Immune recovery and the role of recent thymic emigrated T lymphocytes after pediatric hematopoietic stem cell transplantation.

BACKGROUND AIMS: Adequate re-establishment of thymopoiesis is critical for long-term immune reconstitution after hematopoietic cell transplantation (HCT), potentially impacting patient survival rates. This study aimed to evaluate immune reconstitution in pediatric HCT recipients by quantifying recent thymic emigrants (RTEs), specifically CD3+CD31+CD45RA+ cells. METHODS: We conducted a retrospective analysis of 186 pediatric patients transplanted between 2013 and 2020, undergoing their first allogeneic HCT, who were alive in the first 100 days after transplantation with immune recovery evaluation at three time points: day 100, day 180 and day 360 after HCT. We analyzed the distribution of peripheral blood subsets of T, B and natural killer lymphocytes and assessed the impact of underlying disease, HCT type, stem cell source, recipient age, conditioning regimen, graft-versus-host disease (GVHD) occurrence and cytomegalovirus (CMV) reactivation on immune recovery. RESULTS: At day 100, patients under 10 years exhibited higher RTE CD4+ and CD8+CD31+CD45RA+ counts compared with older patients (5.3 versus 2.2 cells/µL, P = 0.022 and 48 versus 72.8 cells/µL, P = 0.049, respectively). Patients with haploidentical HCT had lower RTE CD4+ counts compared with those with unrelated or related donors (2.4 versus 4.4 versus 7.9 cells/µL, P = 0.024). Administration of rabbit anti-thymocyte globulin negatively impacted RTE CD4+ production (median, 6.5 versus 2.4 cells/µL, P = 0.007). At day 180, the presence of GVHD had a negative influence on RTE production (11.7 versus 56.8 cells/µL, P < 0.001), particularly higher-grade acute GVHD (without, 56.8 cells/µL, grade 1-2, 28.1 cells/µL, grade 3-4, 6.0 cells/µL, P < 0.001). Patients with CMV reactivation had higher CD8+CD31+CD45RA+ compared with those without reactivation (median, 204.6 versus 100.2 cells/µL, P = 0.022). At day 360, no variables significantly affected RTE recovery. Overall survival at 5-year follow-up was 87.7%, with a median of 1170 days (range, 122-3316). Multivariate analysis showed that age >10 years (P = 0.038), negative CMV donor serology (P = 0.0029) and acute GVHD (P = 0.0026) had a negative impact on survival. CONCLUSIONS: This study highlights variations in RTE production based on patient age, donor type and immunosuppression regimen employed.

Main lymphocyte subpopulations in cerebrospinal fluid and peripheral blood in HIV-1 subtypes C and B.

HIV-1 subtype C (HIV-1C) shows reduced Tat protein chemoattractant activity compared with HIV-1B. The impact of HIV-1C Tat on the chemotaxis of the main lymphocyte subpopulations in the cerebrospinal fluid (CSF) and the peripheral blood (PB) is unclear. We hypothesized that there would be a lower frequency of specific lymphocyte subpopulations CD3+ or CD19+ in CSF in HIV-1C than in HIV-1B. The objectives were to detect the differences in the proportions of main lymphocyte subpopulations in CSF and PB, between people with HIV (PWH) and HIV-1-uninfected volunteers (PWoH) and in HIV-1B and HIV-1C. Lymphocyte immunophenotyping was studied in CSF and paired PB samples of PWH (n = 22) and PWoH (n = 14). Lymphocytes were analyzed within the CD45+ gated region. The proportions of CSF CD3+CD4+, CD3+CD8+, and CD3-CD19+ lymphocytes in CSF were comparable in HIV-1B and C. There was an increase in the proportion of CD3+CD8+ cells and a decrease in CD3+CD4+ T cells (ps = 0.016) in the CSF samples of the PWH compared with the PWoH group. In the PWH group, both CD3+CD4+ and CD3+CD8+ lymphocytes were significantly higher in the CSF than in the PB (p = 0.047 and 0.005). The proportion of CD3+CD4+ was lower and that of CD3+CD8+ was higher in the CSF samples of the aviremic group than that of HIV-negative control (p = 0.0008 and < 0.0001, respectively). HIV-1C Tat substitution (C30S) did not interfere with the CNS migration of the main lymphocyte subpopulations. This is the first study to evaluate these lymphocytes in CSF and PB of HIV-1C compared with HIV-1B.

