METHODS: A multiplex analytic microarray system was used to analyze the occurrence of antibodies to 10 different citrullinated peptides (filaggrin [fil307-324], vimentin [Vim2-17, Vim60-75], fibrinogen [Fibα563-583, Fibα580-600, Fibβ36-52, Fibβ62-81a, Fibβ62-81b], enolase [Eno5-21], and type II collagen [CitCII355-378]) in serum samples from 4,089 RA patients (1,231 Malaysian and 2,858 Swedish) and 827 healthy control subjects (249 Malaysian and 578 Swedish). The positive reaction threshold for each peptide was set separately for each population based on a specificity of 98%.
RESULTS: Distinct differences in the frequencies of 5 ACPA fine specificities (Vim60-75, Vim2-17, Fibβ62-81b, Eno5-21, and CitCII355-378) were found between the Malaysian and Swedish RA populations, despite a nearly identical percentage of patients in each population who were positive for anti-cyclic citrullinated peptide 2 antibodies. In Malaysian RA patients compared with Swedish RA patients, the frequencies of antibodies to Vim60-75 (54% versus 44%, corrected P [Pcorr ] = 1.06 × 10-8 ) and CitCII355-378 (17% versus 13%, Pcorr = 0.02) were significantly higher, while the frequencies of antibodies to Vim2-17 (25% versus 32%, Pcorr = 1.91 × 10-4 ), Fibβ62-81b (15% versus 30%, Pcorr = 2.47 × 10-22 ), and Eno5-21 (23% versus 50%, Pcorr = 3.64 × 10-57 ) were significantly lower.
CONCLUSION: Serum ACPA fine specificities differ between RA patients in different populations, although the total proportions of individuals positive for ACPAs are similar. Differing patterns of ACPA fine specificity could be attributed to variations in genetic and/or environmental factors.
METHOD: This retrospective study involved SLE patients who attended the Rheumatology Clinic at the Hospital Kuala Lumpur from January 2014 to December 2016. Vitamin D was categorised as normal, insufficient or deficient, and the clinical variables were compared across vitamin D categories with chi-squared tests and Pearson correlation coefficient.
RESULTS: We included 216 patients. The mean 25(OH)D concentration was 51.3(Standard Deviation; SD 14.8) nmol/L. Fifty (23.1%) patients had vitamin D deficiency, 120 (55.6%) had vitamin D insufficiency, while 46 (21.3%) had adequate vitamin D levels. There were statistically significant associations between vitamin D status and ethnic group, lupus nephritis and hypertension. No correlations were observed between vitamin D status with SLEDAI score (Pearson correlation coefficient -0.015, p=0.829) as well as SDI score (Pearson correlation coefficient -0.017, p=0.801).
CONCLUSION: SLE patients should be screened for vitamin D concentrations and their levels optimised.
METHODOLOGY: All sera for AT1R-Ab were collected at the University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia. The sera were centrifuged and kept refrigerated at -80 °C before being transported to the South Australian Transplantation and Immunogenetics Laboratory (SATIS). Enzyme-linked immunosorbent assay kit (One Lambda) was used for the detection of AT1R-Ab, and it was performed according to the manufacturer's instructions. The level of >17.1 U/mL was considered to be AT1R-Ab positive; 10.0-17.1 U/mL at risk, and <10.0 U/mL negative.
RESULTS: A total of 115 samples were collected from 99 patients pre and post-kidney transplant recipients. From the pre-transplant sera (n = 68) 17.7% were positive, 35.3% were at risk and 47.0% were negative. The positive AT1R-Ab cohort were relatively younger, with a mean age of 34.7 ± 8.3 years old and statistically significant, with a p-value of 0.028. Among the sera that were tested positive, 19.0% were from the Chinese ethnicity, 6.7% from Malay and 16.7% from Indian. There was no difference in the rejection episodes, persistent or de novo HLA-DSA, and graft function between the group (AT1R-Ab negative vs AT1R-Ab at risk and positive) and the results were consistent in a model adjusted for all potential confounders.
CONCLUSION: The prevalence of positive (>17.1 U/mL) pre-transplant AT1R-Ab was 17.7% and 35.3% were at risk (10.0-17.1 U/mL) in our pre-transplant cohort.