Profiles of Birch Allergen Component Sensitization and Its Association with Pollen Food Allergy Syndrome in Northern China

Figures & data

Table 1 Demographic Characteristics of Birch Pollen Allergy Subjects Between PFAS and Non-PFAS Group

variants	Total (n=58)	PFAS (n=44)	Non-PFAS (n=14)	p
Age, media (IQR)	30 (17.75, 38.25)	29 (16.25, 38)	35 (22.75, 43)	0.143
Gender, male (%)	31 (53.4)	24 (54.5)	7 (50.0)	0.766
Seasonality, n (%)				0.004
Spring	16 (27.6)	8 (18.2)	8 (57.1)
Spring and autumn	42 (72.4)	36 (81.8)	6 (42.9)
Combined diseases, n (%)				0.786
Only AR	44 (75.9)	33 (75.0)	11 (78.6)
AR+asthma	14 (24.1)	11 (25.0)	3 (21.4)
Symptoms, n (%)
Local		23 (52.3)
Systemic		21 (47.7)
Allergic foods, n (%)
Fruits		38 (86.4)
Vegetables		26 (59.1)
Nuts		11 (25.0)
Legumes		8 (18.2)
Grains		5 (11.4)
Allergen component positive rate, n(%)
Bet v 1	48 (82.8)	39 (88.6)	9 (64.3)	0.036
Bet v 2	17 (29.3)	16 (36.4)	1 (7.1)	0.036
Bet v 4	0 (0)	0 (0)	0 (0)	NA
Bet v 6	1 (1.7)	0 (0)	1 (7.1)	NA
Numbers of positive allergen components (%)				0.002
0	3 (5.2)	0 (0)	3 (21.4)
1	45 (77.6)	34 (77.3)	11 (78.6)
2	10 (17.2)	10 (22.7)	0 (0)

Abbreviations: NA, not available; PFAS, pollen food allergy syndrome; AR, allergic rhinitis.

Figure 1 Sensitization rates (%) and sIgE levels (kUA/L) of various allergen components of birch pollen.

Notes: (A) sIgE levels of birch allergen components. Bet v 1 had the highest levels among the four components. Sensitization rate of different birch pollen allergen components with Bet v1 as the major component (82.8%), followed by Bet v 2 (29.3%); (B) The correlation among birch pollen allergen and different allergen components; Bet v 1 sIgE level was positively correlated. ***p < 0.001; (C) Birch allergen component sensitization pattern. 63.8% were mono-sensitized to Bet v 1, 10.3% were mono-sensitized to Bet v 2, 19.0% were both sensitized to Bet v 1 and Bet v 2. Only 1 patient (1.7%) was positive to Bet v 6; (D) Venn diagram of different allergen components.

Figure 2 Differences of sIgE levels of birch pollen and its allergen components in participants with food allergy and those not.

Notes: (A) comparison of sIgE levels of birch pollen, Bet v 1, Bet v 2 between PFAS and non-PFAS group. (B) comparison of sIgE levels of birch pollen, Bet v 1, Bet v 2 between AA and non-AA group.

Abbreviations: PFAS, pollen food allergy syndrome; AA, apple allergy.

Figure 3 The results of the ROC analysis indicate that birch pollen allergen components can serve as reliable predictors for PFAS and apple allergy.

Notes: The diagnostic value of allergen components with PFAS (A) and apple allergy (B).

Abbreviation: ROC, receiver operating curve.

Figure 4 Regional variations in sensitization rates to birch allergen components.