Introduction: The successful introduction of immune checkpoint blockade approaches to renal-cell carcinoma (RCC) treatment indicates the importance of molecules regulating the T cell response to RCC risk and progression.Material and methods: In this study, we evaluate the association of variations in the CTLA-4, BTLA and CD28 genes with overall survival (OS) of RCC patients and specifically clear cell RCC (ccRCC) patients. The following single nucleotide polymorphisms (SNPs) previously genotyped using the RFLP method or TaqMan SNP Genotyping Assays were analyzed: CTLA-4 gene: c.49A>G (rs231775), g.319C>T (rs5742909), g.*6230G>A (CT60; rs3087243), g.*10223G>T (Jo31; rs11571302); CD28 gene: c.17+3T>C (rs3116496), c.-1042G>A (rs3181098); BTLA gene: rs2705511, rs1982809, rs9288952, rs9288953, rs2705535 and rs1844089.Results: During long term observation (6.5 years) we discovered that possessing the A allele at BTLA rs1844089 SNP, together with advanced disease (stage ≥ 3, tumor grade > 3, tumor diameter ≥ 70 mm), is an independent risk factor of death which increases the hazard ratio (HR) of death by more than two-fold (HR = 2.21, 95% CI: 1.28–3.83). Furthermore, the OS of patients bearing this allele is 6 months shorter than for homozygous (GG) patients (42.5 vs. 48.2 months).Conclusions: Our results indicate for the first time that genetic variation within the gene encoding BTLA is significantly associated with overall survival in clear cell renal cell carcinoma patients.

Given that we have demonstrated that miR-155-5p is increased in CLL PBMCs and that its reduction with inhibitory siRNA partially restores the immune checkpoint BTLA protein level in CLL B cells, risk stratification for using anti-miR-155-based immunotherapy in CLL seems reasonable, particularly with its potential impact on T cells. Therefore, we aimed to assess the role of miR-155-5p in the epigenetic modification of BTLA levels in CLL T cells, especially since we observed that BTLA expression unfavorably promotes increased proliferative activity and IL-4 secretion in T cells, thus suggesting BTLA malfunction in the CLL T cell subset. Transfection of PBMCs with an inhibitor of miR-155-5p (INH) led to about a ten-fold down-regulation of miR-155-5p levels compared to control siRNA (NC) both in CLL patients and healthy individuals (HC), as assessed by RT-qPCR. Additionally, we did not find any significant differences in BTLA protein expression in T cells after silencing miR-155-5p in either examined group. We demonstrated for the first time that immunotherapy approaches based on systemic administration of anti-miR-155-5p therapeutics would be a favorable strategy in CLL, since they do not affect BTLA expression in T cell populations and could benefit CLL patients with impaired BTLA levels on CLL cells.