Air cleaners and filters - A rostrum

We focus this week on a Rostrum contribution, "Air filters and air cleaners: Rostrum by the American Academy of Allergy, Asthma & Immunology Indoor Allergen Committee," by Sublett et al. (J Allergy Clin Immunol 2009;125:32-38). The authors tackle the topic of air cleaners and air filtration by providing technical information on efficiency testing, and specifications of available technology as well as summarizing a literature review on the effects of air cleaning on asthma and allergy. Two air cleaning modalities are covered: portable room air cleaners and whole-house systems installed in HVAC units. The published studies reviewed by the authors typically presented findings from a single method air cleaner across short durations up to 6 months. The authors note that most results demonstrated minimal or no benefit. Overall, HEPA-filtered, portable air cleaners, and HVAC filtration systems that used high-efficiency filters and frequent routine maintenance had limited benefits. Sublett and coauthors suggest that air cleaning should be viewed as mitigation of disease progression rather than treatment for asthma and allergies. The authors go on to conclude that short-duration, single-method studies are not enough to demonstrate mitigation and that long-duration studies involving multiple air-cleaning methods are needed.

Do you have any questions for the authors, or comments about this study? We want to hear from you. Please feel free to post your own questions or comments. All questions and comments will be forwarded to the authors for a response.

“Long-term clinical efficacy in grass pollen rhinoconjunctivitis after treatment with SQ-standardized grass allergy immunotherapy tablet”

The featured article for this first blog is “Long-term clinical efficacy in grass pollen rhinoconjunctivitis after treatment with SQ-standardized grass allergy immunotherapy tablet” (Durham et al. J Allergy Clin Immunol 2009;125:131-138.e7), from our January issue. The authors report, for the first time, long-term benefit associated with sublingual immunotherapy for timothy grass pollen studied in a multisite, randomized, placebo-controlled trial. They describe significant decreases in daily allergy symptoms as well as medication use both during the study and for 1 year after subjects’ participation ended. Durham and colleagues also report progressive changes in specific IgG4 and IgE-blocking factor in subjects receiving active treatment, demonstrating disease modification, which has been previously reported for subcutaneous administration. Because oral administration was associated with only mild, local adverse effects, such as oral pruritis, Durham et al. suggest that patient-administration with prescription is supported by the safety profile.

We asked lead author Stephen R. Durham, MD, to tell us a little more about this paper, and what follow-up studies are needed:

“The results of this multicentre trial confirm long-term efficacy of sublingual grass pollen allergen tablet immunotherapy and its disease modifying potential. It will be of great interest to see whether these long-term benefits are sustained for more than one year following discontinuation. Patients had confirmed IgE-mediated disease and a suboptimal response to usual pharmacotherapy. Although local side effects of itching/swelling in the mouth were common, in general they resolved within 1-2 weeks and were not bothersome and no serious side effects were observed. The data raise the question whether the treatment should be introduced earlier in the course of the disease and in a broader range of patients. As for the subcutaneous route, initial prescription of sublingual immunotherapy should be by a Specialist in Allergy, with observation of the first dose, whereas the treatment is thereafter suitable for home self-administration. Similar studies are required for other allergens and possible preventive effects should be explored in high risk children with sensitisation with/without associated early atopic disease.”

Do you have any questions for the authors, or comments about this study? We want to hear from you. Please feel free to post your own questions or comments. All questions and comments will be forwarded to the authors for a response.