Association of anti-ribosomal P protein antibodies with neuropsychiatric and other manifestations of systemic lupus erythematosus

The objective of our study was to determine the prevalence of neuropsychiatric manifestations and anti-ribosomal P antibodies (aRP) in SLE and to examine the diagnostic utility and associations of aRP with neuropsychiatric and other disease manifestations. Thirty two consecutive SLE patients, diagnosed according to the updated 1997 ACR criteria, were studied. A full medical history, rheumatological, neurological, psychiatric examination, and psychometric evaluation, including a battery of tests for cognitive dysfunction and the Symptom Checklist-90-Revised depression and anxiety scales were administered to all patients. Disease activity was scored using the SLEDAI. Neuropsychiatric manifestations were diagnosed and categorized according to the 1999 ACR case definitions for 19 NPSLE syndromes. Laboratory and serologic tests including ANA, anti-ds DNA, anti-cardiolipin antibodies (aCL) and aRP (ELISA) were also carried out. Twenty six (81.2%) patients had one or more NP manifestations. Depression (59.4%), headache (46.9%) and cognitive dysfunction (37.5%) were the commonest NPSLE syndromes. Other less commonly detected manifestations included seizures, anxiety, acute confusional state, stroke, and psychosis. aRP was positive in seven (21.9%) patients, all of whom had one or more NPSLE syndromes. Patients with psychiatric manifestations in general and mood disorders in particular had significantly higher mean titers of aRP than patients without these disorders (p < 0.05). aRP were found to be significantly associated with a younger age at the onset of SLE, with more severe articular manifestations and with the presence but not the severity of depression. aRP were highly specific for NPSLE and depression, and they were highly sensitive for psychosis. Neuropsychiatric manifestations are found in 81.2% of unselected Egyptian SLE patients. The presence of aRP antibodies positively predicts patients with psychiatric manifestations in general and mood disorders in particular, for which aRP is specific, but not sensitive. However, aRP is sensitive for psychosis, so that its absence in patients with SLE may help exclude Lupus psychosis.