Fluctuation of anti-endothelial cell antibody titers in " mixed connective tissue disease.
BACKGROUND
Antibodies directed against endothelial cell surface antigens have been described in many disorders and have been associated with disease activity. Since the most prominent histopathologic feature in mixed connective tissue disease (MCTD) is the widespread and unique proliferative vascular lesion, our aim was to evaluate the frequency of anti-endothelial cell antibodies (AECA) in this condition.


OBJECTIVE
To evaluate the frequency of AECA in this disease and assess its clinical and laboratory associations.


METHODS
Seventy-three sera from 35 patients with MCTD (Kasukawa's criteria), collected during a 7 year period, were tested for immunoglobulins G and M (IgG and IgM) AECA by cellular ELISA, using HUVEC (human umbilical vein endothelial cells). Sera from 37 patients with systemic lupus erythematosus (SLE), 22 with systemic sclerosis (SSc) and 36 sera from normal healthy individuals were used as controls. A cellular ELISA using HeLa cells was also performed as a laboratory control method.


RESULTS
IgG-AECA was detected in 77% of MCTD patients, 54% of SLE patients, 36% of SSc patients and 6% of normal controls. In MCTD, IgG-AECA was associated with vasculitic manifestations, disease activity and lymphopenia, and was also a predictor of constant disease activity. Immunosuppressive drugs were shown to reduce IgG-AECA titers. Since antibodies directed to HeLa cell surface were negative, AECA was apparently unrelated to common epitopes present on epithelial cell lines.


CONCLUSIONS
AECA are present in a large proportion of patients with MCTD and these antibodies decrease after immunosuppressive treatment.
Rheumatology Division of Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
Laís V
LV
Lage
Jozélio F
JF
de Carvalho
Maria T C
MT
Caleiro
Natalino H
NH
Yoshinari
Licia M H
LM
da Mota
Munther A
MA
Khamashta
Wilson
W
Cossermelli
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D004730:Endothelium, Vascular / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008137:Longitudinal Studies; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology; D008297:Male; D008947:Mixed Connective Tissue Disease / Q000097:blood / Q000276:immunology*; D012595:Scleroderma, Systemic / Q000097:blood / Q000276:immunology
D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C087589:anti-endothelial cell antibody