Collapsing glomerulopathy

Idiopathic collapsing glomerulopathy is associated with APOL1 high-risk genotypes or Mendelian variants in most affected individuals in a highly admixed population

Collapsing glomerulopathy (CG) is most often associated with fast progression to kidney failure with an incidence apparently higher in Brazil than in other countries. However, the reason for this occurrence is unknown. To better understand this, we performed an integrated analysis of clinical, histological, therapeutic, causative genetic and genetic ancestry data in a highly genetically admixed cohort of 70 children and adult patients with idiopathic CG (ICG). The disease onset occurred at 23 (interquartile range: 17-31) years and approximately half of patients progressed to chronic kidney disease requiring kidney replacement therapy (CKD-KRT) 36 months after diagnosis. Causative genetic bases, assessed by targeted-gene panel or whole-exome sequencing, were identified in 58.6% of patients. Among these cases, 80.5% harbored APOL1 high-risk genotypes (HRG) and 19.5% causative Mendelian variants (MV). Self-reported non-White patients more frequently had HRG. MV was an independent risk factor for progression to CKD-KRT by 36 months and the end of follow-up, while remission was an independent protective factor. All patients with HRG manifested CG at 9-44 years of age, whereas in those with APOL1 low-risk genotype, the disease arose throughout life. HRGs were associated with higher proportion of African genetic ancestry. Novel causative MVs were identified in COL4A5, COQ2 and PLCE1 and previously described causative MVs were identified in MYH9, TRPC6, COQ2, COL4A3 and TTC21B. Three patients displayed HRG combined with a variant of uncertain significance (ITGB4, LAMA5 or PTPRO). MVs were associated with worse kidney prognosis. Thus, our data reveal that the genetic status plays a major role in ICG pathogenesis, accounting for more than half of cases in a highly admixed Brazilian population.

C3 Dominant Collapsing Focal Segmental Glomerulosclerosis - A Report of Two Rare Cases

Collapsing focal segmental glomerulosclerosis (FSGS) a heterogeneous group of disorders, rather than a single disease entity. Kidney biopsy shows segmental or globally collapsed, sclerotic glomerular capillaries. There is also hypertrophy and hyperplasia of overlying glomerular epithelial cells. Immuno-fluorescence is negative or has non-specific deposits of immunoglobulins and C3. We present two cases of C3 dominant collapsing FSGS. Both the cases were non-responsive to therapy and had a poor outcome. This calls for research to study the role of the complement pathway in the pathogenesis of FSGS.

Quantification of Glomerular Structural Lesions: Associations With Clinical Outcomes and Transcriptomic Profiles in Nephrotic Syndrome

RATIONALE & OBJECTIVE

The current classification system for focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) does not fully capture the complex structural changes in kidney biopsies nor the clinical and molecular heterogeneity of these diseases.

STUDY DESIGN

Prospective observational cohort study.

SETTING & PARTICIPANTS

221 MCD and FSGS patients enrolled in the Nephrotic Syndrome Study Network (NEPTUNE).

EXPOSURE

The NEPTUNE Digital Pathology Scoring System (NDPSS) was applied to generate scores for 37 glomerular descriptors.

OUTCOME

Time from biopsy to complete proteinuria remission, time from biopsy to kidney disease progression (40% estimated glomerular filtration rate [eGFR] decline or kidney failure), and eGFR over time.

ANALYTICAL APPROACH

Cluster analysis was used to group patients with similar morphologic characteristics. Glomerular descriptors and patient clusters were assessed for associations with outcomes using adjusted Cox models and linear mixed models. Messenger RNA from glomerular tissue was used to assess differentially expressed genes between clusters and identify genes associated with individual descriptors driving cluster membership.

