Abramson AL. Recurrent respiratory papillomatosis: a complex defect in immune responsiveness to human papillomavirus-6 and -11. APMIS 2010; 118: 455-470. Recurrent respiratory papillomatosis (RRP) is a rare disease of the larynx caused by infection with human papillomaviruses (HPV) -6 or -11, associated with significant morbidity and on occasion mortality. Here we summarize our current understanding of the permissive adaptive and innate responses made by patients with RRP that support chronic HPV infection and prevent immune clearance of these viruses. Furthermore, we provide new evidence of T H 2-like polarization in papillomas and blood of patients with RRP, restricted CD4 and CD8 Vb repertoires, the effect of HPV-11 early protein E6 on T-cell alloreactivity, enriched Langerhans cell presence in papillomas, and evidence that natural killer cells are dysfunctional in RRP. We review the immunogenetic mechanisms that regulate the dysfunctional responses made by patients with RRP in response to HPV infection of the upper airway. In addition, we are identifying T-cell epitopes on HPV-11 early proteins, in the context of human leukocyte antigen (HLA) class II alleles enriched in RRP that should help generate a therapeutic vaccine. Taken together, RRP is a complex, multigene disease manifesting as a tissue and HPV-specific, immune deficiency that prevents effective clearance and ⁄ or control of HPV-6 and -11 infection.
Purpose
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 TH2-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.
Experimental Design
CD4+CD25+CD127low/−Foxp3+ Tregs, and CD4+CD25−CD127low/−Foxp3− T-cells within papillomas were characterized and isolated. Their suppressor function was measured by inhibition of 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 QPCR.
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−CD127low/−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 to unaffected laryngeal tissues from RRP patients and individuals without RRP. PD-L1 was elevated in papillomas compared to control laryngeal tissues.
Conclusions
Papilloma CD4+ T-cells are enriched with functional Tregs, and the adaptive Helios− Treg fraction was increased within the TH2-like papilloma micromilieu. CD4+CD25−CD127low/−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.
Recurrent respiratory papillomatosis (RRP) is a chronic, debilitating disease of the upper airway caused by human papillomavirus type 6 (HPV-6) or HPV-11. We describe responses of peripheral blood mononuclear cells (PBMC) and T cells from RRP patients and controls to the HPV-11 early proteins E6 and E7. PBMC were exposed in vitro to purified E6 or E7 proteins or transduced with fusion proteins containing the first 11 amino acids of the human immunodeficiency virus type 1 protein tat fused to E6 or E7 (tat-E6/tat-E7). T
Recurrent respiratory papillomas (RRP) are benign airway tumors, caused primarily by human papillomaviruses (HPV) types 6 and 11. The disease is characterized by multiple recurrences after surgical removal, with limited effective therapy. To identify novel targets for future therapy, we established transcriptional profiles for actively growing papillomas compared with autologous, clinically normal, laryngeal epithelia (adjacent tissue). Total ribonucleic acid (RNA) from 12 papillomas and 12 adjacent tissues were analyzed by microarray, and the matched sets of tissues compared by paired t test, to identify differentially expressed genes in papilloma tissues while minimizing variations intrinsic to individual patients. Quantitative polymerase chain reaction (PCR) was used to confirm the relative expression levels for a subset of genes. Within the 109 differentially expressed transcripts whose expression varied at least three-fold were two large groups of genes with related functions. The first group consisted of 18 genes related to host defense, including both innate and adaptive immunity. The second group contained 37 genes that likely contribute to growth of papillomas as benign tumors, since the altered pattern of expression also had been reported previously in many cancers. Our results support our previous studies that document a systemic T H 2-like adaptive immune response in RRP, and suggest that there is a role for altered innate immunity in RRP as well. We propose that HPV 6 and 11 infection establishes a tumorigenic microenvironment characterized by alteration of both innate inflammatory signals and adaptive immune responses that prevent effective T H 1-like response, in conjunction with altered expression of numerous genes that regulate cellular growth and differentiation.
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