Renal transplant immunology in the last 20 years: A revolution towards graft and patient survival improvement.

To deride the hope of progress is the ultimate fatuity, the last word in poverty of spirit and meanness of mind. There is no need to be dismayed by the fact that we cannot yet envisage a definitive solution of our problems, a resting-place beyond which we need not try to go. -P.B. Medawar, 1969 * Thomas E. Starlz, also known as the Father of Clinical Transplantation, once said that organ transplantation was the supreme exception to the rule that most major advances in medicine spring from discoveries in basic science [Starzl T. The mystique of organ transplantation. J Am Coll Surg 2005 Aug;201(2):160-170]. In fact, the first successful identical-twin kidney transplantation performed by Murray's team in December 1954 (Murray J et al. Renal homotransplantations in identical twins. Surg Forum 1955;6:432-436) was the example of an upside down translation medicine: Human clinical transplantation began and researchers tried to understand the underlying immune response and how to control the powerful rejection pathways through experimental models. In the last 20 years, we have witnessed an amazing progress in the knowledge of immunological mechanisms regarding alloimmune response and an outstanding evolution on the identification and characterization of major and minor histocompatibility antigens. This review presents an historical and clinical perspective of those important advances in kidney transplantation immunology in the last 20 years, which contributed to the improvement in patients' quality of life and the survival of end-stage renal patients. In spite of these significant progresses, some areas still need substantial progress, such as the definition of non-invasive biomarkers for acute rejection; the continuous reduction of immunosuppression; the extension of graft survival, and finally the achievement of real graft tolerance extended to HLA mismatch donor: recipient pairs.

The role of immune system exhaustion on cancer cell escape and anti-tumor immune induction after irradiation.

Immune surveillance seems to represent an effective tumor suppressor mechanism. However, some cancer cells survive and become variants, being poorly immunogenic and able to enter a steady-state phase. These cells become functionally dormant or remain hidden clinically throughout. Neoplastic cells seem to be able to instruct immune cells to undergo changes promoting malignancy. Radiotherapy may act as a trigger of the immune response. After radiotherapy a sequence of reactions occurs, starting in the damage of oncogenic cells by multiple mechanisms, leading to the immune system positive feedback against the tumor. The link between radiotherapy and the immune system is evident. T cells, macrophages, Natural Killer cells and other immune cells seem to have a key role in controlling the tumor. T cells may be dysfunctional and remain in a state of T cell exhaustion, nonetheless, they often retain a high potential for successful defense against cancer, being able to be mobilized to become highly functional. The lack of clinical trials on a large scale makes data a little robust, in spite of promising information, there are still many variables in the studies relating to radiation and immune system. The clarification of the mechanisms underlying immune response to radiation exposure may contribute to treatment improvement, gain of life quality and span of patients.

Does progesterone administration in preterm labor influence Treg cells?

OBJECTIVES: The aim of this study was to determine if the actions of progesterone on preterm labor are accomplished through modulation of the percentage of regulatory T-cells (Treg). METHODS: The study was a cohort pilot study made in a single center tertiary obstetrical unit with women in preterm labor arrested with tocolytic treatment. Variation of the number and percentage of Treg cells obtained from peripheral blood samples of women with preterm labor were calculated by flow cytometry, before and after progesterone administration. RESULTS: In the paired samples for each patient, there was a significant difference in the Treg cell pool after progesterone treatment, with an increase in both their percentage (48.9 vs. 53; P=0.07) and absolute number (14.8 vs. 56.5 cells/µL; P=0.046). CONCLUSIONS: This research demonstrated a considerable increase in the Treg cell pool after progesterone treatment. This indicates a possible mechanism for progesterone treatment benefits in preterm labor, potentially increasing its more rational use.

Effects of X-radiation on lung cancer cells: the interplay between oxidative stress and P53 levels.

Lung cancer (LC) ranks as the most prevalent and deadliest cause of cancer death worldwide. Treatment options include surgery, chemotherapy and/or radiotherapy, depending on LC staging, without specific highlight. The aim was to evaluate the effects of X-radiation in three LC cell lines. H69, A549 and H1299 cell lines were cultured and irradiated with 0.5-60 Gy of X-radiation. Cell survival was evaluated by clonogenic assay. Cell death and the role of reactive oxygen species, mitochondrial membrane potential, BAX, BCL-2 and cell cycle were analyzed by flow cytometry. Total and phosphorylated P53 were assessed by western blotting. Ionizing radiation decreases cell proliferation and viability in a dose-, time- and cell line-dependent manner, inducing cell death preferentially by apoptosis with cell cycle arrest. These results may be related to differences in P53 expression and oxidative stress response. The results obtained indicate that sensibility and/or resistance to radiation may be dependent on molecular LC characteristics which could influence response to radiotherapy and treatment success.