RESULTS

Three clusters were identified: X (n = 56), Y (n = 68), and Z (n = 97). Clusters Y and Z had higher probabilities of proteinuria remission (HRs of 1.95 [95% CI, 0.99-3.85] and 3.29 [95% CI, 1.52-7.13], respectively), lower hazards of disease progression (HRs of 0.22 [95% CI, 0.08-0.57] and 0.11 [95% CI, 0.03-0.45], respectively), and lower loss of eGFR over time compared with X. Cluster X had 1,920 genes that were differentially expressed compared with Y+Z; these reflected activation of pathways of immune response and inflammation. Six descriptors driving the clusters individually correlated with clinical outcomes and gene expression.

LIMITATIONS

Low prevalence of some descriptors and biopsy at a single time point.

CONCLUSIONS

The NDPSS allows for categorization of FSGS/MCD patients into clinically and biologically relevant subgroups, and uncovers histologic parameters associated with clinical outcomes and molecular signatures not included in current classification systems.

New Insights into the Treatment of Glomerular Diseases: When Mechanisms Become Vivid

Treatment for glomerular diseases has been extrapolated from the experience of other autoimmune disorders while the underlying pathogenic mechanisms were still not well understood. As the classification of glomerular diseases was based on patterns of juries instead of mechanisms, treatments were typically the art of try and error. With the advancement of molecular biology, the role of the immune agent in glomerular diseases is becoming more evident. The four-hit theory based on the discovery of gd-IgA1 gives a more transparent outline of the pathogenesis of IgA nephropathy (IgAN), and dysregulation of Treg plays a crucial role in the pathogenesis of minimal change disease (MCD). An epoch-making breakthrough is the discovery of PLA2R antibodies in the primary membranous nephropathy (pMN). This is the first biomarker applied for precision medicine in kidney disease. Understanding the immune system's role in glomerular diseases allows the use of various immunosuppressants or other novel treatments, such as complement inhibitors, to treat glomerular diseases more reasonable. In this era of advocating personalized medicine, it is inevitable to develop precision medicine with mechanism-based novel biomarkers and novel therapies in kidney disease.

Lessons From APOL1 Animal Models

African-Americans have a three-fold higher rate of chronic kidney disease compared to European-Americans. Much of this excess risk is attributed to genetic variants in APOL1, encoding apolipoprotein L1, that are present only in individuals with sub-Saharan ancestry. Although 10 years have passed since the discovery of APOL1 renal risk variants, the mechanisms by which APOL1 risk allele gene products damage glomerular cells remain incompletely understood. Many mechanisms have been reported in cell culture models, but few have been demonstrated to be active in transgenic models. In this narrative review, we will review existing APOL1 transgenic models, from flies to fish to mice; discuss findings and limitations from studies; and consider future research directions.

Current Understanding of Clinical Manifestations of COVID-19 in Glomerular Disease

Background

The novel coronavirus disease (COVID-19), also known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is an evolving pandemic with significant mortality. Information about the impact of infection on glomerular disease patients in particular has been lacking. Understanding the virus's effect in glomerular disease is constantly changing. This review article summarizes the data published thus far on COVID-19 and its manifestations in pre-existing and de novo glomerular disease.

Summary

While patients with glomerular disease may be at higher risk of severe COVID-19 due to their immunosuppressed status, some data suggest that a low amount of immunosuppression may be helpful in mitigating the systemic inflammatory response which is associated with high mortality rates in COVID-19. There have been a few case reports on COVID-19 causing glomerular disease relapse in patients. Multiple mechanisms have been proposed for kidney injury, proteinuria, and hematuria in the setting of COVID-19. More commonly, these are caused by direct tubular injury due to hemodynamic instability and hypoxic injury. However, the cytokine storm induced by COVID-19 may trigger common post-viral glomerular disease such as IgA nephropathy, anti-GBM, and ANCA vasculitis that have also been described in COVID-19 patients. Collapsing glomerulopathy, a hallmark of HIV-associated nephropathy, is being reported SARS-CoV-2 cases, particularly in patients with high-risk APOL1 alleles. Direct viral invasion of glomerular structures is hypothesized to cause a podocytopathy due to virus's affinity to ACE2, but evidence for this remains under study.

