Type 2 Inflammatory Biomarker Response After Exercise Challenge Testing

Figures & data

Table 1 Subject Characteristics and Baseline Biomarker Concentration in Plasma

	Healthy Controls, n=18	Asthmatics, n=22	p-value
Age, years	25 (22–35)	26 (24–33)	0.76
Sex (male/female), n	9/9	12/10	0.78^a
Atopy, n	4	12	0.04^a
FEV1, l	4.0 (3.3–4.7)	3.8 (2.9–4.5)	0.67
FEV1, %p	101.3 (94.3–111.8)	95.2 (87.5–109.4)	0.25
Positive exercise test, n	1	9	0.013^b
Fall in FEV1 during test, %	4.6 (0.0–6.8)	6.1 (3.0–18.8)	0.067
ICS, n	0	15	<0.001^b
FeNO, ppb	15.8 (9.5–35.1)	21.8 (15.1–37.3)	0.31
Biomarkers in plasma
IL-13, pg/mL	491 (413–104814)	767 (352–12472)	0.81
TARC, pg/mL	75 (52–248)	70 (19–98)	0.26
Periostin, pg/mL	495 (361–748)	522 (329–857)	0.76
Cys-LT, pg/mL	559 (509–660)	646 (521–815)	0.23

Notes: Data are presented as median (IQR) or number. Atopy was defined as having a positive skin prick-test of airborne allergens. Positive exercise test was defined as having ≥10% fall in FEV1 after the exercise challenge test. p-value= statistical difference between healthy controls and asthmatics using Mann–Whitney U-test, Chi²-test^a or Fisher’s Exact test^b.

Abbreviations: FEV_1, forced expiratory volume in 1 s; ICS, inhaled corticosteroids; FeNO, fractional exhaled NO at flow 50 mL/s.

Figure 1 Relative change in plasma levels of IL-13 (A), TARC (B), periostin (C) and Cys-LT (D) before (pre) and 10, 30 and 60 min after an exercise challenge test in controls and asthmatics. Medians and interquartiles are presented. ***=significant change over all time points in all subjects with p<0.001 according to Friedman test.

Figure 2 Urinary levels of IL-13 (A) and LTE₄ (B) before (pre) and 30 and 60 min after an exercise challenge test in controls and asthmatics. Medians and interquartiles are presented and significant changes in all subjects are shown as **=p<0.01 and ***=p<0.001 according to Wilcoxon signed-rank test.

Table 2 Correlations Between Baseline Values of the Respective Biomarkers in Plasma or Urine

Plasma
	IL-13	TARC	Periostin
TARC	r=0.59, p=0.001
periostin	r=0.43, p=0.019	r=0.24, p=0.14
Cys-LT	r=0.58, p=0.001	r=0.33, p=0.040	r=0.27, p=0.087
Urine
	IL-13	TARC	Periostin
Periostin	r=0.61, p=0.14	n.d.
LTE4	r=0.66, p=0.027	n.d.	r=−0.45, p=0.85

Notes: Unit for all plasma biomarkers is pg/mL, and unit for all urine biomarkers is pg/mg creatinine. Significant correlations are shown in bold.