AB1431 EPIDEMIOLOGICAL AND GENETIC FEATURES OF ANTI-3-HYDROXY-3-METHYLGLUTARYL-COA REDUCTASE NECROTIZING MYOPATHY IN NORTHERN SPAIN: SINGLE-CENTER EXPERIENCE

Background

Anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) immune-mediated necrotizing myopathy (IMNM) is an entity of growing interest. However, data on epidemiology and clinical spectrum are still scarce and there is a need for the identification of its potential risk factors.

Objectives

To characterize the demographic, genetic, clinical, and serological features of patients with anti-HMGCR IMNM in a region of northern Spain.

Methods

Study of all patients diagnosed with anti-HMGCR IMNM during a 5-year period at a reference hospital in Northern Spain. Besides clinical and laboratory data, we analyzed the genetic influence of HLA genes and the rs4149056 (c.521T>C) single nucleotide polymorphism (SNP) in the SLCO1B1 gene.

Results

8 patients (5 women, 3 men) with a mean ± SD age of 64.9±7.3 years, fulfilled the criteria for anti-HMGCR IMNM. The incidence rate was 0.6 per 100.000 person-years and the prevalence 3 per 100.000 population. All patients had dyslipidemia and had been exposed to statins. Seven of the 8 of cases complained of myalgia. All of them had predominant lower limb proximal and symmetric muscle weakness that was severe in 2 of them. None of the patients had extra-muscular involvement. No evidence of malignancy was found. All patients had elevated serum CK levels with a median [IQR] of 4488 [2538-9194] IU/L. Serum 25-hydroxy vitamin D levels were decreased in all patients in whom it was determined. The 3 patients with a previous diagnosis of hypothyroidism had abnormal levels of TSH at the time of diagnosis. All patients experienced improvement with different schemes of immunosuppressive therapy. Noteworthy, 7 of 8 patients carried the HLA-DRB1*11 allele. The frequency of the rs4149056 C allele in the SLCO1B1 gene (12.5%) was similar to that of the general population.

Conclusion

In northern Spain, the IMNM anti-HMGCR preferentially affects people over 50 years of age who are carriers of the HLA-DRB1*11 allele and take statins. Both low vitamin D levels and hypothyroidism may play a potential predisposing role in the development of this disease

Table 1.PatientAge/SexHLA DRB1*11rs4149056 genotypeMRC at the weakest muscle group*DysphagiaCK (IU/L) at diagnosisAnti-HMGCR titer (CU)Induction therapy*Maintenance therapyClinical improvement**CK (IU/L) at last follow-up visit156/MYesTT2No8963277.8GC. IVIG.MTXGC. IVIG. MTX. RTXMarked134269/FYesTT0Yes9271235.9GC iv bolus. IVIG.GC. MTX. RTX.Marked890364/FYesTT3No4000242.6IVIG.IVIG.RTXMarked1284479/MYesTT4No4977145.6GC. IVIG.GC. IVIG.Complete92562/FNoTT3No2116210.0GCGC.MTX.Marked236657/FYesTC4No2294259.3IGIVIGIVComplete235768/FYesTT3No3273236.0GC. IGIV. AZA.GC. AZAComplete249864/MYesTC4Yes11000179.0GC iv bolus. AZA.GC. AZAComplete161

AZA: azathioprine; CK: creatinine kinase; CU: chemiluminescence units; F: female; GC: glucocorticoids; IVIG: intravenous immunoglobulins; M: male; MRC: medical research council scale; MTX: methotrexate; RTX: rituximab; ** Induction therapy initiated within 3 months of diagnosis. **Clinical improvement: no improvement (no improvement in MRC grade), mild improvement (improvement of MRC grade but still requiring assistance for activities of daily living), marked improvement (persistence of mild weakness without functional limitation), and complete improvement (return to baseline with no symptoms or signs of weakness).

Disclosure of Interests

None declared

AB0430 CONTRIBUTION OF SCLERODERMA/MYOSITIS-RELATED ANTIBODIES DETECTED BY IMMUNOBLOT TO THE DIAGNOSIS OF SYSTEMIC AUTOIMMUNE RHEUMATIC DISEASES IN 134 PATIENTS FROM A SINGLE REFERRAL CENTER

Background:

Immunoblot assays are increasingly used in clinical practice as part of the diagnostic armamentarium of systemic autoimmune rheumatic diseases (SARDs).

Objectives:

To assess the contribution of an extended scleroderma/myositis-related antibodies (Ab) determination by immunoblot to the diagnosis of patients with SARDs.

