Total error in lymphocyte subpopulations by flow cytometry-based in state of the art using Spanish EQAS data.

OBJECTIVES: Flow cytometry analyses of lymphocyte subpopulations (T, B, NK) are crucial for enhancing clinical algorithms and research workflows. Estimating the total error (TE) values for the percentage and absolute number of lymphocyte subpopulations using the state-of-the-art (SOTA) approach with real data from an external proficiency testing (EPT) scheme was performed. A comparison with previously published Biological Variability (BV)-based specifications was carried out. METHODS: A total of 44,998 results from 86 laboratories over 10 years were analysed and divided into two five-year periods (2012-2016) and (2017-2021). Data come from the IC-1 Lymphocytes scheme of the Spanish External Quality Assurance System (EQAS) GECLID Program. This quantitative scheme includes percentages and absolute numbers of CD3+, CD3+CD4+, CD3+CD8+, CD19+, and CD3-CD56+CD16+ NK cells. The percentage of TE was calculated as: |reported value - robust mean|*100/robust mean for each laboratory and parameter. The cut-off for TE is set at 80 % best results of the laboratories. RESULTS: A significant reduction in the SOTA-based TE for all lymphocyte subpopulations in 2017-2021 was observed compared to 2012-2016. The SOTA-based TE fulfils the minimum BV-based TE for percentages of lymphocyte subpopulations. The parameter with the best analytical performance calculated with SOTA (2017-2021 period)-based TE was the percentage of CD3+ (TE=3.65 %). CONCLUSIONS: The values of SOTA-based specifications from external quality assurance program data are consistent and can be used to develop technical specifications. The technological improvement, quality commitment, standardization, and training, reduce TE. An update of TE every five years is therefore recommended. TE assessment in lymphocyte subsets is a helpful and reliable tool to improve laboratory performance and data-based decision-making trust.

Donor-Derived Cell-Free DNA at 1 Month after Kidney Transplantation Relates to HLA Class II Eplet Mismatch Load.

Kidney transplantation is the preferred therapeutic option for end-stage renal disease; however, the alloimmune response is still the leading cause of renal allograft failure. To better identify immunologic disparities in order to evaluate HLA compatibility between the donor and the recipient, the concept of eplet load has arisen. Regular kidney function monitoring is essential for the accurate and timely diagnosis of allograft rejection and the appropriate treatment. Donor-derived cell-free DNA (dd-cfDNA) has been proposed as a potential biomarker of acute rejection and graft failure in kidney transplantation. The proportion of plasma dd-cfDNA was determined in forty-two kidney patients at 1 month after transplantation. A total of eleven (26.2%) patients had a dd-cfDNA proportion of ≥1.0%. The only pretransplant variable related to dd-cfDNA > 1.0% was the HLA class II eplet mismatch load, mainly the HLA-DQB1 eplet mismatch load. Furthermore, dd-cfDNA was able to discriminate the patients with antibody-mediated rejection (AbMR) (AUC 87.3%), acute rejection (AUC 78.2%), and troubled graft (AUC 81.4%). Increased dd-cfDNA levels were associated with kidney allograft deterioration, particularly rejection, as well as a greater HLA class II eplet mismatch load. Consequently, combining dd-cfDNA determination and HLA eplet mismatch load calculation should improve the assessment of the risk of short- and long-term allograft damage.

Relevant SARS-CoV-2 viremia is associated with COVID-19 severity: Prospective cohort study and validation cohort.

Early kinetics of SARS-CoV-2 viral load (VL) in plasma determined by quantitative reverse-transcription polymerase chain reaction (RT-PCR) was evaluated as a predictor of poor clinical outcome in a prospective study and assessed in a retrospective validation cohort. Prospective observational single-center study including consecutive adult patients hospitalized with COVID-19 between November 2020 and January 2021. Serial plasma samples were obtained until discharge. Quantitative RT-PCR was performed to assess SARS-CoV-2 VL. The main outcomes were in-hospital mortality, admission to the Intensive Care Unit (ICU), and their combination (Poor Outcome). Relevant viremia (RV), established in the prospective study, was assessed in a retrospective cohort including hospitalized COVID-19 patients from April 2021 to May 2022, in which plasma samples were collected according to clinical criteria. Prospective cohort: 57 patients were included. RV was defined as at least a twofold increase in VL within ≤2 days or a VL > 300 copies/ml, in the first week. Patients with RV (N = 14; 24.6%) were more likely to die than those without RV (35.7% vs. 0%), needed ICU admission (57% vs. 0%) or had Poor Outcome (71.4% vs. 0%), (p < 0.001 for the three variables). Retrospective cohort: 326 patients were included, 18.7% presented RV. Patients with RV compared with patients without RV had higher rates of ICU-admission (odds ratio [OR]: 5.6 [95% confidence interval [CI]: 2.1-15.1); p = 0.001), mortality (OR: 13.5 [95% CI: 6.3-28.7]; p < 0.0001) and Poor Outcome (OR: 11.2 [95% CI: 5.8-22]; p < 0.0001). Relevant SARS-CoV-2 viremia in the first week of hospitalization was associated with higher in-hospital mortality, ICU admission, and Poor Outcome. Findings observed in the prospective cohort were confirmed in a larger validation cohort.

