[Anti-beta-2-microglobulin antibodies in systemic lupus erythematosus]

The aim of this work was the study of 88 patients with SLE for clinical, laboratorial and demographical parameters. The patients sera were assayed for the presence of anti-beta-2-microglobulin antibodies by ELISA. These spectrofotometric results were converted in a standard-deviation unity in relation to the average of 29 control individuals values. It was established a cut-off of 2.5 standard-deviation in order to determine the limit of normality as well as the cut-off of 10 standard deviation was chosen in order to defined the higher values. Several statistical significant associations were observed between the anti-beta-2-microgobulin and the clinical and laboratorial parameters. The clinical applications of those associations were determined by the predictive value. It was only considered the values greater then 75%. The negative predictive values found in the lower cut-off were 92% to ANA (homogeneous-peripheral pattern), 89% to high levels CIC, 81% to mucocutaneous vasculitis and 80% to depressed CH50 levels. The positive predictive values found in 88% to high level of mucoprotein, 83% to mucocutaneous vasculitis, 83% to the onset-disease-time lower six years and 78% to limphopenia. Special attention may be paid to the high sensibility and specificity of the anti-beta-2-microglobulin test to some of the parameters in the evaluation of the disease activity, mainly in mucocutaneous vasculitis.