The Chilean socio-ethno-genomic cline.

Studies of the current Chilean population performed using classical genetic markers have established that the Chilean population originated primarily from the admixture of European people, particularly Spaniards, and Amerindians. A socioeconomic-ethno-genetic cline was established soon after the conquest. Spaniards born in Spain or Chile occupied the highest Socioeconomic Strata, while Amerindians belonged to the lowest. The intermediate strata consisted of people with different degrees of ethnic admixture; the larger the European admixture, the higher the Socioeconomic Level. The present study of molecular genomic markers sought to calculate the percentage of Amerindian admixture and revealed a finer distribution of this cline, as well as differences between two Amerindian groups: Aymara and Mapuche. The use of two socioeconomic classifications - Class and Socioeconomic Level - reveals important differences. Furthermore, Self-reported Ethnicity (self-assignment to an ethnic group) and Self-reported Ancestry (self-recognition of Amerindian ancestors) show variations and differing relationships between socioeconomic classifications and genomic Amerindian Admixture. These data constitute a valuable input for the formulation of public healthcare policy and show that the notions of Ethnicity, Socioeconomic Strata and Class should always be a consideration in policy development.

Factores de riesgo cardiovascular en la población Aymara rural del norte de Chile / Prevalence of cardiovascular risk factors in a rural Aymara population from northern Chile

Background: Some rural non-Caucasian ethnic groups have genetic protective factors for the development of chronic non-communicable diseases. Studies performed in Mapuche and Aymara ethnic groups in Chile, found significantly lower prevalence rates. Aymaras are the second most common ethnic population in Chile. Aim: To determine the prevalence of cardiovascular risk factors in a native Aymara ethnic population. Material and Methods: We studied 276 native Aymara people with a median age of 53 years (63% women), registered in the rural clinics of Camiña and Putre. The frequency of hypertension, Type 2 Diabetes Mellitus (DM2), dyslipidemia, overweight, obesity and smoking were determined. Results: The frequency of overweight and obesity was 38% and 38.4% respectively. The prevalence of hypertension and DM2 were 18.5% and 6.9% respectively. Thirty-five percent had elevated total cholesterol, 21% had high LDL cholesterol, 48% had low HDL cholesterol and 45.7% had high triglyceride levels. Two percent smoked. Conclusions: In this group of Aymara individuals, we found a markedly lower prevalence of hypertension and DM2, despite the high prevalence of obesity and dyslipidemia.

[Prevalence of cardiovascular risk factors in a rural Aymara population from northern Chile]. / Factores de riesgo cardiovascular en la población Aymara rural del norte de Chile.

BACKGROUND: Some rural non-Caucasian ethnic groups have genetic protective factors for the development of chronic non-communicable diseases. Studies performed in Mapuche and Aymara ethnic groups in Chile, found significantly lower prevalence rates. Aymaras are the second most common ethnic population in Chile. AIM: To determine the prevalence of cardiovascular risk factors in a native Aymara ethnic population. MATERIAL AND METHODS: We studied 276 native Aymara people with a median age of 53 years (63% women), registered in the rural clinics of Camiña and Putre. The frequency of hypertension, Type 2 Diabetes Mellitus (DM2), dyslipidemia, overweight, obesity and smoking were determined. RESULTS: The frequency of overweight and obesity was 38% and 38.4% respectively. The prevalence of hypertension and DM2 were 18.5% and 6.9% respectively. Thirty-five percent had elevated total cholesterol, 21% had high LDL cholesterol, 48% had low HDL cholesterol and 45.7% had high triglyceride levels. Two percent smoked. CONCLUSIONS: In this group of Aymara individuals, we found a markedly lower prevalence of hypertension and DM2, despite the high prevalence of obesity and dyslipidemia.

Interleukin-6 receptor blockade enhances CD39+ regulatory T cell development in rheumatoid arthritis and in experimental arthritis.

