Objective approach for fending off the sublingual immunotherapy placebo effect in
subjects with pollenosis: double-blinded, placebo-controlled trial.
Author(s): Kralimarkova TZ(1), Popov TA(2), Staevska M(1), Mincheva R(1), Lazarova C(1),
Racheva R(1), Mustakov TB(1), Filipova V(1), Koleva M(1), Bacheva K(1), Dimitrov
VD(1).
Affiliation(s): Author information:
(1)Clinic of Allergy & Asthma, Medical University Sofia, Sofia, Bulgaria.
(2)Clinic of Allergy & Asthma, Medical University Sofia, Sofia, Bulgaria. Electronic
address: ted.popov@gmail.com.
Publication date & source: 2014, Ann Allergy Asthma Immunol. , 113(1):108-13
BACKGROUND: Symptom scoring for the assessment of allergen immunotherapy is
associated with a substantial placebo effect.
OBJECTIVE: To assess the ability of exhaled breath temperature (EBT), a putative
marker of airway inflammation, to evaluate objectively the efficacy of grass
pollen sublingual immunotherapy in a proof-of-concept study.
METHODS: This was a double-blinded, placebo-controlled clinical trial in 56
subjects (mean ± SD 30 ± 12 years old, 33 men) sensitized to grass pollen. The
objective measurements were EBT, spirometry, and periostin and high-sensitivity
C-reactive protein in blood. Overall discomfort scored on a visual analog scale
was used as a proxy for subjective symptoms. Evaluations were performed before,
during, and after the grass pollen season.
RESULTS: Fifty-one subjects (25 and 26 in the active treatment and placebo
groups, respectively) were assessed before and during the pollen season. The mean
pre- vs in-season increase in EBT was significantly smaller (by 59.1%) in the
active treatment than in the placebo group (P = .030). Of the other objective
markers, only the blood periostin level increased significantly during the pollen
season (P = .047), but without intergroup differences. Subjectively, the mean
pre- vs in-season increase in the visual analog scale score was 32.3% smaller in
the active treatment than in the placebo group, although this difference did not
reach statistical significance (P = .116).
CONCLUSION: These results suggest that the efficacy of grass pollen sublingual
immunotherapy can be assessed by EBT, a putative quantitative measurement of
airway inflammation, which is superior in its power to discriminate between
active and placebo treatment than a subjective assessment of symptoms assessed on
a visual analog scale.
TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01785394.
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