Multicolor flow cytometric analysis of TLR2 and TLR9 expression and function in NK cells from patients with ANCA‐associated vasculitis

Abstract

Our data suggest a role of infectious stimuli triggering NK cells in AAV pathogenesis. Poor detection of NK cells in affected tissues suggests a marginal involvement in local inflammatory responses. © 2017 International Clinical Cytometry Society.

HLA-DR-Positive NK Cells Expand in Response to Mycobacterium Tuberculosis Antigens and Mediate Mycobacteria-Induced T Cell Activation

“…It was previously shown that the sensitivity of NK cells to the presence of mycobacteria can differ between individuals ( 6 , 8 ), which may be dependent from KIR receptor haplotype ( 37 ). In the peripheral blood, HLA-DR-expressing CD56 dim NK cells may be one of the “sensors” of Mtb antigens, possibly through the interaction with other cells ( 3 ), or directly through TLR2 expression ( 38 ). In isolated NK cell cultures and without prior stimulation, mycobacterial sonicate had inhibitory effect on NK cell functionality ( Figures 2B, C ), most likely due to virulence factors released after the destruction of bacterial cells.…”

Natural Killer Cells in Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis - A Review of the Literature

“…Hypothetically, this incongruence of data might also be explained by differences in the study population but also by the fact that the amount of NK cells in circulation can vary between AAV disease phenotype, different phases of the disease and in relation to treatment. In most studies of peripheral NK cells in AAV the ratio between CD56 bright and CD56 dim cells was unaltered in AAV compared to controls ( 52 , 54 , 55 , 59 ). However, ANCA-negative AAV patients had a lower proportion of CD56 dim cells compared to healthy controls whereas the frequency of CD56 bright cells and CD56 dim cells expressing high levels of CD57 were not influenced by occurrence of ANCA ( 59 ).…”

“…In most studies of peripheral NK cells in AAV the ratio between CD56 bright and CD56 dim cells was unaltered in AAV compared to controls ( 52 , 54 , 55 , 59 ). However, ANCA-negative AAV patients had a lower proportion of CD56 dim cells compared to healthy controls whereas the frequency of CD56 bright cells and CD56 dim cells expressing high levels of CD57 were not influenced by occurrence of ANCA ( 59 ). Decreased NK cell numbers, and also specifically CD56 dim cells, were further found in the active phase of disease ( 57 ) and levels returned to normal in disease remission ( 56 , 57 ), but these differences were not confirmed in all studies ( 58 ).…”

“…Several publications describe unaltered NK cell numbers and percentages in peripheral blood mononuclear cells (PBMCs) of AAV patients compared to control ( Table 1 ) ( 52 , 54 , 58 , 59 ). The literature focusing on NK cell numbers or percentage in AAV is however inconclusive, and some studies instead report a decrease or increase of NK cell numbers or percentage in these patients ( 23 , 53 , 55 – 57 ), in line with what has been reported for some other autoimmune diseases ( 60 ).…”

Issue Highlights—May 2018 (94B3)

“…In the manuscript, “ Multicolor flow cytometric analysis of TLR2 and TLR9 expression and function in NK cells from patients ANCA‐associated vasculitis ,” Rossana Scrivo and colleagues assessed NK cells in patients with anti‐neutrophil cytoplasmic antibody (ANCA)‐associated vasculitis (AAV). While many studies report decreased NK cell numbers or impaired NK cell cytotoxicity in patients with autoimmune diseases , these authors did not observe major differences in peripheral blood NK cells in AAV patients compared to healthy donors.…”