[The clinical importance of anti-ribosomal-P antibodies]

Anti-ribosomal phosphoprotein autoantibodies (anti-RP Abs) are highly specific for SLE, especially for neuropsychiatric manifestations including psychosis, mood disorders, anxiety, cognitive dysfunction and delirium. In addition to the neuropsychiatric involvement, anti-RP antibodies are believed to be correlated with nephritis, hepatitis and dermal diseases in SLE. Several studies indicate the association between increased titers of anti-RP Abs in the patient's sera and active SLE disease. The reported prevalence of anti-RP Abs among SLE patients is 10%-40%. Recently, a connection between the presence of anti-RP Abs in the serum and class V lupus nephritis has been demonstrated. Anti-RP Abs binds 3 ribosomal proteins identified as P0, P1 and P2 (38, 19 and 17-kDa, respectively) by recognizing a certain epitope found in those 3 proteins. This specific epitope contains 22 amino acids at the C terminal end (C-22) of the protein. There are studies in the literature relating to the involvement of anti-RP Abs in the pathogenesis of organ damage. The main pathways described are cross-reaction with anti-dsDNA antibodies, a cytotoxic effect on mesangium cell proliferation, invasion into living cells and onset of apoptosis, a defect in the synthesis of apolipoprotein B resulting in accumulation of lipids inside the cell, and downregulation of the total protein synthesis. The authors provide an updated review concerning the multisystem involvement of anti-RP Abs in SLE, particularly in the brain, kidney and liver. Moreover, this article includes a summary of the most relevant studies regarding the cellular involvement of anti-RP Abs.