Key Messages

Infection with SARS-CoV-2 may cause glomerular disease in certain patients. The mechanism of de novo glomerular disease in the setting of COVID-19 is under study. The management of patients with existing glomerular disease poses unique challenges, especially with regard to immunosuppression management. Further studies are needed to inform clinician decisions about the management of these patients during the COVID-19 pandemic.

APOL1 risk variants and the development of HIV-associated nephropathy

HIV-associated nephropathy (HIVAN) remains a concern among untreated HIV patients, notably of African descent, as patients can reach end-stage renal disease within 3 years. Two variants (G1 and G2) of the APOL1 gene, common in African populations to protect against African sleeping sickness, have been associated with an increased risk of several glomerular disorders including HIVAN, hypertension-attributed chronic kidney disease, and idiopathic focal segmental glomerulosclerosis and are accordingly named renal risk variants (RRVs). This review examines the mechanisms by which APOL1 RRVs drive glomerular injury in the setting of HIV infection and their potential application to patient management. Innate antiviral mechanisms activated by chronic HIV infection, especially those involving type 1 interferons, are of particular interest as they have been shown to upregulate APOL1 expression. Additionally, the downregulation of miRNA 193a (a repressor of APOL1) is also associated with the upregulation of APOL1. Interestingly, glomerular damage affected by APOL1 RRVs is caused by both loss- and gain-of-function changes in the protein, explicitly characterizing these effects. Their intracellular localization offers a further understanding of the nuances of APOL1 variant effects in promoting renal disease. Finally, although APOL1 variants have been recognized as a critical genetic player in mediating kidney disease, there are significant gaps in their application to patient management for screening, diagnosis, and treatment.

Collapsing focal segmental sclerosis in an HIV-negative patient

Collapsing focal segmental glomerulosclerosis (FSGS) is classically seen in HIV-infected patients and carries a dismal prognosis. It can also occur in HIV-negative patients in which case, early aggressive treatment with glucocorticoids may be helpful with improvement in both proteinuria and renal function.

First Case of COVID-19-Associated Collapsing Glomerulopathy in Sub-Saharan Africa

Although the lungs remain the main target of SARS-CoV-2, other organs, such as kidneys, can be affected, which has a negative impact on the outcomes of COVID-19 patients. Although previous studies of kidney disease in COVID-19 reported mainly SARS-CoV-2-induced tubular and interstitial injury, there is growing evidence coming out of Africa of glomerular involvement, especially collapsing glomerulopathy seen particularly in people of African descent. We report a case of collapsing glomerulopathy revealed by acute kidney injury and a new onset of full blown nephrotic syndrome in a black Congolese patient coinfected with COVID-19 and malaria.

Factors Associated With Rapid Progression to Endstage Kidney Disease in Lupus Nephritis

OBJECTIVE

Lupus nephritis (LN) may lead to endstage kidney disease (ESKD) in 22% of patients over a period of 15 years, with the risk being particularly higher in diffuse proliferative forms. The rate of kidney function decline varies. However, a catastrophic course leading to ESKD within a few years from onset is uncommon. The aim of the present study was to assess the factors associated with rapid progression to ESKD in patients with LN.

METHODS

Patients from the Toronto Lupus Clinic with biopsy-proven LN at presentation and estimated glomerular filtration rate (eGFR) 60 mL/min/1.73 m², who developed ESKD within 3 years were retrieved. Pathology reports were reviewed with particular emphasis on distinct histopathologic features. Demographic, clinical, laboratory, and therapeutic variables were also analyzed.

