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Background: In December 2019, novel coronavirus (SARS-CoV-2) pneumonia (COVID-19) was reported in Wuhan and has since rapidly spread throughout China. We aimed to clarify the characteristics and clinical significance of peripheral lymphocyte subset alteration in COVID-19.Methods: The levels of peripheral lymphocyte subsets were measured by flow cytometry in 60 hospitalized COVID-19 patients before and after treatment, and their association with clinical characteristics and treatment efficacy was analyzed.Results: Total lymphocytes, CD4+ T cells, CD8+ T cells, B cells, and natural killer (NK) cells decreased in COVID-19 patients, and severe cases had a lower level than mild cases. The subsets showed a significant association with inflammatory status in COVID-19, especially CD8+ T cells and CD4+/CD8+ ratio. After treatment, 37 patients (67%) showed clinical response, with an increase in CD8+ T cells and B cells. No significant change in any subset was detected in nonresponsive cases. In multivariate analysis, posttreatment decrease in CD8+ T cells and B cells and increase in CD4+/CD8+ ratio were indicated as independent predictors of poor efficacy.Conclusions: Peripheral lymphocyte subset alteration was associated with clinical characteristics and treatment efficacy of COVID-19. CD8+ T cells tended to be an independent predictor for COVID-19 severity and treatment efficacy. [ABSTRACT FROM AUTHOR]

Objectives: Fingolimod (FTY) potentially inhibits the disease activity of multiple sclerosis (MS), but induces severe lymphocytopenia that might be related viral infections, including progressive multifocal leukoencephalopathy. We use a reduced dosage of FTY treatment to avoid its cessation because of lymphocytopenia. FTY inhibits the egress of CD62L+ cells from lymph nodes, and the number of CD4+CD62L+ cells, a major population of CD62L+ cells, in blood is a maker to evaluate the strength of FTY action in patients with MS treated by intermittent drug holidays of FTY. Methods: A total of 24 Japanese patients with MS were treated with variable dosages of FTY initially based on the number of lymphocytes, and then changed to CD4+CD62L+ cell counts as a marker. Fluorescence‐activated cell sorting analysis was used to evaluate the number of CD4+CD62L+ cells in fresh blood of 21 MS patients treated with FTY for 30–94 months, including the mean period of 27.5 months of daily administration. Results: The CD4+CD62L+ cell counts and the proportion of patients with <2% CD4+CD62L+ cells in total lymphocytes declined from 12 ± 13 cells/mm3 (median 8 cells/mm3) to 31 ± 4 cells/mm3 (median 27 cells/mm3) and 61.5% to 0%, respectively, after further dosage reduction. Their annual relapse rates were kept to <0.03, even after inducing CD4+CD62L+ counts as a monitoring marker. The target range of CD4+CD62L+cells on reduction of FTY dosage was 10–80 cells/mm3. Conclusions: It is critical to monitor CD4+CD62L+ cells rather than total lymphocyte count to avoid excessive FTY administration. [ABSTRACT FROM AUTHOR]

Objective To study the clinical value of lymphocyte subsets, immunoglobulins, and complement C3 and C4 in the evaluation of immune status in children with hand-foot-mouth disease (HFMD). Methods A total of 282 children with HFMD were enrolled as the HFMD group, and 130 healthy children were enrolled as the healthy control group. The percentages of peripheral CD3+, CD4+, and CD8+ T lymphocytes, CD19+ B lymphocytes, and CD56+ natural killer cells were measured. The CD4+/CD8+ ratio was calculated. The levels of immunoglobulin A (IgA), immunoglobulin M (IgM), immunoglobulin G (IgG), and complement C3 and C4 were measured. Results The multivariate analysis showed that compared with the healthy control group, the HFMD group had significantly lower percentages of CD3+, CD4+, and CD8+ T lymphocytes and levels of complement C3 and C4 (P<0.05), as well as significantly higher percentage of CD56+ natural killer cells and level of IgG (P<0.05). The individual effect analysis showed that the children aged 0-3 years in the HFMD group had a significantly higher CD4+/CD8+ ratio than the healthy control group (P<0.05); boys aged 0-3 and ≥3 years in the HFMD group had a significantly higher level of IgM than the healthy control group (P<0.05); boys aged ≥3 years and girls aged 0-3 years in the HFMD group had a significantly lower level of IgA than the healthy control group (P<0.05). Conclusions Cellular and humoral immunity disorders are observed in children with HFMD. The monitoring of lymphocyte subsets and immunoglobulin levels can provide a laboratory basis for immune status assessment in children with HFMD. [ABSTRACT FROM AUTHOR]