SARS-CoV-2 Viremia Precedes an IL6 Response in Severe COVID-19 Patients: Results of a Longitudinal Prospective Cohort.

Background: Interleukin 6 (IL6) levels and SARS-CoV-2 viremia have been correlated with COVID-19 severity. The association over time between them has not been assessed in a prospective cohort. Our aim was to evaluate the relationship between SARS-CoV-2 viremia and time evolution of IL6 levels in a COVID-19 prospective cohort. Methods: Secondary analysis from a prospective cohort including COVID-19 hospitalized patients from Hospital Universitario La Princesa between November 2020 and January 2021. Serial plasma samples were collected from admission until discharge. Viral load was quantified by Real-Time Polymerase Chain Reaction and IL6 levels with an enzyme immunoassay. To represent the evolution over time of both variables we used the graphic command twoway of Stata. Results: A total of 57 patients were recruited, with median age of 63 years (IQR [53-81]), 61.4% male and 68.4% Caucasian. The peak of viremia appeared shortly after symptom onset in patients with persistent viremia (more than 1 sample with > 1.3 log10 copies/ml) and also in those with at least one IL6 > 30 pg/ml, followed by a progressive increase in IL6 around 10 days later. Persistent viremia in the first week of hospitalization was associated with higher levels of IL6. Both IL6 and SARS-CoV-2 viral load were higher in males, with a quicker increase with age. Conclusion: In those patients with worse outcomes, an early peak of SARS-CoV-2 viral load precedes an increase in IL6 levels. Monitoring SARS-CoV-2 viral load during the first week after symptom onset may be helpful to predict disease severity in COVID-19 patients.

Deletion in the BCL11B Gene and Intellectual Developmental Disorder with Speech Delay, Dysmorphic Facies, and T-cell Abnormalities - a Case Report.

Herein we described a retrospective analysis of a 13-year-old female patient with facial dysmorphia and immune disorder caused by BCL11B gene mutation. The patient upon physical examination presented a particular face (thin eyebrows, small mandible, and widened eye distance), delayed language and motor development. Supplementary examination showed expansion of CD8+, absence of type 2 Innate Lymphoid Cells, increased IgG and altered distribution of T cells. Genetic testing revealed a heterozygous frameshift variation in exon 4 of the BCL11B gene; c.1887_c.1893delCGGCGGG (p.Gly630Glyfs*91). Finally, a BCL11B gene mutation could lead to abnormal development of the nervous and immune systems, therefore, it is necessary to consider this syndrome in patients with the clinical and immunological phenotype described below.

Author's reply: Basophil activation test. Tool for the diagnosis of interstitial nephritis / Réplica a la carta al Editor: Test de activación de basófilos. Herramienta para el diagnóstico de nefritis intersticial

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Myeloid-Derived Suppressor Cells in Kidney Transplant Recipients and the Effect of Maintenance Immunotherapy.

Myeloid-derived suppressor cells (MDSC) represent a heterogeneous group of myeloid regulatory cells that were originally described in cancer. Several studies in animal models point to MDSC as important players in the induction of allograft tolerance due to their immune modulatory function. Most of the published studies have been performed in animal models, and the data addressing MDSCs in human organ transplantation are scarce. We evaluated the phenotype and function of different MDSCs subsets in 38 kidney transplant recipients (KTRs) at different time points. Our data indicate that monocytic MDSCs (Mo-MDSC) increase in KTR at 6 and 12 months posttransplantation. On the contrary, the percentages of polymorphonuclear MDSC (PMN-MDSC) and early-stage MDSC (e-MDSC) are not significantly increased. We evaluated the immunosuppressive activity of Mo-MDSC in KTR and confirmed their ability to increase regulatory T cells (Treg) in vitro. Interestingly, when we compared the ability of Mo-MDSC to suppress T cell proliferation, we observed that tacrolimus, but not rapamycin-treated KTR, was able to inhibit CD4+ T cell proliferation in vitro. This indicates that, although mTOR inhibitors are widely regarded as supportive of regulatory responses, rapamycin may impair Mo-MDSC function, and suggests that the choice of immunosuppressive therapy may determine the tolerogenic pathway and participating immune cells that promote organ transplant acceptance in KTR.

