Increase in Double Negative B Lymphocytes in Patients with Systemic Lupus Erythematosus in Remission and Their Correlation with Early Differentiated T Lymphocyte Subpopulations.

B and T lymphocytes demonstrate important alterations in patients with systemic lupus erythematous (SLE), with a significant upregulation of double negative (DN) B cells. The aim of this study was to evaluate the correlation of T cell immunity changes with the distinct B-cell-pattern SLE. In the present study, flow cytometry was performed in 30 patients in remission of SLE and 31 healthy controls to detect DN B cells (CD19+IgD-CD27-) and a wide range of T lymphocyte subpopulations based on the presence of CD45RA, CCR7, CD31, CD28, and CD57, defined as naive, memory, and advanced differentiated/senescent T cells. Both B and T lymphocytes were significantly reduced in SLE patients. However, the percentage of DN B cells were increased compared to HC (12.9 (2.3-74.2) vs. 8 (1.7-35), p = 0.04). The distribution of CD4 and CD8 lymphocytes demonstrated a shift to advanced differentiated subsets. The population of DN B cells had a significant positive correlation with most of the early differentiated T lymphocytes, CD4CD31+, CD4CD45RA+CD28+, CD4CD45RA+CD57-, CD4CD45RA-CD57-, CD4CD28+CD57-, CD4CD28+CD57+, CD4 CM, CD8 CD31+, CD8 NAÏVE, CD8CD45RA-CD57-, CD8CD28+CD57-, and CD8CD28+CD57+. Multiple regression analysis revealed CD4CD31+, CD8CD45RA-CD57-, and CD8CD28+CD57- cells as independent parameters contributing to DN B cells, with adjusted R2 = 0.534 and p < 0.0001. The predominance of DN B cells in patients with SLE is closely associated with early differentiated T lymphocyte subsets, indicating a potential causality role of DN B cells in T lymphocyte activation.

Impact of de novo donor-specific HLA antibodies on pediatric kidney transplant prognosis in patients with acute declined or stable allograft function.

BACKGROUND: This retrospective multicenter long-term cohort study investigates de novo donor-specific HLA antibodies (dnDSA) impact on allograft survival in pediatric kidney transplantation (KTx), depending on allograft function at dnDSA detection. METHODS: Seventy patients with dnDSA screening in the context of acute allograft dysfunction (AAD) (>50% serum creatinine increase) or routine follow-up were included during a 20-year period. Number of dnDSA specificities and HLA total mean fluorescence intensity (MFI-sum) were collected. RESULTS: Median follow-up time was 8.6 years. Among the 22 dnDSA+ patients, 8 patients presented AAD. Compared with dnDSA- patients, allograft survival was shorter only in dnDSA+/AAD+ patients, regardless of dnDSA detection during the 5-year post-transplant period (9 patients) or later (13 patients) (log rank p < .001 and p < .001, respectively). One dnDSA+/AAD-, 7 dnDSA+/AAD+, and 5 dnDSA- patients lost their allograft. Allograft survival was shorter in dnDSA+/AAD+ patients compared with the 16 dnDSA-/AAD+ patients (log rank p < .001) but did not differ between dnDSA+/AAD- and dnDSA-/AAD- patients (log rank p = .157). dnDSA+/AAD+ and dnDSA-/AAD+ patients presented higher risk of allograft failure compared with the other patient groups after adjustment for recipient age at KTx, donor type, and incidence of delayed graft function (HR 11.322, 95% CI 3.094-41.429, p < .001). Concurrent MFI-sum >10 000 and multiple dnDSA specificities were more significantly associated with AAD, compared with each factor separately (p < .001). CONCLUSIONS: In pediatric KTx, AAD shortens allograft survival in dnDSA+ patients, regardless of dnDSA time detection, and is commonly observed when high MFI-sum concurs with multiple dnDSA specificities. dnDSA without AAD incidence does not determinately affect allograft survival.

End stage renal disease has an early and continuous detrimental effect on regulatory T cells.

