ß2-Glycoprotein I/HLA class II complexes are novel autoantigens in antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by thrombosis and/or pregnancy complications. ß2-glycoprotein I (ß2GPI) complexed with phospholipid is recognized as a major target for autoantibodies in APS; however, less than half the patients with clinical manifestations of APS possess autoantibodies against the complexes. Therefore, the range of autoantigens involved in APS remains unclear. Recently, we found that human leukocyte antigen (HLA) class II molecules transport misfolded cellular proteins to the cell surface via association with their peptide-binding grooves. Furthermore, immunoglobulin G heavy chain/HLA class II complexes were specific targets for autoantibodies in rheumatoid arthritis. Here, we demonstrate that intact ß2GPI, not peptide, forms a complex with HLA class II molecules. Strikingly, 100 (83.3%) of the 120 APS patients analyzed, including those whose antiphospholipid antibody titers were within normal range, possessed autoantibodies that recognize ß2GPI/HLA class II complexes in the absence of phospholipids. In situ association between ß2GPI and HLA class II was observed in placental tissues of APS patients but not in healthy controls. Furthermore, autoantibodies against ß2GPI/HLA class II complexes mediated complement-dependent cytotoxicity against cells expressing the complexes. These data suggest that ß2GPI/HLA class II complexes are a target in APS that might be involved in the pathogenesis.

Autoantibodies to IgG/HLA class II complexes are associated with rheumatoid arthritis susceptibility.

Specific HLA class II alleles are strongly associated with susceptibility to rheumatoid arthritis (RA); however, how HLA class II regulates susceptibility to RA has remained unclear. Recently, we found a unique function of HLA class II molecules: their ability to aberrantly transport cellular misfolded proteins to the cell surface without processing to peptides. Rheumatoid factor (RF) is an autoantibody that binds to denatured IgG or Fc fragments of IgG and is detected in 70-80% of RA patients but also in patients with other diseases. Here, we report that intact IgG heavy chain (IgGH) is transported to the cell surface by HLA class II via association with the peptide-binding groove and that IgGH/HLA class II complexes are specifically recognized by autoantibodies in RF-positive sera from RA patients. In contrast, autoantibodies in RF-positive sera from non-RA individuals did not bind to IgGH/HLA class II complexes. Of note, a strong correlation between autoantibody binding to IgG complexed with certain HLA-DR alleles and the odds ratio for that allele's association with RA was observed (r = 0.81; P = 4.6 × 10(-5)). Our findings suggest that IgGH complexed with certain HLA class II alleles is a target for autoantibodies in RA, which might explain why these HLA class II alleles confer susceptibility to RA.

Study on the frequency and risk factors of moderate-to-severe sleep apnea syndrome in rheumatoid arthritis.

OBJECTIVES: We aimed to investigate the frequency of moderate-to-severe sleep apnea syndrome (SAS) that possibly influences long-term prognosis in patients with rheumatoid arthritis (RA), and to analyze the risk factors for this group. METHODS: We examined respiratory disturbance index (RDI) by polysomnography in 62 hospitalized RA patients. Risk factors of moderate-to-severe SAS (RDI ≥20) were analyzed using a multivariate logistic regression analysis. RESULTS: RA was complicated by moderate-to-severe SAS in 13/62 (20.9%) cases. The highest stage of temporomandibular joint abnormality (TMJA) and a high value of health assessment questionnaire-disability index (HAQ-DI) were significant risk factors, according to the results of the multivariate logistic regression analysis (p < 0.0001 and p = 0.010, respectively). Contrary to these results, RDI was not related to the disease activity indexes of RA and other clinical characteristics. CONCLUSION: We clarified that the highest TMJA stage and a high value of HAQ-DI are novel important risk factors for moderate-to-severe SAS in RA patients.

Comparison of the clinical utility of tocilizumab and anti-TNF therapy in AA amyloidosis complicating rheumatic diseases.

