Immunogenicity of meningococcal polysaccharide ACWY vaccine in primary immunized or revaccinated adults.

Meningococcal polysaccharide (Men-Ps) vaccine immunogenicity following either primary immunization or revaccination in adults was evaluated. The study population consisted of subjects who have received tetravalent Men-Ps vaccine once (group 1) or at least twice, with a 2-6 dose range (group 2). Human leucocyte antigen (HLA)-typing was performed by polymerase chain reaction and specific immunoglobulin (Ig)G was measured by enzyme-linked immunosorbent assay. Nine months post-immunization, the percentages of individuals with levels of anti-Men-Ps IgG ≥ 2 µg/ml were comparable in both groups, with the exception of anti-Men-PsW135 IgG, which were significantly higher in group 2. The percentage of subjects doubling IgG levels at 9 months was significantly higher in group 1. The high baseline anti-Men-Ps antibody levels negatively influenced the response to revaccination, suggesting a feedback control of specific IgG. The calculated durability of anti-Men-Ps IgG was 2·5-4·5 years, depending on the Men-Ps, following a single vaccine dose. No interference by other vaccinations nor HLA alleles association with immune response were observed. This study confirms that Men-Ps vaccine in adults is immunogenic, even when administered repeatedly, and underlines the vaccine suitability for large-scale adult immunization programmes that the higher costs of conjugate vaccines may limit in developing countries.

Safety and immunogenicity of co-administered MF59-adjuvanted 2009 pandemic and plain 2009-10 seasonal influenza vaccines in rheumatoid arthritis patients on biologicals.

Rheumatoid arthritis (RA) patients under immunosuppressive therapy are particularly susceptible to infections, mainly of the respiratory tract, thus vaccination may represent a strategy to reduce their incidence in this vulnerable population. In the 2009-10 influenza season, the safety and immunogenicity of co-administered non-adjuvanted seasonal and MF59-adjuvanted pandemic influenza vaccines were evaluated in this study in 30 RA patients under therapy with anti-tumour necrosis factor (TNF)-α agents or Abatacept and in 13 healthy controls (HC). Patients and HC underwent clinical and laboratory evaluation before (T0), 1 (T1) and 6 months (T2) after vaccinations. No severe adverse reactions, but a significant increase in total mild side effects in patients versus HC were observed. Both influenza vaccines fulfilled the three criteria of the Committee for Proprietary Medicinal Products (CPMP). Seroconversion rate for any viral strain in patients and HC was, respectively, 68 versus 45 for H1-A/Brisbane/59/07, 72 versus 81 for H3-A/Brisbane/10/07, 68 versus 54 for B/Brisbane/60/08 and 81 versus 54 for A/California/7/2009. A slight increase in activated interferon (IFN)-γ-, TNF-α- or interleukin (IL)-17A-secreting T cells at T1 compared to T0, followed by a reduction at T2 in both patients and HC, was registered. In conclusion, simultaneous administration of adjuvanted pandemic and non-adjuvanted seasonal influenza vaccines is safe and highly immunogenic. The largely overlapping results between patients and HC, in terms of antibody response and cytokine-producing T cells, may represent further evidence for vaccine safety and immunogenicity in RA patients on biologicals.

Influenza vaccine administration in rheumatoid arthritis patients under treatment with TNFalpha blockers: safety and immunogenicity.

Twenty-eight patients with low-moderate, stable rheumatoid arthritis (RA), under treatment with tumor necrosis factor (TNF) alpha blockers, were immunized at least once with non-adjuvanted trivalent influenza vaccine during three consecutive influenza seasons. Antibodies toward A influenza antigens significantly increased and reached protective levels, still detectable 6 months after vaccination, both in RA patients and healthy controls. Response to B antigen instead was only observed from the second year for healthy controls and in the third year for patients. No significant difference in disease activity and anti-nuclear antibodies was observed as a consequence of vaccine administration, whereas T regulatory cells showed a significant increase 30 days after immunization in RA patients. This study confirms safety of influenza vaccine administration in RA patients treated with TNFalpha blockers. The cohort follow-up revealed the overcoming of poor B vaccine antigen immunogenicity via repeated vaccinations. Finally, protective antibody response was still observed 6 months after vaccination.

Unilineage monocytopoiesis in hematopoietic progenitor culture: switching cytokine treatment at all Mo developmental stages induces differentiation into dendritic cells.

