Objective.To investigate the pathological significance of tubuloreticular structure（TRS） and cylindri- cal confronting cisternae（CCC） in patients with lupus nephritis. Methods. An electron microscopical study of 24 renal biopsy specimens from patients with lupus nephritis was carried out

with particular emphasis on two endoplasmic reticulum（ER）-related structures. Result. TRS was found in 18 cases

and CCC in 10 of them. TRS often appeared in the capillary en- dothelium

and did not correlate well with the activity index of lupus nephritis. CCC appeared frequently in monocyte/macrophage and lymphocyte

and correlated well with both the activity index and the amount of interstitial immune deposits. Conclusion.TRS and CCC derived from inward "budding" of ER membrane were suggested and the morphogenesis and morphologic variations of CCC were discussed. Both TRS and CCC are pathognomonic

though not specific changes. They may be helpful in pathologic diagnosis of lupus nephritis

when properly combined with certain clinical and pathological features.