Biomedical subjects

M E Rossi

Publications and source records attributed to M E Rossi.

64 records · Page 4Linked to original sources

PubMedDate not supplied

Eosinophil cationic protein (ECP) and tryptase in the nasal lavage fluid (NLF) of children with grass pollen rhinitis: levocabastine effect.

This study was carried out to determine the concentrations of eosinophil cationic protein (ECP) and tryptase in the nasal lavage fluid (NLF) of 24 children (C) with grass pollen rhinitis as well as rhinitis symptoms before and after nasal provocation tests with or without a levocabastine (anti-H1 topical antihistamine) pretreatment. All C were monosensitized to grasses only. Twelve patients (Active Group = AG) were tested with a nasal provocation test with grass pollen (NPT) carried out by the insufflation of increasingly higher doses of an allergenic extract powder, while the other 12 patients (Placebo Group = PG) underwent just a nasal provocation test with lactose (placebo) (NPTp). The prechallenge NLF, obtained both before (C) and after (AG) levocabastine pretreatment, was compared to that obtained after periods of 2 and 24 hours postchallenge. In the AG, before and after levocabastine pretreatment, the tryptase concentrations had not significantly increased, whereas the ECP concentrations were found to be significantly higher (p < 0.05) in just the 24-hour postchallenge samples. In the PG the rhinitis symptoms were not induced by the NPTp and there was no significant change in either ECP or tryptase concentrations. In the AG a levocabastine pretreatment induced a significant increase (p < 0.05) in the cumulative allergen doses administered by the NPT. There was a reduction of the nasal symptoms in 7 patients, while in 3 subjects there was only a slight improvement, but in 2 subjects no effect was encountered. In conclusion this study shows that a levocabastine pretreatment before an NPT in patients with grass pollen rhinitis, outside the grass pollen season, induces a significant increase in the cumulative allergen doses (administered by the NPT) which provoked rhinitis symptoms but is not able to demonstrate any significant reduction in the ECP concentrations of the NLF.

Blood Proteins↗

PubMedDate not supplied

[Pseudoallergies].

Pseudo-allergic-reactions (PAR) are clinical manifestations including urticaria, angioedema, conjunctivitis, rhinitis, asthma, and anaphylaxis. The prevalence of PAR ranges from 0.1% to 75% according to various studies. The pathogenetic mechanism of these diseases is not immunologically mediated. Food, additives, and drugs are the main responsibilities for PAR. The diagnosis of PAR is characterized by the absence of specific IgE for the suspected products. The absence of immunological mechanisms is confirmed by in vitro and in vivo tests. The treatment of PAR is similar to that of allergic diseases (antihistamine drugs, steroids, B2 agonists, epinephrine).

Humans↗

PubMedDate not supplied

[Changed levels of substance P and somatostatin in HIV-positive children].

Substance P (sP) and Somatostatin (SOM), so as other neuropeptides can modulate neurologic and immunologic functions. sP has been described to enhance both in vitro and in vivo immunoglobulin synthesis. On the contrary, SOM has an inhibitory effect on the same activity. The modulating effect is more evident on IgA isotype. Hypergammaglobulinemia and in particular high levels of IgA is a common finding in pediatric AIDS and an imbalance among regulatory effects of neuropeptides might be suggested. In order to evaluate the plasma levels of sP in pediatric AIDS we studied 15 children with HIV infection (status P2), 10 seronegative children born to HIV positive mothers and 10 healthy children of the same age. All the HIV positive children had high plasma levels of IgG and IgA. The plasma level of sP was extremely higher in HIV positive children while no significant difference was found between seronegative children born to HIV positive mothers and healthy children. SOM was decreased in HIV positive children when compared to control groups but a significant difference was not reached. It might be supposed that HIV infection, through a dysregulation among neuropeptides interferes on immune functions and in particular on IgA synthesis. On the other hand it might be suggested that the imbalance between sP and SOM depends on the viral infection of immune cells since it has been demonstrated that SOM and other neuropeptide are synthesized by lymphoid tissue. Further studied relevance of neuropeptide disorders in pediatric AIDS.

