Could Lymphocyte Profiling be Useful to Diagnose Systemic Autoimmune Diseases?

Soluble lymphocyte activation gene-3 (sLAG3) and CD4/CD8 ratio dynamics as predictive biomarkers in patients undergoing immune checkpoint blockade for solid malignancies

BACKGROUND

The search for biomarkers to identify suitable candidates for immune checkpoint inhibitor (ICI) therapy remains ongoing. We evaluate how soluble levels of the next generation immune checkpoint Lymphocyte Activation Gene-3 (sLAG-3) and its association with circulating T lymphocyte subsets could pose as a novel biomarker to predict outcome to ICI therapy.

METHODS

Circulating levels of sLAG3 were analyzed using multiplex immunoassay in n = 84 patients undergoing ICI therapy for advanced solid cancer, accompanied by flow cytometry analyses of peripheral blood mononuclear cells (PBMCs).

RESULTS

Uni- and multivariate analysis shows that patients with higher sLAG3 concentrations before ICI therapy had a significantly impaired progression-free (PFS) and overall survival (OS) (HRPFS: 1.005 [95%CI: 1.000-1.009], p = 0.039; HROS: 1.006 [95%CI: 1.001-1.011], p = 0.015). The CD4/CD8 cell ratio and its dynamics during therapy were strong predictors of PFS and OS with patients with a decreasing ratio between baseline and after 1-2 cycles having an improved median OS compared to patients with increasing values (p = 0.012, HR: 3.32). An immunological score combining sLAG3 and the CD4/CD8 ratio showed the highest predictive potential (HROS: 10.3).

CONCLUSION

Pending prospective validation, sLAG3 and correlating circulating T-cell subsets can be used as a non-invasive predictive marker to predict outcome to ICI therapy to help identifying ideal ICI candidates in the future.

Low CD4 + T cell count is related to specific anti-nuclear antibodies, IFNα protein positivity and disease activity in systemic lupus erythematosus pregnancy

BACKGROUND

Lymphopenia, autoantibodies and activation of the type I interferon (IFN) system are common features in systemic lupus erythematosus (SLE). We speculate whether lymphocyte subset counts are affected by pregnancy and if they relate to autoantibody profiles and/or IFNα protein in SLE pregnancy.

METHODS

Repeated blood samples were collected during pregnancy from 80 women with SLE and 51 healthy controls (HC). Late postpartum samples were obtained from 19 of the women with SLE. Counts of CD4 + and CD8 + T cells, B cells and NK cells were measured by flow cytometry. Positivity for anti-nuclear antibodies (ANA) fine specificities (double-stranded DNA [dsDNA], Smith [Sm], ribonucleoprotein [RNP], chromatin, Sjögren's syndrome antigen A [SSA] and B [SSB]) and anti-phospholipid antibodies (cardiolipin [CL] and β2 glycoprotein I [β2GPI]) was assessed with multiplexed bead assay. IFNα protein concentration was quantified with Single molecule array (Simoa) immune assay. Clinical data were retrieved from medical records.

RESULTS

Women with SLE had lower counts of all lymphocyte subsets compared to HC throughout pregnancy, but counts did not differ during pregnancy compared to postpartum. Principal component analysis revealed that low lymphocyte subset counts differentially related to autoantibody profiles, cluster one (anti-dsDNA/anti-Sm/anti-RNP/anti-Sm/RNP/anti-chromatin), cluster two (anti-SSA/anti-SSB) and cluster three (anti-CL/anti-β2GPI), IFNα protein levels and disease activity. CD4 + T cell counts were lower in women positive to all ANA fine specificities in cluster one compared to those who were negative, and B cell numbers were lower in women positive for anti-dsDNA and anti-Sm compared to negative women. Moreover, CD4 + T cell and B cell counts were lower in women with moderate/high compared to no/low disease activity, and CD4 + T cell count was lower in IFNα protein positive relative to negative women. Finally, CD4 + T cell count was unrelated to treatment.

CONCLUSION

Lymphocyte subset counts are lower in SLE compared to healthy pregnancies, which seems to be a feature of the disease per se and not affected by pregnancy. Our results also indicate that low lymphocyte subset counts relate differentially to autoantibody profiles, IFNα protein levels and disease activity, which could be due to divergent disease pathways.

Added value of lymphocyte subpopulations in the classification of Sjögren's syndrome

Sjögren's Syndrome (SjS) is a chronic systemic immune-mediated inflammatory disease characterized by lymphocytic infiltration and consequent lesion of exocrine glands. SjS diagnosis and classification remains a challenge, especially at SjS onset, when patients may have milder phenotypes of the disease or uncommon presentations. New biomarkers are needed for the classification of SjS, thus, we aimed to evaluate the added-value of lymphocyte subpopulations in discriminating SjS and non-Sjögren Sicca patients. Lymphocyte subsets from 62 SjS and 63 Sicca patients were characterized by flow cytometry. The 2002 AECG and the 2016 ACR/EULAR SjS classification criteria were compared with clinical diagnosis. The added discriminative ability of joining lymphocytic populations to classification criteria was assessed by the area under the Receiver-Operating-Characteristic Curve (AUC). Considering clinical diagnosis as the gold-standard, we obtained an AUC = 0.952 (95% CI: 0.916-0.989) for AECG and an AUC = 0.921 (95% CI: 0.875-0.966) for ACR/EULAR criteria. Adding Tfh and Bm1 subsets to AECG criteria, performance increased, attaining an AUC = 0.985 (95% CI: 0.968-1.000) (p = 0.021). Th1/Breg-like CD24^hiCD27⁺ and switched-memory B-cells maximized the AUC of ACR/EULAR criteria to 0.953 (95% CI: 0.916-0.990) (p = 0.043). Our exploratory study supports the potential use of lymphocyte subpopulations, such as unswitched memory B cells, to improve the performance of classification criteria, since their discriminative ability increases when specific subsets are added to the criteria.