We have developed a new culture system whereby human hematopoietic progenitors purified from adult peripheral blood extensively proliferate and gradually differentiate into >95% pure monocytic (Mo) cells. At all developmental stages treatment with interleukin (IL)-4+granulocyte-macrophage colony-stimulating factor or IL-4+c-Kit-ligand+FLT-3 ligand switched the Mo precursors into dendritic cells (DCs). The switching capacity decreased only at the end of the culture, when most Mo cells matured to macrophages. Moreover, the Mo precursors were highly susceptible to transduction with lentiviral vectors: once switched to DCs, they maintained the transgene expression, as well as the phenotype and function of the DC lineage. Our results provide new insight into the potential role of the Mo lineage as a reservoir of DCs in vivo. Furthermore, the methodology for transduction of Mo precursors provides a tool to generate genetically modified, normally functioning DCs potentially useful for immunotherapy.

Two brc-abl junction peptides bind HLA-A3 molecules and allow specific induction of human cytotoxic T lymphocytes.

Intracellular processing of the products of the bcr-abl junction region in CML Philadelphia chromosomes would generate novel peptides which, if they are capable of binding to HLA-class I molecules, would be potential targets of a cytotoxic T cell response. The 18 nonamers corresponding to the b2-a2 and b3-a2 fusions and differing from the parental bcr and abl sequences for at least one amino acid have been synthesized and tested for binding with HLA class I alpha chain preparations from HLA-homozygous B lymphoblastoid cell lines. Two peptides derived from the b3-a2 junction bound to HLA-A3 and elicited detectable specific CTL responses in vitro. The binding affinity of one of the two peptides could be increased by appropriate substitutions of the anchor residues with those of the known HLA-A3 anchor motifs. More important, the modified peptide had increased capacity to prime a specific CTL response in vitro. The interaction with HLA-A3 of these two peptides and their substitution derivatives seems to be promising for target trials aimed at eliciting a specific CD8 T cell response against CML.

The interaction of human dendritic cells with yeast and germ-tube forms of Candida albicans leads to efficient fungal processing, dendritic cell maturation, and acquisition of a Th1 response-promoting function.

T helper cell type 1 (Th1) cell-mediated immunity plays a critical role in protection against the opportunistic pathogen Candida albicans. Virulence of the fungus is closely associated with its ability to form germ-tubes (GT), the early phase of the dimorphic transition from the commensal yeast (Y) to the more invasive hyphal (H) form. In this study, we examined the functional outcome of the interaction of Y or GT forms with human dendritic cells (DCs), professional antigen-presenting cells, which are pivotal for initiation and modulation of T cell responses. DCs phagocytosed and killed Y and GT cells with a comparable efficiency, becoming able to trigger strong proliferative responses by Candida-specific, autologous T cell clones. Both fungal forms induced DC maturation, as indicated by up-regulation of CD83, CD80, CD86, CD40, and major histocompatibility complex classes I and II surface antigens. Chemokine receptors were also modulated in Candida-DCs, which showed increased CCR7/CXCR4 and decreased CCR5 expression. Y- and GT-activated DCs differed in the pattern of cytokine expression. In particular, GT cells, in common with fully differentiated H cells, induced significantly more elevated levels of interleukin (IL)-10 than Y cells. Nevertheless, Y-, GT-, or H-pulsed DCs secreted comparable amounts of IL-12p70. In addition, irrespective of the fungal form triggering DC activation, Candida-DCs acquired the ability to prime naive T lymphocytes with a defined Th1 phenotype. Overall, our findings highlight the induction of substantially similar functional patterns in human DCs encountering the different forms of growth of C. albicans, both seemingly activating the Th1-type immunity which is characteristic of the healthy human subjects, naturally immunized and protected against the fungus.

Lack of evidence for a superantigen in lymphocytes from HIV-discordant monozygotic twins.