Background. The state of the recipient’s immune system may influence significantly the results of transplantation and should be taken into account when choosing the tactics of immunosuppressive therapy. Materials and me­thods. The retrospective analysis of cytometric peripheral blood lymphocytes examination: T cells (CD3+, CD19–), T-helper cells (CD3+, CD4+), T-cytotoxic (CD3+, CD8+), T-activated (CD3+, HLA-DR+), T-NK cells (CD3+, CD16+56+), B cells (CD3–, CD19+, HLA-DR+), NK-cells (CD3–, CD16+56+) was done in 40 adult and 20 pediatric patients with end stage renal disease (ESRD) on haemodialysis the day before kidney transplantation in O.O. Shalimov National Institute of Surgery and Transplantation. Results. Higher B-lymphocytes and lower T-cytotoxic and T-activated levels were found in children with end stage renal disease compared to adult patients. There were also tendencies to decreased T-NK and NK-cell levels, as well as to increased CD4+/CD8+ ratio in pediatric patients. The state of immune system in pediatric patients with ESRD before transplantation differs from that in adults. But, taking into account the contradictory published data on this issue, we consider it necessary to continue the investigation with a mandatory analysis of parameters dynamics in posttransplant period. Conclusions. The differences of lymphocyte subsets repertoire in children before kidney transplantation should be considered when choosing optimal scheme of immunosuppressive therapy.

Therapeutic strategies for achieving sustained virologic remission are being explored in human immunodeficiency virus (HIV)-infected individuals who began antiretroviral therapy (ART) during the early phase of infection. In the evaluation of such therapies, clinical protocols should include analytical treatment interruption (ATI); however, the immunologic and virologic impact of ATI in individuals who initiated ART early has not been fully delineated. We demonstrate that ATI causes neither expansion of HIV reservoirs nor immunologic abnormalities following reinitiation of ART. Our findings support the use of ATI to determine whether sustained virologic remission has been achieved in clinical trials of individuals who initiated ART early during HIV infection. [ABSTRACT FROM AUTHOR]

Background: The objective of this observational study is to determine the changes in the circulating immune cells as a predictor of outcomes in patients who have survived cancer. Materials and Methods: A peripheral blood immune-profile evaluation was performed in all the survivors of cancer (n = 66) during their visit to the hospital for regular follow-up and thereafter followed up for two consecutive years for any morbidity or mortality. The changes in hematological and biochemical parameters were evaluated in all the patients. The frequency of circulating lymphocyte cell population i.e., CD3+, CD4+, and CD8+ lymphocytes were analyzed using flow cytometry in the peripheral blood of the patients. The variability in the circulating lymphocytes was correlated with tumor relapse and overall survival (OS). Results: In the study, 47 of the 66 patients with cancer survived at the end of 2 years observation time period, while 19 patients died due to infection related complications and not due to tumor relapse. A significant reduction in the neutrophil (P < 0.0001) and lymphocyte (P < 0.0001) counts were observed in patients who succumbed to the illness within 2 years when compared to the cohorts that were surviving. A statistically significant reduction in the absolute lymphocyte counts (P < 0.004), absolute CD3 (P < 0.0001), CD4 (P < 0.002), and CD8 (P < 0.04) were observed in the deceased group compared to the surviving group. CD4/CD8 ratios between both live and deceased groups did not show any significant difference. Conclusion: This preliminary observational study indicates a correlation of circulatory lymphocytes to OS in survivors of cancer and that it could be a predictive marker. [ABSTRACT FROM AUTHOR]