Methods:

We reviewed all medical records of patients with positive scleroderma/myositis-related Ab line blot determinations (Euroimmune AG, Lübeck, Germany) in our center from November 2017 to September 2020. These assays were requested due to high suspicion of SARDs in patients presenting with non-specific symptoms.

Results:

134 patients (37men/97women; mean age 59.6 ± 14.8 years) were positive for at least 1 Ab, 25 of them were positive for 2 Abs. Main clinical features at the time of immunoblot requests were: arthralgia/arthritis (n=88), Raynaud’s phenomenon (n=59), rash (n=27), sicca syndrome (n=14.9%), myopathy (n=18). During follow-up, 28 patients were diagnosed with undifferentiated connective tissue disease (UCTD), 26 scleroderma, 23 overlap myositis, 18 interstitial pneumonia with autoimmune features (IPAF), 8 other inflammatory diseases, 8 Sjögren’s syndrome, 7 systemic lupus erythematosus, 5 dermatomyositis, 1 necrotizing myositis. In 10 patients the diagnosis of SARD was finally ruled out (Figure 1). Interstitial lung disease (ILD) was present in 50 patients, being particularly frequent in those with anti-PL12, anti-PL7 and anti-MDA5 Abs. Cancer was detected in 9 (6.7%) patients, 6 of them were anti-Ro52 + (Table 1).

Conclusion:

Immunoblot assays are of great help in the diagnosis of patients with high clinical suspicion of SARDs. While some Abs, such as anti-Ro52, anti-Ku and anti-PMScl75/100, remain to be nonspecific, other Abs including anti-PL12, anti-PL7 or anti-MDA5 are particularly helpful in detecting SARDs patients with associated ILD.

References:

Table 1.Mi-2 (n=5)PL-7(n=6)PL-12(n=4)Jo-1(n=6)MDA5(n=1)antiRo52(n=57)SRP (n=3)Scl-70(n=12)CENP(n=14)Th(n=2)Ku(n=14)Fibrilarina (n=2)PM-Scl75/100 (n=23)NOR90(n=8)RNA pol(n=2)ILD04 (66.7)4 (100)3 (50)1 (100)19 (33.3)07 (58.3)1 (7.1)07 (50)1 (50)9 (39.1)5 (62.5)0Cancer1 (20)00006 (10.5)1 (33.3)0001 (7.1)0000

Disclosure of Interests:

None declared

POS1346 CLINICAL ASSOCIATIONS OF ANTI-RO52 ANTIBODIES IN PATIENTS WITH SYSTEMIC AUTOIMMUNE RHEUMATIC DISEASES

Background:

Anti-SSA/Ro antibodies (Abs) can target Ro60 and Ro52 antigens. The presence of anti-Ro60 Abs has been widely described in patients with systemic autoimmune rheumatic diseases (SARDs). However, the clinical implication of anti-Ro52 Abs for the diagnosis and management of SARDs remains unclear.

Objectives:

To assess the clinical associations of anti-Ro52 antibodies in patients with high clinical suspicion of SARDs.

Methods:

We retrieved the clinical records of all patients with positive anti-Ro52 Abs tested in our hospital between November 2017 and September 2020. Patients were divided into 3 groups: 1) anti-Ro52+Ro60 + 2) antiRo52+Ro60- 3) antiRo52+Ro60+ with other Abs. A comparative study between groups was performed.

Results:

57 patients (43 women/14 men; mean age 62.1±13.6 years) with antiRo52+ Abs were identified. Final diagnosis were: undifferentiated connective tissue disease (UCTD) (n=13), anti-synthetase/overlap myositis (n=12), Sjögren’s syndrome (n=7), interstitial pneumonia with autoimmune features (IPAF) (n=6), scleroderma (n=4), systemic lupus erythematosus (n=2), dermatomyositis (n=2), other systemic inflammatory diseases (n=3). In 8 (14%) patients the diagnosis of inflammatory diseases was finally ruled out. 27 patients were classified in the Ro52+Ro60+ group, 11 in the Ro52+Ro60- group and 19 Ro52+ with other Abs. Patients with Ro52+Ro60- were younger and more often women than patients with Ro52+Ro60+.Interstitial lung disease (ILD) was less frequent in patients with Ro52+Ro60-(Table 1). Isolated Ro52 Abs were more frequently associated with UCTD, while IPAF was more commonly found in patients with anti-Ro52+Ro60+ Abs (Table 1 and Figure 1).