Sarcoidosis and Autoimmune Inflammatory Syndrome Induced by Adjuvants

Currently, sarcoidosis remains one of the diseases with unknown etiology, which significantly complicates its diagnosis and treatment. Various causes of sarcoidosis have been studied for many years. Both organic and inorganic trigger factors, provoking the development of granulomatous inflammation are considered. However, the most promising and evidence-based hypothesis is the development of sarcoidosis as an autoimmune disease, provoked by various adjuvants in genetic predisposed individuals. This concept fits into the structure of the autoimmune/inflammatory syndrome, induced by adjuvants (ASIA) that was proposed in 2011 by Professor Shoenfeld Y. In this paper, the authors reveal the presence of major and minor ASIA criteria for sarcoidosis, propose a new concept of the course of sarcoidosis within the framework of ASIA, and point out the difficulties in creating a model of the disease and the selection of therapy. It is obvious that the data obtained not only bring us closer to understanding the nature of sarcoidosis, but also potentiate new studies confirming this hypothesis by obtaining a model of the disease.

Circulating Regulatory T Cell Subsets in Patients with Sarcoidosis

Over recent years, many researchers have supported the autoimmune theory of sarcoidosis. The presence of uncontrolled inflammatory response on local and system levels in patients with sarcoidosis did not define that the immunoregulatory mechanisms could be affected. The aim of this study was to evaluate the distribution and the disturbance circulating Treg cell subsets in the peripheral blood in patients with sarcoidosis.

MATERIALS AND METHODS

A prospective comparative study was performed in 2016-2018 (34 patients with sarcoidosis (men (67.6%), women (32.3%)) were examined). Healthy subjects-the control group (n = 40). The diagnosis of pulmonary sarcoidosis was performed according to the standard criteria. We used two ten-color combinations of antibodies for Treg immunophenotyping. The first one contained CD39-FITC, CD127-PE, CCR4-PE/Dazzle™ 594, CD25-PC5.5, CD161-PC7, CD4-APC, CD8-APC-AF700, CD3-APC/Cy7, HLA-DR-PacBlue, and CD45 RA-BV 510™, while the second consisted of CXCR3-Alexa Fluor 488, CD25-РЕ, CXCR5-РЕ/Dazzle™ 594, CCR4-PerСP/Сy5.5, CCR6-РЕ/Cy7, CD4-АPC, CD8 АPC-AF700, CD3-АPC/Cy7, CCR7-BV 421, and CD45 RA-BV 510. The flow cytometry data were analyzed by using Kaluza software v2.3. A statistical analysis was performed with Statistica 7.0 and GraphPad Prism 8 software packages.

RESULTS OF THE STUDY

Primarily, we found that patients with sarcoidosis had decreased absolute numbers of Treg cells in circulation. We noted that the level of CCR7-expressing Tregs decreased in patients with sarcoidosis vs. the control group (65.55% (60.08; 70.60) vs. 76.93% (69.59; 79.86) with p < 0.001). We noticed that the relative numbers of CD45RA-CCR7+ Tregs decreased in patients with sarcoidosis (27.11% vs. 35.43%, p < 0.001), while the frequency of CD45 RA-CCR7- and CD45RA+ CCR7- Tregs increased compared to the control group (33.3% vs. 22.73% and 0.76% vs. 0.51% with p < 0.001 and p = 0.028, respectively). CXCR3-expressing Treg cell subsets-Th1-like CCR60078CXCR3+ Tregs and Th17.1-like CCR6+ CXCR3+ Tregs-significantly increased in patients with sarcoidosis vs. the control group (14.4% vs. 10.5% with p < 0.01 and 27.9% vs. 22.8% with p < 0.01, respectively). Furthermore, the levels of peripheral blood EM Th17-like Tregs significantly decreased in the sarcoidosis group vs. the control group (36.38% vs. 46.70% with p < 0.001). Finally, we found that CXCR5 expression was increased in CM Tregs cell subsets in patients with sarcoidosis.

CONCLUSIONS

Our data indicated a decrease in circulating Tregs absolute numbers and several alterations in Treg cell subsets. Moreover, our results highlight the presence of increased levels of CM CXCR5+ follicular Tregs in the periphery that could be linked with the imbalance of follicular Th cell subsets and alterations in B cell, based on the immune response. The balance between the two functionally distinct Treg cell populations-Th1-like and Th17-like Tregs-could be used in sarcoidosis diagnosis and the determination of prognosis and disease outcomes. Furthermore, we want to declare that analysis of Treg numbers of phenotypes could fully characterize their functional activity in peripherally inflamed tissues.

