Immunological analysis of pulmonary hypertension in connective tissue diseases.
OBJECTIVE
To analyze the immunological characteristics of the sera of patients with inflammatory connective tissue diseases complicated by pulmonary hypertension (PH).


METHODS
Sera of 24 patients with mixed connective tissue disease complicated by PH (MCTD-PH), sera of 11 patients with other connective tissue diseases complicated by PH (Other-PH; 6 systemic sclerosis, 3 systemic lupus erythematosus, 2 rheumatoid arthritis), and sera of 15 patients with MCTD not complicated by PH (MCTD-non-PH) were tested for IgG antibodies against U1RNP proteins, U1RNP-70K protein, U1RNP-A protein, and U1RNP-C protein, and for IgG and IgM antibodies to beta2-glycoprotein I dependent cardiolipin (CL) and human umbilical vein endothelial cells. We also measured the serum levels of von Willebrand factor related antigens and interleukin 6 (IL-6).


RESULTS
(1) The titers of the anti-U1RNP, anti-U1RNP-70K, anti-U1RNP-A, and anti-U1RNP-C antibodies were significantly higher in the MCTD-PH and MCTD-non-PH groups than in the Other-PH group. However, there were no statistically significant differences in the titers of these 4 antibodies between the MCTD-PH and MCTD-non-PH groups. (2) The titers of the IgG aCL and the serum IL-6 levels were significantly higher in the MCTD-PH group than in the MCTD-non-PH group. (3) Statistically significant correlations between the anti-U1RNP and IgG anti-CL antibody titers, and between the IgG anti-endothelial cell and IgG anti-CL antibody titers were observed within the MCTD-PH and Other-PH groups, but not within the MCTD-non-PH group.


CONCLUSIONS
The occurrence of anti-U1RNP, anti-endothelial cell, and anti-CL antibodies is associated with PH in certain patients with connective tissue disease.
Nishimaki
T
T
Department of Internal Medicine II, Fukushima Medical College, Fukushima City, Japan.
Aotsuka
S
S
Kondo
H
H
Yamamoto
K
K
Takasaki
Y
Y
Sumiya
M
M
Yokohari
R
R
D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D002308:Cardiolipins / Q000276:immunology; D003240:Connective Tissue Diseases / Q000150:complications / Q000276:immunology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000276:immunology; D017411:Ribonucleoproteins, Small Nuclear / Q000276:immunology
D001323:Autoantibodies; D002308:Cardiolipins; D007074:Immunoglobulin G; D017412:Ribonucleoprotein, U1 Small Nuclear; D017411:Ribonucleoproteins, Small Nuclear; C491260:SNRPC protein, human