Serum beta-2-microglobulin in Sjögren's syndrome

Endothelial Dysfunction in Primary Sjögren's Syndrome: Correlation with Serum Biomarkers of Disease Activity

To assess the relationship between endothelial dysfunction and serum cytokines, anti-SSA and anti-SSB antibodies, beta-2 microglobulin levels, focus score and EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) in primary Sjögren's syndrome (pSS) patients. The study included 90 patients with pSS and 45 healthy subjects, matched for age and gender, as controls. Serum beta-2 microglobulin, total cholesterol, HDL-cholesterol, triglycerides, TNF-α, and IL-6 were analyzed in both the groups. Patients with pSS were also tested for antinuclear antibodies, anti-SAA (anti-Sjögren's syndrome-related antigen A) antibodies, anti-SSB (anti-Sjögren syndrome related antigen B) antibodies, and focus score (the histopathologic one, based on minor salivary gland biopsy). Endothelial dysfunction was assessed by means of flow-mediated dilation (FMD) in the brachial artery. Data are presented as mean ± standard deviation. Statistical analysis was performed using the t-test and the Pearson's correlation. Differences were considered to be statistically significant if the value of p < 0.05. Endothelial dysfunction was identified in pSS patients (p < 0.00001). The serum levels of cytokines (TNF-α, respective IL-6) and beta-2 microglobulin were increased in pSS patients compared with controls (p < 0.00001). Endothelial dysfunction (expressed as FMD%) was correlated with focus score, ESSDAI, levels of anti-SSA and anti-SSB antibodies, beta-2 microglobulin, IL-6, and TNF-α, with statistical significance. Endothelial dysfunction is present in pSS patients and is associated with a high focus score and activity as well as increased concentrations of antibodies, pro-inflammatory cytokines, and beta 2-microglobulin.

Correlation between serum β2-microglobulin level and systemic lupus erythematosus disease activity: A PRISMA-compliant meta-analysis

BACKGROUND

Numerous studies have explored whether serum beta 2-microglobulin (β2-MG) can be used as a biomarker for monitoring systemic lupus erythematosus (SLE) disease activity, but the results are conflicting. Therefore, we performed a systematic meta-analysis to further investigate the correlation between serum β2-MG level and SLE disease activity.

METHODS

PubMed, Web of Science, Embase, and CNKI databases were thoroughly searched for eligible studies through April 2022. Standardized mean differences with 95% confidence intervals (95% CIs) were used to depict the differences in serum β2-MG levels between groups compared in the studies. The correlation between serum β2-MG level and SLE disease activity was assessed using Fisher z-values.

RESULTS

Sixteen articles with combined 1368 SLE patients were included in this meta-analysis. Serum β2-MG levels were significantly higher in SLE patients than in healthy controls (pooled standardized mean difference: 3.98, 95% CI: 2.50-5.46, P < .01). In addition, patients with active SLE had an increased serum β2-MG concentration compared to their inactive SLE counterparts. Furthermore, a positive correlation was observed between serum β2-MG levels and SLE disease activity (pooled Fisher z = 0.78, 95% CI: 0.61-0.96, P < .01).

CONCLUSIONS

This study suggests that patients with SLE have higher serum β2-MG levels than healthy controls and that serum β2-MG levels are positively correlated with SLE disease activity. Thus, serum β2-MG level may be a promising biomarker for monitoring SLE disease activity.

