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Summary: Previous studies have shown that platelets exhibit a H2O2 producing, NADH-dependent system that is activated by interaction with particulate material. Current evidence suggests that this system could be critically involved in the generation of chemotactic factor(s). In the present studies, chemotactic activity for polymorphonuclear leukocytes of supernatants derived from zymosan-stimulated human platelets has been evaluated using an agarose gel technique. Supernatants of opsonized zymosan-stimulated platelets showed significant chemotactic activity (migration index = 300 ± 50), in comparison with supernatants prepared from platelet suspensions stimulated with nonopsonized-zymosan (migration index = 15 ± 15) or resting platelet supernatants (migration index = 15 ± 15). Furthermore, a marked increase in chemotactic activity of the opsonized zymosan-treated platelet supernatants was demonstrated after the additon of NADH (migration index = 525 ± 100). The inclusion of specific inhibitors of the cycloxygenase and lipoxygenase pathways resulted in a marked reduction of chemotactic activity, which was restored in the presence of NADH. Further, the addition of superoxide dismutase completely abolished the chemotactic response induced by NADH. These data suggest that platelets are the source of chemotactic factor(s) derived from the activation of a superoxide generating system.

Acrodermatitis Enteropathica(AE), a rare autosomal recessive disorder is characterized by onset before age 1,failure to thrive diarrhea,alopecia,a vesciculobullous eruption around the mouth, anus hands and feet,high susceptibility to infection.The disorder is related to zinc metabolism and low level of plasma zinc have been reported in these patients.A cellular chemotaxis defect zinc dependent has been demonstrated by Weston et al.(Arch.Dermatol. 1977).We have investigated a 5 month old infant who developed the clinical features of AE when weaned from breast milk to cow's milk. Serum zinc concentration were 50μg%.The evaluation of the immune system revealed a normal T and B lymphocyte functions but a severe defect of neutrophil chemotaxis was present.The therapy with zinc sulphate 40mg/os/daily induced a dramatical clinical improvement, the restoration of plasma zinc level and the correction of neutrophil cellular chemotaxis.When the zinc therapy was discontinued cellular chemotaxis decreased(Tab.).

ConA and Histamine activated T cells and their crude sups were assayed for suppressive activity on IgE producing U-266 cell line.Detectable and comparable degree of suppression was obtained using either the co-culture or the supernatant protocols.Separation of the effector population into T4+ and T8+ subsets showed the most effective cells being in the T8+ fraction.Control experiments demonstrated that the IgE down regulation was select since no impairement of a non-immunoglobulin protein such as beta2 microglobulin occurred in the presence of T cell or T cell derived factors. In addition, a number of HTLV I transformed T cell lines were explored for capacity of producing factors able to suppress IgE synthesis in the U-266 cell line and 4 out of 25 cell lines tested could be shown to do this in a constitutive manner. Kinetic studies suggest the inhibition occurring at a transcriptional level. The data indicate the T cell-myeloma system as an interesting model to better define regulation of IgE in Humans.

We have treated 23 children aged 6-15 years affected with agammaglo bulinemia or severe hypogammaglobulinemia with IgG serum levels lower than 100 mg% with IV gammaglobulin (Sandoglobin) at the dose of 150-300 mg/kg/3 weeks for two years. The children suffered from severe and recurrent bacterial infections, mainly of the respiratory tract, leading to chronic tissue damage. The had been previously treated with IM gammaglobulins (0,8 ml/kg/3 weeks), but their serum IgG values were never higher than 75 mg%. The results are summarized in the following Table, in which we have compared the data of the follow-up after two years of treatment with IV gammaglobulin and of the follow-up after a one-year course of IM gammaglobulins. Minor adverse reactions (chills, fever, abdominal pain) were observed only in some children and in the first months of therapy. These data demonstrate that IV administered serum immune globulin therapy dramatically reduced infectious diseases in children with immunodeficiencies.

