Peripheral Blood Lymphocyte Subpopulations Research Articles

Male patients with primary Sjögren's syndrome have unique clinical manifestations and circulating lymphocyte profiles.

We aimed to explore the relationship between clinical characteristics and circulating lymphocyte profiles in Chinese male patients with primary Sjögren's syndrome (pSS). Data from 397 patients with pSS were analyzed retrospectively. 37 were male, which is a prevalence of 9.3%. The clinical, laboratory, and immunophenotypic profiles of peripheral blood lymphocyte subsets were compared between male and female pSS patients. Male patients with primary Sjögren's syndrome have unique clinical manifestations and circulating lymphocyte profiles. Male patients complained more about xerophthalmia and presented with more extra-glandular manifestations as compared with female patients. The CD4+/CD8+ ratio (P = 0.030), the prevalence of CD4-CD8- T cells in lymphocytes (P = 0.020), the absolute number of CD4-CD8- T cells (P = 0.035), the prevalence of CD4+ T cells in lymphocytes (P < 0.001), and the absolute number of CD4+ T cells (P = 0.023) were significantly lower in male patients compared to female patients. On the other hand, the prevalence of CD8+CD28+ T cells (P = 0.030) and CD4+CD25high T cells (P = 0.040) in lymphocytes was significantly higher in male patients than in female patients. Moreover, compared to females with pSS, an elevated serum IgG level, low C3 and C4 levels, anti-SSB positivity, and ANA titers of ≥ 1:160 positivity were more frequent in male with pSS. Male patients with pSS have distinctive peripheral blood lymphocyte subpopulations, present with more severe clinical symptoms and immunological features, and have an unfavorable prognosis. Key Points • Male patients with pSS have more severe clinical symptoms and specific characteristics of peripheral blood lymphocyte subsets. • Male pSS patients exhibit a higher intensity of the disease (as evaluated by ESSDAI). • Male patients with pSS require individualized treatment regimens and closer follow-up.

CLINICAL AND LABORATORY FEATURES OF THE IMMUNE RESPONSE IN CHILDREN WITH COVID-19 INFECTION

The article presents the results of the analysis of clinical and morphological characteristics and a number of indicators of peripheral blood in children with a new coronavirus infection.&#x0D; The purpose of the study is to give clinical and laboratory characteristics of the immune response in children with a new coronavirus infection.&#x0D; Materials and methods. 102 children with a new coronavirus infection were examined. Evaluation of peripheral blood parameters and lymphocyte subpopulations in children of three age groups 0-4 years, 5-9 years and 10-14 years.&#x0D; Results. In children with a new coronavirus infection, an imbalance of the granulocytic and lymphocytic link is observed, which is most pronounced for children of the younger (0-4 years) and middle (5-9 years) age groups. The general trend of changes is characterized by an increase in lymphocytes and granulocytes at the onset of the disease and a decrease after 2 weeks. The ratio of neutrophils to lymphocytes shows the predominance of neutrophils.&#x0D; Conclusion. The established changes are characterized as specific for most viral infections, but at the same time reflect the pathogenetic specifics of SARS-CoV-2 infection, as a combination of age-related features of the functioning of the immune system and the etiotropic effect of the virus.

Features of Cell-Mediated Immunity in Children with Congenital Ichthyosis and Their Role in the Pathogenetic Management

