Serum pro-hepcidin could reflect disease activity in patients with rheumatoid arthritis

The effect of targeted rheumatoid arthritis therapeutics on systemic inflammation and anemia: analysis of data from the CorEvitas RA registry

BACKGROUND

To evaluate the effects of tumor necrosis factor inhibitors (TNFi), interleukin-6 receptor inhibitors (IL-6Ri), and Janus kinase inhibitors (JAKi) on hemoglobin (Hb) and C-reactive protein (CRP) levels in adults enrolled in CorEvitas (formerly Corrona), a large US rheumatoid arthritis (RA) registry.

METHODS

Patients who initiated TNFi, IL-6Ri, or JAKi treatment during or after January 2010, had Hb and CRP measurements at baseline and 6-month follow-up (± 3 months) and had continued therapy at least until that follow-up, through March 2020, were included in the analysis. Changes in Hb and CRP were assessed at month 6. Abnormal Hb was defined as < 12 g/dL (women) or < 13 g/dL (men); abnormal CRP was ≥ 0.8 mg/dL. Differences in Hb and CRP levels were evaluated using multivariable regression.

RESULTS

Of 2772 patients (TNFi, 65%; IL-6Ri, 17%; JAKi, 17%) evaluated, 1044 (38%) had abnormal Hb or CRP at initiation; an additional 252 (9%) had both abnormal Hb and CRP. At month 6, the IL-6Ri group had a greater Hb increase than the TNFi (mean difference in effect on Hb: 0.28 g/dL; 95% CI 0.19-0.38) and JAKi (mean difference in effect on Hb: 0.47 g/dL; 95% CI 0.35-0.58) groups, regardless of baseline Hb status (both p < 0.001). The CRP decrease at month 6 was greater with IL-6Ri compared with TNFi and JAKi, regardless of baseline CRP status (both p < 0.05).

CONCLUSION

These real-world results align with the mechanism of IL-6R inhibition and may inform treatment decisions for patients with RA.

No association between plasma hepcidin levels and restless legs syndrome - results from the Danish Blood Donor Study

BACKGROUND

Restless Legs Syndrome (RLS) is a neurological sensorimotor disorder that occurs in the evening and night, thereby often impacting quality of sleep in sufferers. The aetiology of RLS is not completely understood although iron dysregulation has been suggested as a likely pathway. The relationship between RLS and the iron regulatory protein hepcidin has not been studied in large cohorts. We aimed to assess whether an association between plasma hepcidin variation and RLS exists in a large cohort of healthy individuals.

METHODS

Plasma hepcidin levels were measured in 9708 Danish blood donors from the Danish Blood Donor Study all of whom correctly completed the validated Cambridge-Hopkins RLS-questionnaire for RLS assessment.

RESULTS

A total of 466 blood donors were determined as current RLS cases in the sample (4.8%). RLS cases had a significantly higher proportion of females (56.7% vs 46.7%; P < 0.001) and were older (median age [IQR] 40.6 years vs 38.0 years; P = 0.010) than controls. RLS cases were also more frequent smokers (P = 0.004). No significant differences were found in body mass index (BMI), alcohol consumption, time of donation and donation history between cases and controls. No difference in plasma hepcidin levels was observed between RLS cases and controls (median concentration [IQR]: 10.5 ng/ml [6.3-16.4] in RLS cases vs 10.5 ng/ml [6.0-16.5] in controls). Using a logistic regression model, we found that hepcidin levels were not associated with RLS after adjusting for age, sex, alcohol consumption, smoking status, donation time and donation history (OR = 1.00 [0.99-1.02] per 1 ng/ml increase of hepcidin; P = 0.429).

CONCLUSION

Our study in Danish blood donors did not find an association between RLS and plasma hepcidin levels. Our findings suggest that plasma hepcidin's role as a potential diagnostic biomarker of RLS is inadequate.

Changes in Hepcidin Serum Levels Correlate with Clinical Improvement in Idiopathic Restless Legs Syndrome Patients

BACKGROUND

Restless legs syndrome (RLS) is a common sensory motor neurological disorder that is related to iron-dopamine dysregulation and immune system alteration. We aimed to assess the effects of serum hepcidin, an iron-regulating hormone, in drug-naive RLS patients compared to healthy controls and to evaluate its role in helping to predict clinical improvement after treatment with dopamine agonist.

