To investigate the role of the complex IgA-alpha-1-antitrypsin (IgA-AT
) in systemic lupus erythematosus (SLE) and in mixed connective tissue
disease (MCTD), and its possible relations to either activity of the
disease or a treatment, we examined a concentration of IgA-AT complex
in 65 SLE and 9 MCTD sera. Complex IgA-AT was evaluated using a double
antibody enzyme-linked immunoassay (ELISA). Twenty nine patients with
SLE (44.6%) and three patients with MCTD (33.3%) had increased serum
IgA-AT levels. The mean values of IgA-AT complex in patients with SLE
and MCTD were higher than in healthy controls. Among the SLE group, pa
tients with current neurological manifestation were characterized by a
n increase in IgA-AT serum concentration (2.45 +/- 2.07 U vs. 0.78 +/-
0.70 U, P < 0.001). No relation was found between this complex and ES
R level, C-reactive protein (CRP) concentration, or hemoglobin level.
Ten SLE patients were treated with CTX intravenously. In this group of
patients, IgA-AT complex level was found to be increased compared wit
h patients without such a treatment (1.82 +/- 1.30 U vs. 0.80 +/- 0.67
U, P < 0.05). The present study provides two new observations. Firstl
y, IgA-AT complex is increased in SLE and MCTD compared with healthy c
ontrols, and secondly, patients with CNS involvement displayed a strik
ing increased IgA-AT level.