OBJECTIVES: Anti-cytokine therapy is reportedly useful in amyloid A (AA) amyloidosis complicating rheumatic diseases. However, to date no studies have directly compared the utility of tumour necrosis factor (TNF) inhibition to that of interleukin-6. The aim of our retrospective study was to compare the clinical utility of tocilizumab (TCZ) and anti-TNF (TNF inhibitor) therapy. METHODS: We studied 42 patients treated with anti-cytokine agents at our hospital: 31 had received a single agent, ten had received two agents and one had received three agents. Patients were divided into a TCZ group (22 patients) and a TNF inhibitor group (32 patients). The main parameters compared were treatment retention rate, serum amyloid A (SAA) profile, renal function profile and clinical disease activity index. RESULTS: The 5-year retention rates were 90.4 (TCZ group) and 34.3 % (TNF inhibitor group) (p = 0.0154, log-rank test). The median SAA fell from 219.2 µg/mL at treatment initiation to 5.0 µg/mL at last observation (TCZ), and from 143.6 to 38.1 µg/mL (TNF inhibitor) (p = 0.0194). Estimated glomerular filtration rate was improved in 72.7 (TCZ) and 34.4 % (TNF inhibitor) of patients (p = 0.0062). The rates of clinical remission or low disease activity at last observation for the TCZ and TNF inhibitor groups were 72.7 and 40.7 % (p = 0.0201), respectively. CONCLUSIONS: Based on these results, we conclude that TCZ was of greater clinical utility than anti-TNF therapy in our patients with AA amyloidosis complicating rheumatic diseases.

Drug free REmission/low disease activity after cessation of tocilizumab (Actemra) Monotherapy (DREAM) study.

OBJECTIVES: To investigate the duration of remission and low disease activity (LDA) after cessation of tocilizumab (TCZ) treatment in rheumatoid arthritis patients who showed remission or LDA as assessed by DAS28 in response to preceding TCZ monotherapy, and to explore the factors contributing to prolonged efficacy duration. METHODS: Disease activity was monitored for 56 weeks. The rate of continued efficacy was estimated by Kaplan-Meier curves. RESULTS: A total of 187 patients were eligible. At baseline of this study, median disease duration was 7.8 years, preceding TCZ treatment period was 4.0 years and DAS28 was 1.5. The rate of continued LDA at 52 weeks was 13.4 % according to the Kaplan-Meier estimate. 19 patients (10 %) were completely drug-free and 17 patients (9.1 %) fulfilled DAS28 remission at 52 weeks. Multivariate Cox regression analysis identified low serum IL-6 and normalisation of MMP-3 levels at cessation of TCZ as independent predictive markers for longer duration of LDA. In patients with low serum IL-6 (<12.9 pg/mL) and normal MMP-3 levels, the rate of continued LDA reached 38.0 % at 52 weeks. CONCLUSIONS: TCZ monotherapy may induce biologics-free remission or LDA without concomitant use of synthetic DMARDs. Serum levels of IL-6 and MMP-3 are useful markers for identifying patients who could discontinue TCZ without acute disease flare.

Retreatment efficacy and safety of tocilizumab in patients with rheumatoid arthritis in recurrence (RESTORE) study.

OBJECTIVES: To evaluate the safety and efficacy of retreatment with tocilizumab (TCZ) in patients who had participated in the DREAM study (Drug free remission/low disease activity after cessation of tocilizumab [Actemar] monotherapy study) and had experienced loss of efficacy. METHODS: Patients were retreated with TCZ or other disease modifying antirheumatic drugs (DMARDs). Disease activity was measured using the 28-joint disease activity score (DAS28) for 12 weeks. RESULTS: A total of 164 eligible patients, including 161 who experienced loss of efficacy within 52 weeks of the DREAM study, resumed treatment: 157 with TCZ and 7 with DMARDs and/or infliximab. Of TCZ-treated patients, 88.5 % (139 patients) achieved DAS28 <2.6 within 12 weeks, whereas among patients treated with DMARDs and/or infliximab only 14.3 % (1 patient) achieved DAS28 <2.6. Adverse events were observed in 70 TCZ-treated patients (44.0 %), but no serious infusion reactions were observed. CONCLUSIONS: Retreatment with TCZ was well-tolerated and effective in patients who had responded to the preceding TCZ monotherapy but had experienced loss of efficacy after cessation of TCZ.

