Background:
Igg4-related disease (ird) is characterized by systemic igg4 antibody responses and by infiltration of igg4-expressing plasma cells into the affected organs. although t helper type 2 (th2) cytokines are implicated in enhanced igg4 responses, molecular mechanisms accounting for the development of igg4 antibody responses are poorly defined. since basophils function as antigen-presenting cells for th2 responses, we tried to clarify the role of basophils in the development of igg4 responses in this study.
Methods:
Igg4 and cytokine responses to various nucleotide-binding oligomerization domain-like receptor and toll-like receptor (tlr) ligands were examined by using basophils isolated from healthy controls and from patients with igg4-related disease.
Results:
Activation of tlrs in basophils from healthy controls induced igg4 production by b cells, which effect was associated with enhanced production of b cell activating factor (baff) and il-13. in addition, activation of tlrs in basophils from patients with ird induced a large amount of igg4 by b cells from healthy controls. this enhancement of igg4 production was again associated with baff and il-13.
Conclusions:
These data suggest that innate immune responses mediated through tlrs may play a role in the development of igg4-related disease, in part by production of baff from basophils.