Renand A, Archila LD, McGinty J, Wambre E, Robinson D, Hales BJ, Thomas WR, Kwok WW. Chronic cat allergen exposure induces a TH2 cell-dependent IgG4 response related to low sensitization.
J Allergy Clin Immunol 2015;
136:1627-1635.e13. [PMID:
26371841 DOI:
10.1016/j.jaci.2015.07.031]
[Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 06/15/2015] [Accepted: 07/17/2015] [Indexed: 01/13/2023]
Abstract
BACKGROUND
In human subjects, allergen tolerance has been observed after high-dose allergen exposure or after completed allergen immunotherapy, which is related to the accumulation of anti-inflammatory IgG4. However, the specific T-cell response that leads to IgG4 induction during chronic allergen exposure remains poorly understood.
OBJECTIVE
We sought to evaluate the relationship between cat allergen-specific T-cell frequency, cat allergen-specific IgE and IgG4 titers, and clinical status in adults with cat allergy with and without cat ownership and the cellular mechanism by which IgG4 is produced.
METHODS
Fel d 1-, Fel d 4-, Fel d 7-, and Fel d 8-specific T-cell responses were characterized by CD154 expression after antigen stimulation.
RESULTS
In allergic subjects without cat ownership, the frequency of cat allergen (Fel d 1 and Fel d 4)-specific TH2 (sTH2) cells correlates with higher IgE levels and is linked to asthma. Paradoxically, we observed that subjects with cat allergy and chronic cat exposure maintain a high frequency of sTH2 cells, which correlates with higher IgG4 levels and low sensitization. B cells from allergic, but not nonallergic subjects, are able to produce IgG4 after cognate interactions with sTH2 clones and Fel d 1 peptide or the Fel d 1 recombinant protein.
CONCLUSION
These experiments suggest that (1) allergen-experienced B cells with the capacity to produce IgG4 are present in allergic subjects and (2) cat allergen exposure induces an IgG4 response in a TH2 cell-dependent manner. Thus IgG4 accumulation could be mediated by chronic activation of the TH2 response, which in turn drives desensitization.
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