Biomarkers of B cell activation in autoimmune connective tissue diseases: More than markers of disease activity

B cells play a central role in the pathogenesis of many autoimmune diseases, acting as antigen-presenting cells, producing inflammatory cytokines, and acting as a source of autoantibodies after differentiating into plasma cells. In this review, we aim to summarize and synthesize the literature for the utility of biomarkers of B cell activation (plasma immunoglobulins (Ig), free light chains (FLCs), and beta-2 microglobulin (β2M)) in monitoring inflammatory rheumatic connective tissue diseases, such as Sjogren's syndrome (SS), systemic lupus erythematosus (SLE), dermatomyositis (DM), and systemic sclerosis (SSc). Clinically, it is quite difficult to gauge prognosis in these conditions as there, historically, have not been many quantitative markers of disease activity available. From our extensive literature review, Ig, FLC, and β2M may function as invaluable prognostic markers of ongoing disease activity, and potentially as biomarkers for response to therapy or disease relapse. They are inexpensive and unsophisticated tests that are vastly underused in the setting of autoimmune disease. However, clinicians still need to be aware of the potential of false positives in times of infection or plasma cell dyscrasia, as these disease states can artificially increase these biomarkers. Ultimately, the utility of serum Ig, FLCs, and β2M is clearly delineated in SS and SLE, and least investigated in DM, and additional prospective studies utilizing these biomarkers, and specific B cell targeted therapies are still needed.

Serum Levels of Beta-2 Microglobulin in Rheumatoid Arthritis Patients and its Relationship with Disease Activity: Can it be used as a Disease Activity Marker?

Background Beta-2 microglobulin (β2M) is mainly released from activated lymphocytes. Increased serum β2M levels have been shown in autoimmune diseases. The aim of this study was to analyse the serum levels of β2M in rheumatoid arthritis (RA) patients and to evaluate its relationship with disease activity measures.

Material and Methods This cross-sectional study included 137 RA patients, 102 ankylosing spondylitis patients (AS) and 50 healthy controls (HC). To assess the disease activity of RA patients, the 28-joint Disease Activity Score-Erythrocyte Sedimentation Rate (DAS28-ESR), the 28-joint Disease Activity Score-C-Reactive Protein (DAS28-CRP), the Simplified Disease Activity Index (SDAI) and the Clinical Disease Activity Index (CDAI) were used. A p value of <0.05 was considered statistically significant.

Results Serum β2M levels were significantly higher in RA patients (2.95±1.19 mg/L) compared with HC (2.21±0.54 mg/L) and AS patients (2.200.58 mg/L) (p<0.001). There was a statistically significant correlation between β2M levels and DAS28-ESR (rs=0.359, p<0.001), DAS28-CRP (rs=0.293, p=0.001), SDAI (rs=0.332, p<0.001) and CDAI (rs=0.291, p=0.001). Serum β2M levels were higher in the RA group with DAS28-ESR ≥3.2 (3.30±1.42 mg/L) than in the DAS28-ESR <3.2 group (2.67±0.87 mg/L) (p=0.002).

Conclusion Our study revealed that serum β2M levels were higher in RA patients than in healthy controls, and, in contrast to other studies, we found positive correlations between β2M levels and RA disease activity measures.

Evaluation of the serum β2 Microglobulin level in patients with systemic lupus erythematosus and its correlation with disease activity

Background: Designation of disease activity is serious for the management of systemic lupus erythematosus (SLE). Serum level of β2 microglobulin (β2M) may be associated with illness activity in SLE disease. Since the role of β2M for assessing of illness activity in SLE is not completely clear, the current study aimed to discern evaluation of β2M in patients with SLE and its correlation with sickness activity.

Materials and Methods: In this case-control study, 50 patients with SLE disease and 25 healthy individuals were selected in Imam Khomeini Hospital in central of Urmia.

Blood samples were collected safely from patients, serum was removed, and β2M measured using an ELISA method. The results for other parameters including C reactive protein, C3, C4, anti dsDNA and erythrocyte sedimentation rate were obtained from patients’ medical record. Data analyzed using appropriate statistical tests including Mann-Whitney U test, Independent f-test, Kruskal-Wallis, and Spearman used for analysis of data.

Results: In the current study, a significant difference was seen between two groups in terms of β2M (p < 0.001). Remarkable correlation was seen between the level of β2M with disease activity (p < 0.001). Furthermore, there are significant relevancy between the level of β2M with 24-hour urine protein, ESR, disease activity score, and CRP (p < 0.05).

