350:
Downregulation Of Type 2 Innate Lymphoid Cells (ILC2s) In The Blood By Aspirin Before But Not After Aspirin Desensitization In Aspirin Exacerbated Respiratory Disease (AERD)
Sunday, March 4, 2018
South Hall A2 (Convention Center)
Maxwell Yisheng Li, MD, Sucai Liu, PhD, Rafeul Alam, MD PhD FAAAAI
RATIONALE:
ILC2s have been implicated in allergic diseases because of their production of high levels of type 2 cytokines. Thus far, little is known concerning ILC2s and their role in aspirin exacerbated respiratory disease (AERD).

METHODS:
Blood samples from AERD patients were processed before and after aspirin desensitization. Blood samples from a non-AERD disease control group were included in the study. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured in aspirin or ethanol as a vehicle for 5 days, and then processed for flow cytometry to quantify the ILC2 population and its cytokine expression.

RESULTS:
We studied 10 AERD patients and 7 disease controls. When cultured with increasing concentrations of aspirin, the frequency of CRTH2+ ILC2s showed a decreasing trend (46% decrease) in AERD but not in disease control patients. This decreasing effect on CRTH2+ ILC2s was lost in blood samples studied after incremental aspirin challenge of AERD patients for desensitization. Interestingly, incremental aspirin challenge of patients in vivo for desensitization was associated with increased (1.6 fold) IL5 expression in CRTH2+ IL2s. Correlational analysis showed a strong linear relationship (R = 0.86) of CRTH2+ ILC2 cell frequency in the blood with total serum IgE in AERD patients.

CONCLUSIONS:
CRTH2+ ILC2s from AERD patients respond to aspirin challenge in vitro and in vivo. The in vitro response to aspirin distinguishes AERD patients from control non-AERD patients. Further studies are needed to determine if this in vitro test could reliably identify AERD patients.