End stage renal disease (ESRD) is followed by disturbed adaptive immunity, together with alterations in T cell subsets, including CD4+CD25+FoxP3+ cells (Tregs). In the present study, we assessed the effect of haemodialysis (HD) on the Treg population. CD3+CD4+, CD3+CD8+ and CD4+CD25+FoxP3+ cells were estimated by flow cytometry in 142 ESRD patients (45 ESRD-preHD, 97 on HD) and 30 healthy controls (HC). Patients on HD were classified into three groups according to time on dialysis (HD vintage - HDV): A < 2 years, B: 2-5 years and C: >5 years on HD. The mean age of patients on HD (M/F 53/44) was 54.8 ± 14 years and the median HDV 58 (78) months. We observed a significant progressive reduction in the percentage and count of lymphocytes (p < .001, p < .001, respectively), CD3+CD4+ (p = .003 and, p < .001, respectively) and Tregs (p = .001 and, p < .001, respectively), between HC, ESRD-preHD and HD patients. HDV had a significant inverse correlation with total lymphocyte, CD3+CD4+ and Treg cell counts (p = .001, p < .001, p < .001, respectively) and, the percentage of lymphocytes and CD3+CD4+ cells (p = .005, p = .01, respectively). Furthermore, we stratified patients on HD into three groups according to HDV: A < 2 years, B: 2-5 years and C: >5 years on HD. Total lymphocytes and Tregs were significantly different among the three vintage groups (Kruskal-Wallis H test, p < .001, p < .001 respectively). CD3+CD4+ and CD3+CD8+ cells were also significantly affected (p < .001 and p = .001, respectively), after at least 2 years of HD. Tregs show prompt and significant reduction at the pre-dialysis stage, and continue to decrease gradually even after long-term HD, in a context of total lymphocyte reduction.

Different Types of Chronic Inflammation Engender Distinctive Immunosenescent Profiles in Affected Patients.

Immunosenescence encompasses a spectrum of lymphocyte phenotypic alterations. The aim of the study was to evaluate immunosenescent effect of two different forms of chronic inflammation, Systemic Lupus Erythematosous (SLE), a systemic autoimmune disease, and End-Stage Kidney Disease (ESKD), a chronic inflammatory disorder. Certain lymphocyte surface molecules, including CD31, CD45RA, CCR7, CD28, CD57, for T, and IgD, CD27 for B lymphocytes, were analyzed by flow cytometry in 30 SLE and 53 ESKD patients on hemodialysis (HD), and results were compared to 31 healthy controls (HC) of similar age, gender, and nationality. Significant Lymphopenia was evident in both SLE and ESKD-HD patients, compared to HC, affecting B cells 75.4 (14.4−520.8), 97 (32−341), and 214 (84−576) cells/µL, respectively, p < 0.0001, and CD4 cells 651.2 (71.1−1478.2), 713 (234−1509), and 986 (344−1591) cells/µL, respectively, p < 0.0001. The allocation of B cell subpopulations was remarkably different between SLE and ESKD-HD patients. SLE showed a clear shift to senescence (CD19IgD-CD27−) cells, compared to ESKD-HD and HC, 11.75 (10)% vs. 8 (6) vs. 8.1 (10), respectively. Regarding T lymphocytes, Central Memory CD8 cells predominated in both SLE and ESKD-HD patients compared to HC, 53 (50)%, 52 (63), and 24 (64)%, respectively, while ESKD-HD but not SLE patients also had increased expression of CD4CD28− and CD8CD28− cells. In conclusion, both diseases are followed by significant lymphopenia; however, the senescent phenomenon affects the B lymphocyte compartment in SLE patients and T lymphocytes in ESKD-HD patients.

Exhausted but Not Senescent T Lymphocytes Predominate in Lupus Nephritis Patients.

Lupus nephritis (LN), a chronic inflammatory disease, is characterized by the substantial disruption of immune homeostasis. This study examines its effects on the T lymphocyte phenotype and, particularly, its senescence- and exhaustion-related immune alterations. T cell subpopulations were determined with flow cytometry in 30 LN patients and 20 healthy controls (HCs), according to the expression of senescence- (CD45RA, CCR7, CD31, CD28, CD57), and exhaustion- (PD1) related markers. The immune phenotype was associated with disease activity and renal histology. LN patients were characterized by pronounced lymphopenia, mainly affecting the CD4 compartment, with a concurrent reduction in the naïve, central and effector memory subsets compared to the HCs. In the CD8 compartment, the naïve subsets were significantly lower than that of the HCs, but a shift in the T cells occurred towards the central memory population. CD4+PD1+ and CD8+PD1+ cells were increased in the LN patients compared to the HCs. However, in CD4 T cells, the increase was limited to CD45RA+, whereas in CD8 T cells, both CD45RA+ and CD45RA- subsets were affected. Disease activity was correlated with CD4+PD1+ and highly differentiated CD4+CD28-CD57+ cells. Histology was only associated with CD4 T cell disturbances, with stage IV presenting reduced naïve and increased senescent subsets. Exhausted T lymphocyte subpopulations predominate within LN patients, while the T cell phenotype varies depending on disease activity.