Simultaneous quantitative analysis of the expression of CD64 and CD35 on neutrophils as markers to differentiate between bacterial and viral infections in patients with rheumatoid arthritis.

OBJECTIVES: The expression level of CD64 on neutrophils can be used to differentiate between an infection and a disease flare in rheumatoid arthritis (RA) patients. However, the CD64 expression is elevated by both bacteria and viruses, so it cannot be used to distinguish the type of infection. We herein investigated the results of a simultaneous quantitative analysis of the expression of CD64 and CD35 on neutrophils to determine whether these molecules can be used to distinguish between bacterial and viral infections in RA patients. METHODS: We collected blood from 22 RA patients with pathogen-proven infections (15 bacterial and 7 viral infections). Blood samples were stained with QuantiBRITE CD64PE/CD45PerCP and CD35PE, and the mean fluorescence intensities were assessed by a flow cytometer. The mean numbers of molecules were calculated using QuantiBrite PE beads. RESULTS: We calculated the ratio of CD64 to the CD35 level (CD35/CD64), and used a cut-off value of 2.8 for the CD35/CD64 ratio. At this value, the sensitivity for diagnosing a bacterial infection was 87%, and the specificity was 86%. CONCLUSIONS: Simultaneous quantitative analysis of CD64 and CD35 expression on neutrophils might be useful to distinguish between bacterial and viral infections in RA patients.

A large-scale association study identified multiple HLA-DRB1 alleles associated with ACPA-negative rheumatoid arthritis in Japanese subjects.

BACKGROUND: HLA-DRB1 is associated with rheumatoid arthritis (RA). However, it has recently been suggested that HLA-DRB1 is only associated with patients with RA who have anticitrullinated peptide/protein antibodies (ACPA), which are specific to RA. OBJECTIVE: To elucidate whether specific HLA-DR alleles are associated with ACPA-negative RA development. METHODS: HLA-DRB1 typing was carried out in 368 Japanese ACPA-negative patients with RA and 1508 healthy volunteers as the first set, followed by HLA-DRB1 typing of 501 cases and 500 controls as the second set. The HLA-DRB1 allele frequency and diplotype frequency were compared in each group, and the results of the two studies were combined to detect HLA-DRB1 alleles or diplotypes associated with ACPA-negative RA. RESULTS: HLA-DRB1*12:01 was identified as a novel susceptibility allele for ACPA-negative RA (p=0.000088, OR=1.72, 95% CI 1.31 to 2.26). HLA-DRB1*04:05 and *14:03 showed moderate associations with ACPA-negative RA (p=0.0063, OR=1.26, 95% CI 1.07 to 1.49 and p=0.0043, OR=1.81, 95% CI 1.20 to 2.73, respectively). The shared epitope was weakly associated with ACPA-negative RA, but no dosage effect was detected (p=0.016, OR=1.17, 95% CI 1.03 to 1.34). A combination of HLA-DRB1*12:01 and DRB1*09:01 showed a strong association with susceptibility to ACPA-negative RA (p=0.00013, OR=3.62, 95% CI 1.79 to 7.30). Homozygosity for HLA-DR8 was significantly associated with ACPA-negative RA (p=0.0070, OR=2.16, 95% CI 1.22 to 3.82). It was also found that HLA-DRB1*15:02 and *13:02 were protective against ACPA-negative RA (p=0.00010, OR=0.68, 95% CI 0.56 to 0.83 and p=0.00059, OR=0.66, 95% CI 0.52 to 0.84, respectively). CONCLUSIONS: In this large-scale association study multiple alleles and diplotypes were found to be associated with susceptibility to, or protection against, ACPA-negative RA.

Successful tocilizumab treatment in a patient with adult-onset Still's disease complicated by chronic active hepatitis B and amyloid A amyloidosis.

