Immunological analysis of pulmonary hypertension in connective tissue diseases

Objective. To analyze the immunological characteristics of the sera of pati ents with inflammatory connective tissue diseases complicated by pulmonary hypertension (PH). Methods. Sera of 24 patients with mixed connective tissue disease complicat ed by PH (MCTD-PH), sera of 11 patients with other connective tissue diseas es complicated by PH (Other-PH; 6 systemic sclerosis, 3 systemic lupus eryt hematosus, 2 rheumatoid arthritis), and sera of 15 patients with MCTD not c omplicated by PH (MCTD-non-PH) were tested for IgG antibodies against UlRNP proteins, UlRNP-70K protein, UlRNP-A protein, and UlRNP-C protein, and for IgG and IgM antibodies to beta(2)-glycoprotein I dependent cardiolipin (CL ) and human umbilical vein endothelial cells. We also measured the serum le vels of von Willebrand factor related antigens and interleukin 6 (IL-6). Results. (1)The titers of the anti-UlRNP, anti-UlRNP-70K, anti-UlRNP-A, and anti-UlRNP-C anti bodies were significantly higher in the MCTD-PH and MCTD -non-PH groups than in the Other-PH group. However, there were no statistic ally significant differences, in the titers of these 4 antibodies between t he MCTD-PH and MCTD-non-PH groups. (2) The titers of the IgG aCL and the se rum IL-B levels were significantly higher in the MCTD-PH group than in the MCTD-non-PH group. (3) Statistically significant correlations between the a nti-UlRNP and IgG anti-CL antibody titers, and between the IgG anti-endothe lial 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. Conclusion. The occurrence of anti-UlRNP, anti-endothelial cell, and anti-C L antibodies is associated with PH in certain patients with connective tiss ue disease.