OBJECTIVE: The rationale for blocking interleukin-6 (IL-6) in rheumatoid arthritis (RA) lies chiefly in the proinflammatory effect of this cytokine. Few studies have evaluated the consequences of anti-IL-6 receptor (IL-6R) antibody treatment on Treg cells. This study was undertaken to elucidate the mechanism of action of anti-IL-6R antibody treatment by studying the effects on Treg cells in an experimental arthritis model and in patients with RA. METHODS: Mice with collagen-induced arthritis (CIA) were treated with a mouse anti-IL-6R antibody (MR16-1), and changes in Treg, Th1, and Th17 cells were assessed at key time points during the course of the disease. Peripheral blood from 15 RA patients was collected on day 0 and after 3 months of tocilizumab treatment for flow cytometry analysis of Th17 and Treg cells. RESULTS: In MR16-1-treated mice, Th17 cell frequencies were unchanged, whereas Treg cell frequencies were increased. The Treg cell phenotype showed marked changes, with an increase in the frequency of CD39+ Treg cells in the lymph nodes and spleen. Interestingly, similar CD39+ Treg cell expansion was observed in RA patients who were tocilizumab responders at 3 months, with no change in Th17 cell frequency. Moreover, fluorescence-activated cell-sorted CD39+ Treg cells from responder RA patients were functionally able to suppress the proliferation of conventional T cells. CONCLUSION: In both CIA and RA, the frequency of functionally suppressive CD39+ Treg cells is increased as a result of anti-IL-6R treatment, whereas Th17 cells are unaffected. The modification of Treg cell frequency and phenotype may be one of the mechanisms involved in the therapeutic effect of IL-6 blockade in RA.

An epidemic of Pneumocystis jiroveci pneumonia in a renal transplantation center: role of T-cell lymphopenia.

Although only 2 cases of Pneumocystis jiroveci pneumonia were observed in our center between 2004 and 2009, we diagnosed 9 cases in 2010. Each patient had been in contact in the hospital with at least 1 other patient suffering P jiroveci pneumonia. Genotyping of P jiroveci pneumonia strains demonstrates a total homogeneity of the DNA sequences in the 7 patients already analyzed. CD4+ lymphocyte count was significantly lower at M3 in P jiroveci pneumonia patients than in controls. Our clinical and molecular data confirm that interhuman transmission of P jiroveci is possible, particularly to lymphopenic transplant recipients.

Strategy for anti-aquaporin-4 auto-antibody identification and quantification using a new cell-based assay.

NMO-IgG is a specific biomarker of neuromyelitis optica (NMO) that targets the aquaporin-4 (AQP4) water channel protein. The current gold standard for NMO-IgG identification is indirect immunofluorescence (IIF). Our aim in this study was to develop a new quantitative cell-based assay (CBA) and to propose a rational strategy for anti-AQP4 Ab identification and quantification. We observed an excellent correlation between the CBA and IIF for NMO-IgG/anti-AQP4 detection. The CBA appeared more sensitive than IIF but on the other hand, IIF allows the simultaneous detection of various auto-Abs, underlining the complementarity between both methods. In conclusion, we propose to use IIF for the screening of patients at diagnosis in order to identify auto-Abs targeting the central nervous system. A highly sensitive, AQP4 specific and quantitative assay such as our CBA could be used thereafter to specifically identify the target of the Ab and to monitor its serum concentration under treatment.

Inhibition of active nuclear transport is an intrinsic trigger of programmed cell death in trypanosomatids.

The link between nucleocytoplasmic transport and apoptosis remains controversial. Nucleocytoplasmic exchange of molecules seems indeed essential for the initiation and execution of the apoptotic programme; but inhibition of nuclear transport factors may also represent a powerful apoptotic trigger. The GTPase Ran (together with its partners), first discovered to be essential in nucleocytoplasmic transport, has multiple key functions in cell biology, and particularly in spindle assembly, kinetochore function and nuclear envelope assembly. Among the Ran partners studied, NTF2 appears to be solely involved in nucleocytoplasmic transport. Here, we localised Ran and several of its partners, RanBP1, CAS and NTF2, at the nuclear membrane in the trypanosomatid Leishmania major. Remarkably, these proteins fused to GFP decorated a perinuclear 'collar' of about 15 dots, colocalising at nuclear pore complexes with the homologue of nucleoporin Sec13. In the other trypanosomatid Trypanosoma brucei, RNAi knockdown of the expression of the corresponding genes resulted in an apoptosis-like phenomenon. These phenotypes show that Ran and its partners have a key function in trypanosomatids like they have in mammals. Our data, notably those about TbNTF2 RNAi, support the idea that active nucleocytoplasmic transport is not essential for the initiation and execution of apoptosis, and, rather, the impairment of this transport constitutes an intrinsic signal for triggering PCD.

