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

Background

There is an unclear association of anti-P with neuropsychiatric (NP) SLE.

Objective

Our objective was to determine the prevalence of anti-P in 150 SLE patients, focusing on psychosis and/or mood disorders, other diffuse NP syndromes and focal NP syndromes, and to analyze the manifestation of NP syndromes regarding SLE duration and anti-P status.

Methods

One hundred and fifty Caucasian SLE patients (133 female, 17 male) were studied, 88 of whom had a disease duration of more than 5 years. IgG anti-P were detected by immunoblotting performed on ribosomal extract of HeLa cells and/or by line immunoassay (INNO LIA ANA). NP manifestations presenting at any time were defined according to ACR case definitions for NP SLE. Patients in whom diffuse and focal NP manifestations occurred at the same time were classified according to the predominant manifestation.

Results

Anti-P were positive in 17/150 (11.3%) patients. Diffuse NP manifestations were diagnosed in 9/17 (53%) anti-P positive patients (Table 1). Statistically significant associations of anti-P were found with (1) psychosis and/or mood disorders (3/11, P < 0.05), (2) other diffuse NP syndromes (6/14, P < 0.0001), and (3) all diffuse NP syndromes (9/25; P < 0.0001), as compared with patients without diffuse NP manifestations (7/92). In the group of 88 patients with disease duration greater than 5 years, an even stronger statistically significant association of anti-P with diffuse NP manifestations was found.

Table 1 Study findings

Conclusion

In our study anti-P antibodies showed a strong association with diffuse but not focal NP syndromes in SLE patients, especially those with disease duration over 5 years.