OBJECTIVE: An HIV-associated superantigen (SAg) has been hypothesized. Here we test whether an SAg is functionally detectable in peripheral blood mononuclear cells (PBMC) from monozygotic twins discordant for HIV infection. DESIGN AND METHODS: The V beta selective T-cell depletion found in minor lymphocyte stimulation (Mls)-positive mice is caused by an SAg encoded by the mouse mammary tumour virus. Mls is a locus whose gene product stimulates a mixed lymphocyte reaction (MLR) in mice strains identical at the major histocompatibility complex locus. If an SAg is present in PBMC and/or sorted CD4+ cells from one HIV-infected monozygotic twin, it would stimulate PBMC from the corresponding healthy monozygotic twin in an MLR. In addition, if an SAg causes V beta-selective T-cell depletion in AIDS patients, a differential proliferation to a panel of staphylococcal enterotoxins (SE) of T lymphocytes from healthy and HIV-infected monozygotic twins should become measurable. RESULTS: No positive MLR or significant differences in the SE-driven proliferation between the healthy and the HIV-infected twins were observed. CONCLUSIONS: Our results suggest that PBMC from the two HIV-infected twins do not express a functionally detectable SAg.

Spectrotype of anti-gp120 antibodies remains stable during the course of HIV disease.

Human immunodeficiency virus (HIV) infection is characterized by a progressive decline in immune functions. The behavior of B-cell clones specifically engaged in the anti-HIV response could play a relevant role in the pathogenesis of such impairment. The spectrotype observed on isoelectric focusing and reverse blotting after antigen challenge is the serum image of antigen-specific B-cell activity and may provide some insight into Ag-dependent B-cell clone recruitment. In this study, we examined the spectrotype of anti-gp120 antibodies in a group of sera from 56 HIV-infected patients, belonging to groups II, III, and IV of the Centers for Disease Control classification, as well as in a group of 31 sera from 12 patients in a 21-month follow-up evaluation (range 7-36 months). All tested sera were positive for gp120 antibodies on Western blot. In the first group of 56 HIV-infected subjects, only 19 displayed well-focused banding patterns. Among these, the spectrotype was found to be consistently oligoclonal, thus confirming clonal restriction of anti-gp120 antibodies previously described by other investigators. No correlation could be established between a particular spectrotype and phase of the disease. The follow-up evaluation in the second group of 31 sera revealed the tendency in each patient to maintain the same spectrotype throughout the course of the disease. These findings confirm clonal restriction of anti-gp120 antibodies in HIV infection and suggest that the number of B-cell clones recruited in the anti-gp120 response remains stable over the course of the disease, at least in the time range explored by us.

Infection of circulating and liver infiltrating T cells by hepatitis C virus of different subtypes.

Hepatitis C virus (HCV) infection display a very high rate of progression to chronicity and, like many other viruses causing persistent infections, it displays a tropism for the cells of the immune system. Peripheral blood mononuclear cells (PBMCs) from 21 HCV chronic carriers and long-term T cell clones derived from circulating or liver infiltrating T lymphocytes were tested by cDNA "nested" PCR for positive and negative strand HCV-RNA. The presence of HCV genomes in PBMCs is a frequent, although not constant, finding and can be accompanied by active viral replication, as suggested by the coexistence of negative strand HCV-RNA. Infected T cells are more represented in livers than in periphery, as indicated by comparing HCV-RNA detection in T cell clones isolated from both the compartments. Sequencing of viral genomes present in PBMCs and liver infiltrating lymphocytes showed that all the three major HCV genotypes present in our population of chronic carriers can infect lymphoid cells. Although each clonal population of T cells is infected by a single strain of HCV, in the same patient lymphoid cells can harbor different viral populations, different from those circulating at that moment in the serum.

Autoimmune T-cell response to the CD4 molecule in HIV-infected patients.

In a previous study, we demonstrated that by downregulating plasma membrane CD4 and increasing its processing, human immunodeficiency (HIV)-1-gp120 unveils hidden CD4 epitopes, inducing an in vitro anti-CD4-specific T-cell response. We report herein that this mechanism may potentially have important implications in HIV immunopathogenesis, because it could take part in the severe depletion of CD4+ cells that characterizes acquired immune deficiency syndrome (AIDS) and be related to disease progression. Freshly isolated peripheral blood lymphocytes (PBMC) from about 1/4 of a conspicuous cohort of HIV-infected patients responded to CD4 and this response was correlated with beta2-microglobulin levels, widely recognized as marker for progression of HIV infection. Moreover, we provide evidence that a CD4-specific T cell priming can occur in vivo, following a gp120 or anti-CD4 monoclonal antibody (mAb)-mediated CD4 molecule downregulation on antigen-presenting cells (APC). To our knowledge, this is the first study indicating that an autoimmune T-cell response is linked to HIV infection and that it could have an important impact on the immunopathogenesis of this disease.