Distinct Lymphocyte Immunophenotyping and Quantitative Anti-Interferon Gamma Autoantibodies in Taiwanese HIV-Negative Patients with Non-Tuberculous Mycobacterial Infections

PURPOSE

The presence of anti-interferon-γ autoantibodies (AutoAbs-IFN-γ) is not rare in patients suffering from persistent non-tuberculous mycobacterial (NTM) infections that are characteristic of adult-onset immunodeficiency syndrome. The immune disturbances in this distinct disorder remain to be elucidated.

METHODS

Patients with NTM infections but without effective response over 3 months' treatment were referred to our institute to quantify their level of AutoAbs-IFN-γ after excluding defective IL12/23-IFN-γ circuit and reactive oxygen species production. The AutoAbs-IFN-γ and percentage of lymphocyte subpopulations most relevant to T and B cell pools were assessed and compared with age-matched healthy controls.

RESULTS

A total of 31 patients were enrolled during the 15-year study period (2008-2022), 20 patients with > 50% suppression of IFN-γ detection at 1:100 serum dilution were classified into the Auto-NTM group. The remaining 11 with negligible suppression were assigned to the No Auto-NTM group. Mycobacterium chimaera-intracellulare group (MAC), M. kansasii, and M. abscessus were the most common pathogens. Pneumonia (19 vs 7), lymphadenitis (11 vs 5), Salmonella sepsis (6 vs 2), osteomyelitis (5 vs 1), and cutaneous herpes zoster (4 vs 4) were the main manifestations in both the Auto-NTM and No Auto-NTM groups who had similar onset-age (55.3 vs 53.6 years; p = 0.73) and follow-up duration (71.9 vs 54.6 months; p = 0.45). The Auto-NTM group had significantly higher transitional (IgM +  + CD38 + +), CD19 + CD21-low, and plasmablast (IgM-CD38 + +) in the B cell pool, with higher effector memory (CD4 + /CD8 + CD45RO + CCR7 -), senescent CD8 + CD57 + , and Th17 cells, but lower naïve (CD4 + /CD8 + CD45RO - CCR7 +) and Treg cells in the T cell pool when compared to the No Auto-NTM and healthy groups. NTM patients with/without AutoAbs-IFN-γ had lower Th1-like Tfh (CD4 + CXCR5 + CXCR3 + CCR6 -) cells. All Auto-NTM patients still had non-remitted mycobacterial infections and higher AutoAbs-IFN-γ despite anti-CD20 therapy in 3 patients.

CONCLUSION

In patients with suspected adult-onset immunodeficiency syndrome, two thirds (20/31) were recognized as having significantly inhibitory AutoAbs-IFN-γ with higher antibody-enhancing transitional, CD19 + CD21-low and plasmablast B cells; as well as higher effector memory, senescent CD8 + CD57 + and Th17 cells, but lower naïve T and Treg cells in contrast to those with negligible AutoAbs-IFN-γ. Such immunophenotyping disturbances might correlate with the presence of AutoAbs-IFN-γ. However, the mutual mechanisms need to be further clarified.

Low Serum Calcium Concentration in Patients With Systemic Lupus Erythematosus Accompanied by the Enhanced Peripheral Cellular Immunity

Objective

This study aims to explore the relationship between serum calcium concentration and peripheral lymphocyte status/Th1/Th2 cytokine levels in SLE patients, and the effect of glucocorticoids (GCs) on the calcium concentration and immune cell activation.

Methods

The peripheral blood TBNK lymphocyte subsets and Th1/Th2 cytokines in SLE patients with low or normal serum calcium concentration and healthy people were analyzed and compared retrospectively. Peripheral white blood cells (PWBCs) from SLE patients or healthy people were stimulated with PMA or GCs in vitro to test their extracellular calcium concentration and CD8⁺ T cell activation.

Results

The percentages of CD8⁺ T in SLE patients increased, but the increase of the number of CD8⁺ T cells only occurred in the SLE patients with low serum calcium concentration, and the number of CD45^hiCD8⁺ T cells also increased, suggesting that SLE patients with hypocalcemia tend to possess an enhanced cellular immunity. The results of Th1/Th2 cytokines in peripheral blood showed that the levels of serum IL-2, IL-10, IL-6 and IFN-γ in SLE patients with hypocalcemia were significantly increased. Although the serum levels of TNF-α in SLE patients were –similar to that in healthy people, it was significantly higher than that in SLE patients with normal serum calcium. When comparing the results of Th1/Th2 cytokines in two times of one patient, the serum levels of TNF-α in SLE patients increased while serum calcium levels decreased. The in vitro experiments showed that the decrease of serum calcium concentration in SLE patients was affected by the immune cell activation and the application of GCs, but GCs did not promote the immune cell activation.

Conclusions

Low serum calcium may make SLE patients in an enhanced cellular immune status and GCs aggravates the decrease of serum calcium levels but has no role on the immune cell activation. It suggests that hypocalcemia possibly promotes the disease activity of SLE patient, which should be paid attention to clinically.

