Classifying Lupus Nephritis: An Ongoing Story

Abstract

The role of the renal biopsy in lupus nephritis is to provide the diagnosis and to define the parameters of prognostic and therapeutic significance for an effective clinicopathological correlation. Various classification schemas initiated by World Health Organization in 1974 have been proposed until the most recent update by International Society of Nephrology/Renal Pathology Society in 2004. In this paper, we reviewed the new classification system with the associated literature to highlight the benefits and the weak points that emerged so far. The great advantage of the classification emerged to provide a uniform reporting for lupus nephritis all over the world. It has provided more reproducible results from different centers. However, the studies indicated that the presence of glomerular necrotizing lesion was no longer significant to determine the classes of lupus nephritis leading to loss of pathogenetic diversity of the classes. Another weakness of the classification that also emerged in time was the lack of discussions related to the prognostic significance of tubulointerstitial involvement which was not included in the classification. Therefore, the pathogenetic diversity of the classification still needs to be clarified by additional studies, and it needs to be improved by the inclusion of the tubulointerstitial lesions related to prognosis.

Rare Case: 70 Year Old Patient with Seronegative Lupus Nephritis

“…If lupus nephritis in an elderly patient was seronegative, it can be difficult to diagnose because of the rareness of such patients. ANA negativity in lupus is seen only in a minority of patients and in fact, lupus nephritis in seronegative SLE patients is less likely to be encountered, but it should not be disregarded 2,3,8 . These patients may be underdiagnosed or misdiagnosed due to lack of clinical experience with these unusual presentations, resulting in an increased morbidity and mortality rate especially in elderly patients.…”

“…Renal biopsy determines the type of lupus nephritis as well as its management and prognosis. Early diagnosis is especially important for the prompt management of kidney involvement in SLE patients 8 . Furthermore, although unusual, lupus nephritis was also reported in patients with ANA-negative SLE 9 .…”

Relation of peritubular capillary features to class of lupus nephritis

“…In 2003, the International Society of Nephrology/Renal Pathology Society (ISN/RPS) classified LN into 6 classes according to the respective glomerular pathological characteristics [4, 5]. In addition to the predominantly glomerular involvement in LN, renal vascular lesions may affect glomerular capillaries, arterioles and arteries leading to thrombotic microangiopathy, lupus vasculopathy and lupus vasculitis [3, 6–9], while tubulointerstitial injury manifests as interstitial inflammation, renal tubular atrophy and/or interstitial fibrosis [10, 11]. Several studies suggest that the severity of vascular and tubulointerstitial injury in LN predicts renal outcome [3, 6–12].…”

“…In addition to the predominantly glomerular involvement in LN, renal vascular lesions may affect glomerular capillaries, arterioles and arteries leading to thrombotic microangiopathy, lupus vasculopathy and lupus vasculitis [3, 6–9], while tubulointerstitial injury manifests as interstitial inflammation, renal tubular atrophy and/or interstitial fibrosis [10, 11]. Several studies suggest that the severity of vascular and tubulointerstitial injury in LN predicts renal outcome [3, 6–12]. However, information on the integrity of the peritubular capillaries (PTC), which is the primary vascular supply for the renal tubules, has been limited to date.…”

An Overlapping Case of Lupus Nephritis and IgG4-Related Kidney Disease

“…Kidney involvement is seen in half of these patients and remains the leading cause of death [ 1 ]. All renal compartments including glomerular, tubulointerstitial, and vascular components may be affected [ 2 ], and the renal biopsy remains essential for classification, prognosis and management of lupus nephritis (LN) [ 3 ].…”