T Follicular Helper Cells and IgA+ B cells in Gut-Associated Lymphoid Tissue are Within Normal Ranges in HIV+ Subjects on Suppressive Antiretroviral Therapy

Zaunders, John

Wednesday, July 15, 2015

Grand Hall and Gallery, Ground Floor & 1st Floor (Maritim Hotel)

John Zaunders, PhD , St Vincent's Hospital, Sydney, Australia

Michelle Bailey, BSc(Hons) , Kirby Institute, UNSW, Sydney, Australia

Kat Marks, MSc , St Vincent's Hospital, Sydney, Australia

Yin Xu, MSc , Kirby Institute, UNSW, Sydney, Australia

Nabila Seddiki, PhD , Kirby Institute, UNSW, Sydney, Australia

David A Cooper, MD , Kirby Institute, UNSW, Sydney, Australia

Anthony D Kelleher, MD , Kirby Institute, UNSW, Sydney, Australia

Mark Danta, MD , St Vincent's Hospital, Sydney, Australia

Kersten Koelsch, MD , Kirby Institute, UNSW, Sydney, Australia

CD4+ T-cells in gut-associated lymphoid tissue (GALT) are depleted early in HIV-1 infection, and possibly not fully reconstituted on antiretroviral therapy (ART). Whether this includes the T follicular helper (Tfh) subset, which helps B cell responses in germinal centres, is not known.

Fifteen healthy controls (HC) and thirteen HIV-1+ subjects on ART provided ten pinch biopsies each from 3 sites: left colon (LC), right colon (RC) and terminal ileum (TI), via endoscopy and colonoscopy. Single cell suspensions were prepared by collagenase digestion, and CD45+ve/EpCam-ve lymphocytes analyzed by flow cytometry, including cell counts of IgA+CD19+CD27+ B cells and Tfh (CD3+CD4+CD45RO+CXCR5+PD-1high).

Median Tfh cell counts from HC subjects were 2743, 4526 and 9714 from LC, RC and TI biopsies respectively, which were not significantly different to corresponding median Tfh cell counts from HIV-1+ subjects (6840, 5236, and 3703, respectively). Median IgA+ B cell counts from HC subjects were 29704, 67780 and 30367 from LC, RC and Ti, respectively, and not significantly different to HIV-1+ subject cell counts (45333, 43641 and 35266, respectively). Cell counts for CD38high IgA+ plasmablasts were also not significantly different between the two subject groups.

In conclusion, HIV+ subjects on ART appeared to have intact GALT B cell responses in vivo, including Tfh and IgA+ B cell levels, comparable to healthy adult controls

ICMI 2015

W.82 T Follicular Helper Cells and IgA+ B cells in Gut-Associated Lymphoid Tissue are Within Normal Ranges in HIV+ Subjects on Suppressive Antiretroviral Therapy