Effect of mizoribine on pulmonary lesions in MRL/lpr/lpr mice.

The present study was made to investigate the effect of mizoribine (MZR), an imidazole nucleoside immunosuppressant, on pulmonary lesions and immunological mode of action of MRL/lpr/lpr mice. Four-week-old female MRL/lpr/lpr mice were injected subcutaneously with 20 mg/kg body weight of MZR every other day. For control, mice were given phosphate-buffered saline (PBS) every other day. MZR caused the delay in the histological development of peribronchial and perivascular lymphocytic infiltrations in the lungs of MRL/lpr/lpr (MRL/lpr) mice. And then, MZR suppressed the number of immunoglobulin (Ig) (IgG and IgM) secreting B cells and anti-DNA-secreting B cells in the spleen of MRL/lpr/lpr mice. The above data indicate that MZR could be useful for the treatment of pulmonary lesions associated with autoimmune disorders such as systemic lupus erythematosus (SLE).