Effect of genetic polymorphisms on development of gout.

OBJECTIVE: To validate the association between genetic polymorphisms and gout in Japanese patients, and to investigate the cumulative effects of multiple genetic factors on the development of gout. METHODS: Subjects were 153 Japanese male patients with gout and 532 male controls. The genotypes of 11 polymorphisms in the 10 genes that have been indicated to be associated with serum uric acid levels or gout were determined. The cumulative effects of the genetic polymorphisms were investigated using a weighted genotype risk score (wGRS) based on the number of risk alleles and the OR for gout. A model to discriminate between patients with gout and controls was constructed by incorporating the wGRS and clinical factors. C statistics method was applied to evaluate the capability of the model to discriminate gout patients from controls. RESULTS: Seven polymorphisms were shown to be associated with gout. The mean wGRS was significantly higher in patients with gout (15.2 ± 2.01) compared to controls (13.4 ± 2.10; p < 0.0001). The C statistic for the model using genetic information alone was 0.72, while the C statistic was 0.81 for the full model that incorporated all genetic and clinical factors. CONCLUSION: Accumulation of multiple genetic factors is associated with the development of gout. A prediction model for gout that incorporates genetic and clinical factors may be useful for identifying individuals who are at risk of gout.

Urinary free light chain is a potential biomarker for ISN/RPS class III/IV lupus nephritis.

OBJECTIVES: To evaluate the use of urinary free light chains (FLCs) as a biomarker for proliferative LN and the potential association between the intensity of plasma cell infiltration of the kidney and urinary FLC levels in LN. METHODS: Forty-three SLE patients were consecutively enrolled in the study. These patients were divided into an International Society of Nephrology and Renal Pathology Society (ISN/RPS) class III/IV LN subset (n = 18) and an ISN/RPS class I/II/V (class non-III/IV) LN subset (n = 25). The expression of κ-LCs, λ-LCs, CD19 and CD138 in kidney specimens was also evaluated with immunohistochemical staining. To measure FLC levels before and after treatment, an additional six patients with class III/IV LN were consecutively enrolled. RESULTS: Urinary FLCs were significantly higher in the class III/IV LN subset than in the class non-III/IV LN subset. Urinary λ-FLC levels were significantly correlated with the urinary protein-creatinine ratio in the class III/IV LN subset (rs = 0.67, P < 0.01). Moreover, the LC-secreting CD19(-)/CD138(+) cell counts in the kidney specimens were higher in the class III/IV LN subset than in the class non-III/IV LN subset. Total urinary FLC levels were correlated with the numbers of CD138(+) cells in the kidney (r = 0.71, P = 0.03). Following treatment, urinary λ-FLCs could not be detected in any of the patients. CONCLUSION: The intensity of plasma cell infiltration of the kidney is associated with urinary FLC levels. Urinary FLCs are potentially useful biomarkers in ISN/RPS class III/IV LN or proliferative LN.

Frequency of class III and IV nephritis in systemic lupus erythematosus without clinical renal involvement: an analysis of predictive measures.

OBJECTIVE: To determine the frequency of International Society of Nephrology/Renal Pathology Society (ISN/RPS) class III or IV lupus nephritis in patients with systemic lupus erythematosus (SLE) without clinical renal involvement. METHODS: We investigated the renal pathology of 195 patients with SLE, including 86 patients without clinical renal involvement. RESULTS: Lupus nephritis other than class I was found in 58% of the patients without clinical renal involvement, and class III and IV nephritis was found in 15% of these patients. To reveal the predictive measures involved in class III or IV lupus nephritis, we explored the clinical measures in patients with SLE who did not have clinical renal involvement. Anti-dsDNA antibody titers were significantly higher (p = 0.0266) and C3 values were significantly lower (p = 0.0073) in patients with class III or IV lupus nephritis than in patients without class III or IV lupus nephritis. The sensitivity and specificity values were 77% and 73%, respectively, for cutoff levels of both 40 IU/ml for anti-dsDNA antibodies and 55 mg/dl for C3 (OR 8.8, p = 0.0011). CONCLUSION: The frequency of nephritis, including ISN/RPS class III and IV, was unexpectedly high in SLE patients without clinical renal involvement. ISN/RPS class III or IV lupus nephritis could be hidden in patients with SLE who present both a high titer of anti-dsDNA antibody and a low concentration of C3, even when they have clinically normal urinary findings and renal function.