METHODS

Nonanemic and drug-naive RLS patients (n = 18) and healthy controls (n = 15) were enrolled. The serum hepcidin and iron-related values in the serum were measured upon the first visit in both groups and 12 weeks later after dopaminergic treatment in 12 patients. Information about sociodemographic characteristics, sleep-related profiles, mood and anxiety was obtained upon the first visit in all participants as well as after treatment in RLS patients.

RESULTS

Serum hepcidin levels exhibited no significant differences between patients with drug-naïve RLS and healthy controls at diagnosis (7.1 ± 2.4 vs. 7.0 ± 3.2 ng/mL, p = 0.357). Decreased hepcidin levels were significantly associated with decreased RLS severity (β = 0.002, 95% CI = 0.00-0.00, p = 0.005) and improved quality of life (β = 0.002, 95% CI = 0.00-7.01, p = 0.044) in a dose-dependent manner after 12 weeks of treatment with a dopamine agonist. This association was independent of age, sex, inflammatory markers, sleep quality, insomnia, daytime sleepiness, depression and anxiety.

CONCLUSIONS

This study demonstrates the role of hepcidin in evaluating the positive therapeutic response in RLS.

Can Calprotectin Show Subclinical Inflammation in Familial Mediterranean Fever Patients?

BACKGROUND

Familial Mediterranean fever (FMF) is an autoinflammatory disease that has self-limiting inflammatory attacks during polyserositis. Hepcidin is a protein, and interleukin-6 stimulation increases hepcidin levels. Calprotectin (CLP) is a recently defined cytokine released from monocytes and neutrophils in response to tissue trauma and inflammation. There are studies in the literature showing that it can be used as a biomarker in rheumatic diseases such as ankylosing spondylitis and rheumatoid arthritis. Here, we compared the levels of hepcidin and CLP in healthy individuals and FMF patients during an attack-free period and show its relation to genetic mutations.

METHODS

This is a cross-sectional study. Between July 2017 and December 2017, 60 patients diagnosed with FMF an admitted to the Cumhuriyet University Faculty of Medicine Department of Internal Medicine Rheumatology as well as 60 healthy volunteers without any rheumatic, systemic, or metabolic diseases were enrolled in this study. Blood was collected from a peripheral vein to measure serum CLP and hepcidin levels. Blood tests were examined by ELISA; the study protocol was approved by the local ethics committee.

RESULTS

Median serum hepcidin level was 468.1 (210.3-807.8) pg/mL in FMF group and 890.0 (495.0-1,716.9) pg/mL in the healthy control (HC) group. There was a statistically significant difference between the two groups (P < 0.001). The median serum levels of CLP in the FMF group were measured as 1,331.4 (969.3-1,584.6 pg/mL and 73.8(45.0-147.9) pg/mL in the HC group. There was a statistically significant difference between the two groups (P < 0.001). Receiver operating characteristic analysis showed that the sensitivity was 66.7% and the specificity was 71.7% at serum hepcidin < 581.25 pg/mL (P < 0.05); the sensitivity was 96.7% and specificity was 100% at CLP > 238 pg/mL (P < 0.05). There was no significant difference between serum hepcidin and CLP levels in FMF patients with M694V homozygous and M694V heterozygous (P > 0.05). There was no significant difference in serum hepcidin levels between FMF patients with and without arthritis, proteinuria, and amyloidosis (P < 0.05). There was no significant correlation between laboratory findings, gender, age, and serum CLP and hepcidin levels (P > 0.05, r < 0.25).

CONCLUSION

Serum CLP levels in FMF patients during an attack-free period are significantly higher than in the HC groups. Serum hepcidin levels in FMF patients are significantly lower than in the HC group. Low levels of hepcidin may be explained by including FMF patients during an attack-free period in the study. CLP may be an important biomarker in FMF. A better understanding of the role of these biomarkers in the diagnosis of FMF is needed to evaluate the results in a more comprehensive way.

Serum hepcidin level and rheumatoid arthritis disease activity

Objective

The present study aimed to determine the relationship between the serum hepcidin level and disease activity in patients with rheumatoid arthritis (RA).

