Th2A subset drives allergic phenotype in humans

T_H2 cells were initially identified based on their capacity to make IL-4 and drive B cell antibody class switch recombination to IgG1  and IgE. However, more recently it became clear that T_H2 cells consist of several subtypes each with its own unique specialization in particular effector function such as IL-13 or IL-25 production that have nothing to do with antibody production. 

Similarly, canonical T_H2 cells were thought to be responsible for allergy phenotype in humans (and mice as well). However, new study in Science Translational Medicine suggests new subset of T_H2 cells, called T_H2A subset, is mainly responsible for food allergy phenotype. 

The authors carried out magnetic enrichment of T cells harvested from allergic patients using HLA-II tetramers. Compared to non-allergic individuals, allergic patents showed expansion of a special population of T_H2 cells expressing CD161 and CD49d. 

Interestingly, patients undergoing antigen-specific desensitization showed selective loss of these T_H2A cells.

In summary, it is clear that different subset of T_H2 cells exist, some naturally others only during pathology, to deal with various foreign antigenic entities.

posted by David Usharauli