Incidence of serious respiratory infections in patients with rheumatoid arthritis treated with tocilizumab.

We aimed to demonstrate the incidence of serious respiratory infections in patients with rheumatoid arthritis (RA) treated with tocilizumab (TCZ) monotherapy. We analyzed the incidence of serious respiratory infections in 601 RA patients enrolled in TCZ clinical trials and their extension studies (TCZ cohort) and in 601 age- and sex-standardized RA patients treated in daily clinical practice at Tokyo Women's Medical University (IORRA subsample cohort). The rates of serious respiratory infections were 1.77 per 100 patient-years from 1999 to 2008 in the TCZ cohort and 0.53 per 100 patient-years from 2000 to 2009 in the IORRA subsample cohort. With the IORRA subsample cohort regarded as a standard population, the standardized incidence ratio (SIR) of serious respiratory infection in the TCZ cohort was 3.64 [95% confidence interval (CI) 2.56-5.01], standardized for age and sex; 2.35 (95% CI 1.66-3.24), standardized for age sex, and corticosteroid use; 1.85 (95% CI 1.30-2.55), standardized for age sex, and pre-existing pulmonary involvement; and 2.41 (95% CI 1.68-3.34) standardized for age sex, and disease activity. The risk of serious respiratory infection in the TCZ cohort was approximately double that in the IORRA subsample cohort after standardizing for corticosteroid use, pre-existing pulmonary involvement, or disease activity. This is comparable to the risk reported when tumor necrosis factor (TNF) inhibitors are used.

Efficacy and safety of tacrolimus in 101 consecutive patients with rheumatoid arthritis.

The objective of this study was to assess the usefulness of tacrolimus (TAC) for rheumatoid arthritis (RA) patients. The first 101 consecutive RA patients in whom TAC treatment was initiated were prospectively registered and their data analyzed. Clinical variables were extracted from the Institute of Rheumatology, Rheumatoid Arthritis (IORRA) database. The 101 patients included 85 females and 16 males. Average doses of TAC were 1.62 mg/day at entry and 2.13 mg/day at month 12. The average doses of concomitantly prescribed prednisolone (6.92 mg/day) and methotrexate (MTX; 8.59 mg/week) were higher than those in all RA patients in the IORRA cohort. At month 12, 57 patients remained on TAC therapy; 18 patients had discontinued TAC due to side effects, and 16 patients had discontinued due to inefficacy. Adverse reactions responsible for discontinuation included gastrointestinal symptoms, renal dysfunction, and infection. According to the European League Against Rheumatism (EULAR) response criteria, 56.5% of the patients who continued TAC at 12 months experienced "good" or "moderate" responses. Through the use of last observation carried forward (LOCF) methodology, the average Disease Activity Score (DAS) 28 significantly improved. We confirmed the usefulness of TAC for the treatment of RA and found that TAC is suitable for RA patients who are unable to use biologic agents or to tolerate a high dose of MTX because of their complications or background factors.

Relative transcriptional activities of SAA1 promoters polymorphic at position -13(T/C): potential association between increased transcription and amyloidosis.

The risk associated with the serum amyloid A (SAA) 1 gene and developing AA-amyloidosis is still controversial. In familial Mediterranean fever or Caucasoid rheumatoid arthritis (RA), the SAA1.1 allele is a risk factor for the development of AA-amyloidosis. However, individuals with the SAA1.3 allele are susceptible to AA-amyloidosis in the Japanese RA population, but those with the SAA1.1 are not. Previous reports have indicated that the -13T/C single nucleotide polymorphism (SNP) at the 5'-flanking region of SAA1 appears to be a better marker of AA-amyloidosis than the exon-3 based haplotype, i.e., SAA1.1 or SAA1.3, in both Japanese and American Caucasian populations. So far, it is unknown why the -13T SNP increases the amyloidogenicity of the patients. In the present study, a luciferase reporter gene assay showed that the transcriptional activity of the SAA1 having the -13T-containing promoter was significantly higher than activities of those with -13C-containing promoters (Fisher's protected least significance difference test). We suggest that having the -13T SNP in the SAA1 promoter correlates with the amyloidogenicity in part as a result of this increased transcriptional activity.