RESULTS

Ten patients (1.8% of the total LN population) developed ESKD within 3 years of diagnosis. Their mean age was 34.2 ± 7.3 years, mean time to ESKD 19.2 ± 12.4 months, initial eGFR 90.2 ± 24.9 mL/min/1.73 m², proteinuria 2.7 ± 1.04 g/24 h. The median rate of kidney function decline was > 43 mL/min/1.73 m²/year. One patient had LN class III, 5 had LN class IV, 2 had membranous LN (class V), and another 2 had mixed IV/V. Moreover, 2 patients had extensive thrombotic microangiopathy, 1 collapsing glomerulonephritis, and 1 concomitant antiglomerular basement membrane (anti-GBM) nephropathy. Four patients showed no unusual kidney pathology; all of them had severe noncompliance (discontinued all medications to follow alternative treatment).

CONCLUSION

Catastrophic progression to ESKD is uncommon in LN. The major associated factors are poor compliance and distinct histopathologic features such as thrombotic microangiopathy, collapsing glomerulopathy, and concomitant anti-GBM nephropathy.

Rituximab in treatment of collapsing FSGS-A case series

BACKGROUND

Collapsing focal segmental glomerulosclerosis (cFSGS) is an aggressive glomerular disease presenting as a nephrotic syndrome that has lower rates of remission with conventional immunosuppressive therapy and rapidly progresses to end-stage-renal-disease (ESRD). We report eight cases of HIV-negative cFSGS treated with rituximab.

METHODS

The current report is a retrospective case series of cFSGS treated with rituximab from January 2011 to March 2020, at varying phases of the disease.

RESULTS

Eight out of the 70 cFSGS patients received rituximab. The median age of patients was 30 years (IQR 24.25-37.5); five patients were males. The median serum creatinine, mean serum albumin and median 24 hours urinary protein at presentation was 0.9 (IQR 0.66-1.27) mg/dL, 2.95 ± 1.15 g/dL, 4.87 (IQR 1.64-5.75) g/day, respectively. Two patients were steroid-resistant, one steroid and tacrolimus dependent, one steroid and cyclosporine dependent, two steroids and tacrolimus resistant, one steroid, tacrolimus, cyclophosphamide, mycophenolate mofetil resistant and one steroid-resistant and tacrolimus dependent before rituximab therapy. Rituximab was given either as targeted therapy (after an initial dose of 375 mg/m² ; patients having CD-19 levels >5/μL or >1% at 1 month received additional low-dose [100 mg] of rituximab), or weekly regimen. Five patients received CD-19 targeted rituximab; three received weekly doses of 375 mg/m² , cumulative doses being 820 ± 228.03 mg, and 1800 ± 721.11 mg, respectively. At the end of median follow-up of 15 months, five (62.5%) patients were in remission (three partial, two complete remissions), two (25%) were resistant to therapy; one (12.5%) progressed to ESRD.

CONCLUSION

Rituximab is reasonably safe and achieves/maintains remission in 60% of cFSGS cases.

Malaria, Collapsing Glomerulopathy, and Focal and Segmental Glomerulosclerosis

BACKGROUND AND OBJECTIVES

Malaria, a potentially life-threatening disease, is the most prevalent endemic infectious disease worldwide. In the modern era, the spectrum of glomerular involvement observed in patients after malarial infections remains poorly described.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We therefore performed a retrospective multicenter study to assess the clinical, biologic, pathologic, and therapeutic characteristics of patients with glomerular disease demonstrated by kidney biopsy in France within 3 months of an acute malaria episode.

RESULTS

We identified 23 patients (12 men), all but 1 of African ancestry and including 10 patients with concomitant HIV infection. All of the imported cases were in French citizens living in France who had recently traveled back to France from an endemic area and developed malaria after their return to France. Eleven patients had to be admitted to an intensive care unit at presentation. Plasmodium falciparum was detected in 22 patients, and Plasmodium malariae was detected in 1 patient. Kidney biopsy was performed after the successful treatment of malaria, a mean of 24 days after initial presentation. At this time, all patients displayed AKI, requiring KRT in 12 patients. Nephrotic syndrome was diagnosed in 17 patients. Pathologic findings included FSGS in 21 patients and minimal change nephrotic syndrome in 2 patients. Among patients with FSGS, 18 had collapsing glomerulopathy (including 9 patients with HIV-associated nephropathy). In four patients, immunohistochemistry with an antibody targeting P. falciparum histidine-rich protein-2 demonstrated the presence of the malaria antigen in tubular cells but not in podocytes or parietal epithelial cells. An analysis of the apoL1 risk genotype showed that high-risk variants were present in all seven patients tested. After a mean follow-up of 23 months, eight patients required KRT (kidney transplantation in two patients), and mean eGFR for the other patients was 51 ml/min per 1.73 m².