We report successful tocilizumab (TCZ) use in a patient with adult-onset Still's disease (AOSD) complicated by chronic hepatitis B (CHB) and AA amyloidosis (AAA). Treatments with corticosteroid and various types of immunosuppressants were unsuccessful. Aggravation of CHB ensued, and entecavir was started. Normalisation of liver function and hepatitis B virus (HBV) DNA were confirmed. TCZ was then started. His arthritis and AAA improved dramatically. TCZ is an excellent treatment for refractory AOSD and is feasible in an HBV-infected patient.

Anti-citrullinated peptide antibody-negative RA is a genetically distinct subset: a definitive study using only bone-erosive ACPA-negative rheumatoid arthritis.

OBJECTIVES: ACPA is a highly specific marker for RA. It was recently reported that ACPA can be used to classify RA into two disease subsets, ACPA-positive and ACPA-negative RA. ACPA-positive RA was found to be associated with the HLA-DR shared epitope (SE), but ACPA negative was not. However, the suspicion remained that this result was caused by the ACPA-negative RA subset containing patients with non-RA diseases. We examined whether this is the case even when possible non-RA ACPA-negative RA patients were excluded by selecting only patients with bone erosion. METHODS: We genotyped HLA-DRB1 alleles for 574 ACPA-positive RA, 185 ACPA-negative RA (including 97 erosive RA) and 1508 healthy donors. We also tested whether HLA-DR SE is associated with RF-negative or ANA-negative RA. RESULTS: ACPA-negative RA with apparent bone erosion was not associated with SE, supporting the idea that ACPA-negative RA is genetically distinct from ACPA-positive RA. We also tested whether these subsets are based on autoantibody-producing activity. In accordance with the ACPA-negative RA subset, the RF-negative RA subset showed a clearly distinct pattern of association with SE from the RF-positive RA. In contrast, ANA-negative as well as ANA-positive RA was similarly associated with SE, suggesting that the subsets distinguished by ACPA are not based simply on differences in autoantibody production. CONCLUSIONS: ACPA-negative erosive RA is genetically distinct from ACPA-positive RA.

Non-autoimmune combined factor XIII A and B subunit deficiencies in rheumatoid arthritis patients treated with anti-interleukin-6 receptor monoclonal antibody (tocilizumab).

INTRODUCTION: Coagulation factor XIII (FXIII) is a plasma fibrin-stabilizing factor comprising A and B subunits (FXIII-A and FXIII-B, respectively) in the form of a heterotetramer (FXIII-A2B2). A humanized monoclonal antibody to the interleukin-6 receptor (tocilizumab, TCZ) has emerged as an effective treatment for rheumatoid arthritis (RA), because it drastically reduces the inflammation of RA. We previously reported that two TCZ-treated RA patients with acquired FXIII deficiency developed pelvic hemorrhage. METHODS: Because TCZ treatment had been shown to be related to low FXIII ammonia release activity and FXIII antigen in the two RA cases, we further examined FXIII-related parameters in 36 TCZ-treated RA patients and compared to 29 healthy controls by employing functional and immunologic assays for FXIII. RESULTS: FXIII-A antigen and FXIII amine incorporation and ammonia release activities were significantly lower in the TCZ-treated group than the control group. The TCZ-treated group also showed mildly low FXIII-A2B2 and FXIII-B levels, and their fibrinogen levels were the lower limit of normal. A significant correlation between FXIII-B and fibrinogen was observed in the control and the TCZ groups, suggesting a common metabolic mechanism(s) for these two hepatic proteins. Because the specific activities of FXIII were normal and neither anti-FXIII-A nor anti-FXIII-B antibody was detected, the overall low FXIII level may have resulted from its impaired synthesis under an unbalanced cytokine milieu caused by TCZ treatment. CONCLUSION: Concomitant deficiencies in multiple hemostatic factors, including FXIII, may lead to an increased risk for hemorrhage in TCZ-treated RA patients.

CD1a+ survivin+ dendritic cell infiltration in dermal lesions of systemic sclerosis.