Background: Flow cytometric enumeration of lymphocyte subsets in peripheral blood can provide important information about immune status. Commutable reference materials (RM) are crucial for maintaining accurate and comparable measurement results over time and space. Commutability assessment of RMs for lymphocyte subsets enumeration has not been reported elsewhere. Methods: Lymphocyte subsets were measured in triplicate on 56 patient samples and eight RMs using two measuring systems commonly used in laboratories (FACS Canto II and Cytomics FC500). The first step was to determine the suitability of RMs and comparability of different systems with patient samples. After the requirements of suitability and comparability were met, the second step was to assess commutability following regression approach and difference in bias approach. Results: Two RMs were not measurable on FC500 system for CD3-CD16/56+ and CD3-CD19+ percentages. The results of comparability showed no significant difference in the two systems. Eight RMs for CD3+CD4+ cell count, six RMs for CD3+ and CD3+CD8+ percentages, five RMs for CD3-CD16/56+ percentage, and three RMs for CD3-CD19+ percentage were commutable using the two approaches. For CD3+, CD3+CD8+ and CD3-CD19+ percentages, the results of regression approach showed that one RM was non-commutable for each parameter, while the other approach showed that the RM was commutable. Conclusions: The suitability of RM and comparability of different measuring systems are prerequisites for assessing commutability. This study indicated that different approaches led to different results. The difference in bias approach is recommended for criteria relating to medical requirements and performance characteristics of measuring systems in use. [ABSTRACT FROM AUTHOR]

Our aim was to evaluate the cost‐effectiveness of a minimal lymphocyte subset quantification (LSQ) by flow cytometry as the first screening in children with clinically suspected primary immunodeficiency (PID). Two hundred sixty‐eight Brazilian patients (0–21 years old) were studied. They were divided by clinical and phenotypical features into those fulfilling criteria for PID (PID phenotype) according to the 2017 International Union of Immunological Societies (IUIS) classification and those not fulfilling these criteria (non‐PID phenotype). We evaluated how many patients had values below the 10th percentile for five lymphocyte subsets in peripheral blood, (suggestive of PID) according to reference values for Brazil, Italy and USA. Three lymphocyte subsets (T CD3/CD4, B CD19 and NK CD16/CD56) had p‐value < 0.05 and Odds Ratio (OR) indicating a risk at least two times higher for the diagnosis of a PID phenotype. The application of Kappa coefficient (k) on Brazilian vs Italian and Brazilian vs US data sets resulted in k compatible with strong or excellent level of agreement between the three classification systems. The authors conclude that a number of CD3+/CD4+, CD19+ and CD16+/CD56+ (NK) cells in peripheral blood <10th percentile represented a significant risk for the diagnosis of PID in this cohort. Natural killer (NK) deficiency is quite rare and has a very specific clinical profile. So, the analysis of these cells could be requested only in some cases, saving even more costs. The minimal immunophenotyping, with quantification of T CD4+, CD19+ and in some cases CD16+/CD56+ cells, may be a useful tool for the first screening of PID, saving costs, especially in developing countries. [ABSTRACT FROM AUTHOR]

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The immune system poses one of the greatest challenges for the scientific community. The general pediatrician should be able to screen and identify an immunodeficient patient based on certain clinical indications. Further investigation is crucial for the distinction between primary or secondary immunodeficiency as well as for between cellular and humoral immunity defects. Full blood count is the best initial laboratory test when suspecting a primary immunodeficiency, focusing on the absolute lymphocyte count, while lymphocyte subset count offers the advantage of detecting the cell type that causes the immune defect. The aim of the present review was to guide the general pediatrician in the investigation and diagnosis of an immunodeficient patient. Even though an immunodeficiency may seem a very difficult disease to diagnose, a balanced and rational way of thinking, along with the help of modern technological advances, can easily guide us in the right direction. [ABSTRACT FROM AUTHOR]