Recent experimental and clinical researches suggest that thymic humoral factors may be helpful in restoring immune balance in patients with T-cell defect. A calf thymic extract (TPl Serono Institute) induces the maturation of pre-T-cells and increases the capacity of mature T-cells to respond to antigen. Our previous investigations have shown a maturation of pre-T-cells in vitro,a clinical and immunological recostitution in primary T-cell defect after TP1 therapy.Now we have treated 10 children suffering from T-cell defect associated with severe viral infections,with TP1 75 mg/m2/day for a week and at the same dose twice a week for 3 months. Our results showed an increase of E-rosette forming cells after incubation of peripheral blood lymphocytes with TP1 in vitro and after 1 month of treatment in vivo (fig) Furthermore, during the therapy, a complete recovery of viral infections was observed in all subjects.

Expression of polymorphic MHC class II antigens by accessory monocytic cells is required for the ability to present antigens to T cells and to regulate immune reactivity.In man it has been shown that HLA-D contains at least three well defined loci:DR,DS(DC)and SB.We demonstrate that fresh isolated human blood monocytes evaluated by two color FACS analysis with respect to the monocyte antigen M3 and the HLA-D determinants DC,DR may be divided into two major subpopulations: M3+ DR+ DC− and M3+ DR+DC+.The HL-60 promyelocitic cell line induced either by 1, 25(OH)2D3 or by PMA acquire phenotypically distinct surface markers with respect to M3 and DR,DC antigens.Indeed 1,25(OH)2D3 preferentially induce the expression of an M3+ DR+DC−monocyte population whereas PMA preferentially induce a population co-expressing the three antigens (M3+ DR+DC+).The evaluation of the ability of the induced cells to perform ADCC showed that 1,25(OH)2D3, in contrast to PMA, induce an increasing killing activity. These data suggest that 1,25(OH)2D3 and PMA induce the differentiation of phenotypically and functional different monocyte subpopulations. The evaluation of ADCC of cell sorted M3+DR+DC− 1,25(OH)2D3 induced HL-60, in comparison to the M3− population showed that the ADCC is mainly restricted to the M3+DR+DC− subset.

Essential fatty acids (EFA) are important components of phospholipids of cell membrane and are precursors of inflammatory mediators such as prostaglandins leukotrienes. Hansen first reported (1937) a decrease in plasmatic levels of EFA in subjects with atopic dermatitis (AD) and a clinical improvement with dietary-supplementation of fresh lard or maze oil. The studies on ecosanoids metabolism have recently focused the attention on the EFA levels in different diseases. We previously showed a correlation between the decrease of C20:4 and C20:3 in PBL of 30 children with moderate to severe AD. In order to investigate the role of EFA in the development of atopic diseases we undertook a prospective study on 34 cord blood lymphocytes of infants “at risk” for atopic diseases and 30 cord blood control. The analyses were performed by a combined technique of thin layer chromatography and gas chromatography on capillary column. The preliminary results showed a significant decrease in C 20;4, C 20:3, and in the ratio polyunsaturated/saturated EFA in the cord blood lymphocytes of infants “at risk” in respect to control group. No relation was found between high (>0.8 U/ml) IgE in cord sera and decreased levels of arachidonic acid in lymphocytes. The clinical and immunological followup of “at risk” infants can clarify if EFA changes may be a basic and predictive feature of AD.

Peripheral blood mononuclear cells(PBMC) from 8 children with AT were evaluated with a panel of Monoclonal Antibodies(Mo.Ab)(OK-T,Ortho Diagnostic System)directed against T-cell subsets and for their in vitro functions in a pokeweed mitogen-induced immunoglobulin(Ig)biosynthesis assay.All the patients had a significantly reduced proportion of cells identified by Mo.Ab to a subpopulation of T lymphocytes with helper activity(OKT4)and produced low amounts or no IgA and IgG in vitro.Ig biosynthesis was increased by the addition of normal x-irradiated PBMC in one of 3 patients.Two patients had increased proportion of suppressor T cells (OKT8),and their cells were able to suppress Ig biosynthesis(IgM=91%;IgG=55%;IgA=80% of suppression)by PBMC untreated from normal donors.A great reduction or absence of Interferon(IFN)production after induction with either Staphylococcal enterotoxin B or galactose-oxidase was showed,while normal values of α IFN were obtained.In one case we observed a low expression of Tac antigen and absent IL2 secretion.The percentage of HNK-1+ mononuclear cells was normal as well as the NK lytic activity.