Vaccinated and Convalescent Donor-Derived Severe Acute Respiratory Syndrome Coronavirus 2-Specific T Cells as Adoptive Immunotherapy for High-Risk Coronavirus Disease 2019 Patients.

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic poses an urgent need for the development of effective therapies for coronavirus disease 2019 (COVID-19). METHODS: We first tested SARS-CoV-2-specific T-cell (CοV-2-ST) immunity and expansion in unexposed donors, COVID-19-infected individuals (convalescent), asymptomatic polymerase chain reaction (PCR)-positive subjects, vaccinated individuals, non-intensive care unit (ICU) hospitalized patients, and ICU patients who either recovered and were discharged (ICU recovered) or had a prolonged stay and/or died (ICU critical). CoV-2-STs were generated from all types of donors and underwent phenotypic and functional assessment. RESULTS: We demonstrate causal relationship between the expansion of endogenous CoV-2-STs and the disease outcome; insufficient expansion of circulating CoV-2-STs identified hospitalized patients at high risk for an adverse outcome. CoV-2-STs with a similarly functional and non-alloreactive, albeit highly cytotoxic, profile against SARS-CoV-2 could be expanded from both convalescent and vaccinated donors generating clinical-scale, SARS-CoV-2-specific T-cell products with functional activity against both the unmutated virus and its B.1.1.7 and B.1.351 variants. In contrast, critical COVID-19 patient-originating CoV-2-STs failed to expand, recapitulating the in vivo failure of CoV-2-specific T-cell immunity to control the infection. CoV-2-STs generated from asymptomatic PCR-positive individuals presented only weak responses, whereas their counterparts originating from exposed to other seasonal coronaviruses subjects failed to kill the virus, thus disempowering the hypothesis of protective cross-immunity. CONCLUSIONS: Overall, we provide evidence on risk stratification of hospitalized COVID-19 patients and the feasibility of generating powerful CoV-2-ST products from both convalescent and vaccinated donors as an "off-the shelf" T-cell immunotherapy for high-risk patients.

T cell markers recount the course of immunosenescence in healthy individuals and chronic kidney disease.

Aging results in substantial changes in almost all cellular subpopulations within the immune system, including functional and phenotypic alterations. T lymphocytes, as the main representative population of cellular immunity, have been extensively studied in terms of modifications and adjustments during aging. Phenotypic alterations are attributed to three main mechanisms; a reduction of naïve T cell population with a shift to more differentiated forms, a subsequent oligoclonal expansion of naïve T cells characterized by repertoire restriction, and replicative insufficiency after repetitive activation. These changes and the subsequent phenotypic disorders are comprised in the term "immunosenescence". Similar changes seem to occur in chronic kidney disease, with T cells of young patients resembling those of healthy older individuals. A broad range of surface markers can be utilized to identify immunosenescent T cells. In this review, we will discuss the most important senescence markers and their potential connection with impaired renal function.

Influence of end stage renal disease on CD28 expression and T-cell immunity.

BACKGROUND: T-cell immunity is affected in end stage renal disease (ESRD). However, whether this happens at pre- or post-dialysis stage and what is the impact of different renal replacement methods, remains unclear. We investigated the alterations of T-cell subtypes in patients at pre-dialysis ESRD and their further changes during dialysis. METHODS: CD4+, CD8+, CD4 + CD28null and CD8 + CD28null T-cells were analysed in 40 ESRD patients at two different time points, (a) the day started on dialysis (ESRD-T0) and (b) 6 months later (ESRD-T6), while being on haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). Twenty-five age matched healthy volunteers served as controls. RESULTS: CD4+ and CD8+ T-cells were significantly reduced in ESRD-T0 patients compared to controls, 604 (105-3551) vs 943 (584-1867)µ/L, P = .001, and 352 (103-1561) vs 422.4 (263-1453)µ/L, P = .05, respectively. However, proportions of CD4 + CD28null and CD8 + CD28null cells were significantly increased, 6.4 (0.3-30)% vs 2.7 (0.1-7.8)%, P = .04 and 58.2 (12.8-85.4)% vs 39 (7.8-57.1)%, P = .01, respectively. Proportion of CD4 + CD28null cells showed significant correlation with serum CRP (r = .4, P = .04) and albumin levels (r = -.5, P = .007) in ERSD patients. ESRD-T0 patients with cardiovascular disease (CVD) had increased CD4 + CD28null and CD8 + CD28null proportions, 8.6 (1-30)% vs 2.1 (0.1-19.8)%, P = .04 and 62.5 (12.8-85.4)% vs 45.5 (5.7-73.7)%, P = .02, respectively, compared to those without. Six months later, both CD4 + CD28null and CD8 + CD28null T-cells were increased in HD compared to CAPD patients, by +110.11 (-27.1 to 311.4)% vs -28.1 (-100 to 30)%, P = .003 and +55.23 (-29.06 to 197.93)% vs -8.34 (-54.99 to 66.72)%, P = .05, respectively. CONCLUSIONS: CD4 + CD28null and CD8 + CD28null T-cells are increased at pre-dialysis ESRD, and correlate with chronic inflammatory markers and the presence of CVD. Dialysis methods seem to have different impact on these subpopulations.