Immunosuppression with Calcineurin Inhibitor after Renal Transplant Failure Inhibits Allosensitization.

Immunosuppression withdrawal after graft failure seems to favor sensitization. A high percentage of calculated panel-reactive antibody (cPRA) and the development of de novo donor specific antibodies (dnDSA) indicate human leukocyte antigen (HLA) sensitization and may hinder the option of retransplantation. There are no established protocols on the immunosuppressive treatment that should be maintained after transplant failure. A retrospective analysis including 77 patients who lost their first renal graft between 1 January 2006-31 December 2015 was performed. Two sera were selected per patient, one immediately prior to graft loss and another one after graft failure. cPRA was calculated by Single Antigen in all patients. It was possible to analyze the development of dnDSA in 73 patients. By multivariate logistic regression analysis, the absence of calcineurin inhibitor (CNI) at 6 months after graft failure was related to cPRA > 75% (OR 4.8, CI 95% 1.5-15.0, p = 0.006). The absence of calcineurin inhibitor (CNI) at 6 months after graft loss was significantly associated with dnDSA development (OR 23.2, CI 95% 5.3-100.6, p < 0.001). Our results suggest that the absence of CNI at the sixth month after graft loss is a risk factor for sensitization. Therefore, maintenance of an immunosuppressive regimen based on CNI after transplant failure should be considered when a new transplant is planned, since it seems to prevent HLA allosensitization.

Growth Differentiation Factor 15: A Biomarker with High Clinical Potential in the Evaluation of Kidney Transplant Candidates.

Kidney transplantation implies a significant improvement in patient survival. Nevertheless, early mortality after transplant remains high. Growth differentiation factor 15 (GDF-15) is a novel biomarker under study as a mortality predictor in multiple scenarios. The aim of this study is to assess the utility of GDF-15 to predict survival in kidney transplant candidates. For this purpose, 395 kidney transplant recipients with pretransplant stored serum samples were included. The median GDF-15 was 5331.3 (50.49-16242.3) pg/mL. After a mean of 90.6 ± 41.5 months of follow-up, 82 (20.8%) patients died. Patients with higher GDF-15 levels (high risk tertile) had a doubled risk of mortality after adjustment by clinical characteristics (p = 0.009). After adjustment by EPTS (Estimated Post Transplant Survival score) the association remained significant for medium hazards ratios (HR) 3.24 95%CI (1.2-8.8), p = 0.021 and high risk tertiles HR 4.3 95%CI (1.65-11.54), p = 0.003. GDF-15 improved the prognostic accuracy of EPTS at 1-year (ΔAUC = 0.09, p = 0.039) and 3-year mortality (ΔAUC = 0.11, p = 0.036). Our study suggests an independent association between higher GDF-15 levels and mortality after kidney transplant, adding accuracy to the EPTS score, an established risk prediction model currently used in kidney transplant candidates.

Test de activación de basófilos. Herramienta para el diagnóstico de nefritis intersticial / Basophil activation test. Tool for the diagnosis of interstitial nephritis

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Conocimiento sobre el VIH y las infecciones de transmisión sexual en inmigrantes latinoamericanos y magrebíes en Cataluña / Knowledge of HIV and sexually-transmitted diseases in Latin American and Maghrebi immigrants in Catalonia (Spain)

