Grass Allergic Patients Research Articles

Grass immunotherapy induces inhibition of allergen-specific human peripheral blood mononuclear cell proliferation.

The peripheral blood mononuclear cells (PBMC) from humans allergic to grass pollens (GR+ subjects) show strong in vitro proliferative responses to purified allergens from Lolium perenne pollen Lol p 1, and to a lesser extent to Lol p 2 and Lol p 3. By contrast, PBMC from grass allergic patients undergoing immunotherapy (GR + IT subjects) exhibit a very poor Lol p-specific proliferative response, similar to that observed in nongrass allergic subjects (GR-subjects). Unlike GR-subjects, both GR+ and GR + IT subjects have high levels of antigen-specific serum IgG and IgE antibodies to Lol p 1, Lol p 2 and Lol p 3. While GR+ subjects exhibit a significant correlation between antigen-specific serum antibody and PBMC responses, GR + IT subjects do not show a correlation between the two responses. The possible mechanisms by which immunotherapy may modulate allergen-specific T cell proliferative response are discussed.

Specific Immunotherapy Suppresses IL-1β and IL-8 Levels in Nasal Secretions: A Possible Explanation for the Inhibition of Inflammatory Cell Migration

The efficacy of specific immunotherapy in the treatment of allergic rhinitis is now clearly established. The fundamental principle of this form of therapy is still not fully understood, although considerable advances have been made in clarifying various aspects of the mechanisms of action. An important effect of the therapy is the inhibition of migration of inflammatory cells into the mucosa. The results of in vitro investigations and characterization of the cytokine profiles in biopsy specimens from skin and nasal mucosa at the time of an allergeninduced late-phase reaction support the view that reorientation of a Th2 lymphocyte immune response in the direction of a Thl reaction is a fundamental aspect of the mechanisms of the immunotherapy. In order to further clarify the reasons for the cellular infiltration and to obtain evidence for the postulated Th2/Th1 switch in the nasal mucosa, we have measured various cytokines in the nasal secretions from 34 grass-allergic patients participating in a randomized double-blind, placebo-controlled study of specific immunotherapy. One group of 17 patients was treated with a grass pollen allergoid preparation (Allergovit®), whilst the other group received a histamine-containing placebo. Cytokine determinations were performed using enzyme-linked immunosorbent assays with nasal lavage samples obtained before the beginning of therapy and at three time points during the pollen season. Interleukins (IL) 4 and 5 are typical Th2 cytokines effecting the stimulation of IgE synthesis and the activation and differentiation of eosinophil granulocytes, respectively, but they were not detectable in significant amounts in the nasal secretions. Therefore, the investigation did not provide evidence for a T helper cell switch. IL-1Β, IL-6, and IL-8 were consistently detectable. Specific immunotherapy had no effect on the nonspecific proinflammatory cytokine IL-6. There were significant reductions in the concentrations of the chemokine IL-8 (p < 0.05) and the important proinflammatory cytokine IL-1Β (p < 0.005) in nasal secretions from the treatment group during the pollen season, but not in the placebo group. These two cytokines play an important role in transendothelial cell migration, and their reduced concentrations as a result of the specific immunotherapy may contribute at least in part to the inhibition of inflammatory cell migration into the nasal mucosa. These observations are in keeping with the anti-inflammatory effect of the specific immunotherapy.

The pattern and kinetics in human skin of erythema and mediators during the acute and late-phase response (LPR)

To investigate the kinetics and pattern of allergenically induced mediator release in the human skin, we have studied 24 ragweed- and grass-allergic patients with a blister-chamber technique. Chambers sealed to the skin around a denuded area, formed by unroofing a blister, were challenged with 0.5 ml of either diluent or 10 or 100 times the concentration of allergen required for 4+ early intradermal reaction. Chamber fluids were removed hourly 1 to 8 hours after antigen challenge and examined for the presence of histamine, leukotriene C 4 (LTC 4), and prostaglandin D 2 to compare inflammatory mediator levels with the clinical early response and late-phase response (LPR), as assessed by erythema around the chamber. An initial erythema developed rapidly and began to subside after 1 hour in all patients, but a late-phase local erythema and subcutaneous swelling around the chamber (i.e., >2.5 cm, the outside diameter of the chamber) developed in 13/15 challenges only when the higher concentration of antigen was used. At both allergen concentrations, histamine levels peaked sharply at the first hour (20.6 ±2.3 ng/ml) and progressively declined during the next 4 hours by 75%, but remained above control levels for at least 7 hours. Despite high control values, LTC 4 levels were significantly elevated ( p < 0.01) 4 to 6 hours after challenge. In visible reactions, maximal LPR around the chamber correlated with LTC 4 levels obtained 6 and 7 hours after challenge ( p < 0.05). Prostaglandin D 2 rose gradually in antigen-challenged chambers to a peak at 5 to 6 hours. Thus, early rises in histamine were temporally related to the immediate erythema, whereas the arachidonic acid metabolites from both cyclooxygenase and lipoxygenase pathways that appeared in the skin after allergen challenge followed kinetics that corresponded to the time course of cutaneous LPR.

Immunochemical studies of Lolium perenne (rye grass) pollen allergens, Lol p I, II, and III.

