Article Text
PDF
Abstract
Introduction Within the UK, eosinophilia is most commonly associated with allergy and respiratory diseases such as asthma. Increasingly raised blood eosinophil counts are seen as a biomarker of heightened Th2 inflammation indicating a need to prescribe steroids in airways diseases. New treatments for severe Th2-high asthma aim to inhibit the eosinophilic pathway to reduce pathological inflammation. However by inhibiting this pathway we risk suppressing the body’s natural defences against parasitic helminth disease – in patients with asymptomatic latent Strongyloides stercoralis there is the risk of catastrophic hyper-infection. Our particular patient cohort in East London is a diverse international community who travel frequently. We therefore sought to evaluate the prevalence of asymptomatic helminth disease in respiratory, and particularly asthma patients, within our Trust, which includes a severe asthma service where we prescribe biologics that inhibit the Th2 pathway.
Methods We prospectively tested eosinophilic patients reviewed in respiratory clinic for helminth infection using serological screening as part of a Service Evaluation. Inclusion criteria were an eosinophilia (≥0.3) or those being considered for treatment with Mepoluzimab. Patients were tested for strongyloidiasis, filariasis and schistosomiasis depending on travel history. Patients symptomatic of helminth infection (e.g., diarrhoea) were excluded from this evaluation.
Results We tested 80 patients, 32 from severe asthma clinic, 42 from the general asthma clinic and 6 from other clinics. From these 16 (20%) had positive parasite serology: 14 of these were for Strongyloides stercoralis and 1 each for filarial and schistosomal. All the positives had asthma and 4 were from the severe asthma service. The average IgE was 433 and the average eosinophil count was 0.7. There was no statistical difference between the eosinophil counts, or total IgEs, between the positive and negative groups.
Conclusion There is a high prevalence of asymptomatic parasitic infection within our cohort, suggesting local patients who have an eosinophilia should be screened for helminth disease even in the presence of another cause eosinophilia. Furthermore, we recommend all patients being assessed for a biologic that would inhibit Th2 responses, such as Mepoluzimab, should be screened for latent Stronglyloides stercoralis infection given the danger of hyper-infection upon immunosuppression.
