Background Systemic lupus erythematosus (SLE) is an autoimmune disorder that affects 0.1% of the world population and central nervous system involvement in the disease neuropsychiatric SLE has been observed in 12–95% of SLE patients. Numerous autoantibodies, including anti–ribosomal P (anti-P) antibodies, have been linked to central nervous system involvement manifestations. Moreover, these antibodies are capable of binding and penetrating neuronal cells of the limbic areas that are associated with olfaction. Involvement of the limbic system (e.g., atrophy of the hippocampus and amygdala) in SLE patients was recently documented utilizing magnetic resonance imaging Recently, links between the olfactory system, the immune system, and various diseases have been identified. Decreased olfaction was observed in patients with several CNS diseases in which immune-mediated mechanisms have been implicated (e.g., Parkinson’s disease, schizophrenia, Alzheimer’s disease, and multiple sclerosis).
Objectives To analyze the prevalence of olfactory disorders in patients with SLE, to correlate the presence of mood disorders (depression and anxiety), disease activity and the presence of cognitive disorders abnormalities of the olfactory, and correlate levels of anti-P with smell disorders.
Methods Olfactory functions were evaluated in 150 SLE patients and 50 age- and sex-matched controls using the Sniffin’ Sticks test. We excluded patients with histories of head injuries, nasofacial operations, or active nasal-sinus or allergic diseases. The test consists of 3 stages: threshold, discrimination, and identification (TDI) of different odors. Neuropsychiatric manifestations were assessed according ACR criteria. Depression was assessed by Beck Depression Scale (BDI), anxiety by the BeckAnxiety Inventory (BAI) and psychiatric manifestations by the Brief Psychiatric RatingScale (BPRS). Disease activity was assessed by the Disease Activity Index (SLEDAI) and the disease is considered active if the sum of points in the SLEDAI exceeds three. The cumulative damage was assessed according to Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). We use Kruskall-Wallis test, Fischer exact test and Spearman correlation. p<0.05 was considered significant.
Results Mean age of SLE patients was 38.49±10.96 years and 35.02±14.15 years in controls (p=0.45). A decrease in the sense of smell was observed in SLE patients (52.48%) and controls (25.64%) (p<0.01), while loss of smell (anosmia) was documented in SLE patients (3.54%) and controls (1.28%) (p<0.01). Patients had an average of 28.80±5.75 total points at the 3 stages of Sniffin’ Sticks test while the controls had mean of 31.27±5.35 points (p=0.02). 8.51% of the patients smoked while of the patients smoked, while in controls this percentage was 5.13% (p=0.427). No significant difference was observed in the smell sense of smokers and nonsmokers (p=0.797). Total TDI scores and individual stages of smell correlated with depression(r=0.278; p<0.01), anxiety (r=0.264; p=0.001) and SDI scores (r=0.302; p=0.010).
Conclusions Reduced olfactory function has been observed in SLE patients and is associated with neurospychiatric manifestations, especilly mood disorders.
Disclosure of Interest F. Peres Grant/Research support from: FAPESP: 2011/15422-2, N. Sinicato Grant/Research support from: 2010/13637-9, M. Postal Grant/Research support from: 2009/11076-2, K. Peliçari Grant/Research support from: 2010/13636-2, A. Ferrari: None Declared, C. Gomes: None Declared, L. Costallat: None Declared, S. Appenzeller Grant/Research support from: FAPESP 2008/02917-0; Conselho Nacional Pesquisa Desenvolvimento-Brasil CNPq (300447/2009-4; 471343/2011-0)
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