Analytical and diagnostic performance of an automated anti-CCP assay.

AIM: Autoantibodies against cyclic citrullinated peptide (anti-CCP) are considered to be a sensitive and specific marker for rheumatoid arthritis (RA). This study evaluated the diagnostic and analytical performances of the automated anti-CCP assay. MATERIALS AND METHOD: Sera from 80 patients with established RA, 65 from other rheumatic diseases (non-RA) and 55 from healthy controls were studied using second generation anti-CCP. Rheumatoid factor (RF) was also assayed in each sample, and the results were compared to the anti-CCP findings. Serum pools were used to determine the precision and linearity. RESULTS: At a cut-off of 7.4 U/ml for anti-CCP, the sensitivity and specificity for RA were 65% and 98% respectively. RF had a sensitivity of 58% and a lower specificity of 93% than anti-CCP. CONCLUSION: The high specificity of the assay suggests that anti-CCP is useful in the diagnosis of rheumatoid arthritis and in our cohort of study population anti-CCP exhibits a better diagnostic value than RF. A considerable proportion (28%) of RF-negative RA patients were anti-CCP positive. Based on analytical performance of the assay, we conclude that full automation and high throughput features of AxSYM makes it an ideal platform for routine testing of anti-CCP.

Vitamin D levels: its relationship to bone mineral density response and disease activity in premenopausal Malaysian systemic lupus erythematosus patients on corticosteroids.

AIM: To determine if baseline vitamin D levels would influence the gain in bone mineral density (BMD) in female systemic lupus erythematosus (SLE) patients on corticosteroids (CS) taking bone-active medication. METHOD: Premenopausal SLE patients participating in a trial assessing the efficacy of calcium alone, calcitriol and calcium, and alendronate and calcium, on BMD in patients on CS, were studied. Patients were randomly allocated to the treatment groups at the start of the study and followed up for 2 years. Serum 25-hydroxy vitamin D [25(OH)D] was measured at baseline. RESULTS: Thirty-eight patients were studied. One (2%) patient had osteoporosis, nine (24%) had osteopenia and all others had normal BMD. The mean baseline 25(OH)D levels were 21.6 ± 4.6 ng/mL (± 1 SD). Twelve (32%) patients had vitamin D deficiency [25(OH)D < 20 ng/mL]. There was a significant negative correlation between SLEDAI scores and 25(OH)D levels, that is, patients with high SLEDAI scores had significantly lower 25(OH)D levels (P = 0.033). Left femoral neck BMD was significantly lower in the deficient compared to insufficient group (P = 0.042). There was a trend toward better BMD gain at 2 years in the vitamin D insufficient compared to the deficient group, which did not reach statistical significance. CONCLUSION: This study showed that in female SLE patients, low vitamin D levels are associated with higher disease activity and suggests that patients who have higher vitamin D levels have a better BMD response during treatment with bone-active agents.

Polymyositis associated with hepatitis B: management with entacavir and prednisolone.

We report a 57-year-old woman with a 20-year history of hepatitis B presenting with progressive proximal lower limb weakness for the previous 1 month. Previous medical history included a pericardial and pleural effusion, of which no cause was found and pulmonary tuberculosis which has been adequately treated. Examination revealed multiple telangiactasia over face and nail beds and bilateral proximal lower limb weakness of power 4/5. Biochemical investigation revealed a raised erythrocyte sedimentation rate of 36 mm/h, elevated creatinine kinase levels (14,363 IU/L) and raised liver enzymes (alanine aminotransferase 445 IU/L, aspartate aminotransferase 606 IU/L) with high hepatitis B virus DNA (1,021,158 copies/mL). Nerve conduction tests and muscle biopsy were consistent with polymyositis. She received entacavir for hepatitis B treatment. Despite treatment with entacavir for 10 weeks, her weakness persisted and prednisolone was added. Upon commencement of prednisolone, her symptoms and biochemical profiles returned to normal.