Systemic complement activation in anti-neutrophil cytoplasmic antibody-associated vasculitis and necrotizing glomerulonephritis.

AIM: Due to the accumulating evidence of complement activation in anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV), we decided to investigate the possibility of systemic complement activation in patients with Necrotizing Glomerulonephritis secondary to AAV. METHODS: Clinical, laboratory and histological findings, and serum levels of complement components, C3a, C5a and Bb fragment of Factor B and C4d, were estimated in patients with AAV and glomerulonephritis, at time of diagnosis, before any treatment had been applied. All patients were treated with the same immunosuppressive protocol and followed up for total 24 months. Twenty age and sex matched healthy individuals served as controls. RESULTS: Serum levels of all complement components were significantly increased in patients, compared to controls; C5a: 19.9(0.02-48) vs 9.06(2.1-16.3)pg/mL, P = .002, Bb: 7.3(0.02-31.4) vs 0.2(0.02-1.6)pg/mL, P < .0001, C3a: 4.7(0.4-7.2) vs 2.4(1.09-5)pg/mL, P = .05 and C4d: 11.6(0.07-70) vs 0.7(0.07-8.2)pg/mL, P = .001, respectively. There was strong correlation between serum Bb levels and eGFR and FFS2009 score at time of diagnosis (r = -.41, P = .002 and r = .41, P = .003 respectively). Also, serum Bb levels were increased in patients with severe interstitial infiltration (P = .04) and focal necrosis (P = .01) on renal biopsy. Serum Bb levels could also predict renal function outcome during the acute phase of disease, but not at the end of follow up. CONCLUSION: We provided strong evidence of systemic activation of complement alternative pathway in the development and progression of AAV and glomerulonephritis. Serum Bb seem to play a critical role in the induction, also predicting disease activity and outcome, yet activation of classical pathway cannot be excluded.

CD28null and Regulatory T Cells Are Substantially Disrupted in Patients with End-Stage Renal Disease Due to Diabetes Mellitus.

BACKGROUND: End-stage renal disease (ESRD) is associated with alterations in T-cell immunity, including increased CD28null and reduced regulatory T cells (Tregs). However, whether immune disturbances are due to ESRD or primary disease is not yet clear. As diabetes mellitus is the leading cause of ESRD, we evaluated its impact on the immune profile of ESRD patients. METHODS: CD28null, Tregs, and natural killer cells were initially analyzed by flow cytometry in 30 predialysis ESRD patients due to diabetes (DM), 30 non-DM (NDM), and 25 healthy controls. Measurements were repeated after 6 months on hemodialysis (HD) or peritoneal dialysis (CAPD). RESULTS: The percentage of CD4 + CD28null cells, CD8 + CD28null cells, and Tregs showed significant differences in DM, NDM, and controls; mean rank 33.71 vs. 25.68 vs. 18.88, p = 0.006, 37.79 vs. 28.82 vs. 17.08, p = 0.008, and 20.79 vs. 26.12 vs. 41.33, p = 0.001, respectively. DM vs. NDM had increased CD4 + CD28null and CD8 + CD28null cells, 11.5% (1.5%-24%) vs. 4.1% (0-42.3%), p = 0.02 and 61.3% (24%-76%) vs. 43% (5.7%-85%), p = 0.04, respectively. After 6 months on HD but not CAPD, DM showed a significant further increase in CD4 + CD28null cells, from 30 (14-100) to 52.7 (15-203), p = 0.02; and CD8 + CD28null cells, from 137 (56-275) to 266 (103-456), p = 0.01. CONCLUSIONS: Diabetes mellitus affects T-cell subtypes even at predialysis stage, though changes become more prominent after commencement on HD.