INTRODUCTION: Proto-oncogene survivin is a member of the inhibitor of apoptosis (IAP) family of proteins. The presence of serous antibodies against survivin in patients with systemic sclerosis has been previously reported; however, there are few reports regarding the pathophysiological relationship between survivin and systemic sclerosis. We herein investigated the expression and function of survivin in SSc patients. METHODS: We performed immunohistochemistry analyses to determine the expression of XIAP, cIAP and survivin in skin lesions from patients with SSc and non-SSc. The expression levels of survivin in peripheral blood mononuclear cells (PBMCs) obtained from SSc patients and healthy controls were evaluated using RT-PCR and flow cytometry. Additionally, the function of survivin was verified with overexpression experiments using monocyte-derived dendritic cells (Mo-DCs). RESULTS: The expression patterns of both XIAP and cIAP were similar, while only the survivin expression differed between the SSc and non-SSc skin lesions. Survivin-overexpressing cells were detected in the SSc dermis frequently. The positive rate of survivin in SSc dermis (64.3%, 9/14) was higher than that in non-SSc dermis (11.2%, 1/9). Furthermore, survivin+ cells expressed CD1a, one of the DC markers. Real-time PCR and FACS analyses revealed that the survivin-WT (wild type) expression levels in PBMCs, in particular CD14+ monocytes, from SSc patients were higher than that from healthy controls. Additionally, the overexpression experiments showed that survivin-WT-overexpressing CD1a+ Mo-DCs have the characteristics of promoting cell cycle progression and decreasing apoptotic cells. CONCLUSIONS: These findings suggest that dermal survivin+ CD1a+ cell infiltration may be a potential biomarker of SSc skin lesions. PBMCs and monocytes from SSc patients also overexpressed survivin; therefore, dermal survivin+ DC may be derived from peripheral blood monocytes. Additionally, survivin may be involved in dermal CD1a+ DC proliferation through cell cycle activation and resistance to apoptosis. Survivin may be an important molecule for the pathogenesis of SSc.

The proto-oncogene survivin splice variant 2B is induced by PDGF and leads to cell proliferation in rheumatoid arthritis fibroblast-like synoviocytes.

Survivin is an independent prognostic factor for joint destruction in rheumatoid arthritis (RA). However, the expression and function of survivin in RA synoviocytes remain unclear. We certified the expression of survivin in RA synovial tissues and performed the experiment using RA fibroblast-like synoviocytes (RA-FLS) treated with siRNA. As a result, the expression levels of wild type (WT) survivin and the 2B splice variants in RA synovial tissues were higher than those in osteoarthritis tissue samples, and, these variants were highly expressed in RA-FLS. The expression levels of survivin-WT and -2B in the RA-FLS were upregulated by PDGF. Treatment with siRNA against survivin-2B led to decreased viability of PDGF-treated RA-FLS due to cell cycle suppression and apoptosis promotion, while the siRNA against all survivin isoforms did not affect the viability. Moreover, an overexpression of survivin-2B in RA-FLS led to cell proliferation through cell cycle activation and by conferring resistance to apoptosis. In conclusion, survivin-2B has an important role in RA-FLS proliferation. These data suggest that survivin-2B might contribute to rheumatoid synovial hyperplasia, and have the potential as a novel therapeutic target for RA.

Sustainable Efficacy of Switching From Intravenous to Subcutaneous Tocilizumab Monotherapy in Patients With Rheumatoid Arthritis.