Measurement of circulating CD21-CD27- B lymphocytes in SLE patients is associated with disease activity independently of conventional serological biomarkers

Determining disease activity in systemic lupus erythematosus (SLE) patients is challenging and limited by the lack of reliable biomarkers. Abnormally activated B cells play a key role in the pathogenesis of SLE, but their measure in clinical practice is currently not recommended. Here, we studied peripheral B cells to identify a valid biomarker. We analyzed peripheral B cells in a discovery cohort of 30 SLE patients compared to 30 healthy controls (HC) using mass cytometry and unsupervised clustering analysis. The relevant B cell populations were subsequently studied by flow cytometry in a validation cohort of 63 SLE patients, 28 autoimmune diseases controls and 39 HC. Our data show an increased frequency of B cell populations with activated phenotype in SLE compared to healthy and autoimmune diseases controls. These cells uniformly lacked the expression of CD21 and CD27. Measurement of CD21⁻CD27⁻ B cells in the blood identified patients with active disease and their frequency correlated with disease severity. Interestingly, we did not observe an increase in the frequency of CD21⁻CD27⁻ B cells in patients with clinically inactive disease but with elevated conventional biomarkers (anti-dsDNA and complement levels). Accordingly, measurement of CD21⁻CD27⁻ B cells represents a robust and easily accessible biomarker to assess the activity of the disease in SLE patients.

Relationship Between C-Reactive Protein/Serum Albumin Ratio, Neutrophil/Lymphocyte Ratio, and ANCA-Associated Vasculitis Activity: A Retrospective Single Center Cohort Study

Objectives

To evaluate the role of C-reactive protein/albumin ratio (CAR), neutrophil/lymphocyte ratio (NLR), and mean platelet volume (MPV) in newly diagnosed AAV patients and examine their clinical significance.

Methods

Data from 79 untreated newly diagnosed AAV patients were collected and 76 health examination subjects were included in the healthy control group. All clinical characteristics of AAV patients were extracted from their medical records. The NLR, CAR, and MPV levels of AAV patients and the healthy controls were compared and the correlation between these markers and clinical characteristics was analyzed. Patients were then divided into two groups based on the 2003 Birmingham Vasculitis Activity Score (BVAS). The correlation between NLR, CAR, and MPV and disease activity was analyzed and their effects on the cumulative survival rate were analyzed.

Results

Compared with the healthy control group, elevated CAR, NLR, and MPV were observed in AAV patients. CAR (r = 0.701, P < 0.0001) and NLR (r = 0.369, P < 0.05) were positively correlated with the BVAS while MPV did not show any significant correlation (P = 0.85). The optimal cutoff value for disease activity evaluation using CAR was 0.80 (sensitivity: 85% and specificity: 82%, P < 0.05). The optimal cutoff value for disease activity evaluation using NLR was 5.15 (sensitivity: 66% and specificity: 72%, P < 0.05). Kaplan–Meier survival analysis revealed that the all-cause mortality rate was higher in patients with CAR ≥ 0.8 than in patients with CAR < 0.8 (P < 0.05). Patients with low NLR also showed a lower cumulative survival rate (P < 0.05).

Conclusions

NLR and CAR can reflect the inflammatory response and disease activity in AAV patients, while MPV is not significantly correlated with disease activity in AAV patients. The all-cause mortality rate was higher in patients with high CAR and NLR than in patients with low CAR and NLR.

Plasma Levels of Interleukin-6 and the Cluster of Differentiation 4/Cluster of Differentiation 8 Ratio in Frailty among Community-dwelling Older People

Background: Frailty has become a major health problem among Indonesian elders. Immunosenescence specifically inflammaging are essential components in the development of frailty. Early screening and timely tailored intervention may effectively prevent or delay the adverse outcomes in elders. This study measured the CD4/CD8 ratio from the immunosenescence pathway and plasma IL-6 levels as inflammatory markers from the inflammaging pathway and observed the correlations between robust and frail elders groups Methods: We conducted a cross-sectional survey. Using multistage random sampling, we enrolled 64 participants across Malang city, divided into frail and robust groups. We analyzed the plasma IL-6 levels and CD4/CD8 ratio using an independent t-test and the Mann–Whitney U test. Results: Significant differences between frail and robust elders were found in age and education level, with the frail participants being older than the robust (p=0.001) and lower educational level (p<0.001). However, plasma IL-6 levels (p=0.936) and the CD4/CD8 ratio (p=0.468) were not statistically different between the groups. Conclusion: Plasma level of IL-6 was found to increase similarly in both groups, while CD4/CD8 ratio was normal and not statistically different between the robust and frail group in elders.

Increased Proportion of CD226+ B Cells Is Associated With the Disease Activity and Prognosis of Systemic Lupus Erythematosus

Background

CD226, an activating receptor expressed on the surface of natural killer (NK) cells and T cells, is also seen on B cells and CD226 polymorphism is associated with systemic lupus erythematosus (SLE). Because the specific roles of CD226⁺ B cells in SLE are still unknown, we investigated the association of CD226⁺ B cells with SLE.

Methods

We measured CD226 expression on B cells and its subsets using flow cytometry in 48 SLE patients and 24 healthy controls (HCs). We assessed the relationships between CD226⁺ B cells and SLE Disease Activity Index 2000 (SLEDAI-2K), clinical manifestations, laboratory data, and prognosis after 12 months.

