Cancer vaccines based on the identification of genes encoding cancer regression antigens

Emerging nanomaterials for cancer immunotherapy

Immunotherapy is a unique approach to treat cancer that targets tumours besides triggering the immune cells. It attempts to harness the supremacy and specificity of immune cells for the regression of malignancy. The key strategy of immunotherapy is that it boosts the natural defence and manipulates the immune system at both cellular and molecular levels. Long-lasting anti-tumour response, reduced metastasis, and recurrence can be achieved with immunotherapy than conventional treatments. For example, targeting cytotoxic T-lymphocyte antigen-4 (CTLA4) by monoclonal antibody is reported as an effective strategy against cancer progression in vivo and chimeric antigen receptor (CAR) modified T-cells are known to express a stronger anti-tumour activity. CTLA4 and CAR are, therefore, beneficial in cancer immunotherapy; however, in clinical settings, both are expensive and cause adverse side effects. Nanomaterials have augmented advantages in cancer immunotherapy, besides their utility in effective delivery and diagnostics. In particular, materials based on lipids, polymers, and metals have been sought-after for delivery technologies. Moreover, the surface of nanomaterials can be engineered using ligands, antigens, and antibodies to target immune cells. In this sense, checkpoint inhibitors, cytokines, agonistic antibodies, surface receptors, and engineered T-cells are promising to regulate the immune system against tumours. Therefore, emerging nanomaterials that can be used for the treatment of cancer is the prime focus of this review. The correlation of mode of administration and biodistribution of various nanomaterials is reviewed here. Besides, the acute and chronic side effects and outcome of clinical trials in the context of cancer immunotherapy are discussed.

Antigenic Essence: Upgrade of Cellular Cancer Vaccines

Simple Summary

Early cancer vaccines include whole-cell formulations, which operate on the principle that you should vaccinate with what you want to develop protection against. Such vaccines have been widely tested in various cancers and their advantages described but have not yet managed to pass clinical trials. Antigenic essence technology offers the possibility to revitalize the field of whole-cell-based vaccination, as the essence comprises the entire diversity of native cellular antigens. At the same time, the technology allows for precise control and purposeful change of essence composition as well as purification of essence from ballast cellular substances and also addresses issues of major histocompatibility complex restriction. Antigenic essence technology makes it possible to update many cellular vaccines that have already been developed, as well as to develop new ones, therefore introducing a new direction for anticancer vaccination research.

Abstract

The development of anticancer immunotherapy is characterized by several approaches, the most recognized of which include cellular vaccines, tumor-associated antigens (TAAs), neoantigens, and chimeric antigen receptor T cells (CAR-T). This paper presents antigenic essence technology as an effective means for the production of new antigen compositions for anticancer vaccination. This technology is developed via proteomics, cell culture technology, and immunological assays. In terms of vaccine development, it does not fit into any of the above-noted approaches and can be considered a new direction. Here we review the development of this technology, its main characteristics, comparison with existing approaches, and the features that distinguish it as a novel approach to anticancer vaccination. This review will also highlight the benefits of this technology over other approaches, such as the ability to control composition, optimize immunogenicity and similarity to target cells, and evade major histocompatibility complex restriction. The first antigenic essence products, presented under the SANTAVAC brand, are also described.

Melanoma and Vitiligo: In Good Company

Cutaneous melanoma represents the most aggressive form of skin cancer, whereas vitiligo is an autoimmune disorder that leads to progressive destruction of skin melanocytes. However, vitiligo has been associated with cutaneous melanoma since the 1970s. Most of the antigens recognized by the immune system are expressed by both melanoma cells and normal melanocytes, explaining why the autoimmune response against melanocytes that led to vitiligo could be also present in melanoma patients. Leukoderma has been also observed as a side effect of melanoma immunotherapy and has always been associated with a favorable prognosis. In this review, we discuss several characteristics of the immune system responses shared by melanoma and vitiligo patients, as well as the significance of occurrence of leukoderma during immunotherapy, with special attention to check-point inhibitors.

Dendritic cells loaded with CD44+ CT-26 colon cell lysate evoke potent antitumor immune responses

Increasing evidence supports the concept that cancer stem cells (CSCs) are responsible for cancer progression and metastasis, therapy resistance and relapse. In addition to conventional therapies for colon cancer, the development of immunotherapies targeting cancer stem cells appears to be a promising strategy to suppress tumor recurrence and metastasis. In the present study, dendritic cells (DCs) were pulsed with whole-tumor cell lysates or total RNA of CD44⁺ colon cancer stem cells (CCSCs) isolated from mouse colon adenocarcinoma CT-26 cell cultures and investigated for their antitumor immunity against CCSCs in vivo and in vitro. In a model of colon adenocarcinoma using BALB/c mice, a sequential reduction in tumor volume and weight was associated with an extended survival in tumor-bearing mice vaccinated with DCs pulsed with RNA or CCSC lysate. In addition, a lactate dehydrogenase assay indicated that cytotoxic T-cells derived from the treated mice exhibited strong cytotoxic activity. Additionally, an enzyme-linked immunosorbent assay revealed that the cytotoxic T-cells of the treated mice released higher levels of interferon-γ against CCSCs compared with those of the control group. In all experiments, the antitumor efficacy of the lysate-pulsed DC-treated and RNA-pulsed DC-treated groups were significantly higher compared with that of the DC-treated and control groups. The results of the present study indicated the potential use of DCs pulsed with cancer stem cell lysates as a potent therapeutic antigen to target CSCs in colon cancer. Additionally, the results provided a rationale for using lysate-pulsed DCs in vivo to eliminate residual tumor deposits in post-operative patients.

Pancreatic Cancer: An Emphasis on Current Perspectives in Immunotherapy

Pancreatic cancer affects both male and female individuals with higher incidences and death rates among the male population. Detection of this malignancy is delayed due to the lack of symptoms in the early-stage cancer, which makes it extremely difficult to treat. Identifying effective strategies has been a challenge for improving the survival rates in pancreatic cancer patients. Resistance to chemotherapy is often developed in pancreatic cancer treatment. Although many strategies are under clinical trials to target certain markers associated with cancer, immunotherapeutic approaches are currently gaining importance. Immunotherapy for pancreatic cancer is in the limelight after preclinical research showed some promise. Immunotherapy approaches were tested along with other treatment options to enhance the treatment effect. Adoptive cell transfer and immune checkpoint inhibitors are currently in clinical trials. The Food and Drug Administration approved pembrolizumab in a fast-tracked review for advanced pancreatic cancer patients. Pembrolizumab blocks the checkpoint protein, programmed cell death protein 1 (PD-1), on T cells to boost the response of the immune system against cancer cells, thereby shrinking tumors. The recent developments in immunotherapy and the early success in other cancers are encouraging to further test immunotherapy in pancreatic cancer. The combination of pembrolizumab and pelareorep, an isolate of human reovirus, is in phase II clinical study in metastatic disease. Depending on the results of current clinical trials and testing, the strategies in the pipeline are expected to increase the use of immunotherapy in the clinical testing setting. Success in immunotherapy is urgently needed to address the side-effects, treating patients with advanced disease and reducing metastasis for increasing the survival rate in pancreatic cancer patients.

