Ikezumi Y, Kondoh T, Matsumoto Y, et al. - Given that M1-type proinflammatory macrophages (MΦ) promote glomerular injury in lupus nephritis (LN), however, it is unclear if this phenotype is altered by steroid therapy, researchers examined the impact of steroid treatment on MΦ phenotype in LN. LN patients (7–18 years old) were split into 2 groups: those without treatment (N) prior to biopsy (n = 17) and those who obtained steroid (S) treatment (3–73 days) prior to biopsy (n = 15). According to findings, age at biopsy, urine findings, and kidney function (eGFR) were similar between the two groups. Initial steroid therapy causes MΦ phenotypic change in LN with acute/active lesions from proinflammatory M1 to anti-inflammatory or profibrotic M2. While steroid treatment is effective for M1-mediated injury resolution, promotion of fibrotic lesions by M2 MΦ is a potential downside of steroid single therapy in LN.