The importance of radiotherapy on diffuse large B cell lymphoma treatment: a current review.

Diffuse large B cell lymphoma is recognized as a heterogeneous group of hematological malignancies; two main subtypes germinal center B and activated B cells are well defined although 15% of patients remain with unclassifiable disease. R-CHOP treatment has proven to provide very effective results in limited or advanced stage of the disease. However, treatment solely involving R-CHOP submits the patient to possible chemotherapy-induced toxicities, which may be avoided with the use of radiotherapy. Patients with early stage localized disease or who are particularly unresponsive to chemotherapy may be more suitable for mixed modality treatment with R-CHOP and consolidative radiotherapy. Although radiotherapy is being slowly phased out by other treatment strategies including chemotherapy and therapeutic drugs, it is still a highly important method of treatment. The different forms of radiotherapy can be used alongside these "new-age" treatment strategies to further improve prognostic outcomes and overall survival rates. The establishment of radiotherapy as a treatment strategy provides a highly beneficial prognostic advantage in early stage, localized disease.

Nucleolin overexpression in breast cancer cell sub-populations with different stem-like phenotype enables targeted intracellular delivery of synergistic drug combination.

Breast cancer stem cells (CSC) are thought responsible for tumor growth and relapse, metastization and active evasion to standard chemotherapy. The recognition that CSC may originate from non-stem cancer cells (non-SCC) through plastic epithelial-to-mesenchymal transition turned these into relevant cell targets. Of crucial importance for successful therapeutic intervention is the identification of surface receptors overexpressed in both CSC and non-SCC. Cell surface nucleolin has been described as overexpressed in cancer cells as well as a tumor angiogenic marker. Herein we have addressed the questions on whether nucleolin was a common receptor among breast CSC and non-SCC and whether it could be exploited for targeting purposes. Liposomes functionalized with the nucleolin-binding F3 peptide, targeted simultaneously, nucleolin-overexpressing putative breast CSC and non-SCC, which was paralleled by OCT4 and NANOG mRNA levels in cells from triple negative breast cancer (TNBC) origin. In murine embryonic stem cells, both nucleolin mRNA levels and F3 peptide-targeted liposomes cellular association were dependent on the stemness status. An in vivo tumorigenic assay suggested that surface nucleolin overexpression per se, could be associated with the identification of highly tumorigenic TNBC cells. This proposed link between nucleolin expression and the stem-like phenotype in TNBC, enabled 100% cell death mediated by F3 peptide-targeted synergistic drug combination, suggesting the potential to abrogate the plasticity and adaptability associated with CSC and non-SCC. Ultimately, nucleolin-specific therapeutic tools capable of simultaneous debulk multiple cellular compartments of the tumor microenvironment may pave the way towards a specific treatment for TNBC patient care.

Impairment of breast cancer cell invasion by COX-2-specific inhibitor NS398: roles of CXCR4 and of uPA system.

Inhibition of cyclooxygenase-2 (COX-2) is known to impair cancer cell metastatic behaviour, but the mechanisms involved largely remain elusive. We aimed to analyse whether the antimetastatic effect of COX-2 inhibition in breast cancer cells could be explained by variations in the expression levels of chemokine receptor CXCR4, vascular endothelium growth factor (VEGF) and UPA/UPAR components of the urokinase plasminogen activator system (uPAR). Breast cancer cell line MDA-MB-231 was exposed to COX-2-specific inhibitor NS398. Experimental data were assessed using Matrigel invasion tests, qRT-PCR, ELISA, flow cytometry and MTT test. Exposure to NS398 had no major effect on cell viability, apoptosis or VEGF production. Cell invasion was significantly decreased with reductions ranging from of 3.6% with 10 µM NS398 to 81.04% with 100 µM NS398. CXCR4 membrane expression was significantly reduced by 18% (P < 0.05) when cells were treated with 100 µM of NS398 for 72 h. UPA mRNA levels were significantly reduced to 78 and 63% after treatment with 10 µM NS398 for 48 and 72 h, respectively (P < 0.05). UPAR mRNA levels also decreased with mild NS398 concentrations, reaching the lowest level of 56% with 50 µM of NS398 for 48 h (P < 0.05). With NS398 higher concentrations, UPAR and UPA expression levels increased. According to our results, impairment of expression of CXCR4, UPA and UPAR differentially contribute to the antimetastatic effect of COX-2 inhibitors depending on drug concentration.

A socio-demographic study of aging in the Portuguese population: the EPEPP study.

