Sensitization to Per a 2 of the American cockroach correlates with more clinical severity among airway allergic patients in Taiwan.

BACKGROUND: In Taiwan, 57.5% of asthmatic patients are allergic to cockroaches, which are a major indoor allergen for immunoglobulin E (IgE)-mediated respiratory diseases.
OBJECTIVE: To determine whether sensitization to different cockroach allergenic components correlates with different clinical manifestations and severities.
METHODS: The complementary DNAs (cDNAs) encoding for Per a 1 through 7 and Per a 9 were generated by reverse transcription polymerase chain reaction and cloned into the Escherichia coli expression system. Sixty-four subjects were divided into 3 groups based on the clinical severity of their allergic reaction: those with persistent asthma and rhinitis (AS), those with allergic rhinitis only (AR), and the nonallergic controls (NA). Serum levels of interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1), chemokine (C-C motif) ligand 20 (CCL-20), and granulocyte macrophage colony-stimulating factor (GM-CSF) were measured, and the binding frequencies to each recombinant allergen were examined.
RESULTS: Serum levels of IL-8, MCP-1, and CCL-20 were significantly higher in the AS group than in the AR and NA groups. The numbers of IgE-binding allergens did not correlate with the clinical severity of airway allergy to cockroaches. However, 81% in the AS group had IgE-binding activity to Per a 2, which was significantly higher than that of the AR group (45%, P < .05). In contrast, 80% of AR patients had IgE-binding activity to Per a 9 compared with only 28.5% of AS patients (P < .01).
CONCLUSION: Allergens from American cockroaches do not have equal importance in terms of pathogenicity. Sensitization to Per a 2 correlates with more severe airway allergy and elevated proinflammatory chemokines. This may help in selecting target allergens for component resolved diagnosis and immunotherapeutic agents.