Promising immunotherapy: Highlighting cytokine-induced killer cells

For many years, cancer therapy has appeared to be a challenging issue for researchers and physicians. By the introduction of novel methods in immunotherapy, the prospect of cancer therapy even more explained than before. Cytokine-induced killer (CIK) cell-based immunotherapy demonstrated to have potentiality in improving clinical outcomes and relieving major side effects of standard treatment options. In addition, given the distinctive features such as high safety, low toxicity effects on healthy cells, numerous clinical trials conducted on CIK cells. Due to the shortcomings that observed in CIK cell immunotherapy alone, arising a tendency to make modifications (combined modality therapy or combination therapy) including the addition of various types of cytokines, genetic engineering, combination with immune checkpoints, and so on. In this review, we have tried to bring forth the latest immunotherapy methods and their overview. We have discussed the combination therapies with CIK cells and the conducted clinical trials. This helps the future studies to use integrated therapies with CIK cells as a promising treatment of many types of cancers.

Astragalus Saponins and Liposome Constitute an Efficacious Adjuvant Formulation for Cancer Vaccines

Cancer vaccines mostly aim to induce cytotoxic T lymphocytes (CTLs) against tumors. An appropriate adjuvant is of fundamental importance for inducing cellular immune response. Since the antigen in particulate form is substantially more immunogenic than soluble form antigen, it is beneficial to interact with antigen-presenting cells membrane to induce robust CD8⁺ T cell activation following vaccination. Based on previous research, we designed an adjuvant formulation by combining Astragalus saponins, cholesterol, and liposome to incorporate antigen into a particulate delivery system, so as to enhance cellular immune response. Meanwhile, angiogenesis contributes to tumor growth and metastasis, and basic fibroblast growth factor (bFGF) is involved in tumor angiogenesis. Therefore, using lipo-saponins adjuvant formulation and a human recombinant bFGF antigen protein, we tried to induce bFGF-specific CTL response to inhibit tumor angiogenesis to achieve antitumor activity. After five immunizations, the lipo-saponins/bFGF complex elicited robust antibody response and markedly higher amount of interferon-γ in BALB/c mice, resulting in superior antitumor activities. Decreased microvessel density in CD31 immunohistochemistry and the lysis of vascular endothelial cells by the T lymphocytes from the immunized mice indicated that the immunity inhibited the angiogenesis of tumors and further led to the inhibition of tumors. Our data suggest that the approach to construct adjuvant formulation between liposome and Astragalus saponins appeared highly desirable, and that Astragalus saponins may be utilized as a valuable additive for enhancing the effectiveness of vaccines and stimulating an appropriate immune response that can benefit tumor therapy.

Signaling lymphocytic activation molecules Slam and cancers: friends or foes?

Signaling Lymphocytic Activation Molecules (SLAM) family receptors are initially described in immune cells. These receptors recruit both activating and inhibitory SH2 domain containing proteins through their Immunoreceptor Tyrosine based Switch Motifs (ITSMs). Accumulating evidence suggest that the members of this family are intimately involved in different physiological and pathophysiological events such as regulation of immune responses and entry pathways of certain viruses. Recently, other functions of SLAM, principally in the pathophysiology of neoplastic transformations have also been deciphered. These new findings may prompt SLAM to be considered as new tumor markers, diagnostic tools or potential therapeutic targets for controlling the tumor progression. In this review, we summarize the major observations describing the implications and features of SLAM in oncology and discuss the therapeutic potential attributed to these molecules.

A nano-liposome vaccine carrying E75, a HER-2/neu-derived peptide, exhibits significant antitumour activity in mice

E75 (HER-2/neu-369-377), is an immunogenic peptide which is highly expressed in breast cancer patients. The purpose of this study was to develop an effective vaccine delivery/adjuvant system by attachment of this peptide to the surface of liposomes consisting of phospholipids including distearoylphosphocholine (DSPC) and distearoyl phosphoglycerol (DSPG) with high transition temperature (Tm) and dioleoylphosphatidylethanolamine (DOPE) (a pH-sensitive lipid for cytosolic antigen delivery) to improve antitumour immune activity against the E75 peptide. For this purpose, the E75 peptide was incorporated into liposomes consisting of DSPC/DSPG/cholesterol (Chol)/DOPE (15/2/3/5 molar ratio) through conjugation with distearoylphosphoethanolamine-N-[maleimide(polyethylene glycol)-2000] (maleimide-PEG₂₀₀₀-DSPE). Immunization of BALB/c mice was performed three times with different forms of liposomal formulations at 2-week intervals and antitumour immunity responses were evaluated. Results of ELISpot and flow cytometry analysis showed that mice vaccinated with DSPC/DSPG/Chol/DOPE/E75 have significantly enhanced the antigen-specific IFN-γ response of CD8⁺ T cells and generated cytotoxic T lymphocytes (CTL) antitumour responses. CTL responses induced by this formulation resulted in inhibition of tumour progression and longer survival time in the mice TUBO tumour model. The results revealed that the liposomes consist of DSPC/DSPG/Chol/DOPE could be suitable candidates for vaccine delivery of E75 peptide for the prevention and therapy of HER2-positive breast cancer and merit further investigation.

The Role of Tumor Microenvironment in Cancer Immunotherapy

The field of tumor immunology and immunotherapy has undergone a renaissance in the past decade do in large part to a better understanding of the tumor immune microenvironment. After suffering countless successes and setbacks in the twentieth century, immunotherapy has now come to the forefront of cancer research and is recognized as an important tool in the anti-tumor armamentarium. The goal of therapy is to aid the immune system in recognition and destruction of tumor cells by enhancing its ability to react to tumor antigens. This traditionally has been accomplished by induction of adaptive immunity through vaccination or through passive delivery of immunologic effectors as in the case of adoptive cell transfer. The recent discovery of immune "checkpoints" whose purpose is to suppress immune activity and prevent auto-immunity has created a new angle by which reactivity to tumors can be enhanced. Blockers of these checkpoints have yielded impressive clinical results and have recently been approved for use in a wide variety of malignancies. With data showing increasing rates of not only treatment response, but complete remissions, immunotherapy is poised to become an increasingly utilized therapy in the treatment of cancer.

