Rapid and Complete Remission of Class IV Lupus Nephritis with Massive Wire Loop Lesions.

Class IV lupus nephritis (LN) often has a poorer prognosis than other classes. However, class IV LN has various phenotypes, including not only segmental and global types but also others. We present the case of a 29-year-old woman with class IV-G LN who had an early response to glucocorticoid monotherapy. In addition, multiple lung nodules such as miliary tuberculosis (TB) were detected on computed tomography. All cultures of sputum, gastric fluid, and bone marrow were negative. A kidney biopsy revealed diffuse endocapillary proliferative glomerulonephritis with marked subendothelial deposition. Electron microscopy revealed massive electron-dense deposits in the subendothelial area, mesangium area, and peritubular capillaries. The histological diagnosis was class IV-G (A) LN. We administered high-dose glucocorticoid monotherapy. After treatment, the LN and the lung lesions had complete, rapid remission for 1 month. The lung lesions were associated with an immune complex similar to wire loop lesions, not TB. Thus, it is important to consider class IV-G LN with massive wire loop lesions as a new subtype.