Differences in HLA-B27 positive and negative patients with ankylosing spondylitis: study of clinical disease activity and concentrations of serum IgA, C reactive protein, and haptoglobin

Predictors of treatment failure of non-steroidal anti-inflammatory drugs in patients with axial spondyloarthritis with focus on haptoglobin, haptoglobin polymorphism and zonulin

According to the Assessment of SpondyloArthritis International Society-European Alliance of Associations for Rheumatology (ASAS-EULAR) recommendations for the management of axial spondyloarthritis (axSpA), patients should undergo at least two courses of non-steroidal anti-inflammatory drugs (NSAIDs) therapy. In our study, we enrolled axSpA patients both at onset and in a flare who had already been treated with NSAIDs ineffectively. Subsequently, according to the recommendations, they received modified NSAID treatment as another attempt to the first-line drug therapy and were monitored from there. We aimed to identify risk factors for treatment failure after 4 weeks (Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score ≥ 4) especially amongst zonulin and haptoglobin concentrations, and haptoglobin polymorphism. Treatment failure was observed in 71% of patients, and the following variables were contributed for occurrence of this state: higher zonulin levels, ankylosing spondylitis, X-ray sacroiliitis, magnetic resonance imaging sacroiliitis, long duration of symptoms, high BASDAI, and high value of spinal pain intensity on visual analogue scale. In addition, the following positive correlations were found: haptoglobin concentration with C-reactive protein (r = 0.56; p = 0.0004), and erythrocyte sedimentation rate (r = 0.62; p < 0.0001), as well as between zonulin levels and white blood count (r = 0.5; p = 0.0003). The results of the study presented the identified factors related to the standard treatment failure in axSpA, amongst them zonulin levels. They might be applied to point out the patients for whom the search for a more appropriate method of treatment should be considered.

HLA-B27 is associated with reduced disease activity in axial spondyloarthritis

HLA-B27 is associated with increased susceptibility and disease activity of ankylosing spondylitis, but the effect of HLA-B27 on the activity of the broader category now called axial spondyloarthritis (AxSpA) is apparently the opposite. A modified Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) was used to assess disease activity among 3435 patients with spondyloarthritis (SpA) who participated in a survey designed to assess the effect of their disease and its treatment on the susceptibility and severity of Covid-19. Chi square testing was used to compare BASDAI scores between HLA-B27 positive and negative subjects. 2836 survey respondents were HLA B27 positive. The average BASDAI for the HLA-B27 negative cohort was 4.92 compared to 4.34 for the HLA-B27 positive subjects. Based on linear regression, a subject’s sex could not fully account for the differing BASDAI score in HLA-B27 negative subjects compared to those who are HLA-B27 positive. The difference between B27 positive and negative subjects was skewed by those with a BASDAI score of one or two. HLA-B27 positive subjects were more than twice as likely to have a BASDAI score of 1 compared to HLA B27 negative subjects and about 60% more likely to have a BASDAI score of 2 (p < 0.0001). HLA-B27 positive subjects have less active spondyloarthritis compared to HLA-B27 negative subjects as measured by a BASDAI score. Our data indicate that patients with mild back pain and a diagnosis of AxSpA are disproportionately HLA-B27 positive. The HLA-B27 test facilitates the diagnosis of axial spondyloarthritis such that patients from a community survey with mild back pain may be disproportionately diagnosed as having AxSpA if they are HLA-B27 positive. The test result likely introduces a cognitive bias into medical decision making and could explain our observations.

Haptoglobin and Its Related Protein, Zonulin-What Is Their Role in Spondyloarthropathy?

Haptoglobin (Hp) is an acute phase protein which supports the immune response and protects tissues from free radicals. Its concentration correlates with disease activity in spondyloarthropathies (SpAs). The Hp polymorphism determines the functional differences between Hp1 and Hp2 protein products. The role of the Hp polymorphism has been demonstrated in many diseases. In particular, the Hp 2-2 phenotype has been associated with the unfavorable course of some inflammatory and autoimmune disorders. Its potential role in modulating the immune system in SpA is still unknown. This article contains pathophysiological considerations on the potential relationship between Hp, its polymorphism and SpA.

The Epidemiology and Clinical Manifestations of Autoimmunity in Selective IgA Deficiency

Selective immunoglobulin A deficiency (SIgAD) is the most common primary immunodeficiency, defined as an isolated deficiency of IgA (less than 0.07 g/L). Although the majority of people born with IgA deficiency lead normal lives without significant pathology, there is nonetheless a significant association of IgA deficiency with mucosal infection, increased risks of atopic disease, and a higher prevalence of autoimmune disease. To explain these phenomena, we have performed an extensive literature review to define the geoepidemiology of IgA deficiency and particularly the relative risks for developing systemic lupus erythematosus, hyperthyroidism, hypothyroidism, type 1 diabetes mellitus, Crohn's disease, ulcerative colitis, rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, and vitiligo; these diseases have strong data to support an association. We also note weaker associations with scleroderma, celiac disease, autoimmune hepatitis, immune thrombocytopenic purpura, and autoimmune hemolytic anemia. Minimal if any associations are noted with myasthenia gravis, lichen planus, and multiple sclerosis. Finally, more recent data provide clues on the possible immunologic mechanisms that lead to the association of IgA deficiency and autoimmunity; these lessons are important for understanding the etiology of autoimmune disease.

Anti-CD74 antibodies have no diagnostic value in early axial spondyloarthritis: data from the spondyloarthritis caught early (SPACE) cohort

BACKGROUND

Anti-CD74 IgG antibodies are reported to be elevated in patients with axial spondyloarthritis (axSpA). This study assessed the diagnostic value of anti-CD74 antibodies in patients with early axSpA.