Isoelectricfocusing and reverse blotting as a diagnostic tool in pediatric HIV infection.

BACKGROUND: Early diagnosis of perinatally acquired HIV-infection is based on either direct HIV detection--by means of viral culture and/or PCR--or anti-HIV antibody detection. However, due to the passive, transplacental passage of maternal immunoglobulin G, antibody detection is nor reliable until 15-18 months of age. In this regard, clonotypic analysis of specific antibodies performed by isoelectricfocusing and reverse blotting (IEF-RB) can be very helpful, as it recognizes possibly different patterns between mother and infant. OBJECTIVES: We used IEF-RB in order to analyze the kinetics of development of anti-HIV antibodies in infants born to seropositive mothers. STUDY DESIGN: Sera from ten mother/infant pairs (all mothers were HIV-infected) were retrospectively analyzed in order to detect different patterns, between mother and infant, in anti-gp120 V3-loop clonotype. RESULTS: We diagnosed the real HIV status of the examined infants no later than month 6 and in one case as early as month 2. CONCLUSIONS: Considering the small size of sample number, these data are preliminary and should be confirmed by larger scale studies. However, they show IEF-RB, when applied to infants born to seropositive mothers, may be useful in evaluating the infants' dynamics of anti-HIV humoral immune response.

Spectrotypic analysis of antibodies to Helicobacter pylori in patients with antral gastritis and duodenal ulcer.

AIMS: To investigate the anti Helicobacter pylori (H pylori) spectrotype associated with (a) antral gastritis and duodenal ulcer; (b) the H pylori eradicating treatment. METHODS: Spectrotypic analysis was performed by isoelectric focusing and reverse blotting (IEFRB) in a cross sectional study on sera from 70 patients with antral gastritis and duodenal ulcer. In addition, a longitudinal study was performed on 40 of these patients (20 with antral gastritis and 20 with duodenal ulcer) who underwent eradicating treatment. RESULTS: The cross sectional study showed that the oligoclonal spectrotype was present in 74% of antral gastritis patients and in 85% of duodenal ulcer patients. In only a minority of subjects (23% with antral gastritis and 3% with duodenal ulcer) was a polyclonal spectrotype observed. The longitudinal study showed a reduction in the intensity of the spectrotypic bands in 5/10 antral gastritis patients with eradicated H pylori as opposed to only 2/10 patients without eradication. A reduction was also observed in 6/11 eradicated v 0/9 non-eradicated patients with duodenal ulcer. Collectively, a reduction in the spectrotype was observed in 11/21 patients (52%) who--independently of the disease--underwent H pylori eradication, as opposed to 2/19 of the non-responder patients (10.5%). The polyclonal spectrotype was found exclusively in four patients with antral gastritis, all belonging to the group without eradication of H pylori after eradicating treatment. CONCLUSIONS: The anti H pylori oligoclonal spectrotype is the most common pattern observed in patients with antral gastritis and duodenal ulcer. After H pylori eradicating treatment the spectrotype does not change qualitatively, but the polyclonal pattern seems to be predictive of a poor response to eradication.

Rapidly progressive periodontitis. Neutrophil chemotaxis inhibitory factors associated with the presence of Bacteroides gingivalis in crevicular fluid.

In the last few years several bacteriological and immunological studies have investigated the role of bacteria and immune defects in order to establish the etiopathogenesis of periodontal disease. With regard to the immune system, a defect in polymorphonuclear neutrophil (PMN) chemotaxis has been frequently reported in patients with rapidly progressive or juvenile periodontitis. The purpose of this study was to investigate in five patients with rapidly progressive periodontitis and normal chemotaxis of peripheral blood PMNs the presence of chemotaxis inhibitory activity in gingival fluid and to relate such activity to three types of bacteria, often involved in rapidly evolving periodontal lesions, that are able to inhibit in vitro PMN chemotaxis: Bacteroides gingivalis, Capnocytophaga sp., and Actinobacillus actinomycetemcomitans. We found strong inhibitory activity in three of these patients. This activity was consistently associated with the finding of B. gingivalis in gingival pockets. We cannot rule out, however, that other substances not of bacterial origin could be responsible for such inhibitory activity. The strict association with B. gingivalis, known to secrete blocking factors, is highly suggestive, although this data must be considered preliminary.

Cord blood mononuclear leukocytes of neonates at risk of atopy have a deficiency of arachidonic acid.