Evaluation of lymphocyte count, T-cell subsets and neutrophil-to-lymphocyte ratio as early predictors for severity and outcome of COVID-19 disease-a report from a highly complex hospital in Brazil.

INTRODUCTION: Lymphopenia is a laboratory marker of poor prognosis and severity of disease in the SARS-CoV-2 infection. This study aims to describe the immune profile of a Brazilian population. METHODS: A total of 121 consecutive patients with severe acute respiratory syndrome (SARS) were analyzed between April and June 2020. Routine peripheral blood counts and multiparametric flow cytometry were performed on admission to assess lymphocytes and subsets (CD3, CD4, CD8). Demographic, clinical and laboratory data were collected from hospital sources. RESULTS: The total of 116 patients included 63 (54.3%) males; 76 (62.8%) COVID-19 patients were divided, based on clinical characteristics and mechanical ventilation (MV) use, into moderate (n = 41; no MV) and severe (n = 35; MV) groups. The control group (n = 40) was comprised of patients with SARS of different etiologies. All patients had lymphopenia, with overall lymphocyte counts and their subsets considerably lower in severe patients, when compared to the moderate and controls. Patients with a high neutrophil-to-lymphocyte ratio (> 15.2) and T-cell lymphopenia (CD3 < 593 cells/µL, CD4 < 326 cells/µL, CD8 < 121 cells/µL) had a higher risk of being intubated and progressing to death. A total of 39 patients (95.1%) in the moderate group and 54.3% (n = 19) in the severe group were discharged; 28 patients died. CONCLUSION: Laboratory assessment of the neutrophil/lymphocyte ratio and T-cell subsets may be predictive of mortality and may be useful for stratifying COVID-19 patients.

CD3+CD56+ and CD3-CD56+ lymphocytes in the cerebrospinal fluid of persons with HIV-1 subtypes B and C.

The transactivator of transcription (Tat) is a HIV regulatory protein which promotes viral replication and chemotaxis. HIV-1 shows extensive genetic diversity, HIV-1 subtype C being the most dominant subtype in the world. Our hypothesis is the frequency of CSF CD3+CD56+ and CD3-CD56dim is reduced in HIV-1C compared to HIV-1B due to the Tat C30S31 substitution in HIV-1C. 34 CSF and paired blood samples (PWH, n = 20; PWoH, n = 14) were studied. In PWH, the percentage of CD3+CD56+ was higher in CSF than in blood (p < 0.001), comparable in both compartments in PWoH (p = 0.20). The proportion of CD3-CD56dim in CSF in PWH was higher than PWoH (p = 0.008). There was no subtype differences. These results showed CNS compartmentalization of NKT cell response in PWH.

Combined Use of Tocilizumab and Mesenchymal Stromal Cells in the Treatment of Severe Covid-19: Case Report.

The coronavirus pandemic is one of the most significant public health events in recent history. Currently, no specific treatment is available. Some drugs and cell-based therapy have been tested as alternatives to decrease the disease's symptoms, length of hospital stay, and mortality. We reported the case of a patient with a severe manifestation of COVID-19 in critical condition who did not respond to the standard procedures used, including six liters of O2 supplementation under a nasal catheter and treatment with dexamethasone and enoxaparin in prophylactic dose. The patient was treated with tocilizumab and an advanced therapy product based on umbilical cord-derived mesenchymal stromal cells (UC-MSC). The combination of tocilizumab and UC-MSC proved to be safe, with no adverse effects, and the results of this case report prove to be a promising alternative in the treatment of patients with severe acute respiratory syndrome due to SARS-CoV-2.

