The search for laboratory measures of outcome in rheumatoid arthritis

Relationship between serum acute-phase proteins and high disease activity in patients with rheumatoid arthritis

PURPOSE

The aim of this study was to assess the relationship between serum acute-phase proteins and high disease activity evaluated by activity score (DAS28) in patients with rheumatoid arthritis.

MATERIAL/METHODS

Studies were carried out on 27 females with RA and 32 control women. Acute-phase proteins were divided into 4 fractions as follows: alpha1-globulins represented by alpha1-acid glycoprotein (AGP) and alpha1-antitrypsin (AAT); alpha2-globulins - haptoglobin (Hp); beta-globulins - complement C3 (C3) and total transferrin (Tf); gamma-globulins - C reactive protein (CRP), rheumatoid factor (RF) and immunoglobulin G (IgG), and determined by immunoturbidimetric methods.

RESULTS

The serum levels of acute-phase proteins changed in RA patients. On account of the alterations of concentration, acute-phase proteins are placed in the downgrade scale as follows: CRP, Hp, AGP, C3, AAT and Tf. None of the acute-phase proteins correlated with the RF and the majority of them were closely related to ESR. Almost all of the acute-phase proteins (without C3) were closely related to RA activity (based on DAS28) and their places in the downgrade scale were as follows: CRP, Tf, AGP, Hp and AAT. The degree of disability evaluated by Health Assessment Questionnaire has affected on the concentrations of AGP, Tf and CRP. Serum AGP, AAT and RF levels significantly correlated with the patient's age. No correlations were observed between IgG, TP levels, and clinical data.

CONCLUSIONS

Among the entire panel, the CRP and AGP appeared to be the most useful biochemical markers for evaluation of the disease activity of patients with RA.

Serum pro-matrix metalloproteinase-3 as an indicator of disease activity and severity in rheumatoid arthritis: comparison with traditional markers

Matrix metalloproteinase-3 (MMP-3) production increases in rheumatoid arthritis (RA) and has been proposed as a marker of disease activity and joint damage. The aim of this cross-sectional study is to examine the usefulness of serum proMMP-3 as an indicator of disease activity and severity in comparison with erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Serum proMMP-3 was measured by a quantitative ELISA in 85 RA patients and 70 healthy subjects. Clinical and laboratory measures of disease activity and severity were obtained. Radiological joint damage was assessed by the method of Larsen. Serum proMMP-3 was significantly higher in RA patients than that in the healthy subjects. The active RA patients had significantly higher serum proMMP-3 than the inactive patients. Serum proMMP-3 was significantly correlated with some parameters of disease activity including swollen joints count, proximal interphalangeal joint score, morning stiffness, and Health Assessment Questionnaire; however, ESR and serum CRP were better correlated with all indicators of the disease activity than proMMP-3. The analysis of receiver operating characteristic supported that ESR and CRP had higher performance for reflection of activity compared to proMMP-3. There were no significant associations among Larsen score and proMMP-3, ESR, and CRP. Our results suggest that the cross-sectional measurement of serum proMMP-3 could not give additional information about RA disease activity compared to ESR and CRP, and could not give any information about joint damage.

Phagocyte-specific calcium-binding S100 proteins as clinical laboratory markers of inflammation

The EF-hand homolog family of S100 proteins comprises the largest group of calcium-binding proteins. Within this S100 family, the phagocyte-specific calcium-binding proteins are pro-inflammatory molecules expressed and secreted by phagocytes, which play a pivotal role within the innate immune system. Although the exact biological functions of these proteins still remain to be defined in greater detail, there is evidence that they are involved in a pro-inflammatory axis associated with various inflammatory conditions. The three members of this group, S100A8, S100A9 and S100A12 are overexpressed at local sites of inflammation. High concentrations are found in synovial fluid, sputum, stool and blood plasma/serum during inflammation. Both the S100A8/S100A9 complex and S100A12 have been proven to be useful as diagnostic markers of inflammation especially in non-infectious inflammatory diseases such as arthritis, chronic inflammatory lung and bowel disease. They indicate phagocyte activation more sensitively than conventional parameters of inflammation. As a consequence, there is a strong correlation to the inflammation of various acute and chronic disorders, making these proteins sensitive parameters for the monitoring of disease activity and response to treatment in individual patients. The phagocyte-specific S100 proteins are able to indicate minimal residual inflammation, which is not detected by other diagnostic tests, and they may even be prospective markers for the outcome of patients. In this review, pro-inflammatory functions of S100 proteins and their usefulness as biomarkers of inflammation are presented.

Serum levels of cartilage oligomeric matrix protein. A predicting factor and a valuable parameter for disease management in rheumatoid arthritis

OBJECTIVE

To examine whether cartilage oligomeric matrix protein (COMP) correlates with inflammation and/or joint destruction of patients with rheumatoid arthritis (RA) and to test COMP as predicting factor for the outcome of patients with established RA.