Results

The proportions of CD226⁺ cells in whole B cells and all its subsets were significantly higher in SLE patients than HCs. In SLE patients, the proportions of CD226⁺ B cells and CD226⁺ switched-memory (SM) B cells were significantly correlated with SLEDAI-2K scores and anti-dsDNA antibody titers, and negatively correlated with serum complement levels. Moreover, basal percentages of CD226⁺ B cells and CD226⁺ SM B cells were low in patients who were in Lupus Low Disease Activity State after 12 months. In patients with renal involvement, the proportion of CD226⁺ B cells increased. Additionally, the proportion of CD226⁺ B cells was higher in patients who were not in complete renal remission after 12 months.

Conclusions

Increased proportion of CD226⁺ B cells was associated with disease activity and prognosis of SLE. CD226⁺ B cells may be a useful biomarker for the management of SLE.

Immune Cells Profiling in ANCA-Associated Vasculitis Patients-Relation to Disease Activity

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are a group of necrotizing multiorgan autoimmune vasculitides that predominantly affect small blood vessels and are associated with the presence of ANCAs. The aim was to assess regulatory and effector cell populations accompanied by the suPAR biomarker level and link the so-defined immune state to the AAV disease activity. The research involved a multicomponent description of an immune state encompassing a range of B and T cell subsets such as transitional/regulatory B cells (CD19+CD24++CD38++), naïve B cells (CD19+CD24INTCD38INT), Th17 cells, T regulatory cells (CD4+CD25+FoxP3+) and cytotoxic CD4+CD28- cells by flow cytometry. The suPAR plasma level was measured by ELISA. The results indicate that AAV is associated with an increased suPAR plasma level and immune fingerprint characterized by an expansion of Th17 cells and T cells lacking the costimulatory molecule CD28, accompanied by a decrease of regulatory populations (Tregs and transitional B cells) and NK cells. Decreased numbers of regulatory T cells and transitional B cells were shown to be linked to activation of the AAV disease while the increased suPAR plasma level-to AAV-related deterioration of kidney function. The observed immune fingerprint might be a reflection of peripheral tolerance failure responsible for development and progression of ANCA-associated vasculitides.

New biomarkers in SLE: from bench to bedside

Biomarkers may have a diagnostic or monitoring value, or may predict response to therapy or disease course. The aim of this review is to discuss new serum and urinary biomarkers recently proposed for the diagnosis and management of SLE patients. Novel sensitive and specific assays have been proposed to evaluate complement proteins, ‘old’ biomarkers that are still a cornerstone in the management of this disease. Chemokines and lectins have been evaluated as surrogate biomarkers of IFN signature. Other cytokines like the B cell activating factor (BAFF) family cytokines are directly related to perturbations of the B cell compartment as key pathogenetic mechanism of the disease. A large number of urine biomarkers have been proposed, either related to the migration and homing of leukocytes to the kidney or to the local regulation of inflammatory circuits and the survival of renal intrinsic cells. The combination of traditional disease-specific biomarkers and novel serum or urine biomarkers may represent the best choice to correctly classify, stage and treat patients with SLE.

Genome-wide association study of individual differences of human lymphocyte profiles using large-scale cytometry data

Human immune systems are very complex, and the basis for individual differences in immune phenotypes is largely unclear. One reason is that the phenotype of the immune system is so complex that it is very difficult to describe its features and quantify differences between samples. To identify the genetic factors that cause individual differences in whole lymphocyte profiles and their changes after vaccination without having to rely on biological assumptions, we performed a genome-wide association study (GWAS), using cytometry data. Here, we applied computational analysis to the cytometry data of 301 people before receiving an influenza vaccine, and 1, 7, and 90 days after the vaccination to extract the feature statistics of the lymphocyte profiles in a nonparametric and data-driven manner. We analyzed two types of cytometry data: measurements of six markers for B cell classification and seven markers for T cell classification. The coordinate values calculated by this method can be treated as feature statistics of the lymphocyte profile. Next, we examined the genetic basis of individual differences in human immune phenotypes with a GWAS for the feature statistics, and we newly identified seven significant and 36 suggestive single-nucleotide polymorphisms associated with the individual differences in lymphocyte profiles and their change after vaccination. This study provides a new workflow for performing combined analyses of cytometry data and other types of genomics data.

Increased Frequencies of Switched Memory B Cells and Plasmablasts in Peripheral Blood from Patients with ANCA-Associated Vasculitis

B cells are thought to play a central role in the pathogenesis of antineutrophil cytoplasmic antibody- (ANCA-) associated vasculitis (AAV). ANCAs have been proposed to cause vasculitis by activating primed neutrophils to damage small blood vessels. We studied a cohort of AAV patients of which a majority were in remission and diagnosed with granulomatosis with polyangiitis (GPA). Using flow cytometry, the frequencies of CD19⁺ B cells and subsets in peripheral blood from 106 patients with AAV and 134 healthy controls were assessed. B cells were divided into naive, preswitch memory, switched memory, and exhausted memory cells. Naive and switched memory cells were further subdivided into transitional cells and plasmablasts, respectively. In addition, serum concentrations of immunoglobulin A, G, and M were measured and clinical data were retrieved. AAV patients displayed, in relation to healthy controls, a decreased frequency of B cells of lymphocytes (5.1% vs. 8.3%) and total B cell number. For the subsets, a decrease in percentage of transitional B cells (0.7% vs. 4.4%) and expansions of switched memory B cells (22.3% vs. 16.5%) and plasmablasts (0.9% vs. 0.3%) were seen. A higher proportion of B cells was activated (CD95⁺) in patients (20.6% vs. 10.3%), and immunoglobulin levels were largely unaltered. No differences in B cell frequencies between patients in active disease and remission were observed. Patients in remission with a tendency to relapse had, compared to nonrelapsing patients, decreased frequencies of B cells (3.5% vs. 6.5%) and transitional B cells (0.1% vs. 1.1%) and an increased frequency of activated exhausted memory B cells (30.8% vs. 22.3%). AAV patients exhibit specific changes in frequencies of CD19⁺ B cells and their subsets in peripheral blood. These alterations could contribute to the autoantibody-driven inflammatory process in AAV.