CONCLUSIONS

In patients of African ancestry, imported Plasmodium infection may be a new causal factor for secondary FSGS, particularly for collapsing glomerulopathy variants in an APOL1 high-risk variant background.

Collapsing Lesions and Focal Segmental Glomerulosclerosis in Pregnancy: A Report of 3 Cases

The relationship between focal segmental glomerulosclerosis (FSGS) and pregnancy is complex and not completely elucidated. Pregnancy in patients with FSGS poses a high risk for complications, possibly due to hemodynamic factors, imbalance between angiogenic and antiangiogenic factors, and hormonal conditioning. Although poor clinical outcomes associated with collapsing FSGS are common outside of pregnancy, the prognosis during pregnancy is not well documented. We report 3 patients who developed collapsing FSGS during pregnancy, 2 of whom had presumed underlying FSGS. Two patients underwent biopsy during pregnancy, and 1, during the puerperium. None of the 3 patients improved spontaneously after delivery, and 1 experienced a rapid deterioration in kidney function and proteinuria after delivery. Aggressive immunosuppressive therapy led to a full response in 1 case (without chronic lesions) and to partial responses in the remaining 2 cases. These cases suggest that collapsing lesions should be considered in patients with FSGS who develop a rapid increase in serum creatinine level or proteinuria during pregnancy and that these lesions may at least partially respond to treatment.

Pathogenesis and Management of Acute Kidney Injury in Patients with Nephrotic Syndrome Due to Primary Glomerulopathies

Acute kidney injury in the context of nephrotic syndrome is a serious and alarming clinical problem. Largely, acute kidney injury is a relatively frequent complication among patients with comorbidities while it has been independently associated with an increased risk of adverse outcomes, including death and chronic kidney disease. Nephrotic syndrome, without hematuria or with minimal hematuria, includes a list of certain glomerulopathies; minimal change disease, focal segmental glomerulosclerosis and membranous nephropathy. In the light of primary nephrotic syndrome, pathophysiology of acute kidney injury is differentiated by the nature of the primary disease and the severity of the nephrotic state. This review aims to explore the clinical circumstances and pathogenetic mechanisms of acute kidney injury in patients with nephrotic syndrome due to primary glomerulopathies, focusing on newer perceptions regarding the pathogenesis and management of this complicated condition, for the prompt recognition and timely initiation of appropriate treatment in order to restore renal function to its baseline level. Prompt recognition of the precise cause of acute kidney injury is crucial for renal recovery. Clinical characteristics, laboratory and serological findings along with histopathological findings, if required, will reveal the implicated pathway leading to individualized approach and management.

