METHODS: Ten adults followed by 25 children (8-14 years) with persistent asthma and cockroach sensitization (both SPT and IgE) received diluent control and up to 8 escalating intranasal doses of German cockroach extract (0.001-2.39 mcg Blag1). NAC responses were assessed by Total Nasal Symptoms Score (TNSS), sneeze counts, Visual Analog Scale (VAS), peak nasal inspiratory flow, and nasal wash albumin and tryptase. Positive NACs were determined by TNSS and/or sneeze count criteria. Peak expiratory flow (PEF) was monitored for safety.
RESULTS: Sixty percent (6/10) of adults and 68% (17/25) of children had a positive NAC: 31% (11/35) were positive based on sneeze count alone, 14% (5/35) on TNSS alone, 20% (7/35) met both criteria. Three children responded to diluent (dose 1) and were not considered to have a positive NAC. The median response dose was 0.120 mcg/mL (dose 5) [IQR 0.0380 mcg/mL (dose 4) – 0.379 mcg/mL (dose 6)]. Other measures did not correlate with a positive NAC. One adult had a PEF decline of 20.5% from baseline during the NAC that resolved without treatment; there was no evidence of asthma exacerbation during or 24-hours post-NAC.
CONCLUSIONS: Cockroach NAC is a feasible and safe procedure in children with asthma, and may be a suitable measure to confirm clinically relevant cockroach sensitization and test clinical response in therapeutic studies for allergic airway disease.