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Biomedical subjects

C H Pionetti

Publications and source records attributed to C H Pionetti.

11 recordsLinked to original sources
PubMedDate not supplied

Immunological changes during cockroach immunotherapy.

Data obtained in a 3-year survey of specific immunotherapy (SIT) with a Periplaneta americana antigen (Pa-1) are presented. Parameters such as serum IgE-paperadioimmunosorbent test, specific IgE and IgG, interleukin (IL)-2, IL-4 and IL-4R levels were recorded before and after SIT. While serum IgE levels and IgE-RAST-anti-Pa-1 did not change throughout SIT (p = not significant), IgG-RAST-anti-Pa-1 showed a marked increase from the first year (p < 0.002 to p < 0.001). Only after 3 years of SIT did the serum levels of IL-2, IL-4 and IL-4R show lower values than before this period (p = 0.05, p = 0.05, p = 0.01, respectively). The comparative statistical analysis of the cytokine data between the nonatopic subjects and the atopic treated patients revealed no significant differences (p = 0.02). The symptomatic scores showed significant results at the third year of SIT in sneezing attacks, nose blowing and nasal obstruction (p = 0.001, p < 0.001, p = 0.001, respectively).

Adolescent↗
PubMedDate not supplied

IgE antibodies against Neisseria flavescens.

Bacterial allergy is still a matter of controversy. We sustain that this name should be employed only in the presence of a specific IgE against antigens from bacteria. In 100 atopic patients and 100 healthy controls with Neisseria flavescens in their pharyngeal exudates, we performed type I immediate skin tests with Neisseria flavescens and IgE-RAST throughout 1 year. Positive wheal and flare reactions were elicited in 8 of 100 atopic patients as well as in 3 of 100 nonatopic subjects. IgE-RAST/anti-Neisseria flavescens was found in 6 of the former group and in 1 of the latter. Neither late-phase nor Arthus-like reactions were recorded. Neisseria flavescens is a non-pathogenic commensal of the oropharynx with scarce antigenic properties and seems not to play an important role in these conditions (rhinitis/asthma). Bacterial immunotherapy should be considered only in the presence of specific IgE antibodies with careful selection of the bacteria or their antigens.

Adult↗
PubMedDate not supplied

Interstitial pneumonitis induced in guinea-pigs by the antigens of Periplaneta americana.

Data concerning the experimental induction in guinea-pigs of hypersensitivity pneumonitis with a cockroach antigen are presented. A glycoprotein obtained from the chitinous structures of Periplaneta americana was aerosolized daily to guinea-pigs during 12 weeks. The presence of specific antibodies (IgG) was detected by serological techniques; histopathological studies of the lungs showed interstitial infiltrates of macrophages and LT-CD8+ cells, as revealed by the MoAb used. Single non-necrotizing granulomas were characteristic from the 10th week to the end of the experiment. The results from this animal model suggest that this hypersensitivity pneumonitis is a typical delayed-type reaction due to chronic contact with the heterologous glycoproteins of P. americana.

Alveolitis, Extrinsic Allergic↗
PubMedDate not supplied

Immunochemical properties of the antigens involved in the pigeon breeder's disease.

The pigeon breeder's disease is a form of extrinsic allergic alveolitis caused by the exposure to pigeon droppings. Chemical analysis of this antigen was carried out employing column fractionation techniques. Sephadex G-50 and DEAE cellulose were performed and several proteins and hexoses peaks were recorded. Molecular weights were determined by comparison with standardized marker proteins passed through a drop counting fraction collector. The whole extract revealed a molecular weight of 100 Kd while fraction 1 showed 66 Kd and fraction 2 only 30 Kd. A guinea pig experimental model was developed with the whole extract injected by the intradermal route, administered by an intragastric catheter or aerosolized in a glass chamber. Histopathological studies were carried out with the lungs, kidneys, liver and spleen obtained by the necropsy of the animals. The lungs and the kidneys showed the paramount changes in their structures with lymphomononuclear infiltrates and an Arthus-like phenomenon surrounding the vessels. Immunological techniques were applied to the sera and the lymphocytes obtained from the animals. Precipitin and hemagglutinating IgG antibodies were detected against the whole extract and the fractions obtained by column fractionation. Sensitized lymphocytes were also detected. This experimental model represents a guide in the approach to the human allergic alveolitis whose immunological findings will be presented in a forth-coming report.

Alveolitis, Extrinsic Allergic↗
PubMedDate not supplied

Immunochemical properties of the antigens of Blattaria sudamericana.

An extract of the cockroach Blattaria sudamericana (BS), a very common insect in Argentina, was passed through Sephadex G-200 and DEAE cellulose ion exchange columns. This method yielded 2 proteins and 6 hexoses whose quantities were determined by absorbance in a LKB Uvicord spectrophotometer at 280 nm and 470 nm respectively. Protein contents were also recorded by the Lowry method and the micro-Kjehldal technique. Adult albino rabbits were immunized with a mixture of BS and complete Freund's adjuvant over a period of thirteen weeks. The antisera obtained were studied by the Ouchterlony method, the immunoelectrophoresis and the passive hemagglutination technique against BS and the eluated fractions with the highest protein content. Molecular weights were studied with the usual marker proteins subjected to gel filtration by a Sephadex G-200 column. Each protein concentration was 13.5 mg/ml in a volume of 1.5 ml meanwhile BS was 42 mg/ml. This antigen showed a molecular weight of 180,000 daltons. Fifty untreated atopic patients of both sexes with ages between 19 and 74 years suffering perennial rhinitis and bronchial asthma were chosen according to the American Thoracic Society criteria. Their IgE levels ranged between 110 and 3000 KU/L with an average of 620 KU/L. IgE anti-BS-RAST showed positive results in half of the patients while type I positive skin tests with BS 1:100 appeared in 62% of the atopic group.

