Could Dirofilaria immitis contribute to occult allergic sensitization? Serological evidence from allergic patients in a hyperendemic area.

Abstract

Introduction: Although human infection with Dirofilaria immitis is classically linked to benign pulmonary nodules, the immunological impact of repeated exposure to infective larvae in allergic individuals remains poorly understood. This study evaluated serological evidence of exposure and sensitization to D. immitis in human patients with allergic diseases living in Gran Canaria, a hyperendemic area for heartworm disease.

Methods: A total of 125 anonymized serum samples from patients diagnosed with allergic conditions were analyzed. Specific Immunoglobulin (Ig) G antibodies against D. immitis and Wolbachia sp., and specific IgE antibodies against D. immitis, were detected by enzyme-linked immunosorbent assay (ELISA). Associations between serological status, epidemiological variables, allergen sensitization, and eosinophilia were explored.

Results: Anti-D. immitis IgE positivity was detected in 23.2% of patients, while 6.4% showed simultaneous IgG positivity against D. immitis and Wolbachia. Peripheral eosinophilia was significantly associated with anti-D. immitis IgE seropositivity, with a higher frequency of positives among patients with eosinophilia ≥6%.

Discussion: These findings suggest that exposure to D. immitis may have immunological relevance in allergic patients from hyperendemic areas and support further investigation into its potential role in occult allergic sensitization.