The alveolar epithelium permeability (AP) in 34 patients with systemic lupus erythematosus (SLE) was measured by Tc-99m DTPA radioaerosol inhalation lung scintigraphy. The degree of AP damage in SLE was represented as the slope of the time-activity curve from the dynamic lung imagings. The patients were divided into two subgroups according to the following two criteria. [A] clinical feature: they were separated as stable or flare stage; and [B] chest X-ray findings: they were separated as positive or negative results. Meanwhile, the quantitative Gallium-67 (Ga) lung scan was performed as Ga uptake index (GUI) to evaluate the severity of inflammation in the lungs in SLE. The results show that [1] there were no significant statistical differences in the degree of AP damage between the two subgroups according to clinical features or chest X-ray findings, and [2] no good correlation between the degree of AP damage and inflammation of the lungs was found. In conclusion, the change of AP in SLE may be a mechanism not related to the presentation of clinical features or chest X-ray findings, and the degree of AP damage in SLE is not related to the severity of pulmonary inflammation.