METHODS

Anti-CD74 IgG and IgA antibodies were first measured in an exploratory cohort of patients with radiographic axSpA (138 patients with ankylosing spondyloarthritis (AS)) and 57 healthy controls and then were measured in patients with early axSpA (n = 274) and with non-SpA chronic back pain (CBP) (n = 319), participating in the spondyloarthritis caught early (SPACE) prospective cohort study of patients under 45 years old with early back pain (for ≥ 3 months, but ≤ 2 years).

RESULTS

In the exploratory cohort, anti-CD74 IgG antibodies were present in 79.7% of patients with AS vs. 43.9% of healthy controls (p < 0.001). Anti-CD74 IgA antibodies were present in 28.5% of patients with AS vs. 5.3% of healthy controls (p < 0.001). In the SPACE cohort, anti-CD74 IgG antibody levels were present in 46.4% of the patients with axSpA vs. 47.9% of the patients with CBP (p = 0.71). Anti-CD74 IgA antibodies were present in 54.7% of the patients with axSpA and 37.0% of the patients with CBP (p < 0.001). This resulted in a positive predictive value of 58.8% (compared to a prior probability of 46.2%) and a negative predictive value of 59.1% (compared to a prior probability of 53.8%). In a regression model, total serum IgA was associated with axSpA odds ratio (OR) 1.19, p < 0.001) whereas anti-CD74 IgA was not (OR) 1.01, p = 0.33). Furthermore, anti-CD74 IgA was associated with sacroiliitis on magnetic resonance imaging (MRI) (OR) = 2.50, p = 0.005) and heel enthesitis (OR) = 2.56, p = 0.002).

CONCLUSIONS

Albeit anti-CD74 IgA is elevated in patients with early axSpA, this elevation is not sufficiently specific to yield significant diagnostic value in patients under 45 years old presenting with early back pain.

Serum levels of IL-1 beta, TNF-alpha, IL-8, and acute phase proteins in seronegative spondyloarthropathies

OBJECTIVES

Some immunological abnormalities have been described in seronegative spondyloarthropathies (SpA). The aim of this study is to determine the serum levels of IL-1beta, TNF-alpha and IL-8, which are proinflammatory cytokines in active and inactive patients with SpA, to compare the results with those of controls and to investigate a relationship with clinical activity and acute phase proteins.

METHODS

Forty-two patients (34 males and eight females) and 22 healthy controls (17 M and 5 F) were included in the study. All patients fulfilled Amor criteria for the classification of SpA. Among patients 23 had active and 19 had inactive disease. IL-1beta, TNF-alpha and IL-8 were determined by enzyme-linked immunosorbent assay ( ELISA), acute phase proteins were measured by nephelometric assay.

RESULTS

There was no statistically significant difference between mean IL-1beta levels of patient groups and controls. Serum mean TNF-a levels in active and inactive patients were significantly increased as compared to that in the controls (P < 0.05, P < 0.05, respectively). Serum mean IL-8 levels in active patients was significantly increased as compared to that in the controls and in inactive patients (P < 0.01, P < 0.01, respectively). High serum IL-8 levels correlated well with C-reactive protein and haptoglobulin, but there was no correlation between IL-1beta or TNF-alpha levels and acute phase proteins such as C-reactive protein, alpha-1 acid glycoprotein, alpha-1 antitrypsin and haptoglobulin.

CONCLUSIONS

These results suggest that serum IL-8 may reflect clinical activity of the disease and may be helpful for monitoring patients with SpA.

Acute phase proteins in the monitoring of inflammatory disorders

The acute phase reaction is in most circumstances a good indicator of (local) inflammatory activity and tissue damage. CRP is a direct and quantitative measure for the acute phase reaction and due to its fast kinetics provides adequate information of the actual situation. The ESR on the contrary is in fact an indirect measure of the acute phase reaction. It does react much slower to changes of inflammatory activity and is influenced by a number of other factors. From studies on the 'behaviour' of CRP it has become clear that diseases may differ with regard to the extent in which they induce an acute phase response. Incidental measurement of the CRP level may add to the diagnostic procedure in selected cases, e.g. in the differentiation between a bacterial and a viral infection or between a bacterial infection and an exacerbation of diseases like SLE. In case of an extremely elevated CRP level (> 100 mg/litre) the possibility of a bacterial infection should always be considered. In clinical practice CRP is particularly useful when serial measurements are performed. The course of the CRP level may be useful for the monitoring of the effect of treatment and for the early detection of postoperative complications or intercurrent infections. The relationship between CRP and the local production and effects of cytokines on the one hand, and the possible functional role of CRP in the inflammatory process on the other hand have surely added a dimension to the clinical use of CRP as a parameter of inflammatory activity.

[Spondylarthropathies and the IgA system]

The spondyloarthropathies (SA) implicate bacterial infections of mucosal origin. IgA synthesis capacity in vitro is normal in AS. IgA increase is secondary to a specific immune response to the bacterial antigens implicated in the disease's pathogenesis. IgA participate to immune complex formation, which may lead to some extraarticular features of the disease (e.g. renal, cutaneous or vascular). There is also an increase of secretory IgA reflecting the activation of the two compartments of this humoral immune response, part of a coherent pathophysiological scheme of the disease. In a practical point of view, IgA serum levels may be considered as a biological parameter of SA activity.

Cutaneous vasculitis and IgA glomerulonephritis in ankylosing spondylitis

Two patients with ankylosing spondylitis were found to have IgA nephropathy and leucocytoclastic cutaneous vasculitis. Immunofluorescence showed perivascular deposition of IgA in the skin of one patient and in the mesangium of both patients. Such an association has been reported only once before. This supports the concept of abnormal IgA immune stimulation in the pathogenesis of ankylosing spondylitis.