Definition and Risks of Cytokine Release Syndrome in 11 Critically Ill COVID-19 Patients With Pneumonia: Analysis of Disease Characteristics

Corona virus disease 2019 (COVID-19) patients with severe immune abnormalities are at risk of cytokine release syndrome (CRS). The definition, prevention, and treatment of symptoms of CRS in critically ill patients with COVID-19 are important problems. We report a single-center case series of 11 COVID-19 patients with acute respiratory distress syndrome from The First Affiliated Hospital of Guangzhou Medical University in China from 26 January 2020 to 18 February 2020. The termination date of follow-up was 19 February 2020. Eight patients were determined to have characteristics of CRS, including pulmonary inflammation, fever, and dysfunction of nonpulmonary organs. An increase in interleukin-6 in peripheral blood was the highest risk factor and an early indicator of CRS in COVID-19.

Definition and Risks of Cytokine Release Syndrome in 11 Critically Ill COVID-19 Patients With Pneumonia: Analysis of Disease Characteristics

Corona virus disease 2019 (COVID-19) patients with severe immune abnormalities are at risk of cytokine release syndrome (CRS). The definition, prevention, and treatment of symptoms of CRS in critically ill patients with COVID-19 are important problems. We report a single-center case series of 11 COVID-19 patients with acute respiratory distress syndrome from The First Affiliated Hospital of Guangzhou Medical University in China from 26 January 2020 to 18 February 2020. The termination date of follow-up was 19 February 2020. Eight patients were determined to have characteristics of CRS, including pulmonary inflammation, fever, and dysfunction of nonpulmonary organs. An increase in interleukin-6 in peripheral blood was the highest risk factor and an early indicator of CRS in COVID-19.

Innate B Cells: the Archetype of Protective Immune Cells

The innate B cell (IBC) population is heterogeneous and involved in the primary immune response. IBC functions include a high ability to produce natural antibodies with IgM isotype, the elimination of apoptotic cells, and a capacity to be cognate help to T cells. Among IBC subsets, B-1 cells and marginal zone B cells are the main producers of IgM, act as rapid immune responders that may relocate to follicular lymphoid and differentiate to cytokine and antibody-secreting cells shortly after infection. IBCs functions are highly dependent on their localization site and the nature of their B cell receptor repertoire, suggesting a high plasticity range of different immune responses. In this review, we will describe the nature and functions of the different innate-like B cell subsets, first in mice and then in humans. Besides this, we will emphasize the strong ability of these cells to undertake different protective functions from the first line of defense against pathogens to the regulatory role of the broader immune response.

Ultra-low dose rituximab as add-on therapy in anti-MDA5-positive patients with polymyositis /dermatomyositis associated ILD

OBJECTIVES

To evaluate the efficacy and safety of ultra-low dose (100 mg) rituximab (RTX) administration in anti-melanoma differentiation-associated gene 5 (MDA5) positive patients with polymyositis/dermatomyositis (PM/DM) associated interstitial lung disease.

METHODS

This retrospective study included anti-MDA5 antibody positive ILD subjects in the First Affiliated Hospital of Guangzhou Medical University from November 2017 to March 2019. Independent predictors for 180-day mortality were measured by Cox regression analysis. Patients were divided into 3 groups: Group 1 (non-cyclophosphamide (CTX)/RTX) (n = 10), Group 2 (CTX only) (n = 19) and Group 3 (RTX with/without CTX) (n = 11). The 180-day mortality was compared among 3 groups with Kaplan-Meier analysis. Post-RTX serological parameters as well as adverse events were evaluated.

RESULTS

Forty patients were included with the mean age of 51.3 years. Elevated IL-10 level and CD4⁺/8⁺ ratio were considered as risk factors of 180-day mortality. Kaplan-Meier analysis showed a trend toward decrease, albeit non-significant, in 180-day mortality in Group 3 (P = 0.26). The administration of 100 mg RTX brought down B cell within 7 days that lasted for 180 days. There were 7 and 6 infection events observed within 2 months of CTX/RTX treatment in Group 2 and 3, with 5 and 2 fatal cases respectively. Cytomegalovirus infection accounted for half infection events in Group 3.

CONCLUSION

We found a pronounced and prolonged B cell depletion following 100 mg RTX infusion and RTX add-on may be effective in anti-MDA5 positive ILD patients. However, infection, especially opportunistic infection, should be concerned during the treatment.

