Objective: To evaluate the presence of anti-PDGFR-α antibodies by immunological methods in patients with systemic sclerosis (SSc).
Methods: Fifty-eight women diagnosed with SSc and 36 healthy women controls were included. IgG anti-PDGFR-α were measured by ELISA and immunoblot. Associations with clinical and immunological findings were also studied.
Results: Non-statistically significant differences were detected between SSc patients and controls: median value: 0.287 (range: 0-2.06) vs. median value: 0.226 (range: 0-2.94), respectively (p = 0.583). None correlation between the presence of anti-PDGFR-α antibodies and clinical and serologic features was observed. Sera from SSc patients and healthy people who showed high titers of anti-PDGFR-α antibodies by ELISA recognized the same band corresponding to PDGFR-α by immunoblot.
Conclusion: Although anti-PDGFR-α antibodies seem to be disease-specific when determined by bioactivity assays, these antibodies are also detected in normal subjects when immunological methods are performed. Thus, our study leads to the hypothesis that anti-PDGFR-α antibodies may arise from natural autoantibodies. It is possible that SSc-autoantibodies recognize a different epitope on the PDGFR-α molecule which triggers its stimulatory effect when analyzed by functional assays. Alternatively, naturally occurring autoantibodies would even become pathogenic after suffering some kind of affinity maturation and class switching in genetically susceptible individuals.
- systemic sclerosis