Background. Congenital ichthyoses (CIs) are a heterogeneous clinical-etiological group of genodermatoses. Typical clinical symptoms of this disease, regardless of the form, are generalized erythroderma, peeling, itching, hyperkeratosis, severe structural and functional disorders of the epidermal barrier, other organs and systems. Patients have an extremely low quality of life due to changes in appearance, discomfort, constant disease symptoms. Thus far, there are no effective treatment methods for ichthyosis. That is why scientific search for new therapies is the topical issue in pediatrics and pediatric dermatology.Objective. The aim of the study is to examine the cell-mediated immunity state in patients with CI via assessment of the pattern of lymphocyte subpopulations in peripheral blood. The research was conducted to study the content of the main and small lymphocyte subpopulations in 86 patients with established diagnosis of CI aged from 1 month to 18 years. The diagnosis was made according to the clinical data and the results of molecular genetic testing. Comparative analysis of blood immunological indicators in children with CI and in patients with other immunemediated chronic dermatoses: atopic dermatitis (AD; n = 68) and psoriasis vulgaris (n = 55).Methods. The level of T lymphocytes, T helpers (Th), cytotoxic T lymphocytes (Tc), B lymphocytes, NK cells, Treg-cells (Treg), activated T helpers (Thact), Th17 lymphocytes in peripheral blood was evaluated via flow cytometry using monoclonal antibodies. Statistical analysis was performed via Statistica 10.0. Differences between the groups were assessed via Mann-Whitney non-parametric test, differences were considered significant at p &lt; 0.05.Results. A significant increase of activated T-helpers level in peripheral blood was revealed in patients with CI and psoriasis compared to children with AD (p &lt; 0.001), as well as an increased levels of B-lymphocytes and Treg in children with CI (p &lt; 0.05).Conclusion. Children with CI have shown some features of cell-mediated immunity such as: pathological activation of Th lymphocytes, impaired terminal differentiation of naive CD4+ cells to Thact, Treg, Th17 lymphocytes and their proliferation. Comparative analysis of mentioned immunological indicators in children with CI, psoriasis and AD has shown comparable results of increased Thact lymphocytes levels in patients in CI and psoriasis groups. This results open up potential of using immunobiological drugs of psoriasis target therapy within the new management strategy for children with CI.

Immune Checkpoint Pathway Expression in Lymphocyte Subpopulations in Patients with Common Variable Immunodeficiency and Chronic Lymphocytic Leukemia.

This study aims to gain a deeper understanding of chronic lymphocytic leukemia (CLL) and common variable immunodeficiency (CVID) by studying immune cells and specific immune checkpoint signaling pathways. The analysis of the percentage of selected immune points and their ligands (PD-1/PD-L1, CTLA-4/CD86, and CD200R/CD200) on peripheral blood lymphocyte subpopulations was performed using flow cytometry, and additional analyses determining the serum concentration of the above-mentioned molecules were performed using enzyme immunoassay tests. The obtained results indicate several significant changes in the percentage of almost all tested molecules on selected subpopulations of T and B lymphocytes in both CVID and CLL patients in relation to healthy volunteers and between the disease subunits themselves. The results obtained were also supported by the analysis of the serum concentration of soluble molecules tested. By uncovering valuable insights, we hope to enhance our comprehension and management of these conditions, considering both immunodeficiencies and hematological malignancies. Understanding the role of these signaling pathways in disease development and progression may lead to the development of modern, personalized diagnostic and therapeutic strategies. Ultimately, this knowledge may enable the monitoring of the immune system in patients with CVID and CLL, paving the way for improved patient care in the future.

Immune cell subpopulations and serum neurofilament light chain are associated with increased risk of disease worsening in multiple sclerosis

Changes is lymphocyte subpopulations in peripheral blood have been proposed as biomarkers for evaluation of disease activity in multiple sclerosis (MS). Serum neurofilament light chain (sNfL) is a biomarker reflecting neuro-axonal injury in MS that could be used to monitor disease activity, response to drugs and to prognosticate disease course. Here we show a moderate correlation between sNfL and lymphocyte cell subpopulations, and our data furthermore suggest that sNfL and specific immune cell subpopulations together could predict future disease worsening in MS.

Elevated complement C3 and increased CD8 and type 1 helper lymphocyte T populations in patients with post-COVID-19 condition

BackgroundBiological markers associated to post-COVID-19 condition (PCC) have not been clearly identified. MethodsEighty-two patients attending our post-COVID-19 outpatient clinic were recruited and classified as fully recovered (40.2%) or presenting with PCC (59.8%). Clinical and radiological data, laboratory markers, cytokines, and lymphocyte populations were analyzed. ResultsMedian number of days after hospitalization was 78.5 [p25-p75: 60–93] days. PCC was significantly more frequent in women, in patients with a previously critical COVID-19, and in those with two or more comorbidities. No differences were found in lymphocyte counts, ferritin, C-reactive protein, D-dimer or sCD25, IL-1β, IL-1Ra, IL-6, CXCL8, IL-17A, IL-18, IL-22, IFN-γ, TNF-α, and IL-10 cytokines levels. PCC patients showed significantly higher levels of complement factor C3 than fully recovered patients: median C3 128 mg/dL [p25-p75:107–135] vs 111 mg/dL [p25-p75: 100–125] (p =.005), respectively. In the flow cytometry assessment of peripheral blood lymphocyte subpopulations, PCC patients showed significantly increased CD8 populations compared to fully recovered patients: median CD8: 529 [p25-p75: 384–683] vs 370/mm3 [p25-p75:280–523], p =.007. When type 1, 2, 17/22, and 17.1 helper and follicular T lymphocyte subpopulations were analyzed, the frequency of Th1 was significantly higher in PCC patients compared to fully recovered patients (30% vs 38.5%, p =.028). ConclusionPatients with a post-COVID-19 condition showed significantly increased immunological parameters of inflammation (complement factor C3 and CD8 and Th1 T lymphocyte populations) compared to fully recovered patients. These parameters could be used as biological markers of this condition.

