Resposta imune e mecanismos de evasão na carcinogênese de lábio: um estudo imunoistoquímico / Immune response and evasion mechanisms in lip carcinogenesis: an immunohistochemical study

A vigilância imunológica, principalmente mediada por linfócitos T CD8+ , reconhece e destrói células malignas ou alteradas. Contudo, através de estratégias imunossupressoras, como as vias de sinalização do ligante de morte celular programada-1 (PD-L1) e do antígeno leucocitário humano-G (HLA-G), estas células mutadas conseguem escapar da resposta imune antitumoral. Este estudo investigou a imunoexpressão de PD-L1, HLA-G, CD8 e granzima B (GrB) no microambiente de carcinomas de células escamosas (CCEs) de lábio (n = 40), de queilites actínicas (QAs; n = 55) e de mucosa labial saudável (MLS; n = 10). As amostras foram submetidas à técnica da imunoistoquímica e as análises das imunomarcações seguiram métodos semi-quantitativos (PD-L1 e HLA-G) e quantitativos (CD8 e GrB). A expressão das proteínas foi comparada entre os três grupos de amostras, bem como com parâmetros clinicopatológicos das lesões e sobrevida global dos pacientes com CCE de lábio. A correlação entre as proteínas e o tipo do microambiente tumoral de acordo com a presença de PD-L1 e CD8 também foram avaliados. Os testes estatísticos incluíram o exato de Fisher, Mann-Whitney, Kruskal-Wallis, correlação de Spearman e log-rank para comparação das curvas de sobrevida global construídas pelo método Kaplan-Meier. O nível de significância foi estabelecido em 5%. Os números de células CD8+ e GrB+ aumentaram progressivamente de MLS para CCEs de lábio, com QAs exibindo números intermediários (p < 0,01). A menor expressão dessas proteínas foi associada à metástase para linfonodos e tumores pobremente diferenciados (p < 0,05). A expressão de PD-L1 e HLA-G em células neoplásicas/ceratinócitos e estroma/tecido conjuntivo foi significativamente maior em CCEs de lábio e QAs, em comparação com MLSs (p < 0,05). PDL1 não foi significativamente associado aos aspectos clinicopatológicos das lesões. A maioria dos CCEs de lábio mostrou coexistência de células PD-L1+ e CD8+ (72,5%) no microambiente tumoral. A expressão de PD-L1 foi diretamente correlacionada à infiltração linfocítica CD8+ e GrB+ em CCEs de lábio (p < 0,05). A expressão das proteínas não foi associada com a sobrevida global dos pacientes com CCEs de lábio (p > 0,05). Nossos achados sugerem que as moléculas imunossupressoras PD-L1 e HLA-G estão consistentemente expressas desde QAs e se mantém até fases avançadas dos CCE de lábio. A correlação entre a expressão de PD-L1 e a expressão de CD8 e GrB nos carcinomas sugere que PD-L1 pode surgir como um mecanismo de escape frente a uma resposta antitumoral ativa (AU).

Immune surveillance, mainly mediated by CD8 + T lymphocytes, recognize and destroy malignant or altered cells. However, through immunosuppressive strategies, such as the signaling pathways of the programmed cell death ligand-1 (PD-L1) and human leukocyte antigen-G (HLA-G), these mutated cells often escape the antitumor immune response. The aim of this study was to investigate and compare the immunoexpression of PD-L1, HLA-G, CD8 and granzyme B (GrB) in the microenvironment of lip squamous cell carcinomas (LSCCs; n = 40), actinic cheilitis (ACs; n = 55), and healthy lip mucosa (HLM; n = 10). The samples were submitted to immunohistochemistry and the analysis followed a semi-quantitative (PD-L1 and HLA-G) and quantitative methods (CD8 and GrB). Protein expression was compared between the three groups of samples, as well as with the lesion's clinicopathologic parameters and overall survival of patients with LSCC. Correlation between proteins and the type of tumor microenvironment according to a presence of PD-L1 and CD8 were also evaluated. Statistical tests included Fisher's exact, Mann-Whitney, Kruskal-Wallis, Spearman's correlation, as well as the log-rank for comparison of the overall survival built through Kaplan-Meier method. Significance was set at p < 0.05. The CD8+ and GrB+ cell numbers progressively increased from HLMs to LSCCs, with ACs exhibiting intermediate numbers (p < 0.01). Lower expression of these proteins was associated with lymph node metastasis and poor tumor differentiation (p < 0.05). PD-L1 and HLA-G expression in neoplastic cells/keratinocytes and stroma/connective tissue was significantly higher in LSCCs and ACs, compared to HLMs (p < 0.05). PD-L1 was not significantly associated with clinicopathological aspects of the lesions. Most LSCCs showed coexistence of PD-L1+ and CD8+ cells (72.5%) in the tumor microenvironment. PDL1 was directly correlated to CD8+ and GrB+ lymphocytic infiltration in LSCCs (p < 0.05). Proteins expression was not associated with overall survival of LSCCs patients (p > 0.05). Our findings suggest that immunosuppressive molecules PD-L1 and HLA-G are consistently expressed from ACs and are maintained until advanced stages of LSCCs. The correlation between PD-L1 expression and the expression of CD8 and GrB in carcinomas suggests that that PD-L1 may appear as an escape mechanism against an active antitumor response (AU).