Methods

This study was conducted on 80 patients with RA (36 cases with anemia of chronic disease [ACD] and 44 patients without ACD). Disease activity was measured by the 28-joint Disease Activity Score based on the erythrocyte sedimentation rate (DAS28-ESR). According to the DAS28-ESR score, 52 and 28 cases were categorized as inactive to moderately active RA (DAS28-ESR≤5.1) and highly active RA (DAS28-ESR>5.1), respectively. In addition, the serum hepcidin level was evaluated in all patients to determine its correlation with the DAS28-ESR score.

Results

There was no significant difference between the RA with ACD and RA without ACD groups in terms of the median (interquartile range) hepcidin level (1207 [985.2] vs. 923.8 [677.3] ng/mL; P=0.57). Likewise, no significant difference was observed between the active RA and inactive to moderately active RA groups in this regard (1131.8 [991.3] vs. 1090.9 [631.4] ng/mL; P=0.53).

Conclusion

Hepcidin has no association with disease activity in RA. Therefore, it is not necessary to measure hepcidin to determine the RA activity.

Serum hepcidin is increased in ANCA-associated vasculitis and correlates with activity markers

Hepcidin is a key regulator of iron metabolism and plays an important role in many pathologies. It is increased by iron administration and by inflammation, while erythropoiesis downregulates its expression. It decreases iron availability and thus contributes to anemia of chronic diseases. The aim of the study was to measure hepcidin as a marker and pathogenetic factor in ANCA-associated vasculitis (AAV). Hepcidin plasma concentration was measured by the immunological method in 59 patients with AAV and compared to patients with non-vasculitic etiology of chronic kidney disease, patients on hemodialysis (HD), with systemic lupus erythematodes (SLE) and to healthy controls and blood donors, and was correlated with the parameters of iron metabolism, inflammation, activity of the process and kidney function. Hepcidin concentration was increased in patients with AAV, SLE and HD and correlated positively with C-reactive protein, serum ferritin and creatinine, and negatively with hemoglobin and serum transferrin. In active form of AAV it correlated with the clinical scoring system (BVAS). Hepcidin can thus be considered as a pathogenetic factor of anemia in AAV and can be used for evaluation of inflammation in AAV and as an additional marker in active forms of the disease.

Pathobiochemical Mechanisms Relating Iron Homeostasis with Parameters of Inflammatory Activity and Autoimmune Disorders in Rheumatoid Arthritis

Aim: To find the correlations between the parameters of iron homeostasis, inflammatory activity and autoimmune disorders in rheumatoid arthritis (RA).

Materials and methods: The present study included 114 patients with RA and 42 healthy controls. We determined the parameters of iron homeostasis: serum iron, total iron binding capacity (TIBC), ferritin and soluble transferrin receptor (sTfR), the parameters of inflammatory activity: C-reactive protein (CRP), interleukin-6 (IL-6) and prohepcidin, and the parameters of autoimmune disorders: rheumatoid factor (RF), anti-cyclic citrullinated peptide (antiCCP) antibodies and DAS 28.

Results: The levels of sTfR, CRP, IL-6 and prohepcidin were significantly higher in RA patients than those in the controls and the level of serum iron was significantly lower in RA than that in the control group. Unlike the controls, in RA, there was a significant positive correlation of sTfR with the parameters of inflammatory activity (IL-6, prohepcidin, ESR) and with the parameters of autoimmune disorders (DAS 28, RF, antiCCP). A negative correlation of serum iron with sTfR was found only in RA patients. Prohepcidin positively correlated with the parameters of inflammation (CRP, ESR) and with the parameters for evaluation of autoimmune disorders (DAS 28 and RF) in the RA group.

Conclusion: Our study shows that the simultaneous determination of the two parameters sTfR and prohepcidin is most informative for evaluation of the changes in iron homeostasis in RA. The increase of both parameters provides information for tissue iron deficiency (assessed by the level of sTfR), caused by the inflammation when prohepcidin is expressed.

Pathobiochemical Mechanisms Relating Iron Homeostasis to Parameters of Inflammatory Activity and Autoimmune Disorders in Rheumatoid Arthritis

Aim: To find the correlations between the parameters of iron homeostasis, inflammatory activity and autoimmune disorders in rheumatoid arthritis (RA).

Materials and methods: The present study included 114 patients with RA and 42 healthy controls. We determined the parameters of iron homeostasis: serum iron, total iron binding capacity (TIBC), ferritin and soluble transferrin receptor (sTfR), the parameters of inflammatory activity: C-reactive protein (CRP), interleukin-6 (IL-6) and prohepcidin, and the parameters of autoimmune disorders: rheumatoid factor (RF), anti-cyclic citrullinated peptide (antiCCP) antibodies, and DAS 28.