Transitional B cells involved in autoimmunity and their impact on neuroimmunological diseases

Transitional B cells (TrB cells) represent a crucial link between immature B cells in the bone marrow and mature peripheral B cells. Although TrB cells represent one of the regulatory B cell subpopulations in healthy individuals, the frequency of CD24^hiCD38^hi TrB cells in circulation may be altered in individuals with autoimmune diseases, such as multiple sclerosis, neuromyelitisoptica spectrum disorders, systemic lupus erythematosus, Sjögren’s syndrome, rheumatoid arthritis, systemic sclerosis, and juvenile dermatomyositis. Although TrB cells play regulatory roles under inflammatory conditions, consequences of their functional impairment vary across autoimmune diseases. Since the origin, development, and function of TrB cells, especially in humans, remain unclear and controversial, this review aimed to discuss the characteristics of TrB cells at steady state and explore their role in various immune diseases, including autoimmune rheumatic diseases and neuroimmunological diseases.

Flip-flops of natural killer cells in autoimmune diseases versus cancers: Immunologic axis

Natural killer (NK) cells play an essential role in the immune response to infections, inflammations, and malignancies. Recent studies suggest that NK cell surface receptors and cytokines are the key points of the disease development and protection. We hypothesized that the interactions between NK cell receptors and targeted cells construct an eventual niche, and this niche has an eventual profile in various autoimmune diseases and cancers. The NK cells preactivated with cytokines, such as interleukin-2 (IL-2), IL-12, IL-15, and IL-18 can have higher cytotoxicity; however, the toxic side effect of IL-2 should be considered. The vicissitudes of NK cell profile and its receptors obey the environmental communications and cell interactions. Our vision around the NK cells as an immune axis remained dual, and we still cannot judge the immune responses based on the NK cell flip-flop. A design of eventual niche to monitor the NK cell and targeted cell interaction is needed to strengthen our ability in diagnosis and treatment approaches based on the NK cells. Here, we have reviewed the shifts in the NK cells and their surface receptors in autoimmune diseases, solid tumors, and leukemia, and also discussed the effective chemokines that affect NK cell activation and proliferation. The main aim of this review is to present a broader vision of the NK cell changes in autoimmune disease and cancers.

Peripheral-blood b-cell subset disturbances in inflammatory joint diseases induced by Tropheryma whipplei

Objective

To look for abnormalities in circulating B-cell subsets in patients with rheumatic symptoms of Whipple’s disease (WD).

Method

Consecutive patients seen between 2010 and 2016 for suspected inflammatory joint disease were identified retrospectively. Results of standardized immunological and serological tests and of peripheral-blood B-cell and T-cell subset analysis by flow cytometry were collected. Patients with criteria suggesting WD underwent PCR testing for Tropheryma whipplei, and those with diagnosis of WD (cases) were compared to those without diagnosis (controls). We used ROC curve analysis to evaluate the diagnostic value of flow cytometry findings for WD.

Results

Among 2917 patients seen for suspected inflammatory joint disease, 121 had suspected WD, including 9 (9/121, 7.4%) confirmed WD. Proportions of T cells and NK cells were similar between suspected and confirmed WD, whereas cases had a lower proportion of circulating memory B cells (IgD^-CD38^low, 18.0%±9.7% vs. 26.0%±14.2%, P = 0.041) and higher ratio of activated B cells over memory B cells (4.4±2.0 vs. 2.9±2.2, P = 0.023). Among peripheral-blood B-cells, the proportion of IgD+CD27- naive B cells was higher (66.2%±18.2% vs. 54.6%±18.4%, P = 0.047) and that of IgD-CD27+ switched memory B cells lower (13.3%±5.7% vs. 21.4%±11.9%, P = 0.023), in cases vs. controls. The criterion with the best diagnostic performance was a proportion of IgD+CD27- naive B cells above 70.5%, which had 73% sensitivity and 80% specificity.

Conclusion

Our study provides data on peripheral-blood B-cell disturbances that may have implications for the diagnosis and pathogenetic understanding of WD.

An explorative study on deep profiling of peripheral leukocytes to identify predictors for responsiveness to anti-tumour necrosis factor alpha therapies in ankylosing spondylitis: natural killer cells in focus

Background

Therapeutic targeting of tumour necrosis factor (TNF)-α is highly effective in ankylosing spondylitis (AS) patients. However, since one-third of anti-TNF-treated AS patients do not show an adequate clinical response there is an urgent need for new biomarkers that would aid clinicians in their decision-making to select appropriate therapeutic options. Thus, the aim of this explorative study was to identify cell-based biomarkers in peripheral blood that could be used for a pre-treatment stratification of AS patients.

Methods

A high-dimensional, multi-parametric flow cytometric approach was applied to identify baseline predictors in 31 AS patients before treatment with the TNF blockers adalimumab (TNF-neutralisation) and etanercept (soluble TNF receptor).

Results

As the major result, the frequencies of natural killer (NK) cells, and in particular CD8-positive (CD8⁺) NK cell subsets, were most predictive for therapeutic outcome in AS patients. While an inverse correlation between classical CD56⁺/CD16⁺ NK cells and reduction of disease activity was observed, the CD8⁺ NK cell subset behaved in the opposite direction. At baseline, responders showed significantly increased frequencies of CD8⁺ NK cells compared with non-responders.