Targeting Myeloid-Derived Suppressor Cells in Cancer

Myeloid derived suppressor cells (MDSC) represent only a minor fraction of circulating blood cells but play an important role in tumor formation and progression. They are a heterogeneous group of cells that influence the tumor microenvironment by depletion of amino acids, oxidative stress, decreased trafficking of antitumor effector cells, and increased regulatory T and regulatory dendritic cell responses. Investigational treatment strategies targeting MDSCs have attempted to inhibit MDSC development and expansion (stem cell factor blockade, modulate of cell signaling, and target MDSC migration and recruitment), inhibit MDSC function (nitric oxide inhibition and reactive oxygen and nitrogen species inhibition), differentiate MDSCs into more mature cells (Vitamins A and D, all-trans retinoic acid, interleukin-2, toll-like receptor 9 inhibitors, taxanes, beta-glucan particles, tumor-derived exosome inhibition, and very small size proteoliposomes), and destroy MDSCs (cytotoxic agents, ephrin A2 degradation, anti-interleukin 13, and histamine blockers). To date, there are no Food and Drug Administration approved therapies selectively targeting MDSCs, but such therapies are likely to be implemented in the future, due to the key role of MDSCs in antitumor immunity.

Cancer gene therapy update

Objective. To provide an update about gene marking and gene therapy trials in cancer patients.

Data Sources. A MEDLINE search using the term “gene therapy” was conducted for the period 1985 to 1998. The reference lists from retrieved articles were reviewed. Meeting abstracts from the American Society of Clinical Oncology annual meeting (published in their proceedings) and the Annual Cancer Gene Therapy Symposium (published in Cancer Gene Therapy) that concerned gene therapy in cancer patients were also included.

Data Extraction. Both authors reviewed the retrieved material and included preclinical data, case reports, and clinical trials related to gene transfer or gene therapy in cancer patients.

Data Synthesis. There are several possible approaches to using gene therapy for the diagnosis and treatment of cancer and for the monitoring of cancer therapy. Exogenous genes may be used to mark cells to help better understand cancer biology or may be used directly for cancer treatment. Gene-marking trials have already provided new information about cancer biology and have demonstrated that reinfused progenitor cells may be a source of relapse in patients with acute or chronic myelogenous leukemia and neuroblastoma.

Approaches using gene therapy for cancer treatment include: using lymphocytes as gene carriers, using foreign genes to increase tumor immunogenicity, introducing tumor regression antigen genes into viruses, introducing “sensitivity” genes to produce new cytotoxic agent(s) within tumors, producing new protein product(s) to protect normal cells, replacing missing or mutant tumor suppressor genes, and inactivating oncogenes. Clinical trials using these strategies have demonstrated that gene transfer is feasible (albeit with low transduction efficiency) and that gene expression occurs; in addition, clinical responses have been noted.

The STEAP1(262-270) peptide encapsulated into PLGA microspheres elicits strong cytotoxic T cell immunity in HLA-A*0201 transgenic mice--A new approach to immunotherapy against prostate carcinoma

BACKGROUND

PLGA microsphere-based vaccination has been proven to be effective in immunotherapy of syngeneic model tumors in mice. The critical step for the translation to humans is the identification of immunogenic tumor antigens and potent vaccine formulations to overcome immune tolerance.

METHODS

HLA-A*0201 transgenic mice were immunized with eight different human prostate cancer peptide antigens co-encapsulated with TLR ligands into PLGA microspheres and analyzed for antigen-specific and functional cytotoxic T lymphocyte responses.

RESULTS

Only vaccination with STEAP1(262-270) peptide encapsulated in PLGA MS could effectively crossprime CTLs in vivo. These CTLs recognized STEAP1(262-270) /HLA-A*0201 complexes on human dendritic cells and prostate cancer cell lines and specifically lysed target cells in vivo. Vaccination with PLGA microspheres was much more potent than with incomplete Freund's adjuvant.

CONCLUSIONS

Our data suggests that there exist great differences in the immunogenicity of human PCa peptide antigens despite comparable MHC class I binding characteristics. Immunogenic STEAP1(262-270) peptide encapsulated into PLGA microspheres however was able to induce vigorous and functional antigen-specific CTLs and therefore is a promising novel approach for immunotherapy against advanced stage prostate cancer.

Annexin A3 as a potential target for immunotherapy of liver cancer stem-like cells

Cancer stem-like cells/cancer-initiating cells (CSCs/CICs) are considered to represent a small population of cancer cells that is resistant to conventional cancer treatments and responsible for tumor recurrence and metastasis. The aim of this study was to establish CSC/CIC-targeting immunotherapy. In this study, we found that Annexin A3 (ANXA3) was preferentially expressed in CSCs/CICs derived from hepatocellular carcinoma (HCC) cells compared to non-CSCs/CICs. In HCC samples, high levels of ANXA3 correlated with expansion of CD133(+) tumor cells representing CSCs/CICs in HCC; the combination of high levels of ANXA3 and CD133 was associated with progression of HCC. Overexpression of ANXA3 increased the proportion of CD133(+) cells, enhancing their tumorigenicity. On the contrary, knockdown of ANXA3 decreased CD133(+) cells and inhibited tumorigenicity. The mechanistic study revealed that ANXA3-mediated maintenance of HCC CSCs/CICs activity was likely involved with the HIF1A/Notch pathway. Using ANXA3 as a target, ANXA3-transfected dendritic cells could induce more functionally active T cells and these effector T cells could superiorly kill CD133(+) HCC CSCs/CICs in vitro and in vivo. Taken together, our findings suggest that ANXA3 plays a role in HCC CSC/CIC maintenance, and that ANXA3 may represent a potential CSC/CIC-specific therapeutic target for improving the treatment of HCC.