Prognostic significance of lymphocyte subpopulations for ICU-acquired infections in patients with sepsis: a retrospective study

To determine the prognostic value of lymphocyte subpopulations in predicting intensive care unit (ICU)-acquired infections among patients admitted to the ICU with sepsis. Data on peripheral blood lymphocyte subpopulations [CD3+ T cells, CD4+ T cells, CD8+ T cells, CD16+CD56+ natural killer (NK) cells and CD19+ B cells] were collected continuously from 188 patients admitted to the study ICUs with sepsis between January 2021 and October 2022. Clinical data collected from these patients, including medical history, number of organ failures, severity of illness scores, and characteristics of ICU-acquired infections, were reviewed. Lymphocyte subpopulation counts were significantly lower in patients who acquired an infection in the ICU compared with those who did not. Univariate analyses showed that the number of organ failures [odds ratio (OR) 3.37, 95% confidence interval (CI) 2.25-5.05], severity of illness scores [Sequential Organ Failure Assessment score - OR 1.69, 95% CI 1.41-2.02; Acute Physiology and Chronic Health Evaluation II score - OR 1.26, 95% CI 0.17-1.36], history of immunosuppressant use (OR 2.41, 95% CI 1.01-5.73) and lymphocyte subpopulations (CD3+ T cells - OR 0.60, 95% CI 0.51-0.71; CD4+ T cells - OR 0.51, 95% CI 0.41-0.63; CD8+ T cells - OR 0.32, 95% CI 0.22-0.47; CD16/CD56+ NK cells - OR 0.41, 95% CI 0.28-0.59; CD19+B cells - OR 0.52, 95% CI 0.37-0.75) were associated with ICU-acquired infections. Multi-factor logistic regression analysis demonstrated that APACHE II score (OR 1.25, 95% CI 1.13-1.38), CD3+ T cells (OR 0.66, 95% CI 0.54-0.81) andCD4+ T cells (OR 0.64, 95% CI 0.50-0.82) were independent significant risk factors for ICU-acquired infections. Assessing CD3+ T cells and CD4+ T cells within 24h of ICU admission may help in identification of patients at risk for developing ICU-acquired infections.

The impact of adjuvanted and non-adjuvanted influenza vaccines on &lt;i&gt;in vitro&lt;/i&gt; lymphocyte immunophenotype

Vaccination is the most effective method of influenza prophylaxis resulting in reduced frequency and severity of complications. Currently, for the prevention of influenza, inactivated split and subunit vaccines as the safest and promoting formation of protective level of strain-specific virus neutralizing antibodies are used. It is known that not all inactivated vaccines are effective enough for select human groups. While nowadays the level of public health is low, there is a need to improve the effectiveness of vaccines that should activate all chains of the immune system. In order to enhance intensity of influenza virus strain-specific antibody production, adjuvant vaccines exerting other mechanisms to activate humoral and cellular immunity compared to non-adjuvant vaccines have been used. The aim of the study was to examine lymphocyte immunophenotype in 27 healthy donors treated with polymer-subunit (immunoadjuvant) and non-adjuvanted split and subunit influenza vaccines.&#x0D; Materials and methods. Peripheral blood lymphocyte subpopulations were studied in vitro by flow cytometer FC-500 Cytomics (Beckman Coulter, USA) using FITC- and PE-labeled monoclonal antibodies (mAbs).&#x0D; Results. All examined influenza vaccines activate the effectors of cellular immunity, increasing the number of NK-cells (CD16/56), NKT-lymphocytes (CD3/CD16/56), B-lymphocytes (CD45/CD20), activated (CD3/HLA-DR) and cytotoxic (CD8/HLA-DR) T-lymphocytes, as well as cells bearing early activation marker (CD45/CD25). Among them the immunoadjuvant vaccine showed the greatest potential to induce cellular response eliciting regulatory mechanisms that prevent hyperactivation, stimulating growth of NK (CD16/56), NKT-cells (CD3/CD16/56), B-lymphocytes (CD45/CD20), activated (CD3/HLA-DR) and cytotoxic (CD8/HLA-DR) T-lymphocytes, T-regulatory cells (Tregs, CD4/CD25/Foxp3).&#x0D; Conclusion. Vaccination against influenza besides the formation of specific antibodies render a transient, immunomodulating effect that is more noticeable after immunoadjuvant vaccine. It can be assumed that vaccination of people with dysfunctions of the immune system an additional prophylactic effect will be observed.