OBJECTIVE: To evaluate the efficacy and safety of switching from intravenous (IV) tocilizumab (TCZ) to subcutaneous (SC) TCZ monotherapy in rheumatoid arthritis patients. METHODS: Patients who had completed 24 weeks of TCZ-SC (162 mg/2 weeks) or TCZ-IV (8 mg/kg/4 weeks) monotherapy in the double-blind period of the MUSASHI study were enrolled in an 84-week open-label extension period. All received TCZ-SC (162 mg/2 weeks) monotherapy. Effects of the IV to SC switch were evaluated at week 36 (12 weeks after switching). RESULTS: Overall, 319 patients received ≥1 dose of TCZ-SC during the open-label extension period; 160 switched from TCZ-IV to TCZ-SC (TCZ IV/SC) and 159 continued TCZ-SC (TCZ SC/SC). Disease Activity Score in 28 joints using the erythrocyte sedimentation rate clinical remission rates were 62.5% (100 of 160) for TCZ IV/SC and 50.0% (79 of 158) for TCZ SC/SC at week 24, and were maintained at 62.5% (100 of 160) and 57.0% (90 of 158), respectively, at week 36. In the TCZ IV/SC group, 9% of patients (9 of 100) who had achieved remission at week 24 could not maintain remission at week 36. In TCZ IV/SC patients weighing ≥70 kg, the percentage with a sufficient serum TCZ concentration (≥1 µg/ml) decreased from 90.9% (10 of 11) at week 24 to 45.5% (5 of 11) at week 36. Overall safety profiles were similar in TCZ IV/SC and TCZ SC/SC except for mild injection site reactions in TCZ IV/SC. CONCLUSION: Efficacy is adequately maintained in most patients switching from TCZ-IV (8 mg/kg/4 weeks) to TCZ-SC (162 mg/2 weeks) monotherapy. Patients receiving TCZ-IV can switch to TCZ-SC without serious safety concerns. Clinical efficacy may be reduced after switching in some patients with high body weight.

An association between amino acid position 74 of HLA-DRB1 and anti-citrullinated protein antibody levels in Japanese patients with anti-citrullinated protein antibody-positive rheumatoid arthritis.

OBJECTIVE: Anti-citrullinated protein antibodies (ACPAs) are highly specific to rheumatoid arthritis (RA), and strong associations between HLA-DRB1 alleles and ACPA levels have been detected in RA patients. We undertook this study to elucidate the associations between particular amino acid positions in HLA-DRB1 and ACPA levels in patients with RA. METHODS: We analyzed ACPA data on a total of 4,371 Japanese ACPA-positive RA patients in whom HLA-DRB1 allele genotyping had been performed. Generalized linear regression analysis and omnibus testing were carried out to determine associations of HLA-DRB1 alleles, amino acid residues, or amino acid positions with levels of ACPA. RESULTS: HLA-DRB1*09:01 and HLA-DR15 were confirmed to be associated with ACPA levels. HLA-DRB1*08:03 and DRB1*14:06 were associated with reduced and increased ACPA levels, respectively. We detected a strong association between ACPA levels and amino acid position 74 (P = 1.9 × 10(-51) ). The association was mainly conferred by alanine residue (P = 4.5 × 10(-51) ). After adjustment for position 74, amino acid positions 60 and 57 were found to be associated with ACPA levels. Amino acid positions 74 and 57 had previously been reported to be associated with susceptibility to ACPA-positive RA in Asians. Combinations of the amino acid residues at position 74 and position 60 or 57 could induce improvement in Akaike's information criterion comparable to that induced by the 5 significant HLA-DRB1 alleles (HLA-DRB1*08:03, DRB1*09:01, DRB1*14:06, DRB1*15:01, and DRB1*15:02). CONCLUSION: Amino acid position 74 in HLA-DRB1 is strongly associated with ACPA levels in ACPA-positive RA, as well as with RA susceptibility. The mechanisms of ACPA production and susceptibility to ACPA-positive RA seem to partly overlap.

Anti-citrullinated peptide/protein antibody (ACPA)-negative RA shares a large proportion of susceptibility loci with ACPA-positive RA: a meta-analysis of genome-wide association study in a Japanese population.