Female↗

PubMedDate not supplied

[Specific IgA against multiple antigens as expression of immunologic deregulation in HIV-positive children].

B-cell dysfunction in HIV-infected children is reflected by hypergammaglobulinemia and high levels of serum IgA. Little is known about antibody specificity since only a small portion of serum IgA appears to be directed against HIV proteins. In the present study the specificity of IgA antibodies against food, inhalant, bacterial and fungi antigens were evaluated in a population of HIV infected children. ELISA method was used for antibody testing. Our results show that in 84.6% of patients IgA against at least one food antigen are present. IgA against inhalant allergens were present in most of HIV-infected children but in none of controls. As for anti-tetanus toxoid antigens and anti-fungi antigens, though present in higher percentage in patients, specific IgA were found also in healthy children. If a gastrointestinal dysfunction might be supposed as the cause of presence of anti-food antigen IgA, it is difficult to consider this factor as the cause of presence of specific IgA directed against different antigens. It is possible to postulate that an immunologic dysregulation based on an imbalance between Th1 and Th2 cells or on higher levels of IL-5 and/or IL-6 may lead to a misfunction of B cell and consequently to hypergammaglobulinemia with high IgA levels.

Antibody Specificity↗

PubMedDate not supplied

[Subclasses of IgG: biological aspects and functional behavior in response to vaccination].

The IgG subclasses are known to have different structure and functions. The IgG1 and IgG3 bind to monocyte and neutrophils and activate the complement more easily then IgG2 and IgG4. The levels of IgG subclasses found in newborns are mainly determined by the transplacental passage since the synthesis, in the first time of life, is very low. The levels found in adults are reached only during the adolescence. The immune response to a protein antigen is mainly in the IgG1 subclass, on the contrary the response to polysaccharide antigens is mainly IgG2. For that reason children, who produce very few IgG2 till they are 2 years old, cannot be vaccinated with carbohydrate vaccines unless a protein conjugate vaccine is used. In addition, the route of subministration, the dose of antigen, the age of vaccinated people and genetic factors can modify the subclass pattern obtained in response to vaccinations. For these reasons, probably, the immune response studied after a vaccination or in individuals who recovered from a natural disease is not always the same. Since the role of the different subclasses is not yet completely clarified, the interpretation of the importance of a selective "choice" of a subclass instead of another after vaccination is still difficult.

Aging↗

PubMedDate not supplied

[Active and passive immunoprevention of hepatitis B in newborn infants with HBsAg-positive mothers].

Infants born to HBsAg-positive mothers are at high risk of contracting perinatal hepatitis B infection. The prevention is based on active as well as passive immunoprophylaxis. We have used hepatitis vaccine in 18 newborns of as many HBsAg-positive mothers. Some haematologic and immunologic parameters are here reported. No alterations were observed as to liver function. Immunoglobulin values were normal for age. Auto-antibodies and rheumatoid factor were constantly absent. Immunecomplexes were present in the serum of some infants. The study of T cell subsets and of natural killer cells activity did not reveal any important changes, whereas minor modifications were present in polymorphonuclear leucocyte function. In all infants submitted to vaccination serum conversion was observed a with different antibody levels.

Female↗

PubMedDate not supplied

[A case of Behçet's disease in a child: clinical, genetic, and immunologic characteristics].

Behçet's disease, which is rarely observed in infancy, is a systemic inflammatory disease of unknown etiology, whose clinical feature consist in the triad of mouth ulcers, genital ulcers and iritis. A 14 years old girl has been studied in whom classical findings of Behøcet's disease were associated with neurological symptoms miming a neuro-Behøcet's syndrome, but which were caused by previous abuse in corticosteroid therapy. Interestingly some features (arthritis, gastrointestinal manifestations), which can be connected with Behøcet's disease, resulted to be present since the very first years of life. Partial features of the disease (arthritis or mouth ulcers) were present in three members of the patient's family on the father's side. Extensive immunological studies have been carried out. T and B lymphocyte number and function were normal. T-cell subsets (defined by monoclonal antibodies) and natural killer activity (both never examined in patients with Behøcet's disease) resulted to be within normal range. Secretory Component, which has been claimed to be absent in these patients, was normally present in saliva. A defect in neutrophil chemotaxis has been found which promptly improved by levamisole therapy. Authors discuss clinical, genetic and immunological findings of the patient, on the basis of a review of literature.