Manipulation of regulatory T cells and antigen-specific cytotoxic T lymphocyte-based tumour immunotherapy

The most potent killing machinery in our immune system is the cytotoxic T lymphocyte (CTL). Since the possibility for self-destruction by these cells is high, many regulatory activities exist to prevent autoimmune destruction by these cells. A tumour (cancer) grows from the cells of the body and is tolerated by the body's immune system. Yet, it has been possible to generate tumour-associated antigen (TAA) -specific CTL that are also self-antigen specific in vivo, to achieve a degree of therapeutic efficacy. Tumour-associated antigen-specific T-cell tolerance through pathways of self-tolerance generation represents a significant challenge to successful immunotherapy. CD4(+)  CD25(+)  FoxP3(+) T cells, referred to as T regulatory (Treg) cells, are selected in the thymus as controllers of the anti-self repertoire. These cells are referred to as natural T regulatory (nTreg) cells. According to the new consensus (Nature Immunology 2013; 14:307-308) these cells are to be termed as (tTreg). There is another class of CD4(+) Treg cells also involved in regulatory function in the periphery, also phenotypically CD4(+)  CD25(±) , classified as induced Treg (iTreg) cells. These cells are to be termed as peripherally induced Treg (pTreg) cells. In vitro-induced Treg cells with suppressor function should be termed as iTreg. These different Treg cells differ in their requirements for activation and in their mode of action. The current challenges are to determine the degree of specificity of these Treg cells in recognizing the same TAA as the CTL population and to circumvent their regulatory constraints so as to achieve robust CTL responses against cancer.

Hampering immune suppressors: therapeutic targeting of myeloid-derived suppressor cells in cancer

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells with suppressive properties that preferentially expand in cancer. Myeloid-derived suppressor cells mainly suppress T-cell proliferation and cytotoxicity, inhibit natural killer cell activation, and induce the differentiation and expansion of regulatory T cells. The wide spectrum of MDSC suppressive activity in cancer and its role in tumor progression have rendered these cells a promising target for effective cancer immunotherapy. In this review we briefly discuss the origin of MDSCs and their main mechanisms of suppression and focus more on the approaches developed up to date targeting of MDSCs in tumor-bearing animals and cancer patients.

Paradigm Shift in Dendritic Cell-Based Immunotherapy: From in vitro Generated Monocyte-Derived DCs to Naturally Circulating DC Subsets

Dendritic cell (DC)-based immunotherapy employs the patients’ immune system to fight neoplastic lesions spread over the entire body. This makes it an important therapy option for patients suffering from metastatic melanoma, which is often resistant to chemotherapy. However, conventional cellular vaccination approaches, based on monocyte-derived DCs (moDCs), only achieved modest response rates despite continued optimization of various vaccination parameters. In addition, the generation of moDCs requires extensive ex vivo culturing conceivably hampering the immunogenicity of the vaccine. Recent studies, thus, focused on vaccines that make use of primary DCs. Though rare in the blood, these naturally circulating DCs can be readily isolated and activated thereby circumventing lengthy ex vivo culture periods. The first clinical trials not only showed increased survival rates but also the induction of diversified anti-cancer immune responses. Upcoming treatment paradigms aim to include several primary DC subsets in a single vaccine as pre-clinical studies identified synergistic effects between various antigen-presenting cells.

Involvement of interferon-gamma genetic variants and intercellular adhesion molecule-1 in onset and progression of generalized vitiligo

Interferon-gamma (IFN-γ) is a paracrine inhibitor of melanocytes and genetic variability due to intron 1 polymorphisms in IFNG has been reported to be associated with increased risk for several autoimmune diseases. The aim of present study was to determine whether intron 1 +874A/T (rs2430561) and CA microsatellite (rs3138557) polymorphisms in IFNG are associated with generalized vitiligo (GV) susceptibility and expression of IFNG and intercellular adhesion molecule-1 (ICAM1) affects the disease onset and progression. Here we report that IFNG CA microsatellite but not +874A/T may be a genetic risk factor for GV; however, +874T allele plays a crucial role in increased expression of IFNG mRNA and protein levels which could affect the onset and progression of the disease. Active GV patients showed increased IFNG levels compared to stable GV patients. The genotype-phenotype analysis revealed that IFNG expression levels were higher in patients with +874 TT genotypes and 12 CA repeats. Patients with the early age of onset showed higher IFNG expression and female GV patients showed higher IFNG and ICAM1 expression implicating gender biasness and involvement of IFN-γ in early onset of the disease. Moreover, the increased IFN-γ levels in patients lead to increased ICAM1 expression, which could be a probable link between cytokines and T-cell involvement in pathogenesis of GV.

Correlation of increased MYG1 expression and its promoter polymorphism with disease progression and higher susceptibility in vitiligo patients

BACKGROUND

MYG1 (Melanocyte proliferating gene 1 or C12orf10) -119C/G promoter and Arg4Gln structural polymorphisms have a functional impact on its regulation. The promoter polymorphism was shown to be associated with vitiligo in Caucasian population.

OBJECTIVE

The present study explores MYG1 polymorphisms and correlates them with MYG1 mRNA expression, disease onset and progression in vitiligo patients.

METHODS

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used for genotyping of MYG1 -119C/G promoter (rs1465073) and 11-12AA/GC structural polymorphisms (rs1534284-rs1534283; Arg4Gln) in 846 vitiligo patients and 726 age-matched unaffected controls. MYG1 mRNA levels were assessed in whole blood of 166 patients and 175 controls by Real-time PCR.

RESULTS

The MYG1 -119C/G promoter polymorphism was found to be in significant association with vitiligo being 'G' allele prevalent in patients. However, 11-12AA/GC structural polymorphism was prevalently monogenic in patients and controls with only MYG1 GC (4Arg) allele being present. Significant increase in MYG1 mRNA expression was observed in vitiligo patients compared to controls. The MYG1 mRNA expression was increased in patients with active and generalized vitiligo as compared to stable and localized vitiligo. MYG1 mRNA expression was increased in patients with susceptible -119 GG genotype compared to controls. Also, patients with susceptible -119 GG genotype had early age of onset of vitiligo. Moreover, patients with age groups 1-20 years and 21-40 years showed increased expression of MYG1 mRNA compared to those of controls. Female patients showed significant increase in MYG1 mRNA and early age of onset of vitiligo compared to male patients.

CONCLUSION

The present study suggests that MYG1 -119C/G promoter polymorphism may be a genetic risk factor for susceptibility and progression of vitiligo. The up-regulation of MYG1 transcript in patients with susceptible -119GG genotype advocates the crucial role of MYG1 in autoimmune pathogenesis of vitiligo.

Tumor-associated antigens in breast cancer

The targets for the immune system are antigens present on cancer cells; however, many are not cancer-specific and may also be found on normal tissues. These antigens are often products of mutated cellular genes, aberrantly expressed normal genes, or genes encoding viral proteins. Vaccines constitute an active and specific immunotherapy designed to stimulate the intrinsic antitumor immune response by presenting tumor-associated antigens expressed on normal tissues that are overexpressed on tumor cells.