Results: The levels of sTfR, CRP, IL-6 and prohepcidin were significantly higher in RA patients than those in the controls and the level of serum iron was significantly lower in RA than that in the control group. Unlike the controls, in RA, there was a significant positive correlation of sTfR with the parameters of inflammatory activity (IL-6, prohepcidin, ESR) and with the parameters of autoimmune disorders (DAS 28, RF, antiCCP). A negative correlation of serum iron with sTfR was found only in RA patients. Prohepcidin positively correlated with the parameters of inflammation (CRP, ESR) and with the parameters for evaluation of autoimmune disorders (DAS 28 and RF) in the RA group.

Conclusion: Our study shows that the simultaneous determination of the two parameters sTfR and prohepcidin is most informative in evaluating the changes in iron homeostasis in RA. The increase of both parameters provides information for tissue iron deficiency (assessed by the level of sTfR), caused by the inflammation when prohepcidin is expressed.

Biomarkers of systemic lupus erythematosus identified using mass spectrometry-based proteomics: a systematic review

Advances in mass spectrometry technologies have created new opportunities for discovering novel protein biomarkers in systemic lupus erythematosus (SLE). We performed a systematic review of published reports on proteomic biomarkers identified in SLE patients using mass spectrometry‐based proteomics and highlight their potential disease association and clinical utility. Two electronic databases, MEDLINE and EMBASE, were systematically searched up to July 2015. The methodological quality of studies included in the review was performed according to Preferred Reporting Items for Systematic Reviews and Meta‐analyses guidelines. Twenty‐five studies were included in the review, identifying 241 SLE candidate proteomic biomarkers related to various aspects of the disease including disease diagnosis and activity or pinpointing specific organ involvement. Furthermore, 13 of the 25 studies validated their results for a selected number of biomarkers in an independent cohort, resulting in the validation of 28 candidate biomarkers. It is noteworthy that 11 candidate biomarkers were identified in more than one study. A significant number of potential proteomic biomarkers that are related to a number of aspects of SLE have been identified using mass spectrometry proteomic approaches. However, further studies are required to assess the utility of these biomarkers in routine clinical practice.

Comparative evaluation of the effects of treatment with tocilizumab and TNF-α inhibitors on serum hepcidin, anemia response and disease activity in rheumatoid arthritis patients

Introduction

Anemia of inflammation (AI) is a common complication of rheumatoid arthritis (RA) and has a negative impact on RA symptoms and quality of life. Upregulation of hepcidin by inflammatory cytokines has been implicated in AI. In this study, we evaluated and compared the effects of IL-6 and TNF-α blocking therapies on anemia, disease activity, and iron-related parameters including serum hepcidin in RA patients.

Methods

Patients (n = 93) were treated with an anti-IL-6 receptor antibody (tocilizumab) or TNF-α inhibitors for 16 weeks. Major disease activity indicators and iron-related parameters including serum hepcidin-25 were monitored before and 2, 4, 8, and 16 weeks after the initiation of treatment. Effects of tocilizumab and infliximab (anti-TNF-α antibody) on cytokine-induced hepcidin expression in hepatoma cells were analyzed by quantitative real-time PCR.

Results

Anemia at base line was present in 66% of patients. Baseline serum hepcidin-25 levels were correlated positively with serum ferritin, C-reactive protein (CRP), vascular endothelial growth factor (VEGF) levels and Disease Activity Score 28 (DAS28). Significant improvements in anemia and disease activity, and reductions in serum hepcidin-25 levels were observed within 2 weeks in both groups, and these effects were more pronounced in the tocilizumab group than in the TNF-α inhibitors group. Serum hepcidin-25 reduction by the TNF-α inhibitor therapy was accompanied by a decrease in serum IL-6, suggesting that the effect of TNF-α on the induction of hepcidin-25 was indirect. In in vitro experiments, stimulation with the cytokine combination of IL-6+TNF-α induced weaker hepcidin expression than did with IL-6 alone, and this induction was completely suppressed by tocilizumab but not by infliximab.

Conclusions

Hepcidin-mediated iron metabolism may contribute to the pathogenesis of RA-related anemia. In our cohort, tocilizumab was more effective than TNF-α inhibitors for improving anemia and normalizing iron metabolism in RA patients by inhibiting hepcidin production.