Conclusion: The results revealed that serum amount of β2M in SLE patients is higher compared to healthy ones, which is significantly correlated to score of illness activity, CRP, and ESR in patients with SLE disease. Hence β2M might be an excellent serological marker helping the prediction of sickness activity and inflammation in SLE patients.

Autoantibodies in Spondyloarthritis, Focusing on Anti-CD74 Antibodies

Spondyloarthritis (SpA) is an inflammatory rheumatic disease with diverse clinical presentation. The diagnosis of SpA remains a big challenge in daily clinical practice because of the limitation in specific biomarkers of SpA, more biomarkers are still needed for SpA diagnosis and disease activity monitoring. In the past, SpA was considered predominantly as auto-inflammatory disease vs. autoimmune disease. However, in recent years several researches demonstrated a broad autoantibody response in SpA patients. Study also indicated that mice lack of ZAP70 in T cell develop SpA featured inflammation. These studies indicated the autoimmune features of SpA and gave rise to the potential use of autoantibody in SpA management. In this article, we reviewed recent reports of autoantibodies associated with SpA patients, revealing the autoimmune features of SpA, suggesting the hypothesis that SpA was also an autoimmune disease, studies about the autoimmune features might provide more insights in the pathogenesis of SpA. In addition, as there are two opposite conclusions in the role of anti-CD74 autoantibody in the diagnosis of SpA, we also gave our own data on the diagnostic value of anti-CD74 in Chinese SpA patients. Though our data indicated that anti-CD74 might not be a good biomarker for SpA diagnosis in Asian people, CD74 was still a good molecule target in the research of SpA pathogenesis.

Beta 2-microglobulin can be a disease activity marker in systemic lupus erythematosus

BACKGROUND

To investigate the clinical significance of beta2-microglobulin in Korean patients with systemic lupus erythematosus (SLE).

METHODS

Blood samples were collected from patients with SLE (n = 100) and normal healthy controls (n = 50). The level of beta2-microglobulin was investigated by enzyme-linked immunosorbent assay. Serial samples from SLE patients were collected at 4.2 +/- 2.6 months after first sampling.

RESULTS

The beta2-microglobulin levels of the SLE patients (2.64 +/- 0.11 microg/mL) were higher than the normal controls (2.14 +/- 0.04 microg/mL, P < 0.001). The patients with SLE with serositis, oral ulcer, or lupus nephritis had significantly higher beta2-microglobulin levels than those without, respectively. A significant correlation was found between the beta2-microglobulin level and each of anti-dsDNA antibody, hemoglobin, complement, and SLE Disease Activity Index. In sequential sampling of patients with SLE, a positive correlation was found between the change of the SLE Disease Activity Index and the change of the beta2-microglobulin levels.

CONCLUSIONS

These data suggest that the measurement of beta2-microglobulin seem to be a useful addition to the laboratory tests that can help in assessment of disease activity of SLE.

Brain-derived neurotrophic factor and nerve growth factor correlate with T-cell activation in primary Sjogren's syndrome

OBJECTIVES

Identification of factors associated with disease activity and B and T cell activation is a challenge in primary Sjogren's syndrome (pSS). Neurotrophins (NTs), recently reported as B cell antiapoptotic, and T-cell activation factors seem to be implicated in autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

METHODS

Samples from 18 pSS patients and 12 control subjects were studied to determine serum levels of nerve-growth factor (NGF) and brain-derived neurotrophic factor (BDNF), and their relationships with T- and B-cell activation and disease activity. Peripheral blood mononuclear cells (PBMCs) from patients with pSS and controls were examined by flow cytometry for HLA-DR expression by activated T cells. B cell activation was evaluated by B cell activating factor (BAFF) serum levels measured by enzyme-linked immunosorbent assay (ELISA) and immunoglobulin (Ig) and free light chain (FLC) levels.

RESULTS

Mean serum levels of BDNF in pSS patients were significantly higher than in healthy controls and correlated directly with disease activity. NGF levels were associated with the subgroup of patients with hypergammaglobulinaemia. The pSS group was characterized by peripheral CD4+ and CD8+ T cell activation that correlated positively with BDNF and NGF levels, respectively.

