ABSTRACT
Abstract The aim of this study was to evaluate tumor necrosis factor alpha (TNF-α), interleukin (IL)- 17A/F levels in the serum of ankylosing spondylitis (AS) patients after anti-TNF therapy, in order to understand how these cytokines are involved in this therapeutic response. Forty-four AS patients were included in the study: thirty using anti-TNF therapy were classified according to their therapy response as responders (15) and non-responders (15) and 14 without anti-TNF therapy were classified as AS control. Fifteen healthy individuals formed the control group. Serum levels of TNF-α were determined using Luminex technology and for IL-17A and IL-17F using ELISA. The non-responder patients presented higher serum levels of TNF-α than the responders and AS control; the same results were found when HLA-B*27 positive or negative patients were separately analyzed. IL-17A and IL17F serum levels were similar for all groups. According to the clinical disease activity, AS patients with BASDAI ≥4 had higher serum levels of TNF-α than AS patients with BASDAI <4. Positive correlation was found between TNF-α levels and BASDAI. In AS patients, TNF-α serum levels were associated with anti-TNF therapy and disease activity independently of HLA-B*27, and IL-17A and IL-17F were not related to anti-TNF treatment.
ABSTRACT
OBJECTIVES: HLA-B27 is strongly associated with ankylosing spondylitis (AS) and its presence helps to confirm AS diagnosis. Due to the high HLA polymorphism and the differentiated contribution of alleles and molecules encoded by them, HLA-B*27 allele identification is relevant in the clinical follow-up, diagnosis, and treatment of this spondyloarthropathy. Inexpensive genotyping techniques with high specificity and sensitivity are of great interest in histocompatibility laboratories. This work aimed to optimize HLA-B*27 genotyping by Polymerase Chain Reaction Sequence-specific Primer (PCR-SSP), which is an accessible and inexpensive technique. METHODS: The PCR-SSP was standardized using 26 HLA-B*27 positive and 3 HLA-B*27 negative samples previously defined by Polymerase Chain Reaction Sequence-specific Oligonucleotide Probes (PCR-SSOP) (medium resolution, One Lambda®) and primers described by Duangchanchot et al. (2009). For validating the technique, 397 samples were genotyped using PCR-SSP as well as PCR-SSOP. RESULTS: The PCR-SSP technique was standardized for identifying the alleles HLA-B*27:02, HLA-B*27:CAFRW (05/13/16/17/28/37/38/39/42), HLA-B*27:CAFRZ (08/26/40), HLA-B*27:09 and HLA-B*27:12, which were found in 90 positive samples (22.67%). There was 100% agreement between the two techniques for heterozygous samples; however, two homozygous samples could not be detected by PCR-SSP. CONCLUSION: The HLA-B*27 genotyping using PCR-SSP, an easy-to-use, specific, and affordable technique, was optimized for heterozygous samples. This technique may contribute to AS diagnosis.