Controlled study of preseasonal immunotherapy with grass pollen extract in tablets: effect on bronchial hyperreactivity

BACKGROUND

Based on experimental results, the sublingual route for immunotherapy (IT) has been accepted as a viable alternative to the injection route, but few data on the effects on asthma are so far available.

OBJECTIVE

In the present open controlled trial we evaluated whether a preseasonal IT with grass polllen in orosoluble tablets added to pharmacotherapy, can improve non-specific bronchial hyperreactivity. The clinical efficacy was evaluated as well.

METHODS

Fifty-one patients (mean age 27.4 years) suffering from rhinoconjunctivitis and/or mild-intermittent/mild-persistent asthma due to grass pollen were allocated to two groups receiving pharmacotherapy alone (n = 25) or pharmacotherapy plus IT in tablets (n = 26). A methacholine test was performed in asthmatic subjects out of the pollen seasons at baseline and after 3 years of treatment. Symptom scores and drug intake were evaluated during pollen seasons by a diary card.

RESULTS

A significant increase p = .01) in the PD20 at the methacholine test was observed in the IT group compared to the control group. A significant clinical improvement both for rhinitis (p = .001) and asthma (p = .001) was observed in the IT group, and this improvement was paralleled by a clear-cut reduction of drug intake (p = .001). An improvement of rhinitis symptoms without modification of drug intake was seen in the control group (p = .01) The treatment was well tolerated and no relevant side effect was reported during the 3 years.

CONCLUSION

The investigated local IT reduced the nonspecific bronchial hyperreactivity. Furthermore, it was clinically effective and safe.

Oral and sublingual immunotherapy: general aspects and critical considerations

Local routes for immunotherapy (IT) such as oral (OIT) and sublingual (SLIT) have the primary aim of avoiding or minimizing the risk of adverse events and of improving the compliance of the patients with IT itself. About the possible mechanisms of action, only few information are available since local IT has been deeply studied only in the last ten years. The current data about pharmacokinetics are controversial and not conclusive, since they are mostly derived from animal models. However, very recent studies have demonstrated that the sublingual/swallow modality is the most promising way of mucosal immunotherapy. Thus, SLIT could be shown to lead to systemic immunological effects and to a decreased responsiveness of target organs. Furthermore, no severe adverse events were reported in the SLIT-studies. Some studies indicate that SLIT is as effective as subcutaneous IT, whilst OIT is not recommended for the clinical practice. SLIT would appear particularly suitable for pediatric patients. Administration schedules include a build-up phase and a maintenance phase which can be administered either preseasonally or continuously, and rush schedules for preseasonal IT are also available. Furthermore, SLIT reduces time and money expenses usually required by SIT since it is self-administered.

Airborne pollens and prevalence of pollenosis in western Liguria: a 10-year study

During the last 15 years aerobiology has become a relevant branch of allergy, making possible the partial clarification of the relationships between clinical diseases and environment. We performed a 10-year survey of pollen counts and pollen sensitization in a confined area on the western Ligurian coast of Italy in order to evaluate possible changes in aerobiological pattern and to correlate them with the prevalence of sensitization. Pollen counts for the area surrounding Bordighera in the period from 1988-1997 were analyzed; the occurrence of skin sensitization in outpatients were also studied during the same period. We considered the following allergens: Parietaria, grasses, Compositae, Cupressaceae, olive and birch. We also examined the possible differences between patients living on the seaside and those living inland. Over the 10-year period a significant increase in the pollen counts was seen for birch and Compositae (p = 0.001); this was accompanied by a parallel significant increase in the rate of sensitization (p = 0.004 and p = 0.01, respectively). Conversely, an increase in sensitization to Cupressaceae (p = 0.001) and olive (p = 0.03) was also seen, although no change in the pollen counts was detectable. Finally, the prevalence of sensitization to Cupressaceae and Compositae was higher in the patients living in the coastal region than those residing inland. These data suggest that a positive correlation between the pollen counts and the rate of sensitization exists for certain pollens. Nevertheless, for other species such a correlation was not apparent, and additional environmental factors maybe involved in the increased prevalence of sensitization.

[Pulmonary metabolism of beta-endorphin in asthmatic patients in asymptomatic periods and after bronchospasm induced by methacholine]

Blood concentration of endogenous beta-endorphines can change during the clinical evolution of chronic bronchopneumopathies. The authors assessed the beta-endorphine concentrations in the pulmonary arterial and systemic arterial blood in 8 asthmatic patients during a symptom-free period and after methacholine-induced bronchospasm. The beta-endorphine analysis was performed in duplicate dor each sample, by means of a RIA assay. There is not difference in the systemic arterial blood concentration of beta-endorphines between asthmatic patients and normal subjects. Furthermore, there is no change in the beta-endorphine blood concentration during the passage through the pulmonary tissue after methacoline-induced bronchospasm.