CONCLUSION

NT levels are potential biomarkers for lymphocyte activation in pSS patients.

The diagnosis value of beta 2-microglobulin and immunoglobulins in primary Sjögren's syndrome

Salivary and serum concentrations of beta 2-microglobulin, salivary levels of the immunoglobulins, and salivary flow (as measured by a gravimetric method) were assessed in 34 patients and 11 controls. Of the 34 study patients, 16 had a primary form of Sjögren's syndrome (pSS) and 18 had sicca syndrome. The salivary and serum concentrations of beta 2-microglobulin and salivary levels of IgA and IgG were much higher in the patients with pSS than in controls or those with sicca syndrome (p < 0.001). Similarly, the salivary IgM levels of patients with pSS were higher (although at a lower degree of statistical significance) as compared to those of patients with sicca syndrome (p < 0.01) or controls (p < 0.05). No correlation was observed among the salivary flow and the salivary IgG and IgM levels, while there was a negative relationship (p < 0.01 with salivary IgA levels in all 45 patients considered as a whole. In 12 patients with pSS, the coefficient of correlation between the salivary gland biopsy focus score and the salivary (but not serum) concentration of beta 2-microglobulin was highly significant (p < 0.001). A similar relationship was observed with the IgG (p < 0.001) and IgM (p < 0.05) levels, but not IgA. In the diagnosis of pSS, the salivary IgA level demonstrates high sensitivity and low specificity. In contrast, serum and salivary concentrations of beta 2-microglobulin, salivary IgG, and to a lesser degree, salivary IgM have high specificity and positive predictive value.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary Sjögren's syndrome--clinical and laboratory markers of disease activity

Primary Sjögren's syndrome is a chronic autoimmune disorder of the lacrimal and salivary glands, reflecting general involvement of the exocrine tissues and leading to functional impairment. This polyglandular disease is often associated with systemic extraglandular manifestations, and laboratory tests usually indicate polyclonal B-lymphocyte hyperactivity. Clinical and laboratory markers monitoring the disease processes are needed for improved management of primary Sjögren's syndrome. However, incomplete knowledge of the long-term course of inflammation as well as of clinical manifestations makes precise and simple directions for monitoring disease activity in primary Sjögren's syndrome difficult. This review describes potential primary (eg, salivary gland histopathology, autoantibodies, soluble interleukin-2 receptors, and beta 2-microglobulin) and secondary disease activity markers (clinical and laboratory signs of glandular and extraglandular organ damage) and their known associations. The importance of genetic characteristics, patient age, and symptom duration for the disease activity markers is indicated. The systematic use of primary and secondary disease activity markers will improve our understanding of primary Sjögren's syndrome and help create better guidelines for monitoring the disease.

Measurement of serum beta 2-microglobulin by a latex nephelometric immunoassay

A rapid and simple technique for the measurement of beta 2-microglobulin on the Behring nephelometer was developed using a commercially available latex-anti beta 2-microglobulin. This is a fully automated assay and no pretreatment of sample is necessary. An excellent correlation with radioimmunoassay (r = 0.972) and time-resolved fluoroimmunoassay (r = 0.914) was obtained. Haemolysis, lipemia, bilirubin, and rheumatoid factor do not cause interference because of the high dilution of samples and the use of Fab fragments of the antibody. The analytical range extends from 0.6 to 10.7 mg/L. Between-run imprecision (CV) ranged from 6 to 8%.