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a rare but fatal clinical syndrome, characterized by severe immune dysfunction and overwhelming inflammatory response. However, the host immune signature and also its role in predicting the clinical outcome are not fully described. The present study aims to investigate the host immune status of sHLH patients in the early stage of the disease, including lymphocyte subsets, phenotypes and cytokines, and also to explore its clinical value in prognosis. Sixty-four patients with sHLH admitted to a tertiary hospital in central China between 2018 and 2022 were enrolled, of which 21 were deceased. The subsets and phenotypes of lymphocytes, and the levels of cytokines in serum were analyzed. In patients with sHLH, the percentages of total T cells, CD8+ T cells, HLA-DR+ T cells, HLA-DR+CD8+ T cells, CD45RO+CD4+ T cells, and the levels of IL-1β, IL-2R, IL-6, IL-8, IL-10 and TNF-α were significantly increased, while the percentages of CD4+ T cells, NK cells, CD45RA+CD4+ T cells, CD45RA+ regulatory T (Treg) cells, the counts of total T cells, total B cells, CD4+ T cells, CD8+ T cells, NK cells, and the ratio of CD4+ T/CD8+ T cells were significantly decreased, compared with healthy controls (HC). In addition, dysregulation of host immune response and high inflammatory status were more obvious in deceased patients than that of survivors. Kaplan-Meier survival analysis and multivariate logistic regression analysis demonstrated that lower levels of CD4+ T cells count and CD28+CD4+ T cells percentage, but higher levels of NK cells percentage and IL-1β were poor prognostic indicators of sHLH. The evaluation of immunological markers has critical value for selecting prognostic markers and potential treatment target among adults with sHLH. [ABSTRACT FROM AUTHOR]

The article discusses research which investigated how the occurrence of lymphopenia may predict the severity and mortality of critically ill patients with coronavirus disease 2019 (COVID-19). Topics explored include the demographic and laboratory characteristics of intensive care unit (ICU) patients with COVID-19 included in the study, the lymphocyte subset counts and patient outcomes recorded, and the reported frequency of lymphopenia in nonsurvivors.

Background: Common variable immunodeficiency (CVID) is one of the most common symptomatic primary immunodeficiency syndromes. The purpose of this article was to broaden our knowledge about CVID for better diagnosis and treatment. Methods: Clinical and immunological features of 40 Chinese patients with CVID were analyzed retrospectively. Results: The median age at onset was 11-year-old (range 4-51 years). The median age at diagnosis was 14.5-year-old (range 5-66 years). The average time of delay in diagnosis was 5.3 years (range 1-41 years). The most common main complaint was fever due to infections (35 cases, 87.5%). Pneumonia (28 cases, 70%) was the most common type of infections. Bronchiectasis was present in 6 patients (15%). Autoimmune disease was detected in 6 cases of CVID, and malignancy in 2 cases. The median total serum levels of IgG, IgA, and IgM at diagnosis were 1.07 g/L, 0.07 g/L, and 0.28 g/L, respectively. The percentages of CD3− /CD19 + B-cells were 1%-3.14%. Conclusions: Infection is the most frequent presentation of CVID. Patients with unexplainable infections should receive further examination including serum immunoglobulin (Ig) and lymphocyte subset analysis. Regular and sufficient substitution with Ig is recommended.

Highlights • We studied the status of lymphocyte subsets in the bone marrow microenvironment at 21 days after allogeneic hematopoietic stem cell transplantation (HSCT). • Natural killer (NK) cell recovery after allo-HSCT affected progression-free survival, nonrelapse mortality, and overall survival. • Infections contributed to outcomes mainly in patients with lower NK cell counts. Abstract Rapid immune recovery following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is important for clinical outcome prediction. In most studies, immune recovery after allo-HSCT is monitored via peripheral blood. However, few reports regarding the status of absolute lymphocyte subsets in the bone marrow (BM) microenvironment have been undertaken. Therefore, we evaluated the clinical impact of immune recovery in the early period following allo-HSCT using BM samples. We showed that delayed natural killer cell recovery was independently associated with a poor prognosis for overall survival (hazard ratio [HR], 3.07; 95% confidence interval [CI], 1.37- 6.89; P =.007), progression-free survival (HR, 3.42; 95% CI, 1.47-7.94; P =.004), and nonrelapse mortality (HR, 6.68; 95% CI, 1.82-25.0; P =.004) by multivariate analysis. In addition, low NK cell counts were associated with the presence of 1 or more bacterial, viral, or fungal infections. Our results indicate that investigating absolute lymphocyte subsets in BM in the early phase following allo-HSCT can be useful for predicting and improving survival outcomes. [ABSTRACT FROM AUTHOR]