Interleukin-1 receptor antagonist gene polymorphism and hepcidin in rheumatoid arthritis: Correlations with clinical and laboratory indices of disease activity

Rheumatoid arthritis (RA) is a systemic autoimmune disease, which is manifested as an inflammatory polyarthritis. Authors aimed to analyze the relationship between serum hepcidin, 25 amino acid protein, concentration and the anemia profiles of RA and to estimate whether it could reflect the disease activity of RA. Also, this study was conducted to explore the linkage between interleukin-1 (IL-1) receptor antagonist gene (IL-1RN) polymorphism, proinflammatory cytokine, and RA. One hundred and eighty five RA patients were enrolled in the study. For all, the following criteria were measured: RA disease activities, anemia profiles, serum concentration of hepcidin using enzyme-linked immunosorbent assay, and DNA samples were used to study genotypes of IL-1RN gene by polymerase chain reaction. Mean concentration of serum pro-hepcidin was (93.6 ± 31.5 ng/mL) in 185 RA patients. An increased frequency of the IL-1RN*1 and IL-1RN*2 alleles was relative to active RA (DAS28 > 5.1) than those with inactive to moderate RA (DAS28 ≤ 5.1). Both hepcidin and IL-1RN gene showed significant correlation with each other as well with RA disease activity parameters and anemia profile. IL-1RN gene was significantly correlated with laboratory anemia profile apart from transferritin. There was a significant difference among pro-hepcidin concentration and IL-1RN frequency regarding patients with anemia of chronic disease and those without. In conclusion, both serum concentration of pro-hepcidin and IL-1RN genotypes frequency reflect the disease activity, regardless of the anemia states in RA patients, thus they may be another potential markers for disease activity of RA.

Oral antigens induce rheumatoid arthritis-like inflammation in a rat model

BACKGROUND AND AIMS

The pathogenesis of rheumatoid arthritis (RA) is to be further elucidated. The present study aims to investigate the role of oral antigen in the induction of RA-like inflammation in the articular joints of rats.

METHODS

An RA animal model was developed by gavage-feeding with antigen and aspirin, and lipopolysaccharide intraperitoneal injection. The gut epithelial barrier function was assessed by the absorption of mannitol and lactose. The absorption of the specific antigen was observed by the immune fluorescent method. The frequency of antigen specific CD4+ T cells in the peripheral system was assessed by flow cytometry. The inflammation in the ankle joints was evaluated by light microscopy and immunohistochemistry.

RESULTS

Rats treated with aspirin showed intestinal barrier dysfunction; high contents of the specific antigen were absorbed into the lamina propria. The antigen specific CD4+ T cells were detected in the spleen that could be activated by exposure to the specific antigen as well as the extracts of joint tissue. High levels of proinflammatory cytokines were detected in the sera. Antigen specific immune complexes were localized in the ankle joints. Heavy extravasation was observed in the synovial cavity. The histology showed an inflammatory feature in the ankle joints.

CONCLUSIONS

Oral antigen can induce RA-like inflammation in the articular joints under certain environment such as gut epithelial barrier dysfunction.

Hepcidin: A useful marker in chronic obstructive pulmonary disease

PURPOSE

This study was designed to evaluate the levels of hepcidin in the serum of patients with chronic obstructive pulmonary disease (COPD).

METHODS

In the study, 74 male patients (ages 45-75) in a stable period for COPD were grouped as Group I: Mild COPD (n:25), Group II: Moderate COPD (n:24), and Group III: Severe COPD (n:25). Healthy non-smoker males were included in Group IV (n:35) as a control group. The differences of hepcidin level among all the groups were examined. Also, in the patient groups with COPD, hepcidin level was compared with age, body mass index, cigarette (package/year), blood parameters (iron, total iron binding capacity, ferritin, hemoglobin, hematocrit [hct]), respiratory function tests, and arterial blood gas results.

RESULTS

Although there was no difference between the healthy control group and the mild COPD patient group (P=0.781) in terms of hepcidin level, there was a difference between the moderate (P=0.004) and the severe COPD patient groups (P=0.002). The hepcidin level of the control group was found to be higher than the moderate and severe COPD patient groups. In the severe COPD patients, hepcidin level increased with the increase in serum iron (P=0.000), hct (P=0.009), ferritin levels (P=0.012), and arterial oxygen saturation (SaO(2), P=0.000).