Urine- and serum beta 2-microglobulin in patients with rheumatoid arthritis: a study of 101 patients without signs of kidney disease

Serum levels and 24-hour urinary excretion of beta 2-Microglobulin (beta 2-M) was investigated in a group of 101 patients with rheumatoid arthritis (RA), without any other signs of renal disease in past or present, and in a comparable control group. Elevated 24-hour urinary beta 2-M excretion, due to renal proximal tubules dysfunction, was observed in 19% of the patients and not in the control group. There was a significant correlation with clinical signs of extra-articular RA. It is postulated that the observed increase may be an early symptom of renal involvement in RA. Elevated serum beta 2 levels, corrected for glomerular filtration rate, were observed in 44% of the RA patients and only in 3% of the control group and correlated with clinical signs of a more severe RA, as well as with increased 24-hour urinary beta 2-M excretion.

Sjögren's syndrome: clinical and laboratory features, immunopathogenesis, and management

Sjögren's syndrome may be accompanied by local oral problems such as dry mouth, rampant caries, candidosis, or sialadenitis, but it is a systemic autoimmune disorder with wide repercussions, including a small premalignant potential. This article reviews the clinical and immunopathogenic features, as well as the etiology, of Sjögren's syndrome and discusses the diagnosis and management of oral complications.

Serum beta 2-microglobulin as a marker of activity in systemic lupus erythematosus

A prospective study of 62 patients with systemic lupus erythematosus (SLE) was performed in order to establish whether serum beta 2m could be a good marker of clinical activity. beta 2m was determined by radio-immunoassay and the values compared with a control group of healthy individuals. The mean value of beta 2m in the control group was 1.48 +/- 0.52 mg/l and 2.87 +/- 2.19 mg/l (p less than 0.001) in the SLE group, 4.53 +/- 2.89 mg/l in the 22 patients with active disease and 2.40 +/- 1.80 mg/l (p less than 0.001) in the 40 patients with inactive disease. High beta 2m values (greater than or equal to 3 mg/l) were observed in 64% of the patients with active SLE, VS. only 12% of the patients with inactive disease (p less than 0.001). Significant differences were also observed when beta 2m of the patients with inactive SLE was compared with the control group (p less than 0.001). The beta 2m with a sensitivity of 64%, a specificity of 87%, and an efficiency of 79% could be a good parameter to detect SLE clinical activity.

Serum beta 2-microglobulin in systemic sclerosis

The role of beta 2 microglobulin (beta 2-m) in Systemic Sclerosis (SS) has been evaluated. Twenty-four female patients have been examined: 15 of them were affected by acrosclerosis (Group 1) and 9 of them by diffuse sclerosis (Group 2). 46.6% of Group 1 and 44.4% of Group 2 had values significantly higher than normal controls. (P less than 0.01 and P less than 0.005 respectively). The authors deal with the validity of the use of B2-m as index of inflammatory activity of the disease.

Beta 2-microglobulin and its binding activity in serum from patients with SLE

Repeated determinations of beta 2-microglobulin (beta 2m) and beta 2-microglobulin binding activity (beta 2m ba) in serum were performed during a follow-up of 23 patients with SLE. beta 2m was determined by a radioimmunoassay. Individual mean values were raised in 65% of the patients. The mean value for all patients, 2.9 mg/l, was significantly higher than that of the controls. The beta 2m concentrations parallelled the clinical disease activity in several cases with different disease manifestations. The beta 2m ba was determined by precipitation of 125I-labelled beta 2m with polyethylene glycol. Increased beta 2m ba was found in 26% of the SLE patients with the 90th percentile in 40 healthy subjects being taken as the upper normal limit. There were, however, no significant differences between the mean values for beta 2m ba in the patients and the controls. Patients with systemic lupus erythematosus (SLE), suffering exacerbation of their disease, had a higher mean beta 2m ba than those with less active disease. Variations of the serum beta 2m ba occurred especially in patients with active disease but did not seem to reflect the clinical course. The beta 2m ba was recovered in the IgG peak when SLE serum was subjected to gel chromatography on Sephadex G-200.