Histology and Immunohistochemistry of Radial Arteries Are Suggestive of an Interaction between Calcification and Early Atherosclerotic Lesions in Chronic Kidney Disease.

Background and Objectives: recent studies suggest an implication of immune mechanisms in atherosclerotic disease. In this paper, the interaction between inflammation, calcification, and atherosclerosis on the vessel walls of patients with chronic kidney disease (CKD) is described and evaluated. Materials and Methods: patients with stage V CKD, either on pre-dialysis (group A) or on hemodialysis (HD) for at least 2 years (group B), in whom a radiocephalic arteriovenous fistula (RCAVF) was created, were included in the study. The control group included healthy volunteers who received radial artery surgery after an accident. The expressions of inflammatory cells, myofibroblasts, and vascular calcification regulators on the vascular wall were estimated, and, moreover, morphometric analysis was performed. Results: the expressions of CD68(+) cells, matrix carboxyglutamic acid proteins (MGPs), the receptor activator of nuclear factor-kB (RANK) and RANK ligand (RANKL), and osteoprotegerin (OPG), were significantly increased in CKD patients compared to the controls p = 0.02; p = 0.006; p = 0.01; and p = 0.006, respectively. In morphometric analysis, the I/M and L/I ratios had significant differences between CKD patients and the controls 0.3534 ± 0.20 vs. 0.1520 ± 0.865, p = 0.003, and 2.1709 ± 1.568 vs. 4.9958 ± 3.2975, p = 0.03, respectively. The independent variables correlated with the degree of vascular calcification were the intensity of CD34(+), aSMA(+) cells, and OPG, R2 = 0.76, p < 0.0001, and, with intima-media thickness (IMT), the severity of RANKL expression R2 = 0.3, p < 0.0001. Conclusion: atherosclerosis and vascular calcification in CKD seem to be strongly regulated by an immunological and inflammatory activation on the vascular wall.

Lower limb clinical and radiographic osteoarthritis in former elite male athletes.

PURPOSE: To investigate the prevalence of lower extremities clinical and radiographic OA in former elite male athletes and referents from the general population and to examine its association with the participants' demographic characteristics. METHODS: Two hundred and eighteen former elite male athletes (soccer, volleyball, martial arts, track and field and basketball players, and skiers) and 181 male controls that reported no systematic athletic activity were examined by means of questionnaire, clinical and radiographic evaluation. Exclusion criteria were age younger than 40 years and a positive history of lower extremity surgery, bone or soft tissue trauma and inflammatory arthropathy. RESULTS: Overall, the prevalence of clinical OA between former elite athletes (15.6 %) and controls (14.4 %) was similar (n.s.). The prevalence of radiographic OA was significantly higher (p = 0.03) in former elite athletes (36.6 %) compared with controls (23.9 %). All the participants with clinical OA who underwent radiographic examination also had radiographic OA. The prevalence of clinical and radiographic OA was similar (n.s.) between former athletes of different sports. Age, body mass index (BMI) and occupation variably predicted the prevalence of hip, knee and ankle OA in both study groups. CONCLUSIONS: In the absence of major bone and soft tissue lower limb trauma during their athletic career, former elite athletes may not be at increased risk of developing clinical OA. Radiographic signs of OA present at a significantly higher incidence and possibly precede the clinical onset of OA. Age, BMI and occupation are identified as strong predictors of the development of OA in former elite athletes.

The prognostic value of two histopathologic classification models of ANCA-associated glomerulonephritis: a prospective study.