Evaluation of lymphocyte count, T-cell subsets and neutrophil-to-lymphocyte ratio as early predictors for severity and outcome of COVID-19 disease-a report from a highly complex hospital in Brazil

ABSTRACT Introduction: Lymphopenia is a laboratory marker of poor prognosis and severity of disease in the SARS-CoV-2 infection. This study aims to describe the immune profile of a Brazilian population. Methods: A total of 121 consecutive patients with severe acute respiratory syndrome (SARS) were analyzed between April and June 2020. Routine peripheral blood counts and multiparametric flow cytometry were performed on admission to assess lymphocytes and subsets (CD3, CD4, CD8). Demographic, clinical and laboratory data were collected from hospital sources. Results: The total of 116 patients included 63 (54.3%) males; 76 (62.8%) COVID-19 patients were divided, based on clinical characteristics and mechanical ventilation (MV) use, into moderate (n = 41; no MV) and severe (n = 35; MV) groups. The control group (n = 40) was comprised of patients with SARS of different etiologies. All patients had lymphopenia, with overall lymphocyte counts and their subsets considerably lower in severe patients, when compared to the moderate and controls. Patients with a high neutrophil-to-lymphocyte ratio (> 15.2) and T-cell lymphopenia (CD3 < 593 cells/μL, CD4 < 326 cells/μL, CD8 < 121 cells/μL) had a higher risk of being intubated and progressing to death. A total of 39 patients (95.1%) in the moderate group and 54.3% (n = 19) in the severe group were discharged; 28 patients died. Conclusion: Laboratory assessment of the neutrophil/lymphocyte ratio and T-cell subsets may be predictive of mortality and may be useful for stratifying COVID-19 patients.

Acute promyelocytic leukemia: evaluation of diagnostic tests from 2000 to 2018 in a public hospital / Leucemia promielocítica aguda: avaliação dos testes diagnósticos entre o período de 2000 e 2018 em um hospital público

ABSTRACT Introduction: Acute promyelocytic leukemia (APL) is caused by t(15;17)(q24;q21) translocation, which product is the fusion oncoprotein PML-RARa (promyelocytic leukemia-retinoic acid receptor alpha). The morphology of leukemic promyelocytes is usually characteristic, with the presence of faggot cells and coarse cytoplasmic granulations; immunophenotype is characteristic in most cases. However, definitive laboratory diagnosis should be performed by detecting t(15;17) or by PML-RARa fusion protein. Objectives: To compare cytomorphology, flow cytometry, and classical cytogenetic of bone marrow samples from patients with APL, treated at the Complexo Hospital de Clínicas da Universidade Federal do Paraná (CHC-UFPR), as well as describe the possible discrepancies between the methodologies. Method: Retrospective analysis of APL cases treated at the CHC-UFPR from January 2000 to July 2018. Results: Eighty-eight patients (42 man/ 46 woman; mean age: 34 years), 42.1% of them presented a high-risk prognosis. Flow cytometry was performed in 83 cases (94.3%); karyotype was performed in 79 cases (89.7%), but translocation t(15;17) was confirmed in only 53 cases (60.2%). From the 28 patients with a non-conclusive karyotype; fourteen (15.9%) of them presented the PML-RARa transcript in the molecular analysis. In total, 35 patients (39 8%) performed research of the PML-RARa gene by molecular biology. Only 45 patients (51.1%) presented concordant diagnosis among the three technical exams (morphology, flow cytometry and cytogenetics). Overall survival was 67% at 4.8 years, with 29 deaths. Conclusion: Genetic confirmation was observed in 76.1% of samples, 60.2% by conventional cytogenetics and 15.9% by molecular biology. There was a disagreement between the methodologies, and a low sensibility of the conventional cytogenetics, demonstrating the importance of performing molecular techniques for diagnostic confirmation.