ObjetivoDescribir y comparar el grado de conocimiento sobre el VIH/sida con el uso del preservativo por la población inmigrante.MétodosEstudio transversal mediante encuesta semiestructurada y entrevista personal realizada en centros asistenciales de las regiones sanitarias de Barcelona y Barcelonés Norte y Maresme a 238 usuarios latinoamericanos y magrebíes en 2003. El cuestionario incluía variables sociodemográficas, de conducta sexual, de conocimientos generales sobre VIH/sida, y sobre la transmisión y la prevención. Para identificar determinantes del “conocimiento inadecuado del VIH/sida” se aplicó un modelo de regresión logística.ResultadosEl 53,8% de los encuestados tenían un conocimiento inadecuado del VIH/sida. En el análisis univariado se asociaban con este desconocimiento los magrebíes, los que no vivían en Barcelona, los que no tenían trabajo y los que no tenían estudios; en el multivariado se asociaban los magrebíes con una situación más desfavorecida respecto a los latinoamericanos [odds ratio (OR)=4,99; intervalo de confianza del 95% (IC 95%): 2,73-9,10] y los inmigrantes sin trabajo (OR=2,59; IC 95%: 1,42-4,73). El uso del preservativo fue valorado como un método de prevención eficaz, pero el 42,1% de los encuestados no lo utilizaba en sus relaciones ocasionales.ConclusionesEs necesario mejorar el conocimiento sobre los mecanismos de transmisión del VIH/sida y eliminar concepciones erróneas de la infección entre los inmigrantes latinoamericanos y magrebíes. La población inmigrante es vulnerable y prioritaria para impulsar intervenciones preventivas, adaptadas a sus especificidades lingüísticas y culturales. Monitorizar la falta de información, las concepciones erróneas y sus conductas sexuales es esencial para evaluar la efectividad de las intervenciones efectuadas(AU)

ObjectivesTo describe and compare levels of knowledge about HIV/AIDS and condom use in the immigrant population.MethodWe performed a cross-sectional study by means of a semi-structured questionnaire and face-to face interviews in 238 Latin American and Maghrebi users of medical centers in the Barcelona and North Barcelona-Maresme health areas. The questionnaire included sociodemographic variables and questions on sexual behavior and general knowledge about HIV/AIDS, transmission mechanisms, and means of prevention. A logistic regression model was used to identify the determinants of ‘inadequate knowledge of HIV/AIDS’.ResultsA total of 53.8% of interviewees had inadequate knowledge of HIV/AIDS. Univariate analysis showed inadequate knowledge to be associated with being from the Maghreb, not living in Barcelona, being without work and not having educational qualifications. Multivariate analysis revealed that the only variables significantly associated with inadequate knowledge were being from the Maghreb as opposed to being from Latin America (OR=4.99; 95% CI: 2.74-5.10) and being unemployed as opposed to being employed (OR=2.59; 95% IC: 1.42-4.73). Condoms were seen as an effective prevention method, but 42.1% of interviewees did not use them in occasional relationships.ConclusionsKnowledge of routes of HIV transmission should be improved and mistaken ideas about infection should be eliminated among Latin American and Maghrebi immigrants. The immigrant population is a vulnerable group that ought to be prioritized to promote prevention programs adapted to its linguistic and cultural specificities. Evaluating the effectiveness of the interventions performed is essential to monitor lack of information, mistaken ideas and sexual behavior in this group(AU)

[Knowledge of HIV and sexually-transmitted diseases in Latin American and Maghrebi immigrants in Catalonia (Spain)]. / Conocimiento sobre el VIH y las infecciones de transmisión sexual en inmigrantes latinoamericanos y magrebíes en Cataluña.

OBJECTIVES: To describe and compare levels of knowledge about HIV/AIDS and condom use in the immigrant population. METHOD: We performed a cross-sectional study by means of a semi-structured questionnaire and face-to face interviews in 238 Latin American and Maghrebi users of medical centers in the Barcelona and North Barcelona-Maresme health areas. The questionnaire included sociodemographic variables and questions on sexual behavior and general knowledge about HIV/AIDS, transmission mechanisms, and means of prevention. A logistic regression model was used to identify the determinants of 'inadequate knowledge of HIV/AIDS'. RESULTS: A total of 53.8% of interviewees had inadequate knowledge of HIV/AIDS. Univariate analysis showed inadequate knowledge to be associated with being from the Maghreb, not living in Barcelona, being without work and not having educational qualifications. Multivariate analysis revealed that the only variables significantly associated with inadequate knowledge were being from the Maghreb as opposed to being from Latin America (OR=4.99; 95% CI: 2.74-5.10) and being unemployed as opposed to being employed (OR=2.59; 95% IC: 1.42-4.73). Condoms were seen as an effective prevention method, but 42.1% of interviewees did not use them in occasional relationships. CONCLUSIONS: Knowledge of routes of HIV transmission should be improved and mistaken ideas about infection should be eliminated among Latin American and Maghrebi immigrants. The immigrant population is a vulnerable group that ought to be prioritized to promote prevention programs adapted to its linguistic and cultural specificities.