Tumor-associated autoantibodies as diagnostic and prognostic biomarkers

In the process of tumorigenesis, normal cells are remodeled to cancer cells and protein expression patterns are changed to those of tumor cells. A newly formed tumor microenvironment elicits the immune system and, as a result, a humoral immune response takes place. Although the tumor antigens are undetectable in sera at the early stage of tumorigenesis, the nature of an antibody amplification response to antigens makes tumor-associated autoantibodies as promising early biomarkers in cancer diagnosis. Moreover, the recent development of proteomic techniques that make neo-epitopes of tumor-associated autoantigens discovered concomitantly has opened a new area of ‘immuno-proteomics’, which presents tumor-associated autoantibody signatures and confers information to redefine the process of tumorigenesis. In this article, the strategies recently used to identify and validate serum autoantibodies are outlined and tumor-associated antigens suggested until now as diagnostic/prognostic biomarkers in various tumor types are reviewed. Also, the meaning of autoantibody signatures and their clinical utility in personalized medicine are discussed. [BMB Reports 2012; 45(12): 677-685]

Injection site and regulatory T cells influence durable vaccine-induced tumor immunity to an over-expressed self tumor associated antigen

Tumor protein D52 (D52) is constitutively expressed in healthy tissues and overexpressed in multiple cancers, including (but not limited to) breast, prostate and ovarian carcinomas. Although the normal functions of D52 are unknown, it is clear that increased D52 expression levels not only stimulate cell proliferation and metastasis, but also correlate with poor prognosis in a subset of breast cancer patients. The murine orthologs of D52 (mD52) shares 86% identity with its human counterpart (hD52) and mirrors hD52 expression patterns. The forced overexpression of mD52 induces anchorage-independent growth in vitro and promotes tumor formation as well as spontaneous metastasis in vivo. We have previously reported that the intramuscular administration of recombinant mD52 elicits immune responses capable of rejecting a challenge with tumor cells and preventing spontaneous metastasis only in 50% of mice. We hypothesized that mechanisms of peripheral tolerance dampen immune responses against mD52, thus limiting the protective effects of vaccination. To test this hypothesis, mice were depleted of CD25⁺ regulatory T cells (Tregs) and subcutaneously immunized with mD52 prior to a tumor challenge. The subcutaneous immunization failed to induce protective antitumor immunity unless accompanied by Treg depletion, which resulted in a rate of protection of 70% as compared with

Tumor necrosis factor B (TNFB) genetic variants and its increased expression are associated with vitiligo susceptibility

Genetic polymorphisms in TNFB are involved in the regulation of its expression and are found to be associated with various autoimmune diseases. The aim of the present study was to determine whether TNFB +252A/G (rs909253) and exon 3 C/A (rs1041981) polymorphisms are associated with vitiligo susceptibility, and expression of TNFB and ICAM1 affects the disease onset and progression. We have earlier reported the role of TNFA in autoimmune pathogenesis of vitiligo, and we now show the involvement of TNFB in vitiligo pathogenesis. The two polymorphisms investigated in the TNFB were in strong linkage disequilibrium and significantly associated with vitiligo. TNFB and ICAM1 transcripts were significantly increased in patients compared to controls. Active vitiligo patients showed significant increase in TNFB transcripts compared to stable vitiligo. The genotype-phenotype analysis revealed that TNFB expression levels were higher in patients with GG and AA genotypes as compared to controls. Patients with the early age of onset and female patients showed higher TNFB and ICAM1 expression. Overall, our findings suggest that the increased TNFB transcript levels in vitiligo patients could result, at least in part, from variations at the genetic level which in turn leads to increased ICAM1 expression. For the first time, we show that TNFB +252A/G and exon 3 C/A polymorphisms are associated with vitiligo susceptibility and influence the TNFB and ICAM1 expression. Moreover, the study also emphasizes influence of TNFB and ICAM1 on the disease progression, onset and gender bias for developing vitiligo.

Increased Tumor Necrosis Factor (TNF)-α and its promoter polymorphisms correlate with disease progression and higher susceptibility towards vitiligo

Tumor Necrosis Factor (TNF)-α, is a paracrine inhibitor of melanocytes, which plays a critical role in the pathogenesis of several autoimmune diseases including vitiligo, as abnormal immune responses have frequently been observed in vitiligo patients. Moreover, vitiligo patients show higher lesion levels of TNF-α. Genetic polymorphisms in the promoter region of TNF-α are involved in the regulation of its expression. The present study explores TNF-α promoter polymorphisms and correlates them with TNF-α transcript and protein levels in vitiligo patients and controls of Gujarat along with its effect on disease onset and progression. PCR-RFLP technique was used for genotyping of these polymorphisms in 977 vitiligo patients and 990 controls. TNF-α transcript and protein levels were measured by Real time PCR and ELISA respectively. The genotype and allele frequencies for the investigated polymorphisms were significantly associated with vitiligo patients. The study revealed significant increase in TNF-α transcript and protein levels in vitiligo patients compared to controls. In particular, haplotypes: AATCC, AACCT, AGTCT, GATCT, GATCC and AGCCT were found to increase the TNF-α levels in vitiligo patients. Analysis of TNF-α levels based on the gender and disease progression suggests that female patients and patients with active vitiligo had higher levels of TNF-α. Also, the TNF-α levels were high in patients with generalized vitiligo as compared to localized vitiligo. Age of onset analysis of the disease suggests that the haplotypes: AACAT, AACCT, AATCC and AATCT had a profound effect in the early onset of the disease. Moreover, the analysis suggests that female patients had an early onset of vitiligo. Overall, our results suggest that TNF-α promoter polymorphisms may be genetic risk factors for susceptibility and progression of the disease. The up-regulation of TNF-α transcript and protein levels in individuals with susceptible haplotypes advocates the crucial role of TNF-α in autoimmune pathogenesis of vitiligo.

Biolistic DNA vaccination against melanoma

We describe here the use of particle-mediated gene transfer for the induction of immune responses against melanoma antigens in murine tumor models using the melanocyte differentiation antigen tyrosinase-related protein 2 (TRP2) as an antigen in a murine B16 melanoma model. We have utilized marker genes such as β-galactosidase (βgal) and EGFP, which can be readily detected, as control antigens to establish the gene delivery and to detect antigen-specific humoral and cellular immune responses. After biolistic DNA vaccination with plasmids encoding the TRP2 gene we observed the induction of TRP2-specific T-cells and antibodies associated with vitiligo-like fur depigmentation and tumor immunity against B16 melanoma cells. Here we describe the preparation of cartridges with DNA-coated gold beads and the in vivo gene transfer into skin using the Helios Gene Gun system. We also describe protocols for the measurement of humoral and cellular immune responses against the melanocyte differentiation antigen TRP2. These protocols can subsequently be adapted to other antigens.

