the active form of the hormone after zinc addition in vitro suggests that low thymulin values found in TM are due not to a thymic failure in synthesizing and secreting the thymic hormone, but a defect in zinc saturation of the hormone. An impairment of cell subset distribution was also demonstrated. This study shows that zinc and thymulin deficiency contribute to the complex mechanisms underlying immune dysfunction in TM.

Bartonella henselae infection is frequent in Tuscany and probably underdiagnosed due to the high frequency of atypical onset of the clinical manifestations. An accurate clinical history and a reasonably wide use of the serological test may allow a rapid and accurate diagnosis, reassuring the family of the patient and avoiding invasive and expensive diagnostic procedures.

Biochemical evidence of hepatic involvement in Epstein-Barr virus disease is common but clinical features of cholestasis are rare in children. We present three children with cholestasis as a presenting feature of Epstein-Barr virus disease.