RESUMEN Introducción: La leucemia promielocítica aguda (LPA) es causada por la translocación t(15;17)(q24;q21), cuyo producto es la oncoproteína de fusión PML-RARa (proteína de la leucemia promielocítica-receptor alfa de ácido retinoico). La morfología de los promielocitos leucémicos suele ser típica, con presencia de células faggot (células en haces) y gruesasgranulaciones citoplásmicas; el inmunofenotipo es característico en la mayor parte de los casos. No obstante, el diagnóstico final de laboratorio debe ser hecho por la detección de la t(15;17) o por la oncoproteína PML-RARa. Objetivos: Comparar la citomorfología, la citometría de flujo y la citogenética clásica de muestras de médula ósea de pacientes con LPA asistidos en el Complexo Hospital de Clínicas da Universidade Federal do Paraná (CHC-UFPR), así como describir lasposibles discrepancias entre los métodos. Método: Análisis retrospectivo de los casos de LPA asistidos en el CHC-UFPR entre enero de 2000 y julio de 2018. Resultados: De los 88 pacientes (42 hombres y 46 mujeres; edad promedio: 34 anos), 42,1% presentaron pronóstico de alto riesgo. Citometría de flujo se realizó en 83 casos (94,3%); cariotipo en 79 casos (89,7%),pero la translocación se confirmó en sólo53 (60,2%) casos. Entre los28 pacientes con cariotipo no concluyente, 14 (15,9%) presentaron el transcripto PML-RARa. En total, 35 pacientes (39,8%) realizaron la pesquisa del gen PML-RARa por biología molecular. Cuarenta y cinco pacientes (51,1%) tuvieron diagnóstico acorde entre los métodos (morfología, citometría de flujo y citogenética). La supervivencia global fue de 67% en 4,8 anos, con 29 muertes. Conclusión: Hubo confirmación genética en 76,1% de las muestras, siendo 60,2% por citogenética y 15,9%por biología celular. Hubo desacuerdo entre los métodos y baja sensibilidad de la citogenética convencional, lo que demuestra la importancia de la realización de técnicas moleculares para confirmación diagnóstica.

RESUMO Introdução: A leucemia promielocítica aguda (LPA) écausada pela translocação t(15;17)(q24;q21), cujo produto éa oncoproteína de fusão PML-RARa (leucemia promielocítica-receptor alfa do ácido retinoico). A morfologia dos promielócitos leucêmicos é habitualmente característica, com presença de faggot cells (células em maços ou feixes) e granulações citoplasmáticas grosseiras; o imunofenótipo é característico na maioria dos casos. Porém, o diagnóstico laboratorial definitivo deve ser feito pela detecção da t(15;17) ou pela oncoproteína PML-RARa. Objetivos: Comparar a citomorfologia, a citometria de fluxo e a citogenética clássica de amostras de medula óssea de pacientes com LPA atendidos no Complexo Hospital de Clínicas da Universidade Federal do Paraná (CHC-UFPR), bem como descrever as possíveis discrepâncias entre as metodologias. Método: Análise retrospectiva dos casos de LPA atendidos no CHC-UFPR entre janeiro de 2000 e julho de 2018. Resultados: Dos 88 pacientes (42 homens e 46 mulheres; média de idade: 34 anos), 42,1% apresentaram prognóstico de alto risco. A citometria de fluxo foi realizada em 83 casos (94,3%); o cariótipo, em 79 casos (89,7%), mas a translocação foi confirmada em apenas 53 (60,2%) casos. Dos 28 pacientes com cariótipo não conclusivo, 14 (15,9%) tinham a presença do transcrito PML-RARa. No total, 35 pacientes (39,8%) realizaram a pesquisa do gene PML-RARa por biologia molecular. Quarenta e cinco pacientes (51,1%) obtiveram diagnóstico concordante entre as metodologias (morfologia, citometria de fluxo e citogenética). A sobrevida global foi de 67% em 4,8 anos;com 29 óbitos. Conclusão: A confirmação genética foi realizada em 76,1% das amostras, sendo 60,2%por citogenética e 15,9% por biologia molecular. Houve discordância entre as metodologias e baixa sensibilidade da citogenética convencional, o que demonstra a importância da realização de técnicas moleculares para confirmação diagnóstica.