This study was performed to evaluate the effect of maternal supplementation with seaweed powder (SWP) on the immune status of piglets. Sows were supplementary fed SWP from 85-days of gestation until delactation. Forty-days old piglets were euthanized and lymphocyte subsets were analyzed. The results showed a significantly higher relative population of CD4+CD8+ T cells in the thymus, lymph node, tonsil (P<0.05), peripheral blood mononuclear cells, spleen and liver (P<0.01) of piglets derived from treated sows. A higher relative population of CD8+ T cells was also observed in the liver and spleen (P<0.05) of the piglets. The data suggested the enhancing effects of maternal supplementation with SWP on immune status of piglets. [ABSTRACT FROM AUTHOR]

We investigated physiological responses and changes in circulating immune cells following exercise in cold and thermoneutral conditions. Participants were short track skaters (n=9) who were acclimatized to cold conditions, and inline skaters (n=10) who were not acclimatized. All skaters were young, and skating at a recreational level three days per week for at least one year. Using a cross-over design, study variables were measured during 60 min of submaximal cycling (65% ·VO2max) in cold (ambient temperature: 5±1°C, relative humidity: 41±9%) and thermoneutral conditions (ambient temperature: 21±1°C, relative humidity: 35±5%). Heart rate, blood lactate and tympanic temperature were measured at rest, during exercise and recovery. Plasma cortisol, calprotectin and circulating blood cell numbers were measured before and after 60 min of cold or thermoneutral conditions, and during recovery from exercise. Heart rate was lower in both groups during exercise in cold versus thermoneutral conditions (P

Immunoglobulin D (IgD) is considered to be an enigmatic Ig molecule because of the lack understanding of its immunological functions. In the present study, a partial δ region of the flounder IgD was recombinantly expressed, purified and used as an immunogen to produce monoclonal antibodies (MAbs) against the H chain of flounder IgD. After fusion, a total of 97 hybridomas were generated and observed under an inverted microscope One of the hybridomas, designated 5G7, gave strong positive results in an indirect enzyme-linked immunosorbent assay (ELISA) and was cloned and subcloned by limiting dilution. Western blot analysis showed that MAb 5G7 could specifically recognize a 118 kDa protein from peripheral blood lymphocytes (PBLs), which was identified to be the H chain of flounder IgD by mass spectrometric analysis. Indirect immunofluorescence assay tests (IIFAT) showed that specific fluorescence signals were observed on the membranes of the PBLs, which suggests that MAb 5G7 could recognize the membrane-bound IgD molecule. Moreover, only the subset of IgD+/IgM + B cells were observed in the PBLs of healthy flounder when tested by flow cytometry analysis. Consistent with the results of flow cytometry, a double immunofluorescence assay test (DIFAT) showed that the positive lymphocytes were stained with both green and red fluorescence signals, which represent the IgM+/IgD + lymphocytes subset. These results demonstrate that the produced MAb 5G7 could specifically recognize the flounder IgD, which provides a useful tool to study the functions of flounder IgD. [ABSTRACT FROM AUTHOR]

Deepened flow cytometry (FCM) analysis of bronchoalveolar lavage fluid (BALF) cells can disclose clonal B and abnormal T lymphocytes in case of lung involvement in non Hodgkin lymphoma (NHL). The possible role of routine FCM BALF analysis in diagnosing NHL involving the lungs is largely undetermined. To evaluate whether differences exist, within FCM screening of lymphocyte subsets, between BALFs from lung NHL and BALFs from reactive diseases. We compared alveolar leukocyte and lymphocyte data obtained using flow cytometry in 17 lung NHL cases with the median corresponding data detected in 208 controls, matched with cases for computed tomography findings. Absolute leukocyte counts did not differ significantly between cases and controls. As calculated within leukocytes, percentages of total, B, T, CD4 and CD8 T lymphocytes, respectively, were significantly higher in B cell NHL cases than in their controls ( P = .003, .023, .009, .004, and .020, respectively). Similarly, percentages of total, and CD8 T lymphocytes, respectively, were significantly higher in T cell NHL cases than in their controls ( P = .046 and .027, respectively). Huger BALF lymphocytosis occurs in pulmonary NHLs than in other lung diseases. Possible lymphocyte cutoffs, that could indicate lung NHL and the subsequent need of a second-step BALF staining shortly following the initial screening, should be prospectively attempted. [ABSTRACT FROM AUTHOR]