The link between lymphocyte subpopulations in peripheral blood and metabolic variables in patients with severe obesity.

Obesity, a public health problem, is a state of metainflammation that influences the development of chronic degenerative diseases, particularly in patients with severe obesity. The objective of this study was to evidence immunometabolic differences in patients with different degrees of obesity, including severe obesity, by determining correlations between lymphocyte subpopulations and metabolic, body composition, and clinical variables. Peripheral blood immune cells (CD4+, CD8+ memory and effector T lymphocytes) were analyzed, and measures of body composition, blood pressure, and biochemical composition (glucose, glycated hemoglobin (HbA1c), insulin, C-reactive protein (CRP), and the lipid profile) were carried out in patients with different degrees of obesity. The patients were classified according to total body fat (TBF) percentage as normal body fat, class 1 and 2 obesity, class 3 obesity, and class 4 obesity. The greater the TBF percentage, the more pronounced the differences in body composition (such as a decrease in the fat-free mass (FFM) that is defined as sarcopenic obesity) and the immunometabolic profile. There was an increase of CD3+ T lymphocytes (mainly CD4+, CD4+CD62-, and CD8+CD45RO+ T lymphocytes) and an increase in the TBF percentage (severity of obesity). The correlations between lymphocyte subpopulations and metabolic, body composition, and clinical variables demonstrated the existence of a chronic, low-intensity inflammatory process in obesity. Therefore, measuring the immunometabolic profile by means of lymphocyte subpopulations in patients with severe obesity could be useful to determine the severity of the disease and the increased risk of presenting obesity-associated chronic degenerative diseases.

SUBPOPULATIONS OF LYMPHOCYTES AND MONOCYTES IN PATIENTS` VENOUS BLOOD WITH ATRIAL FIBRILLATION OR ATRIAL FLUTTER ASSOCIATED WITH HYPERTENSION

Objective: The most common reason of arrhythmia onset nowadays is hypertensive desease. The aim of the study is to compare the subpopulations of lymphocytes (LCTs) and monocytes (MCTs) in blood of patients (pts) with paroxysmal and persistent forms of AF or atrial flutter (AFL) associated with arterial hypertension. Design and method: The study involved 103 patients with atrial fibrillation and flutter that occurred on the backdround of hypertension. Depending on the form of arrhythmia, patients were divided into three main groups: group I – with paroxysmal form of atrial fibrillation, group II – with a persistent form of atrial fibrillation, group III – with a persistent form of atrial flutter. The control groups included patients with hypertension, but without these arrhythmias and healthy individuals who entered groups IV and V, respectively. The lymphocytes and monocytes subpopulation in peripheral blood was assessed by flow cytometry. Results: Analyzing the lymphocyte subpopulations in peripheral blood of patients with atrial fibrillation and flutter (groups I, II and III), it was found that the number of cells with cytotoxic activity (NK and NKT) in both absolute count and percentage values was significantly higher than in healthy individuals. A statistically significant decrease of T-regulatory cells number was found in patients with arrhythmias compared to control groups (p &lt; 0.05). In patients with AF and AFL associated with hypertension, compared to patients with hypertension without these rhythm disturbances or healthy individuals, there is an increased number of classical and intermediate monocytes subpopulations. Conclusions: 1. In patients with atrial fibrillation or atrial flutter associated with hypertension, compared to patients with hypertension without these rhythm disturbances or healthy people, there is an increased number of classical and intermediate monocytes fraction and a decreased content of T-regulatory cells in peripheral blood, an increased number of cells with cytotoxic activity (NK and NKT) compared to healthy individuals. These changes can be one of the factors for the activation of systemic and local inflammatory processes that can lead to fibrosis in the myocardium and the associated electrical and structural remodeling typical for AF and AFL.

Peripheral Th and NK cells are associated with response to lenvatinib plus PD-1 inhibitor in unresectable hepatocellular carcinoma.

