Isotypic analysis of grass pollen-specific antibodies in human plasma. 4. Biological activity of allergen-specific and autoanti-IgE antibody fractions on basophil histamine release.

BACKGROUND: Blocking antibodies are defined as antibodies that compete with IgE for binding to allergens due to their specificity for those allergens. Thus, they may inhibit allergen-induced basophil and mast cell IgE-dependent mediator release both in vivo and in vitro. OBJECTIVE: The present study was designed to evaluate the ability of antibodies isolated from human plasma samples on a Dactylis glomerata (Cocksfoot) pollen affinity-column to inhibit the Dactylis pollen-induced histamine release from human basophils (BHR) in vitro. METHODS: Antibodies from Ig pools containing either high or low IgG4 anti-Dactylis pollen were purified on a Dactylis pollen affinity-column and then separated on an antihuman IgE column. Obtained Ig fractions were incubated for 30 min with Dactylis pollen allergens prior to incubation with basophils from Dactylis pollen-allergic donors. Cell supernatants were assessed for histamine content and the inhibition of BHR was calculated. RESULTS: Unlike control non-isolated Igs, the antibodies isolated on the Dactylis pollen column were able to inhibit efficiently and in a dose-dependent manner Dactylis pollen-induced BHR. The inhibitory activity was increased in isolated antibody samples that had high IgG4 levels. Antibodies isolated on the Dactylis pollen column, however, consisted not only of true allergen-specific (potentially blocking) antibodies but also of autoanti-IgE binding to allergen-specific IgE and mistaken for allergen-specific antibodies thus opening to question the involvement of the true allergen-specific antibodies in the BHR-inhibitory activity. Unlike the true allergen-specific antibodies, the autoanti-IgE were retained on and eluted from the anti-IgE column. Results showed that both the autoanti-IgE-depleted and the autoanti-IgE-containing fractions accounted for the inhibition observed with the related non-depleted sample that had been isolated on the Dactylis pollen column. CONCLUSION: For the first time, the true blocking activity of allergen-specific antibodies is demonstrated, that is, in the absence of the autoanti-IgE which can also inhibit BHR.

Selective recruitment of eosinophils by substance P after repeated allergen exposure in allergic rhinitis.

We have investigated the nasal response to substance P after pollen exposure in seasonal allergic rhinitic patients. Seven patients with strictly seasonal allergic rhinitis were studied during the pollen season, 24 h after nasal challenge with pollen. They received increasing doses of nebulized substance P (0 to 80 nmol) in each nostril. Responses were assessed by measurement of nasal airway resistance by posterior rhinomanometry and quantification of albumin, histamine, and inflammatory cells in the nasal lavage fluid. Nasal airway resistance increased in a dose-dependent manner after substance P challenge. Protein and albumin in nasal lavage fluids increased after administration of substance P: from 2.6 +/- 0.3 to 6.8 +/- 1.1 mg for protein (P < 0.01) and from 0.2 +/- 0.1 to 3.1 +/- 0.6 mg for albumin (P < 0.02). Expressed as a percentage of total protein, albumin increased from 10.5 +/- 3.6% to 39.9 +/- 3.5% (P < 0.02), suggesting occurrence of plasma leakage. No histamine release was observed after challenge with substance P. Total cell counts significantly increased from 11.4 +/- 2.4 to 41.8 +/- 17.3 x 10(3) cells/ml after substance P (P < 0.05). Eosinophils were already numerous before substance P challenge (2.1 +/- 0.7 x 10(3) cells/ml), and the number of eosinophils markedly increased in all patients after substance P (for the whole group, 25.8 +/- 13.3 cells/ml, P < 0.05). In contrast, the number of neutrophils only slightly increased in five patients, and changes did not reach significance for the group as a whole. Our results show that substance P induces nasal obstruction and albumin extrusion in allergic rhinitic patients after repeated pollen exposure. These vascular phenomena are associated with recruitment of eosinophils. Since substance P is known to be released after nasal allergen challenge, our data suggest a role for substance P in the chronic eosinophilic inflammation of the nasal mucosa observed in symptomatic allergic rhinitis.

Winter pollinosis in Paris.

Pollen is rarely investigated as a cause of winter respiratory symptoms. Infectious coryza and asthma are particularly common during winter, and it has been shown that environmental antigens can cause at least some cases in Paris. Recent experimental data from Calhoun et al. (1991) indicate that pollen may act synergistically with viral respiratory infections, which are particularly prevalent in winter. In the present study, we investigated, in 130 consecutive patients presenting with winter aggravation of asthma or rhinitis, winter pollinosis by skin test, radioallergosorbent test (RAST), and specific endonasal challenge test. Totals of 35, 24, and 21 patients reacted positively in skin, RAST (> 0.70 PRU/ml), and endonasal tests, respectively. Clinical features during the season established the diagnosis of winter pollinosis in 20 cases; it was due to alder pollen in 10 patients and hazel pollen in 12. The positive predictive value of the skin test was only 0.57, as compared with 0.86 for the specific endonasal test, which had a negative predictive value of 1. Our results indicate that hazel and alder pollens should be prick-tested for more often as causes of winter respiratory symptoms in Paris, even if similar manifestations were absent during previous winters, were previously present during spring or summer, or were both absent in previous winters and present in spring or summer.