Molecular cancer vaccines: Tumor therapy using antigen-specific immunizations

Vaccination against tumors promises selective destruction of malignant cells by the host's immune system. Molecular cancer vaccines rely on recently identified tumor antigens as immunogens. Tumor antigens can be applied in many forms, as genes in recombinant vectors, as proteins or peptides representing T cell epitopes.Analysis of various aspects indicates some advantage for peptide-based vaccines over the other modalities. Further refinements and extensively monitored clinical trials are necessary to advance molecular cancer vaccines from concepts into powerful therapy.

Multiple linear epitopes (B-cell, CTL and Th) of JEV expressed in recombinant MVA as multiple epitope vaccine induces a protective immune response

Epitope-based vaccination might play an important role in the protective immunity against Japanese encephalitis virus (JEV) infection. The purpose of the study is to evaluate the immune characteristics of recombinant MVA carrying multi-epitope gene of JEV (rMVA-mep). The synthetic gene containing critical epitopes (B-cell, CTL and Th) of JEV was cloned into the eukaryotic expression vector pGEM-K1L, and the rMVA-mep was prepared. BALB/c mice were immunized with different dosages of purified rMVA-mep and the immune responses were determined in the form of protective response against JEV, antibodies titers (IgG1 and IgG2a), spleen cell lymphocyte proliferation, and the levels of interferon-γ and interleukin-4 cytokines. The results showed that live rMVA-mep elicited strongly immune responses in dose-dependent manner, and the highest level of immune responses was observed from the groups immunized with 10⁷ TCID₅₀ rMVA-mep among the experimental three concentrations. There were almost no difference of cytokines and neutralizing antibody titers among 10⁷ TCID₅₀ rMVA-mep, recombinant ED3 and inactivated JEV vaccine. It was noteworthy that rMVA-mep vaccination potentiates the Th1 and Th2-type immune responses in dose-dependent manner, and was sufficient to protect the mice survival against lethal JEV challenge. These findings demonstrated that rMVA-mep can produce adequate humoral and cellular immune responses, and protection in mice, which suggested that rMVA-mep might be an attractive candidate vaccine for preventing JEV infection.

In vitro induction of anterior gradient-2-specific cytotoxic T lymphocytes by dendritic cells transduced with recombinant adenoviruses as a potential therapy for colorectal cancer

Anterior gradient-2 (AGR2) promotes tumor growth, cell migration, and cellular transformation, and is one of the specific mRNA markers for circulating tumor cells in patients with gastrointestinal cancer. We investigated the feasibility of AGR2 as a potent antigen for tumor immunotherapy against colorectal cancer (CRC) cells using dendritic cells (DCs) transduced with a recombinant adenovirus harboring the AGR2 gene (AdAGR2). DCs transduced with a recombinant adenovirus encoding the AGR2 gene (AdAGR2/DCs) were characterized. These genetically-modified DCs expressed AGR2 mRNA as well as AGR2 protein at a multiplicity of infection of 1,000 without any significant alterations in DC viability and cytokine secretion (IL-10 and IL-12p70) compared with unmodified DCs as a control. In addition, AdAGR2 transduction did not impair DC maturation, but enhanced expression of HLA-DR, CD80, and CD86. AdAGR2/DCs augmented the number of IFN-γ-secreting T-cells and elicited potent AGR2-specific cytotoxic T lymphocytes capable of lysing AGR2-expressing CRC cell lines. These results suggest that AGR2 act as a potentially important antigen for immunotherapy against CRC in clinical applications.

Reflections upon human cancer immune responsiveness to T cell-based therapy

Immune-mediated rejection of human cancer is a relatively rare but well-documented phenomenon. Its rate of occurrence progressively increases from the occasional observation of spontaneous regressions to the high rate of complete remissions observed in response to effective treatments. For two decades, our group has focused its interest in understanding this phenomenon by studying humans following an inductive approach. Sticking to a sequential logic, we dissected the phenomenon by studying to the best of our capability both peripheral and tumor samples and reached the conclusion that immune-mediated cancer rejection is a facet of autoimmunity where the target tissue is the cancer itself. As we are currently defining the strategy to effectively identify the mechanisms leading in individual patients to rejection of their own tumors, we considered useful to summarize the thought process that guided us to our own interpretation of the mechanisms of immune responsiveness.

Cellular-based immunotherapies for patients with glioblastoma multiforme

Treatment of patients with glioblastoma multiforme (GBM) remains to be a challenge with a median survival of 14.6 months following diagnosis. Standard treatment options include surgery, radiation therapy, and systemic chemotherapy with temozolomide. Despite the fact that the brain constitutes an immunoprivileged site, recent observations after immunotherapies with lysate from autologous tumor cells pulsed on dendritic cells (DCs), peptides, protein, messenger RNA, and cytokines suggest an immunological and even clinical response from immunotherapies. Given this plethora of immunomodulatory therapies, this paper gives a structure overview of the state-of-the art in the field. Particular emphasis was also put on immunogenic antigens as potential targets for a more specific stimulation of the immune system against GBM.

Tumor-associated antigens for specific immunotherapy of prostate cancer

Prostate cancer (PCa) is the most common noncutaneous cancer diagnosis and the second leading cause of cancer-related deaths among men in the United States. Effective treatment modalities for advanced metastatic PCa are limited. Immunotherapeutic strategies based on T cells and antibodies represent interesting approaches to prevent progression from localized to advanced PCa and to improve survival outcomes for patients with advanced disease. CD8⁺ cytotoxic T lymphocytes (CTLs) efficiently recognize and destroy tumor cells. CD4⁺ T cells augment the antigen-presenting capacity of dendritic cells and promote the expansion of tumor-reactive CTLs. Antibodies mediate their antitumor effects via antibody-dependent cellular cytotoxicity, activation of the complement system, improving the uptake of coated tumor cells by phagocytes, and the functional interference of biological pathways essential for tumor growth. Consequently, several tumor-associated antigens (TAAs) have been identified that represent promising targets for T cell- or antibody-based immunotherapy. These TAAs comprise proteins preferentially expressed in normal and malignant prostate tissues and molecules which are not predominantly restricted to the prostate, but are overexpressed in various tumor entities including PCa. Clinical trials provide evidence that specific immunotherapeutic strategies using such TAAs represent safe and feasible concepts for the induction of immunological and clinical responses in PCa patients. However, further improvement of the current approaches is required which may be achieved by combining T cell- and/or antibody-based strategies with radio-, hormone-, chemo- or antiangiogenic therapy.