The expression of cytotoxic mediators is altered in mononuclear cells of patients with melanoma and increased by interferon-alpha treatment.

BACKGROUND: The role of cytotoxic cells in the control of cancer is now well established. OBJECTIVES: To evaluate the expression of perforin and granzyme A in cytotoxic cells of patients with melanoma and to look for a link between this expression and natural tumour progression; to check if interferon (IFN)-alpha administration increased expression of cytotoxic mediators; and to evaluate if this increase was correlated with the antitumoral effect of IFN-alpha. METHODS: To determine in patients with melanoma the expression of the cytotoxic mediators perforin and granzyme A in peripheral blood natural killer (NK) and T cells, we used flow cytometry before and after IFN-alpha administration. RESULTS: Compared with healthy volunteers, we observed in 82 patients a low percentage of NK cells harbouring perforin [75% (95% confidence interval (CI) 70-79) vs. 92% (95% CI 89-95), P < 0.001] and granzyme A [48% (95% CI 41-55) vs. 73% (95% CI 66-81), P < 0.001]. By contrast, a high percentage of T cells, and particularly of CD56+ T cells, expressed perforin [56% (95% CI 41-71) vs. 28% (95% CI 18-38), P < 0.001], whereas a low percentage of CD56+ T cells expressed granzyme A [30% (95% CI 24-36) vs. 54% (95% CI 43-65), P < 0.001]. In untreated patients, the percentage of CD56+ T cells expressing granzyme A was higher in progressors than in nonprogressors [49% (95% CI 39-58) vs. 16% (95% CI 0-33), P = 0.003]. We followed cytotoxic mediator expression in 17 patients treated with IFN-alpha. IFN-alpha administration increased granzyme A expression in NK cells [44% (95% CI 27-61) and 65% (95% CI 54-76) before and after treatment, respectively, P = 0.010], rather than perforin expression, whereas expression of both perforin [46% (95% CI 30-62), and 58% (95% CI 44-73), P = 0.112] and especially granzyme A [27% (95% CI 14-40) vs. 45% (95% CI 26-64), P = 0.016] was increased in CD56+ T cells after IFN-alpha administration. Yet, this effect was not correlated with the clinical response to IFN-alpha. CONCLUSIONS: Thus, the expression of cytotoxic mediators is altered in cytotoxic cells of patients with melanoma, and increased under IFN-alpha administration.

Rare occurrence of CD30+ circulating cells in patients with cutaneous CD30+ anaplastic large cell lymphoma: a study of nine patients.

BACKGROUND: The presence of a significant percentage of circulating atypical lymphocytes in peripheral blood has already been demonstrated in systemic CD30+ anaplastic large cell lymphoma (ALCL), which implies that a leukaemic component may be present in this subset of lymphomas. However, no similar data are available for the cutaneous counterpart of this particular lymphoproliferation. OBJECTIVES: To assess the presence of atypical cells, CD30+ lymphocytes and of a dominant T-cell clone in peripheral blood in a series of patients with cutaneous CD30+ ALCL. MATERIALS AND METHODS: Nine patients with either primary (four) or secondary (five) cutaneous CD4+ CD30+ ALCL were selected. The percentage of CD30+ CD4+ lymphocytes among peripheral blood mononuclear cells (PBMC) was determined by flow cytometry and the presence of a dominant circulating T-cell clone was assessed by polymerase chain reaction targeting the T-cell receptor gamma chain. A control group composed of apparently healthy individuals was similarly studied at the same time. RESULTS: The mean percentage of CD30+ cells in PBMC was slightly higher in patients than in controls (3.9% vs. 2.7%) but the difference was not statistically significant. Only two patients displayed more than 5% CD30+ cells, both of whom had a minor tumour burden. A dominant circulating T-cell clone was detected in only three cases, including these two latter patients. CONCLUSIONS: The occurrence of a significant percentage of CD30+ CD4+ circulating cells is rare in active cutaneous CD30+ ALCL, either primary or secondary. This percentage is not related to the apparent skin tumour burden but a significant figure appeared to be correlated with the detection of a dominant T-cell clone in peripheral blood. Overall, these data show that, unlike mycosis fungoides, peripheral blood involvement seems infrequent in cutaneous CD30+ ALCL. The hypothesis that a high percentage of CD30+ circulating cells might be related to the presence of a cryptic systemic disease cannot be ruled out.

