Table 2.

Summary of studies showing conflicting evidence about the role of IL-22 in asthma murine models.

Study	Murine Model	Allergen	Route of sensitization	Method to study IL-22 effects	Phase of allergic inflammation investigated	Global effect of IL-22	Effect of IL-22 on Th2 cytokines	Effect of IL-22 on IL-17	Effect on eosinophilic inflammation	Effect on neutrophilic inflammation	Effect on AHR	Effect on airway remodeling
Takahashi et al. (127)	Balb/c	OVA	Ip	Anti-IL22 Ab	Se+Chal	Protective			↓		↓
Taube et al. (128)	C57BL/6	OVA	Ip	IL-22 KO	•Se+Chal •Chal wo Se	Protective during Se			↓		↓
Nakagome et al. (129)	Balb/c	OVA	Ip	•IL-22BP •Inducible-IL-22 expression	•Se •Se+Chal	Protective during Se			↓ only during Se			↓ (mucus) only during Se
Besnard et al. (99)	C57BL/6	OVA	Sc	•Anti-IL22 Ab •IL-22 KO	•Se •Se+Chal	•Pro-inflammatory during Se •Protective during Chal	↑ only during Se	↓	↑ only during Se		↑ only during Se	↑ (mucus) only during Se
Fang et al. (130)	C57BL/6	OVA	Ip	•Lung-inducible IL-22 expression	Se+Chal	Protective	↓		↓		↓	↓ (mucus)
Ito et al. (131)	C57BL/6	HDM	Intratracheal	IL-22 KO	Se+Chal	Protective			↓	↓	↓
Leyva-Castillo et al. (132)	Balb/c	OVA	•Ec •Ip	•Anti-IL22 Ab •IL-22 KO	Se+Chal	Pro-inflammatory with Ec Se			↑ (only after Ec Se)	↑ (requires TNFα) only after Ec Se)	↑ only after Ec Se

OVA, ovalbumin; HDM, house dust mite; Ip, intraperitoneal; Sc, subcutaneous; Ec, epicutaneous; Ab, antibody; KO, knock out gene; IL-22BP, IL-22 Binding Protein; Se, allergen sensitization; Chal, allergen challenge; wo, without; AHR, airway hyperresponsiveness.