Programmed death-1 (PD-1) is an immunoreceptor predominantly expressed on exhausted T cells, which through an interaction with its ligand (PD-L1), controls peripheral tolerance by limiting effector functions of T lymphocytes. qRT-PCR for PD-1, PD-L1 and their splicing forms as well as flow cytometric assessment of surface expression was performed in a cohort of 58 chronic lymphocytic leukemia (CLL) patients. In functional studies, we assessed the influence of the proliferative response of leukemic B-cells induced by IL-4 and CD40L on PD-1 transcripts and expression on the protein level. The median level of PD-1, but not PD-L1, transcripts in CLL patients was higher in comparison to healthy volunteers (HVs, n = 43, p = 0.0057). We confirmed the presence of PD-1 and PD-L1 on the CLL cell surface, and found the expression of PD-1, but not PD-L1, to be higher among CLL patients in comparison to HVs (47.2% vs. 14.8%, p<0.0001). The Kaplan-Meier curves for the time to progression and overall survival in groups with high and low surface expression of PD-1 and PD-L1 revealed no prognostic value in CLL patients. After stimulation with IL-4 and CD40L, protein expression of PD-1 was significantly increased in samples that responded and up-regulated CD38. PD-1, which is aberrantly expressed both at mRNA and cell surface levels in CLL cells might represent a novel immunotolerant molecule involved in the pathomechanism of the disease, and could provide a novel target for future therapies.

Background: The programmed death 1 (PD-1) receptor pathway is responsible for the negative regulation of both T and B lymphocytes upon activation of these cells. There is growing evidence that chronic lymphocytic leukemia (CLL) cells exploit the PD-1 ligand (PD-L1) to resist antitumor immune reactions and maintain their survival by shaping their own microenvironment. Methods: We used a quantitative RT-PCR method to analyze PD-L1 gene expression in bone marrow and peripheral blood mononuclear cells, representing the proliferation and accumulation compartments of CLL. Results: PD-L1 expression was found to be significantly higher in 112 CLL patients than in controls. Levels of PD-L1 expression in bone marrow and peripheral blood were comparable and showed a positive correlation. Furthermore, expression of PD-L1 strongly correlated with expression of PD-1 receptor in mononuclear cells from the same compartment, and was not affected by incubation with immunomodulatory drug thalidomide. Conclusion: PD-L1 expression is shared between CLL cells localized in distinct disease compartments, demonstrating that PD-1/PD-L1 a universal target for therapy.

Programmed death-1 (PD-1) is a negative receptor expressed on lymphocytes including malignant B cells in chronic lymphocytic leukemia (CLL). In this work, we found that patients with CLL had a higher expression of PD-1 transcript (PDCD1) than healthy volunteers (p < 0.0001). PDCD1 expression was comparable between CLL cells from accumulation (peripheral blood) and proliferation (bone marrow) disease compartments. In blood samples of patients with mutated IGHV genes PDCD1 expression was higher than with unmutated IGHV (p = 0.0299). We demonstrated that phosphorylation of SYK and LYN, key B-cell receptor signaling kinases, was independent of PD-1 expression in patients with CLL, while ZAP-70 phosphorylation in negative tyrosine residue 292 showed strong inverse correlation (r = - 0.8, p = 0.0019). No associations between five single nucleotide polymorphisms of PDCD1, their expressions and susceptibility to CLL were found. In conclusion, PD-1 might be an independent, universal marker of CLL cells and a part of their activated phenotype, and subsequently might modulate the function of ZAP-70.

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AIM:To evaluate the clinical utility of multi-antibody strategies in the diagnosis of coeliac disease (CD), the new quantitative Polycheck immunoassays were analysed. METHODS: Retrospective StudyIgA or anti-DGP-IgG (in the case of IgA deficiency) antibodies, typical histopathological changes in duodenal mucosa described in Marsh-Oberhüber classification as at least grade 2. The diagnosis of the majority of the control subjects was functional gastrointestinal disorders. The PCP results were compared with reference EliA Celikey. RESULTS:The usage of PCPs led to the correct identification of all CD patients. In our study, PCPs showed 100% agreement with the histopathological results. PCP IgA test showed a 98% concordance and correlated positively (R = 0.651, P = 0.0014) withEliA Celikey test. The highest specificity and positive predictive value (both 100%) were observed for the detection of Polycheck anti-tTG-IgA antibodies. The highest sensitivity and negative predictive value (both 100%) were achieved by Polycheck anti-DGPIgG antibody detection. The best performance (98% sensitivity and negative predictive value, 100% specificity and positive predictive value, diagnostic accuracy -AU ROC 99%) was observed for the strategy of using both PCP IgA and IgG and determining positive outcomes of the test with two or more coeliac-specific antibodies detected. The majority of coeliac patients had multiple antibodies. All four antibodies were detected in 7 (14%) cases, 19 children (38%) were positive for three antibodies and 23 (46%) were positive for two antibodies. CONCLUSION:The present study showed that detection of coeliac-specific antibodies with multi-antibody PCPs is effective and efficacious in the diagnosis of CD.

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