High serum beta-2-microglobulin levels and circulating immune complexes containing beta 2m and anti-beta 2m antibodies in Felty's syndrome

Serum beta-2-microglobulin (beta 2m) levels, incidence and levels of anti-beta 2m autoantibodies, and quantity of circulating macromolecular complexes containing beta 2m were studied in patients with Felty's syndrome (FS), joint-restricted rheumatoid arthritis (RA), and healthy controls. The serum beta 2m concentrations detected in the FS group (6.95 +/- 2.9 mg/liter) greatly exceeded those of the RA group (3.4 +/- 1.2 mg/liter) and the control group (1.42 +/- 0.69 mg/liter). Autoantibodies to beta 2m were frequent in the FS group. Circulating complexes containing beta 2m, prepared by precipitation in 3% polyethylene glycol, were detected in 65% of FS and 35% of RA patients. In the majority of these cases the solid-phase C1q purified immune complexes also contained beta 2m. Detection of anti-beta 2m antibodies in a significant part of complexes containing beta 2m suggests the presence of specific immune complexes in this fraction of FS and RA patients.

beta 2 Microglobulin in lichen planus

The aim of the present study was to examine idiopathic lichen planus for possible changes in the serum concentration of the immunological marker beta 2 microglobulin (beta 2m), a component of HLA antigens. It was shown that serum levels of beta 2m were not different in lichen planus from those in controls. Although these findings do not support major systemic immunopathological changes in lichen planus, they do not exclude the involvement of local immune mechanisms.

Antibodies to and elevations of beta 2 microglobulin in the serum of ankylosing spondylitis patients

Antibodies to beta 2 microglobulin are found in systemic lupus erythematosus patients and are important in the lymphocytotoxic reactions of sera from such patients. In this study, beta 2 microglobulin antibodies were measured with the use of an enzyme-linked immunosorbent assay with purified beta 2 microglobulin antigen and peroxidase-labeled anti-human IgG or IgM. IgG antibodies to beta 2 microglobulin were found in 68% of 22 patients with ankylosing spondylitis. This incidence was higher than the 5% in 80 controls (P less than 0.01) and similar to the 71% incidence found in 35 patients with systemic lupus erythematosus. Eleven (27%) of 41 patients with rheumatoid arthritis had elevated levels of antibodies to beta 2 microglobulin (P less than 0.01). The mean antibody levels expressed in enzyme units were 0.125 for patients with ankylosing spondylitis, 0.157 for those with systemic lupus erythematosus, 0.101 for those with rheumatoid arthritis, and 0.067 for controls. IgM anti-beta 2 microglobulin was not significantly different from controls. A competitive binding assay with enzyme-labeled beta 2 microglobulin was used to determine serum beta 2 microglobulin. These values were also found to be elevated in 48% of patients in all 3 disease categories (P less than 0.01). Beta 2 microglobulin antibodies and serum beta 2 microglobulin did not correlate with each other, renal diseases or antinuclear antibodies in patients with systemic lupus erythematosus, with rheumatoid factor or severity of articular disease in patients with rheumatoid arthritis, or with peripheral arthritis or iritis in those with ankylosing spondylitis. Although antibodies to beta 2 microglobulin might reflect a general disturbance of immune regulation in patients with systemic lupus erythematosus, their presence in those with ankylosing spondylitis, a disease closely associated with a specific HLA allotype and not usually associated with formation of autoantibody, suggests that they might play a role in the pathogenesis of the latter disease.

Plasma levels of beta 2-microglobulin in rheumatoid arthritis

A simple and inexpensive method is described for the determination of beta 2-microglobulin (beta 2-MG) by enzyme-amplified single radial immunodiffusion. The values obtained with this method correlate well with those determined by means of a commerical RIA kit. Using the immunodiffusion method we have measured the plasma levels of beta 2-MG in 135 patients with rheumatoid arthritis (RA) and normal serum creatinine levels. 33% of the patients had increased concentrations of beta 2 MG, but the levels were found to correlate poorly with the values of several variables generally used as indices of the degree inflammatory activity in RA. Furthermore, in contrast to earlier claims to the contrary, beta 2-MG correlated positively with age. The value of beta 2-MG in plasma as an index of inflammatory activity in RA is questioned.