C5AR2 and allergic contact dermatitis: C5aR2 deficiency led to enhanced inflammatory effects induced by C5a in rodent models of complex lung injury, allergic contact dermatitis, experimental allergic asthma, anti-neutrophil cytoplasmic antibodies (ANCA), and crescentic glomerulo-nephritis, suggesting an anti-inflammatory role for C5aR2 in these models [347-351].