The value of peripheral blood lymphocyte subpopulations in predicting responses to lenvatinib combination with programmed death-1 (PD-1) inhibitors in unresectable hepatocellular carcinoma (HCC) was investigated. Fifteen patients received objective responses (OR) and sixteen patients had non-objective responses (NOR) were analyzed. The counts of peripheral blood lymphocyte subpopulations from patients were measured before treatment, second (at week 3), and third doses (at week 6) of the PD-1 inhibitor administration, and correlated with responses. Helper T (Th) cells and natural killers (NK) cells were more abundant in the OR group and found to be important predictors of OR in a stepwise multivariate logistic regression analysis. These cutoff values of Th and NK cells could help to distinguish OR from NOR cases accurately and provide clinical benefits.

Peripheral blood lymphocyte changes after stereotactic ablative body radiotherapy to lung or liver metastases in patients with oligometastatic cancers.

To perform the analysis of the peripheral blood lymphocyte changes after stereotactic ablative radiotherapy (SABR) in patients with oligometastatic cancers. The dynamics of the immune status in peripheral blood was prospectively evaluated in 46 patients with lung (17 cases) or liver (29 cases) metastases treated by SABR. Flow cytometry of peripheral blood lymphocyte subpopulations was performed before SABR, 3-4 weeks and 6-8 weeks after the end of SABR: 3 fractions of 15-20 Gy or 4 fractions of 13.5 Gy. The number of treated lesions varied from 1 (32 patients) to 2-3 (14 patients). SABR induced a significant increase of T-lymphocytes (CD3+CD19-) (p = 0.001), T-helper (CD3+CD4+) (p = 0.004), activated cytotoxic T-lymphocytes (CD3+CD8+HLA-DR+) (p = 0.001), activated T-helpers (CD3+CD4+HLA-DR+) (p < 0.001). A significant decrease of T-regulated immune suppressive lymphocytes (CD4+CD25brightCD127low) (p = 0.002) and NKT-cells (CD3+CD16+CD56+) (p = 0.007) was recorded after the SABR. The comparative analysis demonstrated that lower doses of SABR (EQD2Gy(α/β=10) = 93.7-105.7 Gy) induced significant increase of T-lymphocytes, activated cytotoxic T-lymphocytes, and activated CD4+CD25+ T-helpers, while SABR with higher doses (EQD2Gy(α/β=10) = 150 Gy) was not associated with these effects. A more efficient activations of T-lymphocytes (p = 0.010), activated T-helpers (p < 0.001), and cytotoxic T-lymphocytes (p = 0.003) were associated with SABR to a single lesion. A significant increase of T-lymphocytes (p = 0.002), T-helpers (p = 0.003), and activated cytotoxic T-lymphocytes (p = 0.001) was observed after SABR for hepatic metastases in contrast to SABR for lung lesions. Changes in peripheral blood lymphocytes after SABR could be influenced by the location or the number of irradiated metastasis, and the dose of SABR.

Половые различия в субпопуляционном составе лимфоцитов периферической крови при язвенном колите отражают специфические особенности иммунопатогенеза воспалительных заболеваний кишечника у мужчин и женщин

Objective. To identify the features of the composition of peripheral blood lymphocyte subsets in women with ulcerative colitis (UC). Patients and methods. The study included 32 women: 21 patients with UC and 11 healthy volunteers (control group) without inflammatory bowel disease (IBD). The major subsets of T and B lymphocytes were detected by multicolor flow cytometry. Results. The analysis of peripheral blood CD3+ T cell differentiation in women with UC in comparison with healthy controls showed that the Tcyt group had a significant decrease in naive Tcyt cells with an increase in the level of Tcyt cell subsets with pronounced effector properties (EM Tcyt and TEMRA Tcyt). In the subsets of central and effector memory Th cells in women with UC compared to healthy controls, Th17.1-CM cells were significantly different among central memory (CM) cells, and Th17-EM and Th17.1-EM cells were significantly different among effector memory (EM) cells. No significant differences were found in any of the Th17 cell subsets, but there was a tendency towards decreased levels of Th17.1 cells. The analysis of the subsets of T follicular helper (Tfh) cells revealed significant changes only in the level of Tfh17/Tfh22-EM cells (Tfh17-EM cell subset). No significant differences in the B cells were revealed, except for plasmocytes with IgD–CD27++ phenotype, which were increased in UC patients. Conclusion. Changes in peripheral blood T- and B-lymphocytes in women with UC can reflect not only activation of the peripheral immune system, but also induction of immunoglobulin production by B cells activated by T follicular helper cells. For the first time, specific differences between women and men in the total pool of Th17/Th22 cells, “double-positive” Th17, Tfh2 and Tfh17/Tfh22 cells were identified. In contrast to men, no manifestations of a Th2-specific response at the cellular level were observed in women with UC. The revealed sex-related differences in the composition of lymphocyte subpopulations in peripheral blood in UC reflect specific features of the IBD immunopathogenesis in men and women and can be considered in the management of patients with IBD. Key words: inflammatory bowel disease, ulcerative colitis, T helper cell subsets, B lymphocytes, sex-related differences