Figure 1.

Conclusion:

Anti Ro52 Abs determination has clinical implications in the diagnosis of SARDs.

Table 1.Anti-Ro52+Ro60+(n=27)Anti-Ro52+Ro60-(n=11)Anti-Ro52+Ro60+ with other Abs(n=19)Age (years), mean ± SD65.7 ± 10.053.8 ± 18.0*61.7 ± 13.6Sex (females), n (%)19 (70.4)10 (90.9) *14 (73.7)Clinical manifestations at anti-Ro52 determination, n (%)Arthralgias/arthritis18 (66.7)7 (63.6)14 (73.7)Raynaud’s phenomenon9 (33.3)4 (36.4)9 (47.4)Myopathy4 (14.8)1 (9.1)2 (10.5)Final diagnosis, n (%)Systemic lupus erythematosus0 (0)0 (0)2 (10.5)Sjögren’s syndrome3 (11.1)1 (9.1)4 (21.1)Scleroderma1 (3.7)03 (15.8)Undifferentiated connective tissue disease3 (11.1)7 (63.6) **3 (15.8)Overlap myositis7 (25.9)1 (9.1)4 (21.1)Dermatomyositis1 (3.7)01 (5.3)IPAF5 (18.5) **00Other systemic inflammatory diseases3 (11.1)00Non inflammatory disease4 (14.8)2 (18.2)2 (10.5)Comorbidities, n (%)ILD11 (40.7)1 (9.1) **7 (36.8)Malignancy5 (18.5)1 (9.1)0 (0.0)

* p< 0.05 (Ro52+Ro60+ vs Ro52+Ro60-)

** p< 0.05 (Ro52+Ro60+ vs Ro52+Ro60- vs Ro52+Ro60+ with other Abs)

Disclosure of Interests:

None declared

OP0118 DECIPHERING THE ANTI-PROTEIN-ARGININE DEIMINASE (PAD) RESPONSE IDENTIFIES PAD1 AND PAD6 AS NOVEL AUTOANTIGENS IN RHEUMATOID ARTHRITIS

Background:

Protein-arginine deiminase (PAD) 4 enzymes play a central role in the pathogenesis of rheumatoid arthritis (RA) and represents an antigenic target. Among the five known family members (PAD1, PAD2, PAD3, PAD4 and PAD6), only PAD2, PAD3 and PAD4 have been described to have autoantigenic properties. Furtheremore, very little is known on the the isotype usage of these autoantibodies. Understanding the molecular basis of the anti-PAD antibody reponse has the potential to open novel approaches for precision medicine in RA.

Objectives:

The objectives of this study were to screen for the presence of antibodies to the five PAD family members and to evaluate the isotype usage of the anti-PAD4 response in RA.

Methods:

First, we developed a panel for the detection of anti-PAD IgG based on a particle-based multi-analyte technology (PMAT), that utilized paramagnetic particles coupled with the different human recombinant PAD proteins (PAD1, PAD2, PAD3, PAD4 and PAD6) and anti-human IgG conjugate. This panel was used to test sera from RA patients (n=33) and non-RA controls (n=36). The controls were comprised of apparently healthy individuals (n=10), and patients with infectious diseases (n=10), systemic lupus erythematosus (n=7), systemic sclerosis (n=9) and Sjogren’s syndrome (n=1). Next, the PAD4-coupled beads were tested with anti-human IgM, IgA and IgG conjugates on an extended cohort of RA patients (n=62) and the same non-RA controls.

Results:

All five anti-PAD IgG (Figure 1) demonstrated the ability to discriminate between RA patients and controls. At greater than 90% specificity, anti-PAD4 IgG, followed by anti-PAD3 IgG, showed the best diagnostic performance. Significantly higher levels of the five antibodies were observed in RAvs.controls (p-values of 0.0041, <0.0001, 0.0014, 0.0039, and 0.0140 for anti-PAD1, 2, 3, 4 and 6, respectively). Significant correlation was observed between all the antibodies, with the highest between anti-PAD1 and anti-PAD4 (Spearman´srho=0.87,p<0.0001) and the lowest between anti-PAD4 and anti-PAD2 (Spearman’srho=0.38,p=0.0015) and anti-PAD4 and anti-PAD6 (Spearman’srho=0.38,p=0.0011). While principal component analysis (PCA) (Figure 2) showed an association between all anti-PAD antibodies, there was further discrimination that displayed closer association between anti-PAD1, 3 and 4 on one hand, and between anti-PAD2 and 6. For the extended testing of anti-PAD4 with IgG, IgA and IgM, all three isotypes were identified in the sera of RA patients. Higher levels of the three isotypes were observed in RA patients with erosive disease when compared with the patients without erosion, but this association was only significant for anti-PAD4 IgA (p=0.0086).