Collapsing glomerulopathy in older adults

Collapsing glomerulopathy has been described in settings of viral infections, drug, genetic, ischemic, renal transplant, and idiopathic conditions. It has a worse prognosis than other morphologic variants of focal segmental glomerulosclerosis, and may be treated with aggressive immunosuppression. In this study, we sought to characterize the clinical and morphologic findings in older adults with collapsing glomerulopathy. Renal biopsies and associated clinical data from patients aged 65 or older with a diagnosis of collapsing glomerulopathy were retrospectively reviewed at 3 academic institutions. Patients (n = 41, 61% male, median age 71) usually had hypertension (88%), nephrotic range proteinuria (91%), and renal insufficiency (median serum creatinine 2.5 mg/dL). A likely precipitating drug (5%) or vascular procedure (5%) was identified in a minority of cases; viral infections were infrequent. Renal biopsies contained a median of 40% globally and 16% segmentally sclerotic glomeruli. Approximately 60% of cases had moderate or severe arteriosclerosis, arteriolar hyalinosis, and/or tubular atrophy and interstitial fibrosis; 7% had atheroembolic disease and 5% had thrombotic microangiopathy. In 28 patients with available follow-up information, eight (19%) were treated with immunosuppressives, which were not tolerated by 2. At a median interval of 14 months, 5 (18%) patients had died, 12 (43%) had end stage renal disease, and 12 were alive with renal insufficiency and proteinuria. Treatment with immunosuppressive therapy did not have a significant benefit with regard to the primary outcome of overall or renal survival. One steroid-treated patient with diabetes died 6 weeks after biopsy, with invasive rhinoorbital Rhizopus infection. In conclusion, collapsing glomerulopathy in older patients is usually not associated with viral infections, and is accompanied by significant chronic injury in glomeruli, vasculature, and tubulointerstitium. Aggressive immunosuppression likely contributed to one death in a patient with diabetes, and did not yield an overall or renal survival advantage in this cohort.

Collapsing glomerulopathy in a child with LCHAD deficiency: a rare association

Metabolic disorders, although rare, can involve multiple organ systems and have a varied presentation. Renal involvement has been reported in several metabolic disorders in the pediatric age group. We report a rare metabolic disorder, long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency, in a child who developed steroid-resistant nephrotic syndrome at the age of 5 years. Renal biopsy showed features of collapsing glomerulopathy. The child had progressive chronic kidney disease. Alternative immunosuppressants including tacrolimus failed to show any clinical improvement. There have been no reports of children with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency developing steroid-resistant nephrotic syndrome and collapsing glomerulopathy. This case highlights the need to monitor renal function and proteinuria among this group of children.

Collapsing glomerulopathy: update

Collapsing glomerulopathy (CG) is a rare entity as a glomerular disease. Although it has been considered as a variant of focal segmental glomerulosclerosis, the fact is that the podocyte lesions show different features with respect to the typical focal segmental glomerulosclerosis, an aspect that has been attributed to a type of podocytopathy. In CG, the podocyte lesion is typically characterised by a dysregulated podocyte phenotype, reflected by the loss of expression of mature podocyte markers. CG can be a primary disease or it can be associated with several causal factors that develop a common histopathological entity. The clinical expressiveness of CG is often characterised by the presence of a nephrotic syndrome and a rapid deterioration of the renal function than other variants of the focal segmental glomerulosclerosis. The prognosis of these patients is a rapid progression towards end-stage renal disease with poor response to treatment.

Collapsing glomerulonephritis with podocyte markers in hemophagocytic syndrome secondary to hepatosplenic T-cell lymphoma

The hemophagocytic syndrome is a serious clinical-histological entity secondary to different diseases. Collapsing glomerulonephritis is a proliferative podocytopathy that usually has an unfavorable renal prognosis. We present a case in which both entities were associated, which is an infrequent form of hepatosplenic T-cell lymphoma. In addition, we review the role of the markers of podocyte dedifferentiation in this glomerulopathy and its pathophysiology and treatment.

Collapsing Glomerulopathy and Thrombotic Microangiopathy in Postpartum Period: Two Case Reports

Collapsing glomerulopathy (CG) is a distinct histopathologic pattern of glomerular injury characterized by global/segmental wrinkling of the glomerular basement membrane with podocyte hyperplasia and hypertrophy along with tubulointerstitial changes. There is no specific treatment for CG due to etiological heterogeneity, and newer insights into the pathogenesis may lead to the development of targeted therapy. The most common form of CG is the primary or idiopathic followed by secondary (due to viral infections, autoimmune disease, drugs, etc.) and genetic causes. Thrombotic microangiopathy (TMA) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ failure of variable severity. We here present two young women with preeclampsia who presented with acute kidney injury, anemia, and schistocytes in peripheral smear suggestive of TMA. Renal biopsy showed interesting histopathology of CG in addition to TMA in the first patient and CG alone in the second. Both the patients received supportive therapy while the first patient also received plasmapheresis. One patient had complete recovery, and other had partial recovery of renal function at last follow-up. Combined histopathological lesion of CG with TMA has never been reported in postpartum period so far in literature.

