Is soluble CD40 ligand an indicator of immunopathological disturbance in silicosis patients?
Silicosis patients（SIL）develop respiratory fibrosis caused by inhaled silica particles, and autoimmune disorders such as rheumatoid arthritis and systemic sclerosis（SSc）. Silica is known as one of the most important environmental factors leading to the development of SSc. Various soluble cytokines such as interleukin (IL)-2 receptor (sIL-2R) and CD155/CD40 ligand（sCD40L）, soluble endoglin, von Willebrand factor antigen（vWFAg）, and soluble Fas show elevated levels in SSc. Among these parameters, sCD40L was targeted as a possible subclinical parameter in SIL. Factor analysis using the data of ten SIL showed that sCD40L was correlated only with sFas, whereas sCD40L formed a factor showing immunological alteration（without respiratory progression）with several other immunopathological parameters such as the titer of anti-nuclear antibodies（ANA）and immunoglobulin（Ig）G. However, sCD40L assays using ten healthy donors（HD）, ten SIL and ten SSc patients did not show a higher level for SSc, although ANA and sIL-2R levels were correlated with a progressive ranking （HD as 1, SIL as 2, SSc as 3）. The overall results suggest that sCD40L in SSc should be examined in regard to the state of the disease. At present, sCD40L is not considered a good indicator of subclinical disturbance in SIL. (Accepted on January 1, 2009)