Urticaria and silent parasitism by Ascaridoidea: Component-resolved diagnosis reinforces the significance of this association

Abstract

Urticaria remains a major problem in terms of aetiology, investigation, and management, and although parasitic diseases are considered potential causes, the absence of a consistent link between parasitic infections and skin allergy symptoms leads to the need for a deeper study of parameters that support this association. The objectives of this study were to analyse a possible relationship between parasitism by Ascarididae (Toxocara canis and Anisakis simplex) and the clinical expression of urticaria and to identify possible parasitic molecular markers for improving the diagnosis of unknown urticaria aetiology. The prevalence of Toxocara and Anisakis infestations was evaluated by measuring the levels of specific IgG (sIgG) and IgE (sIgE) antibodies against crude extracts and isolated components from whole larvae of Anisakis simplex (Ani s 1, Ani s 3 and Ani s 7) and Toxocara canis (TES-120, TES-70, TES-32 and TES-26) using immunologic and molecular diagnostic methods. A cross-sectional study was performed in a group of 400 individuals. The study group consisted of 95 patients diagnosed with urticaria (55 with chronic urticaria and 40 with acute urticaria). A control group consisted of 305 subjects without urticaria (182 diagnosed with respiratory allergy and 123 without allergy). Statistically significant differences were demonstrated in the seroprevalence of specific IgG and IgE antibodies between the urticaria patients and the healthy general population when isolated ascarid antigens were evaluated. The prevalence of IgG antibodies against Ani s 1, IgE antibodies against TES-120 and IgE antibodies against TES-70 were significantly different between the control individuals (healthy general population) and patients with urticaria. Moreover, the urticaria patient group demonstrated a higher seroprevalence of antibodies (sIgE and sIgG) against Anisakis simplex larva whole extract than the control group but just with statistically diferences when sIgE was evaluated. The presence of IgE and/or IgG antibodies against Ani s 3 (tropomyosin) can help to discriminate between patients with and without urticaria. Both ascarids seem to be associated with urticaria, although in our region, Anisakis seems to have greater involvement than Toxocara in this relationship. Molecular diagnostics can be used to associate urticaria with parasite infestations. Tropomyosin and Ani s 1 were the most relevant PLOS NEGLECTED TROPICAL DISEASES

Analysis of Ani s 7 and Ani s 1 allergens as biomarkers of sensitization and allergy severity in human anisakiasis

“…A preferential response to some other Anisakis allergens such as Ani s 4 (cystatin), Ani s 5 (SXP/RAL protein), Ani s 11 or Ani s 13 (haemoglobin) 41 – 43 , can explain that some sera test positive by ImmunoCAP and negative to Trisakis 170. Also, cross-reactions due to Ascaris infections was also reported as a possible cause of detecting sensitization to Anisakis in asymptomatic patients 30 , 44 , 45 , which can be related with IgE responses to pan-allergens as paramyosin (Ani s 2) 31 , 46 .…”

“…Recently, Viñas et al 30 reported that the presence of IgG and IgE antibodies to Ani s 1 and Ani s 3 allergens in serum can aid to differentiate between patients with and without urticaria in regions where Anisakis infections are frequent. Also, cross reactivity between A. simplex allergens and those from house dust mites (HDM) or shellfish among others has been proposed as the origin of positive sIgE to complete A. simplex extract (ImmunoCAP) in asymptomatic population 31 , 32 .…”

Proteomic and Bioinformatic Investigations of Heat-Treated Anisakis simplex Third-Stage Larvae

“…The present study confirmed the immunoreactivity of the heated/autoclaved Anisakis antigens with anti- A. simplex IgG antibodies that were linked to delayed IgG-based allergy. This type of hypersensitivity is associated with chronic urticaria that is a frequent symptom of anisakiasis [ 56 , 57 ]. Detection of IgG antibodies specific to Anisakis is also useful in the serodiagnosis of anisakiasis [ 42 ].…”

The Quantification of IgG Specific to α-Gal Could Be Used as a Risk Marker for Suffering Mammalian Meat Allergy

“…A receiver operating characteristic (ROC) curve was constructed to establish the sIgG cut-off value to α-Gal in order to differentiate the patients bitten by ticks who developed AGS from the control groups (atopic subjects and healthy individuals) not bitten by ticks [53].…”