Subpopulations of lymphocytes and monocytes in blood of patients with atrial fibrillation or atrial flutter associated with hypertension

Atrial fibrillation (AF) remains one of the most common arrhythmias, second only to supraventricular extrasystoles, but the universal cause of its occurrence is still unknown. The inflammatory theory of arrhythmogenesis attracts the attention of researchers around the world. The purpose of the study is to compare the subpopulations of lymphocytes and monocytes in blood of patients with paroxysmal and persistent forms of atrial fibrillation or atrial flutter (AFL) that associated with arterial hypertension. Materials and methods. The study involved 103 patients with atrial fibrillation and flutter that occurred secondary to hypertension. Depending on the form of arrhythmia, they were divided into three main groups: group I – with paroxysmal form of atrial fibrillation, group II – with a persistent form of atrial fibrillation, group III – with a persistent form of atrial flutter. The control groups included patients with hypertension, but without these arrhythmias and healthy individuals who entered groups IV and V, respectively. The lymphocytes and monocytes subpopulation was assessed by flow cytometry in peripheral blood. Results and discussion. Analyzing the lymphocyte subpopulations in peripheral blood of patients with atrial fibrillation and flutter (groups I, II and III), it was found that the number of cells with cytotoxic activity (NK and NKT) in both absolute count and percentage values was significantly higher than in healthy individuals. A statistically significant decrease of T-regulatory cells number was found in patients with arrhythmias compared to control groups (p ≤ 0.05). In patients with AF and AFL associated with hypertension, compared to patients with hypertension without these rhythm disturbances or healthy individuals, there is an increased number of classical and intermediate monocytes subpopulations. Conclusions. In patients with atrial fibrillation and atrial flutter that occurred as a result of hypertension, compared to patients without arrhythmias or healthy people, there is an increased content of pro-inflammatory subpopulations of blood monocytes, T-cytotoxic cells and a decrease in the content of T-regulatory cells.

Correlation between peripheral blood lymphocyte subpopulations and primary systemic lupus erythematosus.

This study explored the correlation between peripheral blood CD3＋, CD3＋/CD4＋, CD3+/CD8+, CD4＋/CD8＋, CD3−/CD16+ CD56+, and CD3−CD19+ and disease activity of different subtypes of systemic lupus erythematosus (SLE). The percentages of CD3+, CD3+/CD4+, CD3+/CD8+, CD4+/CD8+, CD3−/CD16+ CD56+, and CD3−CD19+ in the peripheral blood of patients (n = 80) classified into lupus nephritis, blood involvement, and joint involvement and SLE in different active stages were detected by flow cytometry. Their correlations with baseline clinical experimental indicators of SLE patients’ SLE disease activity index score (SLEDAI) and complement C3 were analyzed. The results showed that CD3+, CD3+/CD4+, and CD3+/CD8+ at baseline level were negatively correlated with SLEDAI scores. These were positively correlated with C3. In conclusion, T-lymphocyte subpopulations are closely related to SLE activity and can be used as reference indicators to evaluate the SLE activity.

Application of the diagnostic criteria for Common Variable Immunodeficiency in resource-limited settings.

Common variable immunodeficiency (CVID) is the most prevalent symptomatic humoral deficiency; however, its heterogeneous presentation makes the diagnosis difficult. The present study is aimed to verify the CVID diagnostic criteria as established by the European Society for Immunodeficiencies in 42 CVID patients from our outpatient clinic. Information was collected from their medical records and when needed, lymphocyte subpopulations in peripheral blood (PB) were performed by flow cytometry. All the patients fulfilled the clinical working definition for CVID and showed decreased serum IgG and IgA at diagnosis. Over two-thirds of the patients had decreased memory B cell percentages. However, the remaining patients exhibited other quantitative B cell defects in PB. Evaluation of vaccination responses was only found in 13 records and 69% were not responsive. None of the patients were subjected to vaccination studies to both, T-cell dependent and independent antigens. The two required tests to evaluate T cell responses were performed in 84.2% of the patients and reported normal. Without the support of third-party payers, only 34.2% of our patients would have completed the required evaluations. Further efforts are needed to speed up CVID diagnosis in low-resourced settings, increasing the availability of the required resources and optimizing the healthcare supply chain.