Figure 1.

Receiver operating characteristics (ROC) analysis of the discrimination between rheumatoid arthritis (RA) and controls of IgG to protein-arginine deiminase (PAD) 1, PAD2, PAD3, PAD4 and PAD6. The area under the curve (AUC) values are shown in brackets for each biomarker.Abbreviations:TPF: true positive fraction; FPF: false positive fraction

Figure 2.

Two dimensional principal component analysis (PCA) plot of the anti-PAD levels in RA patients (n=33) and controls (n=36). Anti-PAD1, 3 and 4 have the main contribution to PC1, which explains 51.7% of the variance, and anti-PAD2 and 6 to PC2, that represents 20.8% of it.Abbreviations:PC: principal component

Conclusion:

Our study is the first to describe PAD1 and PAD6 as novel antigenic targets in RA and to demostrate that the anti-PAD4 B-cell immune response uses all three isotypes (IgG, IgA and IgM). The strong and significant association between anti-PAD4 IgA and joint erosion is of particular clinical relevance.

Disclosure of Interests:

Laura Martinez-Prat Employee of: I am an employee of Inova Diagnostics, an in vitro diagnostics company., Mary Ann Aure Employee of: I am an employee of Inova Diagnostics, an in vitro diagnostics company., Chelsea Bentow Employee of: I am an employee of Inova Diagnostics, an in vitro diagnostics company., David Lucia Employee of: I am an employee of Inova Diagnostics, an in vitro diagnostics company., Marcos Lopez-Hoyos Consultant of: Inova Diagnostics, an in vitro diagnostics company., Michael Mahler Employee of: I am an employee of Inova Diagnostics, an in vitro diagnostics company.

B-Cell-Activating Factor Levels Are Associated With Antibody-Mediated Histological Damage in Kidney Transplantation

INTRODUCTION

Along with death engraftment, in recent years, antibody-mediated damage has been identified as the leading cause of loss of kidney transplants. Despite the recognition of the role of the B-lymphocyte subpopulation in the development of both tolerance and rejection, little is known about the trigger mechanisms and effectors of this humoral response.

BACKGROUND

We analyzed the relationship between B lymphocyte subpopulations and levels of B-cell-activating factor (BAFF) with the histological findings in biopsies of renal transplantation.

MATERIAL AND METHODS

We selected 35 patients whose kidney transplant biopsy was performed between January and November 2015. The biopsy specimens were classified according to Banff criteria. At the moment of the biopsy BAFF levels and B-lymphocyte subpopulations in blood were measured using enzyme-linked immunosorbent assay (ELISA) and using flow cytometry, respectively.

RESULTS

Mean BAFF levels were 493 ± 245 pg/mL. The median performance of biopsy post-transplantation was 12.9 (11.7-23.9) months. BAFF levels correlated with pretransplantation antibodies (r = 0.523; P = .002) but not with kidney function. In biopsies performed more than 1 year after transplantation BAFF levels correlated with the severity of chronic glomerular (cg) involvement (r = 0.625; P = .003). Histological variables related to antibody-mediated injury selected by principal component analysis (glomerulitis, peritubular capillary, and chronic glomerulopathy) related to BAFF levels (B factor, 116; 95% confidence interval [CI], 12-220; P = .029). Biopsy specimens with transplant glomerulopathy (TG) showed lower levels of circulating naive CD19 + subpopulation, IgD+, and CD27- (32.7 ± 28.1 vs 87.9 ± 79.1; P = .017) compared with biopsy specimens without TG.

CONCLUSIONS

Elevated levels of BAFF are associated with increased presence and severity of TG and a set of variables related to antibody-mediated histological damage. TG is associated with changes in circulating B-lymphocyte subpopulations that could contribute to its pathogenesis.