CONCLUSION

The serum hepcidin level that is decreased in severe COPD brings into mind that it may play a role in the mechanism to prevent hypoxemia. The results suggest that serum hepcidin level may be a useful marker in COPD. Larger prospective studies are needed to confirm our findings between hepcidin and COPD.

Restless legs syndrome--theoretical roles of inflammatory and immune mechanisms

Theories for restless legs syndrome (RLS) pathogenesis include iron deficiency, dopamine dysregulation and peripheral neuropathy. Increased prevalence of small intestinal bacterial overgrowth (SIBO) in controlled studies in RLS and case reports of post-infectious RLS suggest potential roles for inflammation and immunological alterations. A literature search for all conditions associated with RLS was performed. These included secondary RLS disorders and factors that may exacerbate RLS. All of these conditions were reviewed with respect to potential pathogenesis including reports of iron deficiency, neuropathy, SIBO, inflammation and immune changes. A condition was defined as highly-associated if there was a prevalence study that utilized an appropriate control group. Small case reports were recorded but not included as definite RLS-associated conditions. Fifty four diseases, syndromes and conditions have been reported to cause and/or exacerbate RLS. Of these, 38 have been reported to have a higher prevalence than age-matched controls, 9 have adequate sized reports and have general acceptance as RLS-associated conditions and 7 have been reported in case report form. Overall, 42 of the 47 RLS-associated conditions (89%) have also been associated with inflammatory and/or immune changes. In addition, 43% have been associated with peripheral iron deficiency, 40% with peripheral neuropathy and 32% with SIBO. Most of the remaining conditions have yet to be studied for these factors. The fact that 95% of the 38 highly-associated RLS conditions are also associated with inflammatory/immune changes suggests the possibility that RLS may be mediated or affected through these mechanisms. Inflammation can be responsible for iron deficiency and hypothetically could cause central nervous system iron deficiency-induced RLS. Alternatively, an immune reaction to gastrointestinal bacteria or other antigens may hypothetically cause RLS by a direct immunological attack on the central or peripheral nervous system.

Rheumatoid factor and its interference with cytokine measurements: problems and solutions

Use of cytokines as biomarkers for disease is getting more widespread. Cytokines are conveniently determined by immunoassay, but interference from present antibodies is known to cause problems. In rheumatoid arthritis (RA), interference of rheumatoid factor (RF) may be problematic. RF covers a group of autoantibodies from immunoglobulin subclasses and is present in 65–80% of RA patients. Partly removal of RF is possible by precipitation. This study aims at determining the effects of presence of RF in blood and synovial fluid on cytokine measurements in samples from RA patients and finding possible solutions for recognized problems. IL-1β, IL-4, IL-6, and IL-8 were determined with multiplex immunoassays (MIA) in samples from RA patients prior to and after polyethylene glycol (PEG 6000) precipitation. Presence of RF does interfere with MIA. PEG 6000 precipitation abolishes this RF interference. We recommend PEG precipitation for all immunoassay measurements of plasma samples from RA patients.

Proteome analysis of biological fluids from autoimmune-rheumatological disorders

Autoimmune-rheumatological diseases are worldwide distributed disorders and represent a complex array of illnesses characterized by autoreactivity (reactivity against self-antigens) of T-B lymphocytes and by the synthesis of autoantibodies crucial for diagnosis (biomarkers). Yet, the effects of the autoimmune chronic inflammation on the infiltrated tissues and organs generally lead to profound tissue and organ damage with loss of function (i.e., lung, kidney, joints, exocrine glands). Although progresses have been made on the knowledge of these disorders, much still remains to be investigated on their pathogenesis and identification of new biomarkers useful in clinical practice. The rationale of using proteomics in autoimmune-rheumatological diseases has been the unmet need to collect, from biological fluids that are easily obtainable, a summary of the final biochemical events that represent the effects of the interplay between immune cells, mesenchymal cells and endothelial cells. Proteomic analysis of these fluids shows encouraging results and in this review, we addressed four major autoimmune-rheumatological diseases investigated through proteomic techniques and provide evidence-based data on the highlights obtained in systemic sclerosis, primary and secondary Sjogren's syndrome, systemic lupus erythematosus and rheumatoid arthritis.