PB2276: EARLY ADMINISTRATION OF REMDESIVIR PLUS CONVALESCENT PLASMA THERAPY IS EFFECTIVE TO TREAT COVID-19 PNEUMONIA IN B-CELL DEPLETED PATIENTS WITH HEMATOLOGICAL MALIGNANCIES

Background: Patients with hematological malignancies are at a higher risk of developing severe form and protracted course of COVID-19. Remdesivir, an inhibitor of RNA polymerase was identified early as a promising therapeutic regimen for COVID-19, while convalescent plasma (CP) therapy with anti-SARS-CoV-2 antibodies can aid the treatment of COVID-19 in B-cell depleted patients. Aims: Here we investigated whether the combination of externally administered immunoglobulins (Ig) via CP therapy and specific inhibition of viral replication might be sufficient to effectively treat B-cell depleted patients with COVID-19. Methods: We enrolled a series of 20 consecutive patients who suffered from various hematological malignancies with profound B-cell lymphopenia and COVID-19 pneumonia between December 2020 and May 2021. These patients demonstrated a profound B-cell lymphopenia based on flow cytometry analysis of peripheral blood lymphocyte subpopulations. Consequently, they showed undetectable baseline anti-SARS-CoV-2 Ig levels before CP therapy according to anti-SARS-CoV-2 nucleocapsid- and S1-RBD-specific total Ig tests. Each patient received a complete course of remdesivir and at least one unit (200 ml) of AB0 compatible convalescent plasma during their treatment for COVID-19. Results: Previous anti-CD20 therapy resulted in a more prolonged SARS-CoV-2 PCR positivity compared to other causes of B-cell lymphopenia (p=0.004). Timing of CP therapy showed a significant impact on the clinical outcome. Simultaneous use of remdesivir and CP reduced time period for oxygen weaning after diagnosis (p=0.017), length of hospital stay (p=0.007), and PCR positivity (p=0.012) compared to patients who received remdesivir and CP consecutively. In addition, time from the diagnosis to CP therapy affected the length of oxygen dependency (p<0.001) and hospital stay (p<0.0001). In those cases where there were at least ten days from the diagnosis to plasma administration, oxygen dependency was prolonged vs. patients with shorter interval (p<0.001). Summary/Conclusion: Via combined administration of remdesivir and CP, we experienced an overwhelming survival rate in COVID-19 patients with hematological malignancies. Inhibition of viral replication with passive immunization proved to be efficient and safe. Our results suggest the clear benefit of early administration of CP to avoid protracted COVID-19 disease in patients with B-cell lymphopenia.

Innate and Acquired Cellular Immunity in Children with Familial Hypercholesterolemia Treated with Simvastatin.

The aim of this cross-sectional study was to assess the influence of simvastatin treatment in children with familial hypercholesterolemia (FH) on parameters of cellular immunity. Twenty-six children with FH were included, of which thirteen were treated with 10 mg simvastatin for at least 26 weeks, and thirteen were age- and sex-matched with a low-cholesterol diet only. Total WBC count and lipid profile were measured. Flow cytometry was used to identify lymphocyte subsets and determine the expression of adhesion molecules (AM) and toll-like receptors (TLRs) on leukocytes. No differences were found in the basic values of peripheral blood count and subpopulations of lymphocytes between groups. The percentage of granulocytes with the expression of AM was higher in those treated with statins. The TLR-2 expression on granulocytes and monocytes showed higher values, whereas the TLR-4 expression was lower on lymphocytes and granulocytes in simvastatin-treated children. Treatment with simvastatin in children with FH is not associated with alterations in the amounts of granulocytes and monocytes. There is no association between statin treatment and the pattern of peripheral blood lymphocyte subpopulations. The role of AM and TLRs needs further investigation, given the effect of statins on the innate immunity may be important for their efficacy and safety during growth.

Lymphocyte Subsets in Defense Against New Pathogens in Patients with Cancer.