The increase in life expectancy (LE) observed in Western societies, has resulted in a steep rise of older population. This stresses the importance of the research on aging, to better adequate health and social care organization and improve the quality of life (QoL). The aim of the EPEPP-1 (abbreviated from the Portuguese name: Estudo do Perfil de Envelhecimento da População Portuguesa) study was to characterize the socio-demographic components of the elderly Portuguese population in order to disclose factors that could play a role in the aging process and in the elderly QoL. This observational descriptive study, was performed in 2672 individuals older than 54 years taking into account gender and the residence area (rural vs. urban). A questionnaire about social network (marital status, living alone, the hours spent alone, confidents), and social status (education, occupation) was applied. Social network score revealed significant age and gender trends, women and older people performing worst, but with no difference according to residence area. Almost a third was unmarried and spent eight or more hours per day alone, and a fifth lived alone. Social status revealed that being older female and resident in a rural area quoted worst in the prevalence of illiteracy and undifferentiated occupation. The authors concluded that social isolation, illiteracy and undifferentiated occupation are prevalent in Portuguese older population. Identification of further determinants of isolation, adjustment of procedures to be included in social networks and development of actions directed to education are important fields of intervention influencing the elderly QoL.

CD26/DPPIV expression and 8-azaguanine response in T-acute lymphoblastic leukaemia cell lines in culture.

Dipeptidyl peptidase IV, a cell membrane surface protease also known as CD26 (CD26/DPPIV), is known to play multiple functions in human organism, where it is largely expressed, for instance, in the development of human cancer and metastasis as well as in chemotherapy response. The objective of this work was to study the CD26 membrane expression and DPPIV activity in T-acute leukaemia cell lines (CEM and MOLT3) in culture, in order to observe the modification of its expression under the 8-azaguanine treatment. Cell line samples were incubated, some without different azaguanine concentration and others with, ranging from 10 to 100muM. Cell surface CD26 expression has been identified by flow cytometry and DPPIV activity, in cultured medium, was fluorimetrically measured. Results we have observed showed that 8-azaguanine induced a decrease in cell viability in a dose, time and cell type dependent manner with MOLT3 cells being the most sensitive to 8-azaguanine citotoxic effects (24h IC50: +/-10muM) when compared with CEM cells (24h IC50: +/-100muM). In the same experimental conditions, MOLT3 cell treated with 8-azaguanine shows an increase in CD26 expression (MIF) compared with that of CEM cell submitted to the same conditions (65.4+/-1.3 versus 18.7+/-1.7). DPPIV activity in culture medium supernatant of CEM versus MOLT3 controls cells (1.91+/-0.43 versus 2.06+/-0.50) and of CEM versus MOLT3 treated cells (2.10+/-0.16 versus 1.89+/-0.04) did not show a significant difference. These preliminary results suggest that 8-azaguanine stimulates CD26 expression which may be related to cellular sensitivity to 8-azaguanine.

CD26/DPPIV and response to hepatitis B vaccination.

The prevention of hepatitis B is important, since it is responsible for significant morbidity and mortality around the world. Unfortunately, hepatitis B vaccine does not always induce protective immunity. The lack of immune response to vaccine (non-responders) can depend on individual characteristics. The objective of this study was to correlate the CD26/DPPIV cellular expression and DPPIV serum activity with HBV vaccine response and its possible role as an indicator of immune competence acquisition. We also determined the cellular expression of CD3, CD19, CD56 and CD25 in peripheral blood T lymphocytes. Blood samples were obtained from 28 healthy human volunteers who were enrolled with a vaccination program. There were "responders" (RM = 13) and "non-responders" (NRM = 15), after vaccination. The lymphocyte populations were identified by flow cytometry. DPPIV serum activity was measured fluorimetrically. CD26 expression in responders (55.9 +/- 7.7%) versus in non-responders (51.9 +/- 7.0%) did not show a significant difference. The DPPIV serum activity in responders compared to in non-responder subgroup (59.9 +/- 8.4/50.3 +/- 10.6U/L) showed, however, a significant difference (P < 0.05). The expression of CD3, CD19 and CD56 on peripheral lymphocytes was similar between responders and non-responders. The expression of CD3CD26 (52.2 +/- 8.6%) and CD3CD25 (10.9 +/- 3.8%) in responders versus the expression of CD3CD26 (48.0 +/- 5.7%) and CD3CD25 (8 +/- 4.6%) in non-responders did not show statistically significant difference. CD25 referred as a marker of T lymphocyte activation was increased in responders (15.8 +/- 4.5%) versus in non-responders (10.1 +/- 4.8%), showing a significant difference (P = 0.003). It was, however, impossible to demonstrate an increase in CD3CD25 and CD3CD26 in the responder subgroup. This suggests that different lymphocyte subsets other than T cells are implicated in the response to hepatitis B vaccination.