METHODS

Serum levels of COMP were measured in sera of 62 patients, suffering from RA according to the ACR criteria and treated in intervals in our department, over a period of 5 years. A commercially available sandwich--type ELISA-kit developed by AnaMar Medical AB, Sweden, was used. The results of serum COMP were compared with the Disease Activity Score (DAS), the Larsen Score, and clinical and laboratory parameters.

RESULTS

We found a positive correlation between serum levels of COMP at baseline and deterioration of Larsen score even after 5 years (p < 0.007; r = 0.34). To confirm serum COMP as an independent predicting factor for patients with RA we looked at a subgroup of patients (n = 17) with elevated serum levels of COMP (mean 11,7 U/l) and low clinical prognostic factors. In this subgroup we also found a significant correlation with delta Larsen score (p < 0.01; r = 0.59) after 5 years.

CONCLUSION

Serum levels of COMP is known to reflect increased cartilage turnover. The results indicate that serum COMP may be used as a prognostic marker of cartilage degradation in a patient group with established RA.

Lysosomal peptidases and glycosidases in rheumatoid arthritis

Lysosomal serine and cysteine proteases are reported to play a role in collagen degradation. In this study, the activities of the lysosomal cysteine proteases cathepsin B and H, dipeptidyl peptidase I, and the serine protease tripeptidyl peptidase I and dipeptidyl peptidase II, all ascribed a role in collagen digestion, were compared with those of the aspartate protease cathepsin D, and lysosomal glycosidases in leukocytes from rheumatoid arthritis patients at different stages of the disease. In all patients the activities of cysteine protease cathepsin B, dipeptidyl peptidase I, aspartate protease cathepsin D, and two glycosidases were elevated, but the activities of the serine proteases tripeptidyl peptidase I, dipeptidyl peptidase II, and the cysteine protease cathepsin H was unchanged. The magnitude of the increased activity was correlated with the duration of the disease. Patients with long-standing RA (10 years or more) had higher cysteine protease activity in their leukocytes than did those with disease of shorter duration. This tendency suggests that elevated lysosomal cysteine protease activities, together with aspartate protease cathepsin D and lysosomal glycosidases (but not serine proteases), are associated with progression of rheumatoid arthritis.

Proteins of rat serum IV. Time-course of acute-phase protein expression and its modulation by indomethacine

Changes in the concentration of major serum proteins were monitored from day 0 to day 4 in three experimental groups: rats injected with turpentine, rats receiving the turpentine shot and daily doses of indomethacine, and rats given indomethacine alone. In inflamed animals, peak changes for acute-phase reactants, evaluated by two-dimensional electrophoresis (2-DE), were usually observed between 48 and 72 h after the phlogistic stimulus. By itself, indomethacine was found to affect the synthesis of most proteins (except one of the thiostatin variants and ceruloplasmin); the changes in serum levels, whether positive or negative, were the same as upon inflammation (except for kallikrein-binding protein), but their extent and/or timing usually differed. When inflamed animals were given indomethacine, a clear-cut difference in the concentration of some proteins was observed versus inflamed rats not given medication, at 24 h after the start of the treatments. Proteins mainly affected were alpha2-macroglobulin, alpha2-HS-glycoprotein, C-reactive protein and kallikrein-binding protein.

Only high disease activity and positive rheumatoid factor indicate poor prognosis in patients with early rheumatoid arthritis treated with "sawtooth" strategy

OBJECTIVES

To investigate the prognostic significance of clinical and genetic markers on the outcome of patients with recent-onset rheumatoid arthritis (RA) treated actively with slow acting antirheumatic drugs (SAARDs).

METHODS

A total of 142 consecutive patients with early RA (median disease duration of 7 months) were treated according to the "sawtooth" strategy and prospectively followed up for an average of 6.2 years. Several clinical parameters at start as well as genetic markers were related to the functional outcome (ARA Functional class and HAQ disability score) and radiographic joint damage (Larsen's score) at the latest visit.

RESULTS

In logistic regression analysis only Mallya score (including morning stiffness, pain scale, grip strength, Ritchie's articular index, haemoglobin, and erythrocyte sedimentation rate) at baseline, and Mallya score and rheumatoid factor (RF) positivity at one year were found to be of significance with respect to the radiographic outcome of the patients. Furthermore, at the latest visit HAQ score was related to radiographic score. At baseline the mean ages of the DR4 positive patients and the patients with RA associated DR alleles were statistically significantly lower than those without the above mentioned risk factors (44 v 49, p = 0.03 and 41 v 53, p = 0.04, respectively). However, these genetic markers had no prognostic significance on the functional or radiographic outcome of the patients.

CONCLUSION

High clinical disease activity at baseline and RF positivity especially at one year after the institution of SAARD treatment are the best predictors of poor prognosis in early RA. However, from the clinical point of view, the disease outcome of an individual patient with early RA, cannot be predicted accurately enough by present means.