Seasonal increase of spontaneous histamine release in washed leucocytes from rhinitis patients sensitive to grass pollen.

The spontaneous histamine release (SHR) in basophils from patients sensitive to grass pollen has been studied before and during the 1987 grass pollen season. Nineteen patients were recruited on seasonal rhinitis symptoms, positivity for cutaneous tests and for serum-specific IgE with grass pollen. At the time of the biological investigations the patients were following a clinical trial of hyposensitization, including placebo, calcium phosphate and aluminium hydroxide-adsorbed grass pollen extract treatments. During the pollen season, grass pollen counts and clinical scores were checked over a 40-day period. Mean SHR was significantly higher during the pollen period than before, for the whole population of 19 patients (10.9% and 4.6%; P less than 0.005) as well as when the high SHR responders were excluded (5.5% and 3.6%; P less than 0.01). No significant correlation existed between SHR and clinical scores or treatments. SHR could be inhibited at 4 degrees C, in absence of CA++ or of oxidative metabolism and thus originated from cells actively secreting histamine.

[Specific desensitization with allergen extracts absorbed on calcium phosphate (Pasteur Institute). Clinical and biological study apropos of 107 cases]. / Désensibilisation spécifique à l'aide d'extraits allergéniques adsorbés sur phosphate de calcium (Institut Pasteur). Etude clinique et biologique à propos de 107 cas.

107 allergic patients (71 children and 36 adults) were desensitized with allergen extracts adsorbed on calcium phosphate. Patients were selected following their symptoms (asthma, rhinitis, juvenile bronchitis, pollinosis), skin tests (ID or Prick) and total or specific IgE levels (PRIST and RAST). A mean of 17 month treatment, usually with house dust and mite extracts, rarely with house dust extract alone and in 6 cases with a mixture of grass and cereal pollens. The major aim of this study was to test the immunotherapy efficiency and to compare the IgE level variations and the clinical results. The treatment was found very good in 62% of the cases, good in 28%, and negative in 10% of the cases. The mean total IgE level has decreased of 58%, and the specific IgE level has decreased in 77% of the patients. The number of patients with a RAST class O to house dust and mites has increased respectively of 23% and 24.4% after the treatment. Besides some very good cases where the IgE levels have dropped there are lew relations between the total or specific IgE antibodies and the clinical results. The tolerance of the hyposensitization treatment was judged excellent. In conclusion, the calcium phosphate absorbed allergen extracts are confirmed as efficient and safe in immunotherapy.

Calcium phosphate adjuvanted allergens.

Calcium phosphate has been used for many years as an adjuvant for vaccines. Results of field trials using calcium phosphate in several countries have been published and demonstrate high immunogenicity and the absence of untoward reactions. This paper presents preliminary results of studies on the use of calcium phosphate, instead of aluminum compounds, for preparing adsorbed allergens. These were performed with purified house dust, mite, and grass pollen extracts. Immunotherapy with house dust and mite extracts gave a high rate (70%) of satisfactory therapeutic results. Efficacy was compared with immunization carried out with fluid preparations under the same conditions. It was found that satisfactory results were of the same order, but elicited a higher number of injections. Immunotherapy with calcium phosphate adjuvanted allergens was also equal, as with aluminium adjuvanted allergens, according to published data. Good tolerance was noted for adsorbed grass pollen extracts, but clinical evaluation of results can only be reported after treatments during at least three seasons.

Calcium-phosphate-adjuvanted allergens: total and specific IgE levels before and after immunotherapy with house dust and Dermatophagoides pteronyssinus extracts.

Results of total and specific IgE levels before and after immunotherapy carried out with calcium-phosphate-adjuvanted house dust and mite allergens for 36 patients are reported here. Total and specific IgE levels were evaluated by radioimmunological methods based on the IgE/anti-IgE interaction. Total IgE levels were not significantly different before and after immunotherapy; most of the specific IgE levels remained on the same order. IgE levels after immunotherapy varied only slightly in most patients and were not correlated with therapeutic results. Advantages of calcium phosphate compared to aluminium compounds are reported.

[Undetected cryoglobulinaemia may alter the serum protein results and mask dysglobulinaemia (author's transl)]. / Une cryoglobulinémie non soupçonnée peut fausser les résultats des protides sériques et faire méconnaître une dysglobulinémie.

By reporting a case of massive cryoglobulinaemia where precipitation of the cryoglobulins occurred at 35 degrees C but with no apparent clinical symptoms the authors want to draw attention to the fact that if cryoglobulinaemia remains undetected it may alter the serum protein results and mask dysglobulinaemia. However if protein electrophoresis is carried out at the same time, it is possible to detect a slight abnormality due to cryoglobulin fraction not entirely removed during centrifugation of the blood sample. This finding should incite one to look for cryoglobulins according to the usual procedure (at 37 degrees C) as well as to measure serum proteins on a sample also collected at 37 degrees C. Thus occasionally one happens to detect such dysglobulinaemia and if all results point to a diagnosis of myeloma -- as was the case here -- treatment can then be started early with advantage.