Immunity in cancer patients is modified both by the cancer itself and by oncospecific treatments. Whether a patient's adaptive immunity is impaired depends on their levels of naive lymphocytes and other cell populations. During the COVID-19 pandemic, cancer patients are at greater risk of progressing to severe forms of the disease and have higher mortality rates than individuals without cancer, particularly while they are receiving cancer-specific therapies. An individual's protection against infection, their response to vaccines, and even the tests that determine the humoral immune response to SARS-CoV-2, depend on lymphocyte populations, meriting their study. Estimate blood concentrations of lymphocytes involved in the immune response to new pathogens in cancer patients. We carried out an analytical study of 218 cancer patients; 124 women and 94 men, 26-93 years of age, who were treated at the National Oncology and Radiobiology Institute in Havana, Cuba, March-June, 2020. Patients were divided into five groups: (1) those with controlled disease who were not undergoing cancer-specific treatment; (2) those undergoing debulking surgery; (3) patients undergoing chemotherapy; (4) patients undergoing radiation therapy and (5) patients currently battling infection. We evaluated the following peripheral blood lymphocyte subpopulations via flow cytometry: B lymphocytes (total, naive, transitional, memory, plasmablasts and plasma cells); T lymphocytes (total, helper, cytotoxic and their respective naive, activated, central memory and effector memory subsets); and total, secretory and cytotoxic natural killer cells and T natural killer cells. We also estimated neutrophil/lymphocyte ratios. Lymphocyte concentrations were associated with controlled disease and standard cancer therapy. For variables that did not fall within a normal distribution, ranges were set by medians and 2.5-97.5 percentiles. The two-tailed Mann-Whitney U test was used to measure the effect of sex and to compare lymphocyte populations. We calculated odds ratios to estimate lymphopenia risk. All cancer patients had lower values of naive helper and cytotoxic T lymphocyte populations, naive B lymphocytes, and natural killer cells than normal reference medians. Naive helper T cells were the most affected subpopulation. Memory B cells, plasmablasts, plasma cells, activated T helper cells, and cytotoxic central memory T cells were increased. Patients undergoing treatment had lower levels of naive lymphocytes than untreated patients, particularly during radiation therapy. The risk of B lymphopenia was higher in patients in treatment. The odds ratio for B lymphopenia was 8.0 in patients who underwent surgery, 12.9 in those undergoing chemotherapy, and 13.9 in patients in radiotherapy. Cancer and conventional cancer therapies significantly affect peripheral blood B lymphocyte levels, particularly transitional T helper lymphocytes, reducing the immune system's ability to trigger primary immune responses against new antigens.

Secondary Immunosuppression in Pediatric Kidney Transplant Recipients.

Currentimmunosuppressive treatments for kidney transplant recipients have improved graft viability at the expense of impaired immune surveillance. The tools for monitoring immune status in pediatric kidney transplant recipients have not been widely investigated. Better knowledge could help recognize over immunosuppression and allow implementation of individualized preventive strategies. This retrospective and observational study included 28 pediatric kidney transplant recipients treated at a tertiary hospital. We measured peripheral blood lymphocyte subpopulations, immunoglobulins, immunosuppressivedrug levels, and viral loads. Reference analytical values for different age ranges were used to determine immune status. We recorded overall hospitalizations due to opportunistic infections and positive viral loads posttransplant. We found hypogammaglobulinemia and lymphopenia in 19% and 41% of the patients, respectively. Peripheral blood lymphocyte subpopulations were below normal limits in one-third of the sample. These parameters were not related to the current number or plasma levels of immunosuppressive drugs. During follow-up, cytomegalovirus, Epstein-Barr virus, and BK virus viremias were detected in 60.7% of the patients. Admissions due to opportunistic infections happened in 57.1%, mainly related to severe viral disease (30%) or gastrointestinal infections (26.7%). Most occurred in younger transplant recipients and during the first 2 years posttransplant (73.3%). We found no significant relation between peripheral blood lymphocyte subpopulations and hospital admissions for opportunistic infections or positive viral loads during follow-up. Recurrent hospitalizations for opportunistic infections and analytical disorders in the immune system suggested that secondary immunosuppression in pediatric kidney transplant recipients was frequent. Immunosuppression was not directly related to plasma drug levels or the number of immunosuppressive drugs. Thus, immune monitoring might be helpful in combination with immunosuppressant levels to assess immunosuppression status and to establish individualized preventive measures.