The olfactory system and neurospychiatric manifestations in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune, chronic, multisystemic disorder characterized by periods of activity and remission. Neuropsychiatric manifestations occur in 12-95 % of SLE patients, depending on the diagnostic criteria applied and are associated with a high morbidity and mortality. Several antibodies have been associated with neuropsychiatric manifestations in SLE. These antibodies are more often associated with antiphospholipid antibody, a subtype of double-stranded DNA and antiribosomal P antibodies. Recent studies have demonstrated the high specificity of antiribosomal P antibodies for SLE, suggesting that antiribosomal P antibodies may be a biomarker for disease activity. Antiribosomal P antibodies are able to bind to neuronal cells in areas of the limbic system which are responsible to the olfactory. The objectives of this study were to analyze the prevalence of olfactory disorder in SLE, to correlate olfactory changes to mood disorders, anxiety, presence of neuropsychiatric manifestations, disease activity and damage, and also to associate of the presence of antiribosomal P antibodies with olfactory disorders, presence of neuropsychiatric manifestations and disease activity. One hundred and twenty SLE patients included in the study were followed at the outpatient rheumatology UNICAMP, from March 2011 to December 2013. The control group was consisted of 135 healthy volunteers matched by age and sex. They had no history of autoimmune or allergic diseases, with no changes in upper airway and no history of use of inhalant drugs. Anxiety was observed in 67.5 % SLE patients and in 39.2% controls. Depression was identified in 46.6 % SLE patients and in 28.8% controls. Olfactory changes were observed in 51.6 % SLE patients and in 29.6 % controls. Anti-ribosomal P antibodies were identified exclusively in SLE patients and were present in 13 (10.8%) of them. Olfactory changes had significantly lower averages in all three phases of the olfactory evaluation and, consequently, in the total sum test (LDI). The olfactory also inversely associated with anxiety (p = 0.004, R = -0.18), depression (p = 0.01, R = -0.232), cumulative damage (p = 0.002 R = -0.282) and age (p <0.001 , R = -0.353). We did not observe an association between olfactory changes and gender or disease activity (p = 0.891 and p = 0,914), respectively. The TDI was correlated with a CNS involvement, and patients with NPC [mean of 28.35 (SD ± 5.30] points, whereas patients without CNS involvement had a mean TDI of 30.8 (SD ± 4.51) points (p < 0.05). Antiribosomal P antibodies were not associated with the presence of CNS involvemnt (p = 0.730), but when we analyzed each subitem of CNS involvement separately, we observed an association between the presence of antiribosomal P antibodies and psychosis (p < 0.05). We also observed an association between antiribosomal P antibodies and disease activity (p < 0.05). We concluded that SLE patients show a significant decrease of smell when compared to healthy controls. Olfactory changes are associated with a history of neuropsychiatric symptoms, anxiety, depression, cumulative damage, and older age. Antiribosomal P antibodies were exclusively observed in SLE patients compared to healthy controls and were associated with psychosis and disease activity (AU)