CD4 T cell surface CCR5 density as a host factor in HIV-1 disease progression.

OBJECTIVE AND DESIGN: We have recently shown that the number of CCR5 molecules at the surface of peripheral blood CD4 T cells (CCR5 density) correlates with the viral RNA plasma level in HIV-1-infected individuals. As viral load is a strong predictor of outcome in HIV infection, the present study examines the correlation between CCR5 density and HIV-1 disease progression. METHODS: Using a quantitative flow cytometry assay, we measured CCR5 density in HIV-1-infected adults and control healthy volunteers. The CCR5 genotype (presence of a Delta 32 allele) was also determined. RESULTS: CCR5 density was stable over time on non-activated, HLA-DR(-)CD4 T cells of infected individuals. In a study cohort of 25 patients, asymptomatic and non-treated, we observed a correlation between CCR5 density on HLA-DR(-)CD4 T cells and the CD4 T cell slope (P = 0.026), which was independent of the presence or absence of the Delta 32CCR5 deletion. In particular, slow progressors expressed lower CCR5 densities than non-slow progressors (P = 0.004) and non-infected control subjects (P = 0.002). CONCLUSION: These results are compatible with the hypothesis that CCR5 density, which is a key factor of HIV-1 infectability, determines in-vivo HIV production, and thereby the rate of CD4 cell decline. Consequently, CCR5 density quantitation could be a new valuable prognostic tool in HIV-1 infection. Moreover, these data emphasize the therapeutic potential of treatments that reduce functional CCR5 density.

Immunomodulation induced by Avène spring water on Th1- and Th2-dependent cytokine production in healthy subjects and atopic dermatitis patients.

Avène spring water (ASW) is commonly used in France for treating atopic dermatitis and psoriasis. Previous works demonstrated modulation of cell membrane fluidity by ASW. The aims of the present study were (a) to investigate a possible in vitro effect of ASW on Th1- and Th2-dependent cytokine production using peripheral blood mononuclear cells from healthy individuals and (b) to investigate both the in vitro effect of ASW on AD patients' cells and the in vivo cellular and clinical modifications induced by a 3-week Avène Medical Spa water cure (AMSWC). The effect of ASW was tested on lymphocyte cultures, which were stimulated in vitro by various mitogens and a superantigen of staphylococcal origin. The lymphocyte proliferation and the production of the cytokines IL-2, IL-4 and IFN-gamma were tested. The results showed that ASW-containing medium enhanced the lymphoproliferative response to some mitogens. IL-2 and IFN-gamma production were also increased in stimulated culture supernatants. Conversely, ASW-containing medium induced a decrease in IL-4 production by normal peripheral blood lymphocytes. Furthermore, AMSWC was able to amend the clinical features as well as the immunological Th2 profile of atopic dermatitis.

Decreased expression of Fas (APO-1/CD95) on peripheral blood CD4+ T lymphocytes in cutaneous T-cell lymphomas.

BACKGROUND: The usually protracted and indolent course of cutaneous T-cell lymphoma (CTCL) is consistent with an accumulation of lymphocytes rather than being a true proliferative disorder, perhaps as the result of defective lymphocyte apoptosis. Fas (CD95) is the main signalling membrane molecule involved in postactivation T-lymphocyte apoptosis. OBJECTIVES: To evaluate expression of Fas on circulating CD4+ lymphocytes in patients with CTCL. METHODS: Fas expression on peripheral blood CD4+ T cells in 16 patients with mycosis fungoides (patch and infiltrated plaque stages) and in four patients with Sézary syndrome was compared with that in 25 matched patients with lymphocyte-mediated cutaneous benign inflammatory disorders and in 15 subjects without inflammatory cutaneous diseases. RESULTS: Fas expression on peripheral CD4+ lymphocytes was significantly lower in patients with CTCL compared with subjects with benign inflammatory cutaneous disorders and with healthy donors. CONCLUSIONS: This pattern supports the hypothesis that a defect in T-cell apoptosis may play a part in the pathophysiology of CTCL, perhaps through abnormalities of the Fas/Fas ligand system. Alternatively, this decrease could be the result of the presence of the soluble Fas ligand molecule in the sera of patients with CTCL.