BACKGROUND: Berden Classification and anti-neutrophil cytoplasmic antibody (ANCA) Renal Risk Score are classification models for rating renal histology and predicting outcome in patients with ANCA-associated Vasculitis/Glomerulonephritis (AAV/GN). In the present study we compare their ability to predict renal function outcome in short- and long-term follow up. METHODS: Patients with an initial diagnosis of AAV/GN based on kidney biopsy were classified according to Berden and Renal Risk Score, started on the same treatment protocol, and were followed prospectively for up to 60 months. Renal function was recorded at 3mo(T3), 6mo(T6) and 60mo(T60), and results were compared to both classification systems. RESULTS: Ninety four AAV/GN patients, M/F = 36/58, age = 60.05 (18-82)yrs were included. Based on Berden classification, patients grouped as Focal (n = 24), Crescentic (n = 35), Mixed (n = 21) and Sclerotic (n = 14), had significant differences in estimated glomerular filtration rate (eGFR) only at T3, while the percentage of those requiring hemodialysis differed at T0, T3, T6 but not at T60. According to the Renal Risk Score, patients were classified as Low (n = 8), Medium (n = 47) and High (n = 39) risk, and showed significant differences in both eGFR levels, proportion of hemodialysis, at T0, T3, T6 and end-stage kidney disease (ESKD) at T60. Even patients classified as Mixed (Berden) and as Medium or High risk (Renal Risk Score) had significant improvement from T0 to T6. Relapse could not be predicted by either system. CONCLUSION: Both methods were able to predict short-term renal function outcome and need for hemodialysis, but the Renal Risk Score showed significant superiority in predicting renal function outcome and ESKD after long-term follow up.

HLA variations in patients with diffuse large B-cell lymphoma and association with disease risk and prognosis: a case-control study.

Introduction: Human leukocyte antigen (HLA) polymorphisms have been associated with the development of various autoimmune diseases, as well as malignant neoplasms. Non-Hodgkin lymphomas (NHLs) are a heterogenous group of lymphoid malignancies in which a genetic substrate has been established and is deemed to play a crucial role in disease pathogenesis. This study aimed to identify whether variations in the HLA gene region were associated with diffuse large B-cell lymphoma (DLBCL) risk and prognosis. Methods: We defined HLA class I (HLA-A, HLA-B, HLA-C) and class II (HLA-DRB1, HLA-DQB1) alleles in 60 patients with DLBCL and compared the results to those found by 236 healthy adult donors from the bone marrow bank of Northern Greece. HLA typing was performed by two molecular methods, Sequence - Specific Oligonucleotide HLA typing (SSO) and Sequence - Specific Primer HLA typing (SSP), from white blood cells recovered from peripheral blood. The phenotypic frequencies of HLA-A, HLA-B, HLA-C, HLA-DRB1 and HLA-DQB1 between patients and controls were compared with the 2-sided Fisher's exact test. Results with p-value <0.05 were considered statistically significant. Odds Ratios with 95% Confidence Intervals were calculated to further strengthen the results. The 2-sided Fisher's exact test was also applied to alleles found only in one of the two groups, while the odds ratios together with the confidence intervals were corrected with Haldane-Anscombe method. Results: Among the studied HLA polymorphisms, the frequency HLA-C*12 allele was significantly lower in patients with DLBCL compared with control subjects (6.7% vs. 34.7%, OR = 0.16, 95% CI: 0.04-0.44). Frequency of HLA-B*39 was significantly lower in patients with DLBCL compared with controls, but due to the low frequency of this polymorphism in the studied population and small sample size, determinations regarding the significance of this findings were limited. Survival analysis revealed that the presence of HLA-C*12 was not associated with improved or worsened overall and progression-free survival. No statistically significant associations were observed in the phenotypic frequencies of HLA-A, HLA-DQB1, HLA-DRB1 and the rest of HLA-B alleles between the control and DLBCL groups. Discussion: Collectively, our results provide valuable insight regarding the role of HLA variations on DLBCL risk. Further studies are required to consolidate our findings and ascertain the clinical implications of these genetic variations on DLBCL management and prognosis.

Evaluation of Regulatory B Cell Subpopulations CD24++CD38++, CD24++CD27+, Plasmablasts and Their Correlation with T Regs CD3+CD4+CD25+FOXP3+ in Dialysis Patients and Early Post-Transplant Rejection-Free Kidney Recipients.