Adult↗
PubMedDate not supplied

[Chemical and immunologic study of pollen from the gramineous plant Lolium perenne].

In order to study the chemical composition and immunologic reactivity of an extract of rye grass pollen (RGP), aliquots of this antigen were passed through Sephadex G-50 and DEAE-cellulose ion-exchange columns. This method yielded 7 proteins and 10 sugars, whose quantities were determined by absorbance in a LKB Uvicrd spectrophotometer at 280 nm and 470 nm respectively. Protein contents were also recorded by the Lowry method and the micro-Kjehldal technique. Adult albino rabbits were immunized with a mixture of RGP and complete Freund's adjuvant over a period of eight weeks. The antisera obtained were studied by the Ouchterlony method and the passive hemagglutination technique against RGP and all the eluated fractions. Skin tests with RGP and its fourteen most conspicuous eluated fractions were performed in 29 untreated atopic patients with seasonal rhinitis and bronchial asthma, high reactivity to a whole grass mixture and RGP and high levels of serum IgE. Results were recorded after 15 minutes for the immediate reaction when the histamine positive control had reached near maximal size and in the morning. Molecular weights were studied with the usual marker proteins subjected to gel filtration by a Sephadex G-50 column. Each protein concentration was 13,5 mg/ml in a volume of 1,5 ml, meanwhile RGP was 12 mg/ml. PRIST and RAST were carried out with human sera to determine IgE levels and specific IgE and IgG anti-RGP antibodies. Ouchterlony showed precipitin lines among the rabbit RGP-antiserum, whole grass mixture, RGP and the fractions from tubes 38 and 359, meanwhile Boyden's technique appeared positive only between the anti-serum and whole grass mixture and RGP (1:256). The other fractions gave negative results as all of the human sera of both groups. Skin tests in the atopics showed type I reactions with whole grass mixture, RGP, proteins no 33 (Sephadex), 25 and 38 (DEAE-cellulose) and sugars no 56, 192 and 360, but negative results in the controls. Molecular weights obtained were for fraction no 13 68.000, for fraction no 28 25.500 and for fraction no 33 18.400 daltons respectively. RAST revealed in 28 sera a IgG anti-RGP before hyposensitization therapy and an IgE anti-RGP of class 2 only in 8 sera and in 10 of class 1. This surprising result needs further investigation to clarify if the ratio IgE/IgG anti-RGP plays any role in the pathogenesis of pollinosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMedDate not supplied

Isolation and characterization of soluble fractions of Dermatophagoides farinae.

Dermatophagoides farinae extract was filtered through Sephadex G-50 and DEAE-cellulose columns to study its chemical composition. Fractionation on Sephadex G-50 resulted in one definite peak of protein and in three sugar peaks. Fractionation of the protein peak on DEAE-cellulose produced four more protein peaks and another five sugar peaks. Twenty-one untreated allergic patients suffering from perennial rhinitis and bronchial asthma with clinical sensitivity to house dust were subjected to skin tests with house dust 1:100, dermatophagoides farinae 1:100 and also its thirteen eluted fractions 1:100. Positive results were recorded with house-dust, mite and six or perhaps seven fractions consisting of three or four proteins and three sugars. Immunization in rabbits with mite extract revealed only one slight precipitin band by the Ouchterlony technique and a 1:20 titer of hemagglutinating antibodies. The antigen or antigens of mite extract seemed to be producers of type I reactions rather than circulating antibodies of the IgG class. This represented a point of controversy for the therapeutic application of Dermatophagoides farinae in human desensitization.

Allergens↗
PubMedDate not supplied

Comparison among delayed-type skin tests, serum IgE levels and peripheral blood CD4 in HIV-positive patients.

Three groups of HIV-positive men and a control group of healthy subjects were evaluated simultaneously by delayed-type skin tests with recall antigens detection of CD4 cell counts in peripheral blood and the IgE serum levels. Delayed-type skin test reactivity and CD4 cell counts in peripheral blood decreased while IgE serum levels increased as immune imbalance progressed with the worsening of HIV infection (p = 0.003 between controls and HIV-positive patients). The existence of atopy did not significantly influence IgE serum levels in the groups of HIV-positive patients (p < 0.2). Candidin appeared as a useful antigen in the delayed-type skin tests considering that it was the only antigen that remained positive with low values of CD4 cell counts (< or = 250/mm3). The detection of serum IgE levels as well as the performance of delayed-type skin tests with recall antigens are useful tools to evaluate immunological status whereas the number of CD4 in peripheral blood is critical for determining the initiation of antiretroviral therapy.

Adolescent↗