Essential fatty acids and their delta-6-desaturated derivatives are major components of cellular membrane phospholipids, contributing to their stability and functions. They are also precursors of inflammation mediators such as prostaglandins and leukotrienes, and are involved in cellular immunoregulation. Recent studies have stressed the importance of essential fatty acids in various diseases. Patients with atopic dermatitis have altered essential fatty acids levels in plasma and a clinical improvement has been shown after oral administration of essential fatty acids. The aim of our study was to investigate the distribution of essential fatty acids in the membranes of cord blood mononuclear leukocytes of newborns at risk of atopy, and to correlate the levels of essential fatty acids at birth with total IgE values and with the onset of atopic disease. Newborns at risk of atopic disease have a significant reduction in arachidonic acid in the membranes of cord blood mononuclear leukocytes. Our data show a significant decrease in arachidonic acid in neonates at risk of atopy, suggesting that the abnormality of essential fatty acids is a primary phenomenon associated with atopic status.

Antibody classes & subclasses induced by mucosal immunization of mice with Streptococcus pyogenes M6 protein & oligodeoxynucleotides containing CpG motifs.

BACKGROUND & OBJECTIVES: Type-specific antibodies against M protein are critical for human protection as they enhance phagocytosis and are protective. An ideal vaccine for the protection against Streptococcus pyogenes would warrant mucosal immunity, but mucosally administered M-protein has been shown to be poorly immunogenic in animals. We used a recombinant M type 6 protein to immunize mice in the presence of synthetic oligodeoxynucleotides containing CpG motifs (immunostimulatory sequences: ISS) or cholera toxin (CT) to explore its possible usage in a mucosal vaccine. METHODS: Mice were immunized by intranasal (in) or intradermal (id) administration with four doses at weekly intervals of M6-protein (10 microg/mouse) with or without adjuvant (ISS, 10 microg/mouse or CT, 0,5 microg/mouse). M6 specific antibodies were measured by enzyme linked immunosorbent assay using class and subclass specific monoclonal antibodies. RESULTS: The use of ISS induced an impressive anti M-protein serum IgG response but when id administered was not detectable in the absence of adjuvant. When used in, M-protein in the presence of both ISS and CT induced anti M-protein IgA in the bronchoalveolar lavage, as well as specific IgG in the serum. IgG were able to react with serotype M6 strains of S. pyogenes. The level of antibodies obtained by immunizing mice in with M-protein and CT was higher in comparison to M-protein and ISS. The analysis of anti-M protein specific IgG subclasses showed high levels of IgG1, IgG2a and IgG2b, and low levels of IgG3 when ISS were used as adjuvant. Thus, in the presence of ISS, the ratio IgG2a/IgG1 and (IgG2a+IgG3)/IgG1 >1 indicated a type 1-like response obtained both in mucosally or systemically vaccinated mice. INTERPRETATION & CONCLUSION: Our study offers a reproducible model of anti-M protein vaccination that could be applied to test new antigenic formulations to induce an anti-group A Streptococcus (GAS) vaccination suitable for protection against the different diseases caused by this bacterium.

Flow cytometric analysis of cell function: cytosolic Ca++ modulation in human polymorphonuclear leukocytes and T lymphocytes.

Flow cytometry and fluo-3/AM have been used to track cytosolic Ca++ modulation in human polymorphonuclear leukocytes (PMN) and T lymphocytes. The chemotactic peptide N-formylmethionyl-phenylalanine (FMLP) but not the phorbol ester PMA induced cytosolic Ca++ modulation in PMN along with forward and side scatter modification. PMA inhibited FMLP activity when preincubated with PMN. T lymphocytes were antigen specific T cell clones and were stimulated with various amounts of diverse superantigens or PHA. Data show that superantigens can induce either activation or anergy depending on culture conditions. The biological significance of these data are discussed.

The effects of hypobaric hypoxia on specific B cell responses following immunization in mice and humans.