Conclusions

This is the first study demonstrating that the composition of the NK cell compartment has predictive power for prediction of therapeutic outcome for anti-TNF-α blockers, and we identified CD8⁺ NK cells as a potential new player in the TNF-α-driven chronic inflammatory immune response of AS.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1692-y) contains supplementary material, which is available to authorized users.

Association between memory B-cells and clinical and immunological features of primary Sjögren's syndrome and Sicca patients

B-cells play a pivotal role in primary Sjögren's syndrome (pSS) pathogenesis. We aim to (1) evaluate the distribution of B-lymphocyte subpopulations in pSS and Sicca patients, (2) establish cut-off points that discriminate pSS from controls, (3) evaluate the association between memory B-cells and phenotypic features in pSS. We included 57 pSS patients, 68 Sicca and 24 healthy controls. Circulating B-cells were characterized by flow cytometry as naïve and memory subsets and classified from Bm1 to Bm5. Compared to controls, pSS patients had lower percentages (29.5 vs 44.4%) and absolute numbers (47 vs 106 cells/µl) of memory B-cells. Through ROC curves, a cut-off of ≤ 58 total memory B-cells/µl yielded a specificity of 0.88 and a sensitivity of 0.60 for pSS, and was met by 59.6% of pSS patients, 38.8% of Sicca and 12.5% of controls. A cut-off of < 23.5 Switched-memory B-cells/µl yielded a specificity of 0.88 and a sensitivity of 0.54 and was met by 54.4% of pSS patients, 37.3% of Sicca and 12.5% of controls. In pSS, lower total memory B-cells count was associated with longer disease duration (14.3 vs 8.1 years, p = 0.006) and more active disease profile, as evaluated by the European League Against Rheumatism (EULAR) Sjögren's Syndrome Disease Activity Index (ESSDAI) (3.1 vs 1.4, p = 0.043). Decreased numbers of memory B-cells clearly discriminated pSS from controls and can also have prognostic value. It remains to be clarified whether Sicca patients with decreased memory B-cells represent pSS and if B-cell profiling could help in the diagnosis of pSS.

Heterogeneity of Metazoan Cells and Beyond: To Integrative Analysis of Cellular Populations at Single-Cell Level

In this paper, we review some of the recent advances in cellular heterogeneity and single-cell analysis methods. In modern research of cellular heterogeneity, there are four major approaches: analysis of pooled samples, single-cell analysis, high-throughput single-cell analysis, and lately integrated analysis of cellular population at a single-cell level. Recently developed high-throughput single-cell genetic analysis methods such as RNA-Seq require purification step and destruction of an analyzed cell often are providing a snapshot of the investigated cell without spatiotemporal context. Correlative analysis of multiparameter morphological, functional, and molecular information is important for differentiation of more uniform groups in the spectrum of different cell types. Simplified distributions (histograms and 2D plots) can underrepresent biologically significant subpopulations. Future directions may include the development of nondestructive methods for dissecting molecular events in intact cells, simultaneous correlative cellular analysis of phenotypic and molecular features by hybrid technologies such as imaging flow cytometry, and further progress in supervised and non-supervised statistical analysis algorithms.

Prenatal alcohol exposure is a risk factor for adult neuropathic pain via aberrant neuroimmune function

BACKGROUND

Clinical studies show that prenatal alcohol exposure (PAE) results in effects that persist into adulthood. Experimental animal models of moderate PAE demonstrate that young adults with PAE display potentiated sensitivity to light touch, clinically termed allodynia, following sciatic nerve chronic constriction injury (CCI) that coincides with heightened spinal glial, spinal macrophage, and peripheral immune responses. However, basal touch sensitivity and corresponding glial and leukocyte activation are unaltered. Therefore, the current study explored whether the enduring pathological consequences of moderate PAE on sensory processing are unmasked only following secondary neural insult.

METHODS

In middle-aged (1 year) Long Evans rats that underwent either prenatal saccharin exposure (control) or moderate PAE, we modified the well-characterized model of sciatic neuropathy, CCI, to study the effects of PAE on neuro-immune responses in adult offspring. Standard CCI manipulation required 4 chromic gut sutures, while a mild version applied a single suture loosely ligated around one sciatic nerve. Spinal glial immunoreactivity was examined using immunohistochemistry. The characterization and functional responses of leukocyte populations were studied using flow cytometry and cell stimulation assays followed by quantification of the proinflammatory cytokines interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α). Data were statistically analyzed by ANOVA and unpaired t tests.

RESULTS

The current report demonstrates that mild CCI generates robust allodynia only in PAE rats, while the pathological effects of PAE following the application of a standard CCI are revealed by enhanced allodynia and elevated spinal glial activation. Additionally, mild CCI increases spinal astrocyte activation but not microglia, suggesting astrocytes play a larger role in PAE-induced susceptibility to aberrant sensory processing. Leukocyte populations from PAE are altered under basal conditions (i.e., prior to secondary insult), as the distribution of leukocyte populations in lymphoid organs and other regions are different from those of controls. Lastly, following in vitro leukocyte stimulation, only PAE augments the immune response to antigen stimulation as assessed by heightened production of TNF-α and IL-1β.

CONCLUSIONS

These studies demonstrate PAE may prime spinal astrocytes and peripheral leukocytes that contribute to enduring susceptibility to adult-onset neuropathic pain that is not apparent until a secondary insult later in life.