Expression of programmed death 1 and its ligands in the liver of autoimmune hepatitis C57BL/6 mice / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease with unknown etiology. Programmed death 1 (PD-1) and its ligands (PD-L1 and PD-L2), B7-H1/PD-L1 and B7-DC/PD-L2, are new CD28-B7 family members that are involved in the regulation of immune responses. Previous observation suggests that PD-1 system plays an inhibitory role in regulating peripheral blood T cells, B cells and myeloid cells, thus their abnormality may be related to autoimmune diseases. This study aimed to explore the role of PD-1/PD-L1, L2 system in the pathogenesis of AIH.</p><p><b>METHODS</b>The mice model of experimental autoimmune hepatitis (EAH) was established in C57BL/6 mice and the expression levels of PD-1 and PD-L1, L2 in the murine liver and the cytokines, including interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha and interleukin (IL)-4 in the spleen were detected using reverse transcription-polymerase chain reaction (RT-PCR), and the results were compared with those of normal controls.</p><p><b>RESULTS</b>The expression levels of PD-1, PD-L1, PD-L2 mRNA were higher in EAH compared with normal controls (P < 0.05), the PD-L2/PD-1 ratio was relatively lower in EAH (EAH -0.08 +/- 0.35, normal controls 0.52 +/- 0.07, P = 0.009). In the EAH, the expression of the three cytokines were all upregulated compared with normal controls. PD-L1 had a positive correlation with the expression of IFN-gamma (r = 0.289, P < 0.05), while PD-L2 showed a positive correlation with both expressions of IL-4 (r = 0.378, P< 0.01) and IFN-gamma (r = 0.261, P < 0.05). While TNF-alpha showed no correlation with PD-L1 (r = 0.044, P = 0.736) or PD-L2 (r = 0.127, P = 0.335).</p><p><b>CONCLUSIONS</b>The expression of PD-1/PD-L1, L2 is upregulated in EAH and regulated by IFN-gamma and IL-4. PD-1 system may play an important role in the pathogenesis of AIH.</p>

PD-1 expression in peripheral T cells of patients with HBV infection and its significance / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To analyze the expression levels of PD-1 (program death factor-1) in peripheral T cells from patients infected with HBV, and to investigate its relationship with HBV serological markers.</p><p><b>METHODS</b>A total of 65 HLA-A2+ subjects, including 31 patients with chronic hepatitis B (CHB), 9 with acute resolved hepatitis B (AHB), 15 with HBV related liver cirrhosis (LC) and 10 healthy blood donators, were enrolled. The expression of PD-1 in peripheral T cells and PD-1 ligands PD-L1 and PD-L2 in PBMCs were determined by relative quantitative real-time PCR. The serum HBV markers, HBV DNA load and liver function were also measured.</p><p><b>RESULTS</b>Taken the PD-1 and PD-ligands expression in normal controls as a baseline level, the expression of PD-1 and PD-L1 from CHB patients was significantly increased, while the expression of PD-L2 was relatively low in all groups. In CHB patients, the PD-1 expression in peripheral T cells from patients with high viral load was much higher than that from those with low viral load or from normal controls. And the PD-1 expression level positively correlated with serum HBV DNA load (r=0.41, P<0.01) but not with serum ALT level.</p><p><b>CONCLUSION</b>Long-term exposure to HBV antigens in CHB patients may increase the expression of PD-1 in T cells and thus leads to the virus persistent infection.</p>

Investigation on the effects of soluble programmed death-1 (sPD-1) enhancing anti-tumor immune response / 华中科技大学学报（医学）（英德文版）

By using semi-quantitative RT-PCR method, it was found that PD-L1 mRNA but not PD-L2 mRNA was expressed in H22 hepatoma cells and both PD-L1 and PD-L2 mRNAs were expressed in tumor tissues of tumor-bearing mice and upregulated as compared with muscle tissues in normal mice and H22 hepatoma cells. PD-L1 and PD-L2 were also expressed on the surface of the activated T cells. The soluble recombinant sPD-1 expressed from the constructed eukaryotic expression vector could enhance the lysis of tumor cells by lymphocytes stimulated specifically with antigen. The expresssion of sPD-1 by local gene therapy on the inoculation site of H22 hepatoma cells could inhibit the growth of tumor. The results of this study indicate that expression of soluble receptor of negative costimulatory molecules could reduce the inhibitory effect on T cells in tumor microenvironment and enhance the cytotoxicity of T cells on tumor cells. This possibly provides a new method of improving efficacy of tumor gene therapy.