[Low-dose antithymocyte globulins in kidney transplantation: results of a protocol of intermittent administration]. / Globulines antilymphocytaires à faibles doses en transplantation rénale: intérêt d'un protocole d'administration intermittente.

BACKGROUND: Despite the long history of use of antithymocyte globulins (ATG) in renal transplantation, ideal doses and duration of ATG administration based on the monitoring of T lymphocytes have yet to be defined. METHODS: Two immunosuppressive regimens based on low dose rabbit ATG (thymoglobuline, Imtix-Sangstat, Lyon-France) were assessed during the first year post-transplant: daily ATG (n = 32) where 50 mg of ATG were given every day and intermittent ATG (n = 24) where similar doses of ATG were given for the first three days and then intermittently only if CD3+T lymphocytes (measured by flow cytometry) were > 10/mm3. Both groups received steroids, azathioprine and cyclosporin A (CsA). RESULTS: ATG-induced depletion was similar for PBL and T cells in both groups: it began at day one post-transplant, was submaximal at day 3 and reached maximum intensity between days 6 and 8 from which time cell counts progressively increased. However, T cell depletion was still present at day 20. The total ATG dose per patient (361 +/- 105 vs 556 +/- 119 mg/patient) and the mean cumulative daily dose of ATG (0.60 +/- 0.17 vs 0.80 +/- 0.14 mg/kg/d) were significantly lower in the IATG group (p = 0.0001, and 0.0006 respectively). The overlap of ATG and CsA treatment was 6.7 +/- 3 vs 7.4 +/- 4.3 days (p = ns) and the mean duration of ATG therapy was 12 +/- 3 vs 11 +/- 2.5 days in the IATG and DATG groups respectively (p = ns). ATG were given in an average of one dose every 1.6 days in the IATG group compared to one dose daily in the DATG group (p = 7 x 10(-7). There was no significant difference in renal graft function, the number of acute graft rejections or ATG related side effects and complications. Despite daily immunological follow-up, there was a net saving of 920 $/patient in the cost of treatment in the intermittent ATG group. CONCLUSION: Intermittent ATG had the advantage of a reduction in the dose of ATG and in the cost of treatment while offering similar T cell depletion and effective immunosuppression. This approach could be proposed as an induction protocol, particularly for patients with poor graft function in whom CsA introduction has to be delayed.

Natural killer cell and alphabeta and gammadelta lymphocyte traffic into the liver graft immediately after liver transplantation.

BACKGROUND: The persistence and migration of donor leukocytes has been well established, but cellular kinetics immediately after revascularization and the potential relevance of these different lymphocyte populations to spontaneous tolerance remain unclear. During the early hours of revascularization, there is a transitory "congestion" of the liver graft, which is evidence of an early phase that we have termed "first cellular contact." METHODS: We have carried out by flow cytometry a prospective comparative study of the peak kinetics of lymphocyte subpopulations contained in: (a) peripheral blood and liver grafts at the time of multi-organ extraction from 14 brain-dead donors, (b) recipient peripheral blood before transplantation, and (c) recipient peripheral blood and liver grafts after (t=2 h) declamping and vascularization of the liver graft. RESULTS: Before transplantation, the liver grafts contained large numbers of natural killer (NK) and NK-like cells with early lymphocyte activation. Immediately after revascularization, there was an influx of recipient NK and NK-like cells into the liver. CONCLUSIONS: NK and CD3+CD56+ (NK-like) cells flooding into the liver graft immediately after revascularization could rapidly destroy allogeneic cells. However, spontaneous tolerance and the persistence of donor lymphocytes after orthotopic liver transplant could be a result of donor TCRalphabeta NK1.1 liver graft lymphocytes, which may be involved in the destruction of CD8+ T lymphocytes that would have received the apoptosis signal, and to NK and NK-like cell inhibition via inhibitory NK receptors. The decrease in gammadelta T lymphocytes in the two compartments suggests a mechanism of recirculation and capture in other lymphoid organs.

CD4+ T cell surface CCR5 density as a determining factor of virus load in persons infected with human immunodeficiency virus type 1.

