Local Intranasal Immunotherapy with High-Dose Polymerized Ragweed Extract

The possibility of local hyposensitization in allergies was envisaged since the first decades of the century and then sporadically employed, whereas controlled clinical trials of local nasal immunotherapy (LNIT) were performed only during the last 20 years. Studies currently available agree on the clinical efficacy of the treatment. LNIT was demonstrated capable of reducing symptoms both in pollen- and mite-induced rhinitis, and of modifying the specific target organ responsivity. Indeed, aqueous extracts appeared to be more effective than modified ones but were also charged by troublesome local side effects, while the recently introduced powdered extracts seemed to overcome this problem, maintaining a favourable clinical effectiveness. In a recent study we demonstrated a significant effect of LNIT on local allergic inflammation. LNIT reduced both the inflammatory infiltration and ICAM-1 expression on nasal epithelial cells upon specific nasal challenge. The effects on specific challenge appeared long-lasting, but the clinical efficacy seemed to depend strictly upon preseasonal treatment. LNIT with powdered extracts appears an effective, safe and well-tolerated treatment for allergic rhinitis. Nevertheless, its particular administration technique requires a careful choice of patients. Finally, a socioeconomical analysis shows a favourable cost/benefit ratio for LNIT if compared to classic subcutaneous immunotherapy.

Section: Experimental Results: Efficacy Safety Side Effectsmentioning

confidence: 99%

Local nasal immunotherapy: experimental evidences and general considerations

Passalacqua

Albano

Riccio

et al. 1997

“…Detection of IgE-reactive components in the systemic circulation when an allergenic extract is given intranasally introduces a new element of discussion about the possible mechanisms by which this form of treatment, recently proposed as an alternative to the parenteral route, produces clinical efficacy in rhinitic patients (15,19,21,30,33). Various hypotheses have been put forward: a common finding in allergic patients after local therapy is a rise in the threshold value as determined by specific provocation tests at the target organ, while the induction of local immunological protection (IgA and IgG blocking antibodies) is suggestive, but results are still contradictory (12,15). Recent studies in mice and rats showed that repeated inhalation of aerosols containing egg albumin or ragweed antigens induced a transient IgE response which switched oii spontaneously despite continuous exposure (10,13,26).…”

Section: Discussionmentioning

confidence: 99%

Detection of IgE‐binding activity in serum after intranasal treatment of normal rabbits with P. judaica extract

Mistrello

Rapisarda

Falagiani

1991

Local intranasal immunotherapy relieves the allergic symptoms of rhinitic patients but little is known about the absorption and distribution of inhaled allergens in the body. The aim of this study was to establish whether allergenic proteins are able to reach the bloodstream by penetrating through the nasal mucosa when aqueous P. judaica extract was administered into the nostrils of normal rabbits. Optimal conditions for a sensitive modified RAST (immunocapture RAST) were set up and the method was used to detect clinically relevant allergenic activity in the systemic circulation. The kinetic profile after intranasal treatment was compared with the profile after intravenous injection of the allergenic extract. The findings are discussed in relation to the mechanism by which local immunotherapy acts.

“…2) The effectiveness of local immunotherapy (1,2,5,7,8,13,17). This kind of treatment causes an increase of threshold dosage and a significant decrease of hyperreactivity symptoms (rhinorrhoea and obstruction).…”

Section: Discussionmentioning

confidence: 99%

Specific nasal provocation test with powder allergen

Salzano¹

1997

Reported here are the results of a large-scale trial conducted under the guidance of Prof. Giovanni Motta, which I coordinated. A total of 656 patients with nasal hyperreactivity were recruited in 51 Italian centres (18 in the north of Italy, 20 in central Italy and 13 in the south). The trial's results were as follows. 1) A clear clinical prevalence of sensitization to different allergens in the different areas of Italy, which could be roughly classified thus: a) in Northern Italy birch and grasses were in the main species; b) in Central Italy mites prevailed but oleaceae were also significant; c) in Southern Italy parietaria and oleaceae were the prevailing species. 2) Most cases were sensitive to several allergens, although a considerable proportion (22%) actually presented reactions only to one allergen and those responding account of the patients sensitive to only one allergen and those responding to a main allergen, the proportion of patients reacting clinically to only one allergen rises to 64%. 4) The specific nasal provocation test (sNPT) offers specificity comparable to in vivo diagnostic methods such as the prick test, and in vitro methods such as RAST, but is much more sensitive. 5) The sNPT can be done in any season. 6) The sNPT is highly specific below a threshold value of nasal reactivity, which can be identified for each allergen studied and expressed in Allergenic Units. 7) In patients in whom the prick test shows multiple sensitivity, the specific NPT identifies the allergen presumably responsible for the nasal reactions (main allergen). In the light of these findings double-blind specific immunotherapy was started, to last 1 year, in 107 patients (49 given placebo and 58 active treatment), with nasal allergy to grasses, parietaria and mites. The results of this treatment were as follows: 74.1% of patients presented a reduction in nasal resistance, measured by dynamic anterior rhinomanometry, indicating relief of nasal obstruction; mucociliary transport time became normal in 81% of patients, meaning that rhinorrhoea had become less marked; there was significant rise in the nasal reactivity threshold in 74.1% of patients, illustrating the degree of desensitization achieved; nasal IgA increased by 62.5% of patients and IgG in 55.2% indicating improvement in the local immunological picture. No such improvements were detectable in the patients given placebo. In conclusion, therefore, the findings of this trial in allergic rhinitis underline that the specific NPT proved more sensitive than other in vivo and in vitro diagnostic methods and is unquestionably a fundamental investigational approach for assessing nasal allergies, identifying the allergens causing the symptoms and setting up rational local immunotherapy. The sNPT also showed the efficacy of specific intranasal immunotherapy.