Escherichia coli infection induces autoimmune cholangitis and anti-mitochondrial antibodies in non-obese diabetic (NOD).B6 (Idd10/Idd18) mice

Several epidemiological studies have demonstrated that patients with primary biliary cirrhosis (PBC) have a higher incidence of urinary tract infections (UTI) and there is significant homology of the immunodominant mitochondrial autoantigen, the E2 component of the pyruvate dehydrogenase complex (PDC-E2), between mammals and bacteria. Previous work has demonstrated that non-obese diabetic (NOD).B6 Idd10/Idd18 infected with Novosphingobium aromaticivorans developed liver lesions similar to human PBC. It was postulated that the biliary disease was dependent upon the presence of the unique N. aro glycosphingolipids in activating natural killer T (NK T) cells. To address this issue, we infected NOD.B6 Idd10/Idd18 mice with either Escherichia coli, N. aro or use of a phosphate-buffered saline (PBS) vehicle control and serially followed animals for the appearance of liver pathology and anti-mitochondrial autoantibodies (AMA). Of striking importance, the biliary disease of E. coli-infected mice was more severe than N. Aro-infected mice and the titre of AMA was higher in E. coli-infected mice. Furthermore, the immunopathology did not correlate with the ability of bacterial extracts to produce antigen-dependent activation of NK T cells. Our data suggest that the unique glycosphingolipids of N. aro are not required for the development of autoimmune cholangitis. Importantly, the data highlight the clinical significance of E. coli infection in a genetically susceptible host, and we suggest that the appearance of autoimmune cholangitis is dependent upon molecular mimicry. These data highlight that breach of tolerance to PDC-E2 is probably the first event in the natural history of PBC in genetically susceptible hosts.

Hospital mortality prognostication in sepsis using the new biomarkers suPAR and proADM in a single determination on ICU admission

PURPOSE

The soluble form of the urokinase-type plasminogen activator receptor (suPAR) and proadrenomedullin (proADM) are two new and promising sepsis biomarkers. We assessed the prognostic value of a single determination of proADM and suPAR, comparing them with C-reactive protein (CRP) and procalcitonin (PCT), and evaluating whether their addition to severity scores (APACHE II and SOFA) could improve their prognostic accuracy.

METHODS

A single-centre prospective observational study conducted in an adult intensive care department at Marques de Valdecilla University Hospital in Spain. APACHE II and SOFA scores, CRP, PCT, suPAR and proADM levels on the day of ICU admission were collected.

RESULTS

A total of 137 consecutive septic patients were studied. The best area under the curve (AUC) for the prediction of in-hospital mortality was for APACHE II (0.82) and SOFA (0.75) scores. The ROC curve for suPAR yielded an AUC of 0.67, higher than proADM (0.62), CRP (0.50) and PCT (0.44). Significant dose-response trends were found between hospital mortality and suPAR (OR Q4 = 4.83, 95% CI 1.60-14.62) and pro-ADM (OR Q4 = 3.00, 95% CI 1.06-8.46) quartiles. Non-significant associations were found for PCT and CRP. The combination of severity scores and each biomarker did not provide superior AUCs.

CONCLUSIONS

SuPAR and, to a lesser extent, proADM levels on ICU admission were better tools in prognosticating in-hospital mortality than CRP or PCT. However, neither of the two new biomarkers has been demonstrated to be excessively useful in the current setting. The prognostic accuracy was better for severity scores than for any of the biomarkers.

Quantitative assessment of serum free light chains in renal transplantation

Plasma cell dyscrasias can cause renal disease. Sensitive methods have recently been introduced to quantify serum free light chains (sFLCs). Renal function may influence the variability of these methods, as shown in chronic kidney disease (CKD) patients, but this problem has not been widely addressed in renal transplant patients. Herein, we examined the association between polyclonal sFLC concentrations and renal function among a population of renal transplant patients. We studied 102 kidney allograft recipients and 53 CKD patients classified according to KDOQI (Kidney Disease Outcomes Quality Initiative) stages. None of them had been diagnosed with monoclonal gammopathy. sFLCs were quantified by nephelometry. Both serum κ and λ free light chain concentrations rose progressively through each stage of KDOQI among both transplant and nontransplant patients (P<.0001). In the former setting, sFLC concentrations significantly correlated, using a Spearman coefficient, with serum creatinine, and serum cystatin concentrations as well as estimated glomerular filtration rate: namely, 0.723, 0.797, and -0.711 for sκFLC and 0.705, 0.759, and -0.694 for sλFLC, respectively (P<.0001 in all cases). Spearman correlation coefficients in nontransplant patients were: 0.559, 0.848, and -0.766 for sκFLC and 0.702, 0.875, and -0.855 for sλFLC, respectively (P<.0001 in all cases). In conclusion, sFLCs must be interpreted cautiously due to their clear association with renal function. Therefore, renal transplantation did not produce changes that were different from those dependent on renal function.

