CD9+ B cells induce T follicle helper cell apoptosis to mediate adenoid atrophy through the ALCAM-CD6 axis

Additionally, CD9+ B cells had a significant impact on the activation of death signals in adenoid tissue during the immune development stage. Adenoid hypertrophy was closely related to an increase in Tfh cells, along with a decrease in CD9+ B cells.

The absence of CD9 can result in a significant decrease in serum IgG levels in mice, as indicated by Cd9 knockout mice. Our findings indicate that the CD9+ B cell subset causes Tfh cells to apoptosis via the ALCAM-CD6 signaling pathway, leading to the natural atrophy of adenoids. These findings provide novel clues in the mechanisms that regulate GC regression and termination.