Intracellular signal transduction and modification of the tumor microenvironment induced by RET/PTCs in papillary thyroid carcinoma

RET gene rearrangements (RET/PTCs) represent together with BRAF point mutations the two major groups of mutations involved in papillary thyroid carcinoma (PTC) initiation and progression. In this review, we will examine the mechanisms involved in RET/PTC-induced thyroid cell transformation. In detail, we will summarize the data on the molecular mechanisms involved in RET/PTC formation and in its function as a dominant oncogene, on the activated signal transduction pathways and on the induced gene expression modifications. Moreover, we will report on the effects of RET/PTCs on the tumor microenvironment. Finally, a short review of the literature on RET/PTC prognostic significance will be presented.

Vaccines for glioblastoma and high-grade glioma

Vaccination by administering tumor antigen plus cell-free or cellular adjuvant has garnered hope for more effective, less toxic therapy for patients with malignant brain tumors including glioblastoma multiforme. To determine if this approach demonstrates ample clinical promise, all published reports of vaccination for glioma were evaluated. These reports suggest vaccination is associated with low toxicity and favorable clinical outcomes. The possibility of selection bias is evident in many published vaccine trials, but several of the more recent ones appropriately attempt to account for bias. Effective induction of antitumor immunity is consistently observed, and, in the latest trials, correlates with significant clinical improvement.

Telomerase as a tumor-associated antigen for cancer immunotherapy

Telomerase reverse transcriptase hTERT is an attractive target for cancer immunotherapy given its broad expression in human tumors and its demonstrated immunogenicity. Human and murine model systems demonstrate that CD8(+) cytotoxic T-lymphocytes (CTL) and CD4(+) helper T-lymphocytes can recognize dominant epitopes derived from TERT. CTL kill TERT-positive tumor cells of multiple histologies, although there is some disagreement regarding the level of processing and presentation of certain TERT peptides within the context of MHC class I molecules. CTL recognizing modified, low-affinity cryptic TERT epitopes have also been generated that protect against tumor challenge in a murine model. Several phase I clinical trials testing hTERT as a cancer vaccine target have shown the induction of T-cell immune responses but minimal toxicities, including bone marrow toxicity, in patients with multiple types of cancer. Several studies report some patients experiencing clinical benefit, including partial tumor regression, providing further encouragement for hTERT as broadly applicable target for cancer immunotherapy.

Antitumor activity of liposomal ErbB2/HER2 epitope peptide-based vaccine constructs incorporating TLR agonists and mannose receptor targeting

Synthetic and molecularly defined constructs containing the minimal components to mimic and amplify the physiological immune response are able to induce an efficient cytotoxic response. In the current study this approach was applied to the development of highly versatile liposomal constructs to co-deliver peptide epitopes in combination with TLR agonists in order to induce a specific anti-tumor cellular immune response against ErbB2 protein-expressing tumor cells. Liposomes containing ErbB2 p63-71 cytotoxic T lymphocyte (CTL) and HA307-319 T- helper (Th) peptide epitopes associated to innovative synthetic TLR2/1 (Pam(3)CAG) or TLR2/6 agonists (Pam(2)CAG and Pam(2)CGD), were injected in mice bearing ErbB2 protein-expressing tumor cells. Mannosylated ligands were also incorporated into the constructs to target antigen-presenting cells. We showed that the TLR2/6 agonists were more efficient than the TLR2/1 agonists for the eradication of tumors expressing ErbB2 protein. Furthermore, mannose-targeted liposomes displayed higher therapeutic efficiency against tumor allowing treatment with decreased quantities of both TLR ligands and peptide epitopes. Our results validated that antigen-associated mannosylated liposomes combined with efficient TLR ligands are effective vectors for vaccination against tumor. In this study we developed useful tools to evaluate the vaccination efficiency of various adjuvants and/or targeting molecules and their potential synergy.

Recent developments in cancer vaccines

The adoptive transfer of cancer Ag-specific effector T cells in patients can result in tumor rejection, thereby illustrating the immune system potential for cancer therapy. Ideally, one would like to directly induce efficient tumor-specific effector and memory T cells through vaccination. Therapeutic vaccines have two objectives: priming Ag-specific T cells and reprogramming memory T cells (i.e., a transformation from one type of immunity to another, for example, regulatory to cytotoxic). Recent successful phase III clinical trials showing benefit to the patients revived cancer vaccines. Dendritic cells (DCs) are essential in generation of immune responses, and as such represent targets and vectors for vaccination. We have learned that different DC subsets elicit different T cells. Similarly, different activation methods result in DCs able to elicit distinct T cells. We contend that a careful manipulation of activated DCs will allow cancer immunotherapists to produce the next generation of highly efficient cancer vaccines.

Dendritic cells and immunity against cancer

T cells can reject established tumours when adoptively transferred into patients, thereby demonstrating the power of the immune system for cancer therapy. However, it has proven difficult to maintain adoptively transferred T cells in the long term. Vaccines have the potential to induce tumour-specific effector and memory T cells. However, clinical efficacy of current vaccines is limited, possibly because tumours skew the immune system by means of myeloid-derived suppressor cells, inflammatory type 2 T cells and regulatory T cells (Tregs), all of which prevent the generation of effector cells. To improve the clinical efficacy of cancer vaccines in patients with metastatic disease, we need to design novel and improved strategies that can boost adaptive immunity to cancer, help overcome Tregs and allow the breakdown of the immunosuppressive tumour microenvironment. This can be achieved by exploiting the fast increasing knowledge about the dendritic cell (DC) system, including the existence of distinct DC subsets that respond differentially to distinct activation signals, (functional plasticity), both contributing to the generation of unique adaptive immune responses. We foresee that these novel cancer vaccines will be used as monotherapy in patients with resected disease and in combination with drugs targeting regulatory/suppressor pathways in patients with metastatic disease.