It was reported earlier that human immune responses to three perennial rye grass (Lolium perenne) pollen allergens, Lol p I, II, and III, are associated with histocompatibility leukocyte antigen (HLA)-DR3. Rye-allergic people are often concordantly sensitive to all three of these allergens. Since earlier studies suggested that these antigens are non-cross-reactive, their immunologic relatedness by double antibody radioimmunoassay (DARIA) was studied in order to understand further the immunochemical basis for the concordant recognition of the three allergens. Direct binding DARIA studies were performed with human sera from 189 allergic subjects. Inhibition DARIA studies were carried out with 17 human sera from grass-allergic patients who were on grass immunotherapy, one goat anti-serum, and six rabbit antisera. None of the sera detected any significant degree of two-way cross-reactivity between Lol p I and II, or between Lol p I and III. However, the degree of two-way cross-reactivity between Lol p II and III exhibited by individual human and animal antisera varied between undetectable and 100%. In general, the degree of cross-reactivity between Lol p II and III was higher among human sera than among animal sera. Taken together with earlier findings that antibody responses to Lol p I, II and III are associated with HLA-HDR3, and that most Lol p II and III responders are also Lol p I responders, but not vice versa, our present results suggest the following: the HLA-DR3-encoded Ia molecule recognizes a similar immunodominant Ia recognition site (agretope) shared between Lol p I and Lol p II and/or III; in addition, Lol p I appears to contain unique Ia recognition site(s) not present in Lol p II and III. However, further epitope analyses are required to investigate these possibilities.

Further evaluation of local intranasal immunotherapy with aqueous and allergoid grass extracts

In a double-blind study, 45 grass-allergic patients received local nasal immunotherapy (LNIT) with either aqueous mixed-grass extract, formaldehyde-treated, mixed-grass extract (allergoid), or histamine placebo. Twenty-four patients received LNIT for a second successive year, and 21 patients received LNIT for the first year. The aqueous extract-treated patients had significantly lower symptom-medication scores than either allergoid- or placebo-treated subjects. There was no difference in symptom-medication scores in patients receiving allergoid and placebo treatment or in patients receiving 1 and 2 yr of LNIT. The aqueous extract stimulated a rise in serum grass-specific IgE. There was no serum or local antibody response after allergoid-extract treatment. Postseasonal rises in serum-IgE titers were observed in all three groups. These data suggest that LNIT with aqueous mixed-grass extract significantly reduces the symptoms of allergic rhinitis. The allergoid grass extract was ineffective in the second year of treatment. No cumulative effect of LNIT could be demonstrated in successive years of therapy.

Immunochemical characterization of a high molecular weight basic allergen (HMBA) of rye grass ( Lolium perenne) pollen

A high molecular weight basic allergen (HMBA) was isolated from the mixture of non-dialysable components of the aqueous extract of defatted rye grass pollen by a combination of gel filtration and isoelectrofocussing. HMBA, a glycoprotein of mol. wt 56,800 (17% carbohydrate) contained all naturally occurring amino acids. A hyperimmune rabbit anti-HMBA serum gave only a single precipitin band with the crude extract of the rye grass pollen in crossed immunoelectrophoresis. Thus. it was concluded that HMBA was a unique and highly purified antigen. The allergenicity of HMBA was revealed by its ability to elicit immediate skin reactions in grass allergic patients. Moreover, all patients' sera tested had IgE antibodies to HMBA detectable by direct RAST with HMBA allergosorbent discs, These observations indicated that HMBA was a major allergenic constituent of rye grass pollen. Treatment of HMBA by 6 M guanidine HC1 led to a significant reduction in its ability to combine with human IgE antibodies. The treatment also resulted in the complete loss of allergenicity (i.e. inability to elicit PCA reactions with a murine reaginic antiserum to HMBA) and antigenicity (inability to form precipitins with rabbit anti-HMBA): hence, it would appear that the allergenic and antigenic determinants of HMBA are ‘conformational’.

Local intranasal immunotherapy for grass-allergic rhinitis

In a double-blind controlled study, local intranasal immunotherapy was evaluated for the treatment of grass pollenosis. On the basis of serum grass-specific IgE levels, 50 grass-allergic patients were randomly divided into three groups and treated with either an aqueous solution of mixed-grass extract, a formaldehyde-modified mixed-grass extract (allergoid), or a histamine solution (placebo). Intranasal solutions were administered in gradually increasing doses over a preseasonal 10 wk period, Ad' verse local reactions from the aqueous grass extract were frequent during treatment. Few adverse reactions occurred from the allergoid or histamine solutions. During the pollen season, patients receiving both grass extracts had much lower symptom/medication scores than patients receiving placebo. The severity of eye symptoms was the same in all groups. After treatment, serum grass-specific IgE rose in patients receiving aqueous and allergoid extract; no change was noted in patients receiving placebo therapy. Grass nasal secretory-specific IgA titers in each group did not change during the study. The results of this study suggest that local intranasal immunotherapy with either aqueous or allergoid grass extracts is clinically effective for the treatment of grass pollenosis. Adverse reactions associated with the aqueous extract may limit its usefulness. No correlation was present between the secretory immune response and clinical benefit.

The effect of immunotherapy (IT) on IgE antibody response of lymphocytes from ragweed and grass allergic patients using reverse hemolytic plaque assay (RHPA)

The effect of immunotherapy (IT) on IgE antibody response of lymphocytes from ragweed and grass allergic patients using reverse hemolytic plaque assay (RHPA)