Background: B and T regulatory cells, also known as Bregs and Tregs, are involved in kidney transplantation. The purpose of this study is to monitor changes in the frequency and absolute numbers of Tregs (CD3+CD4+CD25+FoxP3+), transitional Bregs (tBregs) (CD24++CD38++), memory Bregs (mBregs) (CD24++CD27+), and plasmablasts before (T0) and six months (T6) after transplantation. Additionally, we aim to investigate any correlation between Tregs and tBregs, mBregs, or plasmablasts and their relationship with graft function. Methods: Flow cytometry was used to immunophenotype cells from 50 kidney recipients who did not experience rejection. Renal function was assessed using the estimated glomerular filtration rate (eGFR). Results: At T6, there was a significant decrease in the frequency of Tregs, plasmablasts, and tBregs, as well as in the absolute number of tBregs. The frequency of mBregs, however, remained unchanged. Graft function was found to have a positive correlation with the frequency of tBregs and plasmablasts. A significant correlation was observed between the frequency and absolute number of tBregs only when the eGFR was greater than 60 but not at lower values. At an eGFR greater than 60, there was a positive correlation between the absolute numbers of Tregs and mBregs but not between Tregs and tBregs. No correlation was observed for any cell population in dialysis patients. Conclusions: The data show a correlation between the frequency and absolute number of tBregs and the absolute number of Tregs and mBregs with good renal function in the early post-transplant period.

Cellular and Humoral Responses in Dialysis Patients after Vaccination with the BNT162b2 or mRNA-1273 Vaccines.

The outbreak of SARS-CoV-2 has raised considerable concern about the detrimental effects it can induce in public health, with the interest of the scientific community being focused on the development of preventive and therapeutic approaches. Patients with end-stage renal disease (ESRD) are amongst vulnerable populations for critical illness owing to the presence of other comorbidities, their defective immune system, and their inability of self-isolation. To date, vaccination constitutes the most promising method to manage viral dispersion. Therefore, it is particularly important to investigate the effectiveness of available vaccines against SARS-CoV-2 in this risk group. Here, we summarize initial experience regarding the humoral and cellular immune responses elicited in dialysis patients after completion of the recommended vaccination regimen, as well as after booster dose administration, with one of the two mRNA vaccines, namely, BNT162b2 and mRNA-1273. In conclusion, a significantly diminished and delayed immune pattern was observed in ESRD patients compared to healthy population, with a peak in antibody titers occurring 3-5 weeks after the second dose. A booster dose significantly augmented the immune response in dialysis patients with either mRNA-based vaccine. Variables adversely correlating with the weak immunogenicity observed in dialysis patients include immunosuppressive therapy, older age, comorbidities, longer time in hemodialysis treatment, and higher body mass index. On the contrary, previous COVID-19 infection and administration of the mRNA-1273 vaccine are deemed to induce a more favorable immune response. Further investigation is needed to thoroughly understand the efficacy of mRNA-based vaccines in hemodialysis patients and define predictive factors that can influence it.

Relapse of Monoclonal Gammopathy of Renal Significance after mRNA COVID-19 Vaccination: A Case Report.

This case report represents the first suspected case of light chain deposition disease relapse associated with mRNA COVID-19 vaccination. The 75-year-old female patient of Greek ethnicity was admitted to the clinic for the investigation of worsening renal function detected on routine lab examinations, two weeks after she received the second dose of the Moderna COVID-19 vaccine (mRNA-1273). Rapidly progressive glomerulonephritis and anemia were the most notable findings. She had a history of LCDD, which had remained stable for four years. Serum protein immunofixation showed monoclonal kappa zones, and a bone marrow biopsy revealed 5% plasma cell infiltration. These, along with other investigations, established the diagnosis of LCDD recurrence. The patient was started on chemotherapy, which improved her immunological profile, but not her renal function. The patient has remained on hemodialysis since. The association between mRNA vaccinations and LCDD relapse may be grounds for investigations into the pathophysiology of MGRS, given the patient's previous long-term remission. This case report is not intended to directly inform changes in clinical practice. We must stress the importance of following all standardized vaccination protocols, especially in immunocompromised patients.

Immunosenescence and Immune Exhaustion Are Associated with Levels of Protein-Bound Uremic Toxins in Patients on Hemodialysis.

BACKGROUND: The accumulation of protein-bound uremic toxins (PBUTs) in chronic kidney disease may affect patients' immune status. The aim of the study was to evaluate their potential impacts on lymphocyte alterations in patients on hemodialysis (HD). METHODS: The plasma levels of PBUTs were assessed in 54 patients on HD and 31 healthy individuals, using ultra-performance liquid chromatography. The results correlated with the senescent and exhausted status of lymphocytes, based on certain surface molecules, analyzed by flow cytometry. RESULTS: The plasma levels of PBUTs were significantly increased in the patients on HD compared with the healthy controls. The patients with residual kidney function had reduced hippuric acid (HA) levels, total (p = 0.03) and free (p = 0.04), and free IxS levels (p = 0.02). The total and free HA levels correlated negatively with less differentiated subpopulations, CD4+CD45RA+CD31+ (p = 0.037 and p = 0.027), CD8+CD28+CD57- (p = 0.01, p = 0.01), and naïve B cells (CD19+IgD+CD27-) (p = 0.04, p = 0.03). Both the total and the free pCS levels correlated positively with exhausted CD4 cells, p = 0.02 and p = 0.01, respectively. A multivariate analysis showed that IxS and age were the main independent parameters implicated in the reduction intotal CD4 and B lymphocytes and their naïve and early differentiated subsets. CONCLUSIONS: Increased PBUTs levels are associated with immune disturbances of patients on HD, HA, and IxS in the immunosenescent and pCS in the immunoexhaustion alterations.