Retrovirally engineered T-cell-based immunotherapy targeting type III variant epidermal growth factor receptor, a glioma-associated antigen

The isotype of epidermal growth factor receptor variant III (EGFRvIII) is often identified in glioblastomas. Previously, we created a mouse monoclonal antibody, 3C10 (IgG2b), that specifically recognized EGFRvIII, and a recombinant single-chain variable fragment of 3C10. The aim of the current study was to develop genetically engineered T cells, termed T-bodies, that express a chimeric receptor consisting of the 3C10 single-chain variable fragment coupled to signaling modules such as the CD3zeta (ζ) chain, for the treatment of tumors expressing mutant EGFR. After successful construction of the chimeric 3C10/CD3ζ T-cell receptor, its expression on the T-body was observed using western blotting and flow cytometry. The specificity of the T-body for EGFRvIII was evaluated using an interferon-gamma Elispot assay and a standard (51) Cr-release cytotoxicity assay. Furthermore, we demonstrated that the systemically delivered T-body infiltrated the intrabrain tumor and significantly delayed tumor growth. These results indicate that the T-body expressing the chimeric 3C10/CD3ζ T-cell receptor specifically recognized glioma cells expressing EGFRvIII. In conclusion, T-body-based immunotherapy appears to be a promising approach for the treatment of glioma.

Dendritic cell-based immunotherapy for prostate cancer

Dendritic cells (DCs) are professional antigen-presenting cells (APCs), which display an extraordinary capacity to induce, sustain, and regulate T-cell responses providing the opportunity of DC-based cancer vaccination strategies. Thus, clinical trials enrolling prostate cancer patients were conducted, which were based on the administration of DCs loaded with tumor-associated antigens. These clinical trials revealed that DC-based immunotherapeutic strategies represent safe and feasible concepts for the induction of immunological and clinical responses in prostate cancer patients. In this context, the administration of the vaccine sipuleucel-T consisting of autologous peripheral blood mononuclear cells including APCs, which were pre-exposed in vitro to the fusion protein PA2024, resulted in a prolonged overall survival among patients with metastatic castration-resistent prostate cancer. In April 2010, sipuleucel-T was approved by the United States Food and Drug Administration for prostate cancer therapy.

Vaccination with agonist peptide PSA: 154-163 (155L) derived from prostate specific antigen induced CD8 T-cell response to the native peptide PSA: 154-163 but failed to induce the reactivity against tumor targets expressing PSA: a phase 2 study in patients with recurrent prostate cancer

We conducted a clinical trial of peptide prostate specific antigen (PSA): 154-163 (155L) vaccination in human leukocyte antigen (HLA)-A2 patients with detectable and rising serum PSA after radical prostatectomy for prostate cancer (Clinicaltrials.gov identifier NCT00109811). The trial was a single dose-level, phase 2 pilot trial of 1 mg of PSA: 154-163 (155L) emulsified with adjuvant (Montanide ISA-51). The primary endpoint was the determination of immunogenicity of the vaccine; secondary outcomes were determination of toxicity and effect on serum PSA. The vaccine was given subcutaneously 7 times on weeks 0, 2, 4, 6, 10, 14, and 18. Peptide-specific CD8 T-cell responses in the peripheral blood mononuclear cells (PBMC) of patients were measured by interferon (IFN)-gamma enzyme-linked immunosorbent spot assay. CD8 T-cell cultures were also established by in vitro stimulation with the peptide presented by autologous dendritic cells. Five patients were enrolled and completed all vaccinations. No IFN-gamma response to PSA: 154-163 (155L) was detected in unfractioned PBMC in any patient either before or after vaccination. Three of 5 patients demonstrated strong IFN-gamma responses to PSA: 154-163 (155L) and native PSA: 154-163 peptides in CD8 T-cell cultures derived from postvaccination PBMC. However, peptide-specific T cells failed to recognize HLA-A2 positive targets expressing endogenous PSA. There were no significant changes in serum PSA level in any subject. No serious adverse events were observed. PSA: 154-163 (155L) is not an effective immunogen when given with Montanide ISA-51. The PSA: 154-163 peptide is poorly processed from endogenous PSA and therefore represents a cryptic epitope of PSA in HLA-A2 antigen-presenting cells.

Selected climatic variables and blood pressure in Central European patients with chronic renal failure on haemodialysis treatment

BACKGROUND/AIMS;Higher blood pressure (BP) in winter has been documented in healthy and hypertensive adults. It may potentially contribute to the observed excess winter cardiovascular mortality in the general population. The aim of the study was to assess whether BP varies similarly among patients with chronic renal failure on haemodialysis treatment, who present an increased risk of cardiovascular death.

METHODS

We retrospectively analysed values of pre-dialysis BP and parameters of fluid retention--pre-dialysis body weight and inter-dialytic weight gain measured in 49 patients (23 male, 26 female; aged 46.0+/-13.5 years) from 1995 to 1998. For each patient we calculated deviations of monthly mean values of systolic BP, diastolic BP, pre-dialysis body weight and inter-dialytic weight gain from the lowest monthly means of these parameters in a given year. Monthly means of these deviations for the whole study group (dSBP, dDBP, dBW, dWG, respectively) were subsequently computed. Monthly means of air temperature (T), air relative humidity (H) and atmospheric pressure (AP) were provided by the local Institute of Meteorology. The Wilcoxon paired test was applied to compare mean values of BPs and parameters of fluid retention of every patient in three warmest and three coldest months of each year. Spearman rank correlation analysis was employed to evaluate relationships between dSBP, dDBP and climatic variables, dBW or dWG.

RESULTS

Systolic BP was higher in summer than in winter (146.6+/-20.5 vs 143.4+/-18.9 mmHg; p<0.00001). Diastolic BP was also higher in summer than in winter (82.6+/-8.5 vs 79.6+/-7.3 mmHg; p<10(-9)). Pre-dialysis body weight and inter-dialytic weight gain did not differ between summer and winter (66.0+/-13.2 vs 66.0+/-13.2 kg; p=0.98 and 2.27+/-0.6 vs 2.29+/-0.5 kg; p=0.53). There was a positive correlation between dSBP and T (RS=0.424, p<0.003), as well as dDBP and T (RS=0.591, p<0.00001) and an inverse correlation between dSBP and H (RS=-0.372, p<0.01), as well as dDBP and H (RS=-0.408, p<0.004). There were no significant associations between BPs and AP, dBW or dWG.

CONCLUSIONS

In haemodialysed patients from southern Poland, BP is higher in summer than in winter. Changes in BP are related to seasonal changes in climatic variables--air temperature and air relative humidity. Seasonal variation in BP is not associated with variation in fluid retention. Possible alteration of cardiovascular reactivity to changes in climatic environment in haemodialysed chronic renal failure patients may be one of the potential explanations of these observations.