Circulating cytokines in active polymyalgia rheumatica

Objective:

To characterise the circulating cytokine profile and the cellular source of circulating cytokines in polymyalgia rheumatica (PMR).

Methods:

The study included 34 patients with active untreated PMR and 17 age-matched healthy controls (HC). Circulating cytokines were measured by cytometric bead array and ELISA. Intracellular cytokines were assessed in CD3+ and CD14+ cells by flow cytometry. Cytokines in cell culture supernatants were also determined after polyclonal stimulation of patients’ peripheral blood mononuclear cells.

Results:

Circulating levels of interleukin-6 (IL6) were significantly higher in subjects with active PMR than in HC. Corticosteroid (CS) treatment was followed by a decrease in the level of IL6. Intracellular cytokine staining showed that circulating monocytes did not produce higher amounts of proinflammatory cytokines in patients with PMR than in HC. There was a discordance between serum levels and cytokine-producing monocyte and T cells, and it was not possible to demonstrate a Th1 bias in the peripheral compartment.

Conclusions:

Active PMR is characterised by increased serum levels of IL6, but not of other proinflammatory cytokines, that are rapidly suppressed by CS treatment. As circulating monocytes do not show increased production of proinflammatory cytokines, IL6 may be mainly produced in the inflamed tissue. A study of the circulating cytokine profile and its cellular source may provide a clue to new therapeutic options.

Lack of effect of rapamycin in anti-CCP antibody production in a rheumatoid arthritis kidney allograft recipient

Autoimmune diseases may lead to end-stage renal disease and, as a consequence, kidney transplantation. Classical immunosuppressive drugs, such as cyclosporine or corticosteroids, are well-established therapies for both transplantation and autoimmune diseases. Rapamycin is a new immunosuppressant useful for allograft transplantation and with a promising future for autoimmune diseases, although it has not been extensively studied in humans. Here the case of a patient diagnosed with rheumatoid arthritis (RA) who received a renal allograft is reported. She was started on prednisolone, azathioprine and cyclosporine immunosuppression and changed to rapamycin instead of cyclosporine 4 years after transplantation, because of chronic allograft nephropathy. At present, the patient has a functioning graft. However, the arthritis symptoms reappeared after the change in immunosuppressant. Titers of RA-specific anti-cyclic citrullinated peptides antibodies increased whereas rheumatoid factor titers decreased. This case report suggests that rapamycin used for kidney transplantation might have a different influence on the spectrum of RA autoantibodies.

Antibodies to carbonic anhydrase and IgG4 levels in idiopathic chronic pancreatitis: relevance for diagnosis of autoimmune pancreatitis

BACKGROUND

Increased serum antibodies against carbonic anhydrase II (CA-II Ab) or IgG4 levels have been reported in cases of autoimmune chronic pancreatitis (ACP).

AIM

To assess the relevance of serum CA-II Ab and IgG4 levels for the diagnosis of ACP in idiopathic CP (ICP) versus alcoholic CP and Sjogren's syndrome (SS).

SUBJECTS

This was a multicentre study involving 227 subjects divided into four groups: ICP (n = 54), normal controls (n = 54, paired by age and sex with ICP patients), alcoholic CP (n = 86), and SS (n = 33).

METHODS

CA-II Ab was measured by ELISA and confirmed by western blotting. A score of easy clinical use with major clinical, morphological, and biochemical parameters for the diagnosis of ACP was applied.

RESULTS

The percentage of patients with increased serum CA-II Ab was higher in the ICP group (28%) than in controls (1.9%) and in patients with alcoholic CP (10.5%), but lower than in patients with SS (64%). The proportion with elevated IgG4 levels was higher in the ICP group (15%) compared with controls (1.9%) and SS (0%) but not significantly different from alcoholic CP (8%). Most ICP patients (7/8) with high IgG4 levels exhibited increased CA-II Ab and a compatible ACP score. A definitive diagnosis of ACP by histological analysis was associated with other autoimmune disorders, an increase in both serum IgG4 and CA-II Ab levels, and IgG4 positive plasma cells.

CONCLUSIONS

The increase in serum IgG4 levels was strongly associated with elevated CA-II Ab levels, manifestations compatible with ACP, and lymphoplasmacytic infiltration when surgical specimens were available.