Little is known about the characteristics of lymphocyte subsets and the association with patient outcomes in COVID-19 with and without impaired kidney function. Lymphocyte subsets were compared in COVID-19 patients with or without kidney dysfunction. The primary outcome was a composite of all-cause mortality or intensive care unit admission. Secondary outcomes included duration of viral shedding, length of hospital stay, and acute kidney injury. Lymphocyte subset cell counts demonstrated the lowest in patients with severe/critical COVID-19 and kidney dysfunction. Among all lymphocyte subset parameters, Th cell count was the most significant indicator for outcomes. ROC of the combined model of Th cell count and eGFR presented better predictive value than that of the other parameters. Th cell count <394.5 cells/μl and eGFR <87.5 ml/min/1·73m2 were independently associated with poor outcomes. The propensity score matching analysis revealed consistent results. Reduced Th cell count and eGFR may be applied as promising predictive indicators for identifying COVID-19 patients with high risk and poor outcomes. [ABSTRACT FROM AUTHOR]

Background: Accumulating evidence implicates the neuroendocrine immunomodulation (NIM) network in the physiopathological mechanism of Alzheimer's disease (AD). Notably, we previously revealed that the NIM network is dysregulated in the PrP-hAβPPswe/PS1ΔE9 (APP/PS1) transgenic mouse model of AD. Methods: After treatment with a novel Liuwei Dihuang formula (LW-AFC), mice were cognitively evaluated in behavioral experiments. Neuron loss, amyloid-β (Aβ) deposition, and Aβ level were analyzed using Nissl staining, immunofluorescence, and an AlphaLISA assay, respectively. Multiplex bead analysis, a radioimmunoassay, immunochemiluminometry, and an enzyme-linked immunosorbent assay (ELISA) were used to measure cytokine and hormone levels. Lymphocyte subsets were detected using flow cytometry. Data between two groups were compared using a Student's t test. Comparison of the data from multiple groups against one group was performed using a one-way analysis of variance (ANOVA) followed by a Dunnett's post hoc test or a two-way repeated-measures analysis of variance with a Tukey multiple comparisons test. Results: LW-AFC ameliorated the cognitive impairment observed in APP/PS1 mice, including the impairment of object recognition memory, spatial learning and memory, and active and passive avoidance. In addition, LW-AFC alleviated the neuron loss in the hippocampus, suppressed Aβ deposition in the brain, and reduced the concentration of Aβ1-42 in the hippocampus and plasma of APP/PS1 mice. LW-AFC treatment also significantly decreased the secretion of corticotropin-releasing hormone and gonadotropin-releasing hormone in the hypothalamus, and adrenocorticotropic hormone, luteinizing hormone, and follicle-stimulating hormone in the pituitary. Moreover, LW-AFC increased CD8+CD28+ T cells, and reduced CD4+CD25+Foxp3+ T cells in the spleen lymphocytes, downregulated interleukin (IL)-1β, IL-2, IL-6, IL-23, granulocyte-macrophage colony stimulating factor, and tumor necrosis factor-α and -β, and upregulated IL-4 and granulocyte colony stimulating factor in the plasma of APP/PS1 mice. Conclusions: LW-AFC ameliorated the behavioral and pathological deterioration of APP/PS1 transgenic mice via the restoration of the NIM network to a greater extent than either memantine or donepezil, which supports the use of LW-AFC as a potential agent for AD therapy. [ABSTRACT FROM AUTHOR]

