Follicle Lysis in HIV-Free Lymphoid Tissues

Abstract

Follicle lysis (FL), the ‘moth-eaten’ degeneration of follicular dendritic cells (FDCs), previously regarded as specific for HIV-infected lymph follicles, was later claimed to exist in HIV-free patients. This study was performed to clarify the differences between HIV-free and HIV-induced FL. HIV-free and HIV-infected lymphoid tissues were analyzed immunohistologically. Most of HIV-free FLs were shown to lack the dark zones, the areas in germinal center composed mostly of much larger and clumped noncleaved cells, whereas HIV-induced FL in persistent generalized lymphadenopathy (PGL) lymph nodes included highly proliferative dark zones. Thus, FL in HIV-free lymphoid organs was suggested to be a physiological degenerative process with poor proliferative activity, while FL in PGL nodes includes two processes, FDC degeneration and B lymphocyte proliferation.

TGF-β Inhibits Fas-Mediated Apoptosis of a Follicular Dendritic Cell Line by Down-Regulating the Expression of Fas and Caspase-8: Counteracting Role of TGF-β on TNF Sensitization of Fas-Mediated Apoptosis

“…Many in vivo studies have shown that the FDC network degenerates in the resolution stage of normal GC responses or in certain pathological conditions (32)(33)(34)(35)(36)(37)(38). Whether the decrease or loss of the active form of TGF-␤ in local environment of involuting follicles may contribute to the degeneration of the FDC network is a subject of open question.…”