RESUMEN
OBJECTIVE: Brain-derived neurotrophic factor (BDNF) is associated with the pathogenesis of several neuropsychiatric (NP) diseases, but there are few studies involving SLE. The aim of this study was to investigate whether plasma BDNF levels are associated with disease activity in SLE patients with severe NPSLE and non-NPSLE manifestations. METHODS: We assessed 131 SLE patients and 24 randomly selected healthy individuals. SLE patients were evaluated in a cross-sectional study allocated according to the presence or not of NP manifestations and disease activity: (i) active NPSLE (n = 40), (ii) inactive NPSLE (n = 26), (iii) active SLE (n = 29) and (iv) inactive SLE (n = 36). In addition, NPSLE patients (n = 40) were evaluated before and after treatment. Disease activity was assessed according to the SLEDAI score. The plasma BDNF was measured by ELISA. RESULTS: BDNF levels were increased in inactive NPSLE when compared with active SLE and controls (P < 0.0001). We observed similar findings in inactive SLE when compared with active SLE (P < 0.0001). In addition, we found an inverse correlation between plasma BDNF levels and the SLEDAI (r = -0.54, P < 0.0001) and a positive correlation with complement levels. We also observed an increase in BDNF levels in parallel with the improvement in NP symptoms. CONCLUSION: Plasma BDNF level is increased in SLE patients and this increase is independent of the occurrence of NP manifestations. In addition, plasma BDNF levels increased with control of SLE activity, which points to the potential use of BDNF as a biomarker of response to treatment.