Immune suppression in premalignant respiratory papillomas: enriched functional CD4+Foxp3+ regulatory T cells and PD-1/PD-L1/L2 expression.
OBJECTIVE
Respiratory papillomas, caused by human papillomaviruses types 6 and 11 (HPV6/11), are premalignant lesions with potential for malignant conversion. The cytokine and chemokine micromilieu of papillomas is T(H)2-like with a marked absence of IFN-γ expression. To illuminate why patients with recurrent respiratory papillomatosis (RRP) fail to effectively control their disease, we further investigated the suppressive cellular microenvironment in papillomas.


METHODS
CD4(+)CD25(+)CD127(low/-)Foxp3(+) regulatory T cells (Treg) and CD4(+)CD25(-)CD127(low/-)Foxp3(-) T cells within papillomas were characterized and isolated. Their suppressor function was measured by inhibition of peripheral blood mononuclear cell (PBMC) proliferation. Expression of PD-1, CD69, and Helios was identified on these T cells. PD-L1, PD-L2, CCL17, and CCL22 mRNA was also identified in papillomas by quantitative PCR.


RESULTS
Functional Tregs were markedly enriched in papillomas and strongly inhibited anti-CD3 and anti-CD28 antibody activated PBMC proliferation. The natural Treg marker Helios was reduced on Tregs from papillomas, indicating that the majority of Tregs in papillomas are adaptive. The majority of the papilloma-derived CD4(+) T cells expressed the CD4(+)CD25(-)CD127(low/-)Foxp3(-)PD1(+)CD69(+) phenotype and failed to suppress PBMC proliferation, suggesting that they are chronically activated and exhausted. The Treg-attracting chemokine CCL22 was equally expressed by all laryngeal tissues examined. However, CCL17 was robustly expressed by papillomas compared with unaffected laryngeal tissues from RRP patients and individuals without RRP. PD-L1 was elevated in papillomas compared with control laryngeal tissues.


CONCLUSIONS
Papilloma CD4(+) T cells are enriched with functional Tregs, and the adaptive Helios(-) Treg fraction was increased within the T(H)2-like papilloma micromilieu. CD4(+)CD25(-)CD127(low/-)Foxp3(-) T-cells failed to suppress PBMC proliferation and may be exhausted. The PD-1/PDL-1 pathway may represent an additional immunosuppressive mechanism that contributes to defective HPV6/11 clearance in RRP.
The Feinstein Institute for Medical Research, 350 Community Drive, Room 1239, Manhasset, NY 11030, USA.
Lynda J
LJ
Hatam
James A
JA
Devoti
David W
DW
Rosenthal
Fung
F
Lam
Allan L
AL
Abramson
Bettie M
BM
Steinberg
Vincent R
VR
Bonagura
D060890:B7-H1 Antigen / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D049109:Cell Proliferation; D054414:Chemokine CCL17 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D054422:Chemokine CCL22 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D052140:Human papillomavirus 11 / Q000276:immunology; D052163:Human papillomavirus 6 / Q000276:immunology; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008297:Male; D010212:Papilloma / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D030361:Papillomavirus Infections / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011230:Precancerous Conditions / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D061027:Programmed Cell Death 1 Ligand 2 Protein / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D061026:Programmed Cell Death 1 Receptor / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D012142:Respiratory Tract Neoplasms / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism; D059016:Tumor Microenvironment / Q000276:immunology
D060890:B7-H1 Antigen; C106230:CCL17 protein, human; C515482:CCL22 protein, human; C423236:CD274 protein, human; D054414:Chemokine CCL17; D054422:Chemokine CCL22; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C105992:PDCD1 protein, human; C556977:PDCD1LG2 protein, human; D061027:Programmed Cell Death 1 Ligand 2 Protein; D061026:Programmed Cell Death 1 Receptor