Effect of Lymphocyte Phenotypic Alterations on the Humoral Response to Vaccination Against SARS-COV-2 in Dialysis Patients.

Background: The response to vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) varies depending on comorbidities. This study evaluated the clinical and immunological factors affecting the humoral response of patients with end-stage renal disease (ESRD) to the BNT162b2 vaccine. Methods: Humoral immunity was evaluated in 54 ESRD patients using serum levels of anti-receptor-binding domain (RBD) and neutralizing antibodies (NAbs), measured by a chemiluminescent immunoassay 30 (T1), 60 (T2), and 120 (T3) days after the second vaccine dose. The results were correlated to baseline patient T- and B-lymphocyte subpopulations determined by flow cytometry. Results: The proportion of seroconverted patients based on the NAb titer decreased from 83.3% at T1 to 53.7% at T3. Age was negatively correlated to the NAb titer at T1 and T2. Patients receiving hemodiafiltration had higher NAb titers at T3. Diabetes was associated with a lower response rate at T3. Univariate analysis revealed a positive correlation between the naïve CD4 T-lymphocyte population and RBD titer at T1 and the NAb titer at T3, with no association observed with naïve CD8 T lymphocytes. NAb titers at T3 were significantly correlated with late-differentiated CD4 T lymphocytes and terminally differentiated effector memory cells re-expressing CD45RA (TEMRA) CD8 T lymphocytes. RBD levels were positively correlated with naïve and memory B-lymphocyte counts at T3. Conclusions: Age, diabetes, and hemodialysis prescription had significant impacts on the response to vaccination. T- and B-lymphocyte phenotypes are major determinants of the humoral response potency to SARS-CoV-2 vaccination with BNT162b2 in patients with ESRD.

Prospective Analysis of B Lymphocyte Subtypes, before and after Initiation of Dialysis, in Patients with End-Stage Renal Disease.

End-stage renal disease (ESRD) is followed by alterations in adaptive immunity. The aim of this study was to evaluate B lymphocyte subtypes in ESRD patients before and after hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). PATIENTS AND METHODS: CD5, CD27, BAFF, IgM and annexin were evaluated by flow cytometry on CD19+ cells in ESRD patients (n = 40), at time of initiating HD or CAPD (T0) and 6 months later (T6). RESULTS: A significant reduction in ESRD-T0 compared to controls was noticed for CD19+, 70.8 (46.5) vs. 171 (249), p < 0.0001, CD19+CD5-, 68.6 (43) vs. 168.9 (106), p < 0.0001, CD19+CD27-, 31.2 (22.1) vs. 59.7 (88.4), p < 0.0001, CD19+CD27+, 42.1 (63.6) vs. 84.3 (78.1), p = 0.002, CD19+BAFF+, 59.7 (37.8) vs. 127.9 (123.7), p < 0.0001 and CD19+IgM+ cells, 48.9 (42.8) vs. 112.5 (81.7) (K/µL), p < 0.0001. The ratio of early/late apoptotic B lymphocytes was reduced (16.8 (10.9) vs. 110 (25.4), p = 0.03). CD19+CD5+ cells were the only cell type with an increased proportion in ESRD-T0 patients (2.7 (3.7) vs. 0.6 (1.1), p < 0.0001). After 6 months on CAPD or HD, CD19+CD27-(%) and early apoptotic lymphocytes were reduced further. The HD patients also showed a significant increase in late apoptotic lymphocytes, from 1.2 (5.7) to 4.2 (7.2) K/mL, p = 0.02. CONCLUSIONS: B cells and most of their subtypes were significantly reduced in ESRD-T0 patients compared to controls, the only exception being CD19+CD5+ cells. Apoptotic changes were prominent in ESRD-T0 patients and were exacerbated by HD.