In order to get some insight on the physiology of the immune system during prolonged exposure to hypobaric hypoxia we evaluated the effects of high altitude on the in vivo immune response to a T-independent antigen. A group of 18 men who participated in a scientific project EV-K2-CNR to Mount Poumori, Nepal for 20 d at 4,930 m (16,174 ft) were immunized with a single subcutaneous dose of antimeningococcal vaccine Menpovax A + C (Sclavo) containing 50 micrograms of polysaccharide A (PsA) and 50 micrograms of polysaccharide C (PsC) of N. meningitidis. A group of 18 men of comparable age were vaccinated at sea level. Antibody titers against both polysaccharides were determined by enzyme-linked immunosorbent assay (ELISA) before and 18 d after vaccination. All subjects examined developed a good antibody response and no statistically significant differences were observed between the two groups. Spectrotypic analysis of antibody response to PsC was also performed by isoelectric focusing. No qualitative differences in the antibody response to PsC were found in the hypoxia-exposed group with respect to the control group. A group of 10 BALB/c inbred mice were kept in a hypobaric chamber at 5,500 m (18,000 ft) for 30 d. After 10 d, the mice were vaccinated with 1 micrograms of Menpovax A + C. Anti-PsA and anti-PsC antibodies were quantified by ELISA in sera collected at day 0 and 30. A control group of 10 mice of the same strain underwent the same study protocol but at sea level. Both groups developed a good antibody response to both polysaccharides and no significant differences were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of HBV markers in the Italian Armed Forces and HBV vaccination.

Hepatitis B (HBV) markers were studied in 710 subjects who had been on active duty for over 6 months in the Italian Armed Forces. The prevalence of HBsAg carriers was found to be 4.4%, while 31.6% of the subjects were positive for various HBV antibodies. A total of 137 subjects were vaccinated with an anti-HBV vaccine (HB-VAX, MSD). The percentages of non-responders and low responders were 13.86% and 13.14%, respectively. Boosters administered 3 months post-vaccination schedule, with or without immunostimulatory treatment, resulted in seroconversions and/or substantial increases in HBsAb levels in 50% of these subjects.

Cross sectional retrospective study of prevalence of atopy among Italian military students with antibodies against hepatitis A virus.

OBJECTIVE: To investigate the working hypothesis that common infections occurring early in life prevent atopy. DESIGN: Cross sectional, retrospective study of young Italian men with results for hepatitis A serology and atopy. SETTING: Air force school of military students in Caserta, Italy. SUBJECTS: 1659 male students aged 17-24, most of whom (90%) were from central and southern Italy. MAIN OUTCOME MEASURES: Skin sensitisation and specific IgE antibodies to locally relevant airborne allergens; diagnosis of respiratory allergy (asthma or rhinitis, or both); hepatitis A seropositivity. RESULTS: 443 of the 1659 subjects (26.7%) were positive for hepatitis A virus antibody. Atopy was less common among seropositive than seronegative subjects according to skin sensitization (weal reaction > or = 3 mm) to one or more allergens (21.9% (97/443) v 30.2% (367/1216), P < 0.001); polysensitisation (sensitive to three or more allergens) (2.7% (12/443) v 6.4% (78/1216), P < 0.01); high specific IgF concentration (9.7% (43/443) v 18.4% (224/1216), P < 0.00005); and lifetime prevalence of allergic rhinitis or asthma, or both (8.4% (37/443) v 16.7% (203/1216), P < 0.001). Hepatitis A seropositivity remained inversely associated with atopy after adjusting for father's education, the number of older siblings, and the area of residence (based on the number of inhabitants). The prevalence of atopy was constantly low among seropositive subjects, whatever the number of older siblings; by contrast, it increased with a decreasing number of older siblings among seronegative subjects. CONCLUSION: Indirect but important evidence is added to the working hypothesis as common infections acquired early in life because of the presence of many older siblings (among seronegative subjects) or because of unhygienic living conditions (among seropositive subjects) may have reduced the risk of developing atopy.

[The prevention of allergic diseases in 174 children "at risk" for atopy]. / Prevenzione delle malattie allergiche in 174 bambini "a rischio" per atopia.

Recent studies have demonstrated that it is possible to reduce allergic diseases in subjects "at risk" for atopy through the adoption of particular dietetic-environmental manipulations in the first few months of life. We have followed-up prospectively 174 infants, children and/or brothers of atopics, born at San Giovanni Calibita Hospital of Rome. In all cases, exclusive breast feeding for the first 6 months of life was recommended, with integration/replacement with soy milk (Isomil, Abbott), delayed weaning beyond the 6th month of life and rigorous hygienic environmental manipulation. The low prevalence of atopic disease (10%) and the absence of serious allergic manifestations in this "at risk" population confirms the advantage of such preventive programs.