Adolescent↗

PubMedDate not supplied

[Reduced natural killer function in children with recurrent respiratory tract infections].

Respiratory infections are the major cause of disease in childhood in the industrialized areas of the world. This essentially depends on two factors: immunological immaturity and immunological naivety. In most cases a virus has been considered the causative agent in respiratory infection. A defect in immune responses has been described in children with recurrent respiratory infections and in particular a decrease in CD4/CD8 T lymphocyte ratio or in IL-2 and IFN-gamma production. Our results show that Natural Killer (NK) cell activity is defective in children with recurrent respiratory infections. That is particularly noteworthy since NK cells play an important role in host defense against viral infections. At present it is difficult to understand whether the NK defect is a primary defect or it is secondary to viral infections. Further studies will help to clarify whether NK decreased activity depends on a cell damage directly caused by virus or it depends on the decreased levels of cytokines.

Adolescent↗

PubMedDate not supplied

[IgG subclasses against bovine alpha-lactalbumin and beta-lactoglobulin in infants fed with a seroprotein hydrolysate].

Prevention of food allergy in infancy has been the aim of important researches in the last years but many studies have produced conflicting conclusions. The use of hydrolysate formulas seems to be an helpful tool in prevention of cow milk protein allergy but confusion often remains about capability of small hydrolysate molecules to be "allergens" or "antigens". In order to clarify this point IgE, IgG and IgM as well as IgG subclasses against alfa-lactoalbumin (ALA) and beta-lactoglobulin (BLG) have been evaluated in 41 infants at risk for allergy and in 30 controls at the fourth month. The same evaluation has been done on their mothers. The 41 "at risk" children were fed with breast milk or with an hypoallergenic formula (Nidina HA, Nestlè) or both. The control children received an adapted formula. No difference between the two groups of children was found regarding IgM or IgG against ALA while antibodies against BLG were more frequently found in controls than in "at risk" children. Only one child in the group fed with Nidina HA developed specific IgE against whole milk. Therefore hydrolysate formula seems to be as antigenic (not allergenic) as adapted formula in respect of ALA while BLG contained in adapted formula seems to be a stronger immunogen. The pattern of specific IgG subclasses against ALA and BLG is different between the two groups of children because of the absence in "at risk" group of specific IgG2 and IgG3. As for the mothers, the presence in their sera of IgG against ALA or BLG seems to induce in infants a reduced response to the same antigen.

Albumins↗

PubMedDate not supplied

[Hepatitis B virus: new markers and their immunology].

Hepatitis B virus (HBV) is one of the most important causes of chronic liver disease. HBV is a DNA virus with an external glycoprotein surface and an internal nucleocapsid which contains the viral genome. HBV infection is revealed by the appearance of specific markers. Some of these markers are well known and their presence in serum is important to understand the behaviour of the disease. Among them HBsAg, HBeAg, anti-HBs and anti-HBe are found in serum, so as anti-Core; the HBcAg may be found in hepatic tissue and marks infectivity and virus replication. In the few last years some new antigens and antibodies have been studied and their importance in diagnosis and follow-up of hepatitis has been recognized. HBxAg, Pre-S and DNA-Polymerase (Pol) seem to be specific and early signals of viral replication. More studies showed the trans-activating properties of HBxAg; actually the X protein seems to be involved in replicative cycle of HBV. Many Authors also demonstrated a relationship between the presence of X in serum and/or liver and the progression of disease to cirrhosis and hepatocellular carcinoma. The Pol antigen and its antibody seem to be very common markers of HBV infection in serum of patients with hepatitis. Moreover their presence is the only signal of viral infection in some patients which have no other marker of HBV. More studies are of course needed to exactly establish the significance of these new markers and their importance for diagnosis and prognosis of HBV infection.

Animals↗