Clinical utility of anti-CCP antibodies in the differential diagnosis of elderly-onset rheumatoid arthritis and polymyalgia rheumatica

BACKGROUND

In a significant number of patients the differential diagnosis between elderly-onset rheumatoid arthritis (EORA) and polymyalgia rheumatica (PMR) is very difficult because of the lack of specific serum markers. Anti-cyclic citrullinated peptide antibodies (anti-CCP Abs) have recently been shown to be highly specific for rheumatoid arthritis (RA). This is the first study addressing the utility of these antibodies in the differential diagnosis between EORA and PMR.

METHODS

Serum samples from 57 EORA patients and 49 PMR patients were studied for the presence of anti-CCP Abs and rheumatoid factor (RF). As controls, samples from 41 RA patients (age at onset <60 yr) and 24 aged healthy subjects were analysed.

RESULTS

Sixty-five per cent of EORA patients had anti-CCP Abs, whereas none of the PMR patients or the aged healthy subjects was positive for those antibodies. Ten of the EORA patients started with polymyalgic symptoms and two of them were positive for anti-CCP Abs. Interestingly, there was a significant correlation between anti-CCP Abs and RF in EORA but not in young RA patients.

CONCLUSIONS

The presence of anti-CCP Abs in a patient with clinical symptoms of PMR must be interpreted as highly suggestive of EORA.

Selective T cell receptor decrease in peripheral blood T lymphocytes of patients with polymyalgia rheumatica and giant cell arteritis

OBJECTIVES

To investigate the phenotype and T cell receptor (TCR) use in peripheral blood T cells in patients with polymyalgia rheumatica (PMR) and giant cell arteritis (GCA).

METHODS

Circulating T lymphocyte phenotype and TCR repertoire were studied by flow cytometry using specific monoclonal antibodies in 23 healthy controls and 37 patients with PMR/GCA.

RESULTS

Patients with active PMR/GCA showed an inverse relation between naive and memory CD4+ T cells and unchanged expression of activation surface markers compared with controls. CD4+ TCR BV expansions were seen in 12 (52%) controls and in 8 (22%) patients with active disease (p = 0.03). Within the CD8+ subset, the frequency of expansions was similar between groups. Most T cell expansions remained stable over time. Seventeen of the 23 patients with active PMR/GCA disclosed a simultaneous CD4+ and CD8+ T cell depletion for at least one particular BV family with a clear predominance of BV5S2/S3.

CONCLUSIONS

The phenotype of circulating T cells in patients with PMR/GCA is similar to that found in aged healthy subjects, except for the surface markers of naive and memory cells and a striking non-activated phenotype. Specific BV expansions in CD4+ and CD8+ T cells, which remain stable over time, are frequent in aged subjects, including patients with PMR/GCA. TCR BV changes in patients with active disease seem to be also age related, except for the significant decrease in certain BV families in both CD4+ and CD8+ T cell subsets, which may favour the participation of a superantigen stimulation in PMR/GCA.

Homocysteine levels in polymyalgia rheumatica and giant cell arteritis: influence of corticosteroid therapy

OBJECTIVES

It has been suggested that patients with giant cell arteritis (GCA) may share a common pathway with atherosclerosis. Furthermore, patients with GCA and polymyalgia rheumatica (PMR), in addition to advanced age, are treated for prolonged periods of time with corticosteroids, a factor that can also accelerate atherosclerosis. Hyperhomocysteinaemia is considered an independent risk factor for atherosclerosis, and might play a role in ischaemic manifestations that occur with a variable frequency during the course of GCA. The purposes of the present study were: (i). to analyse the plasma levels of homocysteine in patients with GCA and PMR, (ii). to determine the influence of corticosteroid therapy on the homocysteine levels and (iii). to analyse if the levels of homocysteine may predict the development of ischaemic complications in patients with GCA.

METHODS

Plasma homocysteine concentration was measured in 56 patients with active PMR/GCA (17 GCA and 39 isolated PMR) before steroid treatment and 23 healthy age-matched volunteers were used as controls. The total plasma homocysteine level was quantified using a fluorescent polarization immunoassay.

