Alpha-Gal Syndrome: Clinical Presentation, New Concepts, and Unmet Needs

Impact of Unexplored Data Sources on the Historical Distribution of Three Vector Tick Species in Illinois

We updated the Illinois historical (1905-December 2017) distribution and status (not reported, reported or established) maps for Amblyomma americanum (L.) (Acari: Ixodidae), Dermacentor variabilis (Say) (Acari: Ixodidae), and Ixodes scapularis (Say) (Acari: Ixodidae) by compiling publicly available, previously unexplored or newly identified published and unpublished data (untapped data). Primary data sources offered specific tick-level information, followed by secondary and tertiary data sources. For A. americanum, D. variabilis, and I. scapularis, primary data contributed to 90% (4,045/4,482), 80% (2,124/2,640), and 32% (3,490/10,898) tick records vs 10%, 20%, and 68%, respectively from secondary data; primary data updated status in 95% (62/65), 94% (51/54) and in 90% (9/10) of the updated counties for each of these tick species; by 1985 there were tick records in 6%, 68%, and 0% of the counties, compared to 20%, 72%, and 58% by 2004, and 77%, 96%, and 75% of the counties by 2017, respectively for A. americanum, D. variabilis, and I. scapularis. We document the loss of tick records due to unidentified, not cataloged tick collections, unidentified ticks in tick collections, unpublished data or manuscripts without specific county location, and tick-level information, to determine distribution and status. In light of the increase in tick-borne illnesses, updates in historical distributions and status maps help researchers and health officials to identify risk areas for a tick encounter and suggest targeted areas for public outreach and surveillance efforts for ticks and tick-borne diseases. There is a need for a systematic, national vector surveillance program to support research and public health responses to tick expansions and tick-borne diseases.

Prevalence and Impact of Type I Sensitization to Alpha-Gal in Patients Consulting an Allergy Unit

BACKGROUND

Alpha-gal syndrome is a complex allergy with high clinical relevance regarding mammalian-derived food and drugs and is characterized by the presence of IgE antibodies directed at the carbohydrate galactose-α-1,3-galactose. As not all alpha-gal sIgE-positive individuals pre-sent clinical symptoms upon consumption of mammalian meat, the diagnostic value of alpha-gal sIgE has yet to be clarified.

OBJECTIVE

To investigate the prevalence of alpha-gal-sIgE positivity among allergy patients, examine the impact of tick bites as associated risk factors and determine the diagnostic value of alpha-gal-sIgE positivity.

METHODS

A retrospective cross-sectional study evaluating patients in the Allergy Unit was performed. Alpha-gal-sIgE levels were assessed by ImmunoCAP assay. Exposure to tick bites was assessed by a questionnaire. A receiver operating characteristics (ROC) curve analysis was performed to determine the diagnostic value of alpha-gal sIgE for the diagnosis of alpha-gal syndrome.

RESULTS

In the study population (n = 1369), the overall prevalence of alpha-gal-sIgE-positive (≥0.10 kUA/L) individuals was 19.9%, and the highest prevalence (30.2%) was found in patients with insect venom allergies. A reported tick bite within the 12 months prior to blood sampling significantly increased the risk of alpha-gal-sIgE positivity (OR 2.084). The ROC curve analysis indicated alpha-gal sIgE ≥0.54 kUA/L as the optimal cutoff point for assessing the diagnostic value of alpha-gal syndrome in allergy patients.

CONCLUSIONS

In allergy care settings, alpha-gal-sIgE positivity is a common finding. Alpha-gal sIgE is a sensitive marker in the diagnosis of alpha-gal syndrome but has limited predictive value for the characteristics or severity of this allergy.