PurposeLymphocyte subset recovery is an important factor that determines the success of hematopoietic stem cell transplantation (HSCT). Temporal differences in the recovery of lymphocyte subsets and the factors influencing this recovery are important variables that affect a patient's post-transplant immune reconstitution, and therefore require investigation.MethodsThe time taken to achieve lymphocyte subset recovery and the factors influencing this recovery were investigated in 59 children who had undergone HSCT at the Department of Pediatrics, The Catholic University of Korea Seoul St. Mary's Hospital, and who had an uneventful follow-up period of at least 1 year. Analyses were carried out at 3 and 12 months post-transplant. An additional study was performed 1 month post-transplant to evaluate natural killer (NK) cell recovery. The impact of pre- and post-transplant variables, including diagnosis of Epstein-Barr virus (EBV) DNAemia posttransplant, on lymphocyte recovery was evaluated.ResultsThe lymphocyte subsets recovered in the following order: NK cells, cytotoxic T cells, B cells, and helper T cells. At 1 month post-transplant, acute graft-versus-host disease was found to contribute significantly to the delay of CD16+/56+ cell recovery. Younger patients showed delayed recovery of both CD3+/CD8+ and CD19+ cells. EBV DNAemia had a deleterious impact on the recovery of both CD3+ and CD3+/CD4+ lymphocytes at 1 year post-transplant.ConclusionIn our pediatric allogeneic HSCT cohort, helper T cells were the last subset to recover. Younger age and EBV DNAemia had a negative impact on the post-transplant recovery of T cells and B cells.

Objective: Most patients with coronavirus disease (COVID-19) have abnormalities of lymphocyte subsets. This study aimed to determine the distribution of lymphocytes in patients with various severity levels of COVID-19 and to describe the relationship between the CD4 + T helper and prognosis., Materials and Methods: Adult (>18 years old) patients with COVID-19 who followed up in a tertiary hospital were included in the study prospectively. Demographic and clinical characteristics of the patients were obtained from the hospital records. Peripheral flow cytometry was studied in patients with different severity of COVID-19 and different prognoses. Next, we analyzed the characteristics and predictive values of lymphocyte subsets in COVID-19 patients., Results: Totally 86 patients were included in the study, of which 21 (24.4%) had asymptomatic, 23 (26.7%) had mild/moderate, and 42 (48.8%) had severe/critical COVID-19. Severe/critical patients had lower lymphocyte levels and older age than asymptomatic patients ( p <0.001 and p <0.001, respectively). We determined that decreased CD4 + T cell ratio ( p <0.001) and CD4 + /CD8 + ratio ( p <0.001) were indicative of the severity of the disease. CD4 + T cell ratio on admission (odds ratio [OR]=0.858; p =0.033), day seven CD4 + T cell ratio (OR=0.840; p =0.029), and C-reactive protein (CRP) levels (OR=1.014; p =0.043) were prognostic factors for mortality. According to receiver operating characteristics (ROC) curve analysis, the area under the curve was greater than 0.9 for decreased CD4 + T cell ratio on admission and the seventh day., Conclusion: A low CD4 + T helper ratio predicts a poor prognosis. In combination with CRP, it can be used in clinical follow-up., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Infectious Diseases and Clinical Microbiology.)

Sirolimus can significantly amplify regulatory T cells (Tregs) in vivo and in vitro, but the specific mechanism of this has not been well documented. The role of regulatory B cells (Bregs) in the Tregs-amplifying effect of Sirolimus was investigated in peripheral blood mononuclear cells (PBMCs) in vitro in this study. The results showed that the percentages of both CD19 + CD24 + CD38 + TGF-β1 + Bregs and CD19 + CD24 + CD38 + IL-10 + Bregs to B cells were elevated by Sirolimus in PBMCs including B cells. Sirolimus significantly enhances the cytokine production of transforming growth factor-β1 (TGF-β1) and interleukin-10 (IL-10) in PBMCs with B cells, and the enhancement significantly decreased in PBMCs without B cells. The percentage of CD4 + CD25 + Foxp3 + Tregs to T cells was also elevated by Sirolimus in PBMCs including B cells. The elevation of Tregs percentage decreased in PBMCs without B cells and recovered when additional TGF-β1 and IL-10 were added. The amplification of Tregs by Sirolimus was partially inhibited when either TGF-β1 or IL-10 was neutralized, and it even disappeared when these two cytokines were both neutralized. These results indicate that Sirolimus can amplify Bregs and Tregs in PBMCs in vitro, and Bregs may be the why Sirolimus amplifies Tregs. [ABSTRACT FROM AUTHOR]