The intensity of expression of the chemokine receptor CCR5 is involved in in vitro cell infectability by human immunodeficiency virus (HIV)-1 R5 isolates. Because CCR5 expression varies among individuals, the hypothesis that this expression could determine virus load in HIV-1-infected persons was tested. The mean number of CCR5 molecules per cell was measured on peripheral blood CD4+ T lymphocytes (CCR5 density) from HIV-1-infected, asymptomatic, nontreated adults. There was a strong correlation between HIV RNA plasma level and CCR5 density (P=.009) that was independent of cell activation and was not due to an HIV-induced CCR5 up-regulation. These data are compatible with the hypothesis that CCR5 density is a key factor governing cell infectability and in vivo virus production and explain the protective effect of the Delta32CCR5 deletion, which results in low CCR5 expression. CCR5 density might be of critical predictive value in HIV infection.

Low dose antithymocyte globulins in renal transplantation: daily versus intermittent administration based on T-cell monitoring.

BACKGROUND: Despite the long history of use of antithymocyte globulins (ATG) in renal transplantation, ideal doses and duration of ATG administration based on the monitoring of T lymphocytes have yet to be defined. METHODS: Two immunosuppressive regimens based on low-dose rabbit ATG (Thymoglobuline; Imtix-Sang-stat, Lyon, France) were assessed during the first year after transplantation: daily ATG (DATG; n=23) where 50 mg of ATG was given every day and intermittent ATG (IATG; n=16) where similar doses of ATG were given for the first 3 days and then intermittently only if CD3+ T lymphocytes (measured by flow cytometry) were > 10/mm3. Both groups received steroids, azathioprine, and cyclosporine. RESULTS: ATG-induced depletion was similar for peripheral blood lymphocytes and T cells in both groups: it began at day 1 after transplantation, was submaximal at day 3, and reached maximum intensity between days 6 and 8, from which time cell counts progressively increased. However, T-cell depletion was still present at day 20. The total ATG dose per patient (381.5+/-121 vs. 564+/-135 mg/patient) and the mean cumulative daily dose of ATG (0.60+/-0.17 vs. 0.80+/-0.14 mg/kg/day) were significantly lower in the IATG group (P=0.0001 and 0.0006, respectively). The overlap of ATG and cyclosporine treatment was 6.7+/-3 vs. 7.4+/-4.3 days (P=NS), and the mean duration of ATG therapy was 11.3+/-3.2 vs. 11.6+/-2.7 days in the IATG and DATG groups, respectively (P=NS). ATG was given in an average of one dose every 1.6 days in the IATG group compared with one dose daily in the DATG group (P=7 x 10(-7)). There was no significant difference in renal graft function, the number of acute graft rejections, or ATG-related side effects and complications. Despite the daily immunological follow-up, there was a net saving of $760/patient in the cost of treatment in the IATG group. CONCLUSION: IATG had the advantage of a reduction in the dose of ATG and in the cost of treatment, while offering similar T-cell depletion and effective immunosuppression. This approach could be proposed as an induction protocol, particularly for patients with poor graft function in whom cyclosporine introduction has to be delayed or those with increased risk of cytomegalovirus infections or secondary malignancies.

Intracytoplasmic Th1 and Th2 cytokines in rheumatoid arthritis blood and synovial tissue.

In rheumatoid arthritis (RA), T cells have been proposed either as a main actor or as an epiphenomenon in such a primarily synoviocyte-driven disease. A major issue remains the remarkable paradox between the T cell infiltrate and the relative failure to detect definite markers of their activity. To determine the Th1/Th2 cytokine profile in RA synovium, we used a single cell flow cytometric assay for interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-4 and IL-10 in paired peripheral blood (PB) and synovial tissue (ST) lymphocytes from RA and osteoarthritis (OA) patients and PB lymphocytes from healthy controls. Cytokines were undetectable in unstimulated PB and ST lymphocytes. More stimulated PB and ST CD4(+)lymphocytes produced IFN-gamma than IL-4, for all individuals tested. RA PB CD4(+)lymphocytes showed the same Th1 cytokine pattern as normal controls. No increase of such a Th1 profile was observed for ST lymphocytes. A specific recruitment of T CD4(+)lymphocytes in the rheumatoid inflamed synovium could not be concluded on the basis of these results.