INTRODUCTION: Although susceptibility genes for anti-citrullinated peptide/protein antibodies (ACPA)-positive rheumatoid arthritis (RA) have been successfully discovered by genome-wide association studies (GWAS), little is known about the genetic background of ACPA-negative RA. We intended to elucidate genetic background of ACPA-negative RA. METHOD: We performed a meta-analysis of GWAS comprising 670 ACPA-negative RA and 16,891 controls for 1,948,138 markers, followed by a replication study of the top 35 single nucleotide polymorphisms (SNPs) using 916 cases and 3,764 controls. Inverse-variance method was applied to assess overall effects. To assess overlap of susceptibility loci between ACPA-positive and -negative RA, odds ratios (ORs) of the 21 susceptibility markers to RA in Japanese were compared between the two subsets. In addition, SNPs were stratified by the p-values in GWAS meta-analysis for either ACPA-positive RA or ACPA-negative RA to address the question whether weakly-associated genes were also shared. The correlations between ACPA-positive RA and the subpopulations of ACPA-negative RA (rheumatoid factor (RF)-positive and RF-negative subsets) were also addressed. RESULTS: Rs6904716 in LEMD2 of the human leukocyte antigen (HLA) locus showed a borderline association with ACPA-negative RA (overall p = 5.7 × 10(-8)), followed by rs6986423 in CSMD1 (p = 2.4 × 10(-6)) and rs17727339 in FCRL3 (p = 1.4 × 10(-5)). ACPA-negative RA showed significant correlations of ORs with ACPA-positive RA for the 21 susceptibility SNPs and non-HLA SNPs with p-values far from significance. These significant correlations with ACPA-positive RA were true for ACPA-negative RF-positive and ACPA-negative RF-negative RA. On the contrary, positive correlations were not observed between the ACPA-negative two subpopulations. CONCLUSION: Many of the susceptibility loci were shared between ACPA-positive and -negative RA.

An allele of serum amyloid A1 associated with amyloidosis in both Japanese and Caucasians.

Serum amyloid A1 (SAA1), one of the two isotypes of acute phase SAA, is the predominant precursor to amyloid A (AA) protein, the chief constituent of fibrillar deposits in reactive (AA) amyloidosis. Prolonged hyperexpression of SAA protein accompanying chronic inflammation is critical to, but seems not to be sufficient for, the development of AA amyloidosis. Several previous studies have investigated the possibility of linkage between SAA1 exon 3 polymorphisms and susceptibility to amyloidosis. While the SAA1.1 allele was found to have a negative association with amylodosis in Japanese subjects, it showed a positive association in Caucasians. Moriguchi and colleagues recently showed that a single nucleotide polymorphism (SNP) at position -13 in the SAA1 5' flanking region was more strongly associated with amyloidosis than was the exon 3 polymorphism. To test whether this SNP may be an amyloidogenic factor common to Japanese and Caucasians, we have analyzed the SAA1 gene in amyloid and non-amyloid patients of both ethnic groups for the presence of T or C at position -13 and for exon 3 polymorphisms (SAA1.1, 1.3 or 1.5). The frequency of the -13T allele was 0.708 and 0.521 in Japanese rheumatoid arthritis patients with and patients without AA amyloidosis, respectively, and 0.536 and 0.196 in American Caucasian patients with AA amyloidosis and control subjects, respectively. In Caucasians, the -13T allele had a stronger association with amyloidosis than did the SAA1.1 allele. These findings suggest that -13T is a genetic background for AA amyloidosis in both Japanese and Caucasians and the difference in prevalence of AA amyloidosis in the two ethnic groups may be due, at least in part, to a difference in the frequency of the -13T SAA1 allele.

Tocilizumab improved clinical symptoms of a patient with systemic tophaceous gout who had symmetric polyarthritis and fever: An alternative treatment by blockade of interleukin-6 signaling.

Chronic tophaceous gout is the end stage of gout. We employed a blockade of interleukin-6 signaling therapy by tocilizumab instead of anakinra, an interleukin-1 receptor antagonist, for a 61-year-old Japanese woman diagnosed with tophaceous gout. Laboratory data showed that serum interleukin-6 concentration was elevated. Serum interleukin-1ß concentration was under the detectable level, although serum uric acid was elevated due to renal dysfunction. The secretion patterns of interleukin-1ß, tumor-necrosis factor-α, interleukin-6, and interleukin-8 from peripheral mononuclear cells isolated from the patient exhibited no remarkable differences compared with those of healthy volunteers. After treatment with the interleukin-6 receptor antagonist tocilizumab, serum interleukin-6 concentration decreased followed by improved clinical symptoms, such as reduced size of the subcutaneous nodules, no fever, and no acute gouty attacks during the treatment. Our case suggests that tocilizumab markedly improves clinical and laboratory manifestations in tophaceous gout with arthritis and fever as well as interleukin-1 blockade therapy.