RESULTS

Homocysteine concentrations were higher in PMR and GCA patients than age-matched controls (P < 0.05). Patients with GCA had slightly higher levels of plasma homocysteine than those with isolated PMR (13.6+/-4.3 vs 12.7+/-3.1 micromol/l, P=0.6). In 30 of these patients (12 GCA and 18 PMR) a second measurement of homocysteine concentration was done when they were in clinical remission with steroid treatment. The post-treatment levels of homocysteine were significantly increased in GCA rather than in PMR patients. In 13 patients with homocysteine levels above the normal upper limit of our laboratory, therapy with folic acid and/or vitamin B12 was started. After 3 months of vitamin supplements, the homocysteine concentration significantly decreased from 19.2+/-3.1 to 13.6+/-3.2 micromol/l (P=0.001). Such decrease was less marked in the PMR than in GCA patients. Ten out of the 17 patients with GCA had ischaemic manifestations of the disease. The levels of homocysteine were slightly higher in GCA patients with ischaemia than in those without ischaemic manifestations, although the difference did not reach statistical significance (15+/-4.9 vs 11.6+/-1.9 micromol/l, P=0.46).

CONCLUSIONS

Patients with active PMR and GCA had elevated plasma concentrations of homocysteine. Corticosteroid therapy significantly increased such levels, especially in GCA patients. Treatment with supplements of folic acid and/or vitamin B12 reduced the homocysteine concentrations. These data support the hypothesis that patients with GCA (and to a lesser extend PMR patients) may share a common pathway with atherosclerosis and suggest a new atherogenic mechanism of corticosteroids.

Reactive arthritis after BCG immunotherapy: T cell analysis in peripheral blood and synovial fluid

OBJECTIVE

To investigate the pathogenic mechanism of reactive arthritis after instillation of Calmette-Guérin bacillus (BCG). Although the clinical features of reactive arthritis after BCG therapy are well described, only a few reports have studied the possible pathogenic mechanisms.

METHODS

We analysed by flow cytometry the phenotype and T-cell receptor (TCR) expression of peripheral blood (PB) and synovial fluid (SF) T cells in a patient who developed reactive arthritis (ReA) following intravesical BCG immunotherapy for bladder cancer. The proliferative response of short-term T-cell lines (TCL) from PB of this patient to mycobacterial antigens was tested by bromodeoxyuridine incorporation.

RESULTS

CD4(+) and CD8(+) SF T cells with activated and memory phenotype were observed at the onset of arthritis. We were able to detect BV-restricted expansion of CD8(+) T cells in PB (BV17) and in SF (BV5S1 and BV12). The percentage of PB and SF CD8(+) T cells that expanded diminished when the symptoms remitted. The strongest response of CD4(+) TCL from the patient in vitro was obtained for human hsp-60 in an inversely dose-dependent manner. Very important was the finding that CD8(+) TCL from the patient demonstrated no proliferative response to any antigenic challenge that was reversed after the addition of exogenous interleukin 2.

CONCLUSION

Although the identity of the stimulating antigen that led to the expansions observed in this patient is not clarified by the present data, both CD4(+) and CD8(+) T cells might play a role in the development of ReA following intravesical administration of BCG.

Familial aggregation of polymyalgia rheumatica and giant cell arteritis: genetic and T cell repertoire analysis

OBJECTIVE

Several reports of familial aggregation of giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) have been described although detailed genetic and immunological studies are scarce. Our aims were to investigate the influence of HLA-DRB1 alleles and to analyze the phenotype and T cell receptor (TCR) usage of circulating T lymphocytes in a familial case of GCA and PMR.

METHODS

HLA-DRB1 typing was carried out using polymerase chain reaction amplification with specific primers. The study of the circulating T cell repertoire was performed by staining with specific monoclonal antibodies and flow cytometry analysis.

RESULTS

Patient 1 developed GCA at the age of 71, four years prior to the diagnosis of PMR in her older brother. The HLA-DRB1 typing of Patient 1 was DRB1*04 (DRB1*0401)/DRB1*12 and in Patient 2 was DRB1*07/DRB1*12. In our patient population, GCA was associated with an increased frequency of HLA-DRB1*04 compared with PMR patients. Regarding T cell phenotype, the brother with active PMR had a higher expression of surface markers indicating activation in both T cell subsets (CD25 and HLA-DR). The sister with GCA showed a pronounced decrease of CD4+/CD45RA+ T cells with respect to her brother with PMR. Both patients carried a significant depletion of CD28 in both subsets, specially within the CD8+ T cell compartment. The BV gene usage differed from one patient to the other. T cell expansions were identified in both patients but the specificities were different.

CONCLUSION

We describe an association of GCA and PMR between two first degree relatives with significant genetic and immunologic differences. Our results suggest that the pathogenic mechanisms leading to the development of GCA and PMR are probably multifactorial, and both genetic and environmental factors may contribute to the development of these diseases.