Molecular Mechanisms of Proteinuria in Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is the most common primary glomerular disease resulting in end-stage renal disease in the USA and is increasing in prevalence worldwide. It is a diverse clinical entity with idiopathic, genetic, metabolic, infectious, and other causes that culminate in a characteristic histologic pattern of injury. Proteinuria is a hallmark of FSGS as well as other primary and secondary glomerular disorders. The magnitude of proteinuria at disease onset and during treatment has prognostic implications for renal survival as well as associated cardiovascular morbidity and mortality. Significant advances over the last two decades have shed light on the molecular architecture of the glomerular filtration barrier. The podocyte is the target cell for injury in FSGS. A growing list of disease-causing gene mutations encoding proteins that regulate podocyte survival and homeostasis has been identified in FSGS patients. Several pathogenic and regulatory pathways have been uncovered that result in proteinuria in rodent models and human FSGS. The recurrence of proteinuria and FSGS after kidney transplantation is supporting evidence for the role of a circulating permeability factor in disease pathogenesis. These advances reviewed herein have significant implications for disease classification and therapeutic drug development for FSGS.

De novo glomerular diseases after renal transplantation: How is it different from recurrent glomerular diseases?

The glomerular diseases after renal transplantation can occur de novo, i.e., with no relation to the native kidney disease, or more frequently occur as a recurrence of the original disease in the native kidney. There may not be any difference in clinical features and histological pattern between de novo glomerular disease and recurrence of original glomerular disease. However, structural alterations in transplanted kidney add to dilemma in diagnosis. These changes in architecture of histopathology can happen due to: (1) exposure to the immunosuppression specifically the calcineurin inhibitors (CNI); (2) in vascular and tubulointerstitial alterations as a result of antibody mediated or cell-mediated immunological onslaught; (3) post-transplant viral infections; (4) ischemia-reperfusion injury; and (5) hyperfiltration injury. The pathogenesis of the de novo glomerular diseases differs with each type. Stimulation of B-cell clones with subsequent production of the monoclonal IgG, particularly IgG3 subtype that has higher affinity to the negatively charged glomerular tissue, is suggested to be included in PGNMID pathogenesis. De novo membranous nephropathy can be seen after exposure to the cryptogenic podocyte antigens. The role of the toxic effects of CNI including tissue fibrosis and the hemodynamic alterations may be involved in the de novo FSGS pathophysiology. The well-known deleterious effects of HCV infection and its relation to MPGN disease are frequently reported. The new concepts have emerged that demonstrate the role of dysregulation of alternative complement pathway in evolution of MPGN that led to classifying into two subgroups, immune complex mediated MPGN and complement-mediated MPGN. The latter comprises of the dense deposit disease and the C3 GN disease. De novo C3 disease is rather rare. Prognosis of de novo diseases varies with each type and their management continues to be empirical to a large extent.

Collapsing Glomerulopathy- A Troublemaker for the Renal Allograft: Lessons Learnt

Collapsing glomerulopathy (CG) is a well-recognized distinct morphological pattern of proliferative parenchymal injury leading to rapid graft failure. We conducted a single-center retrospective study to evaluate the prevalence, clinicopathological features, and prognosis of CG in renal transplant recepient. We analyzed 2518 renal allograft biopsies performed from 2007 to 2015 and correlated their clinicopathological features. The prevalence of CG was 0.83% (21 out of 2518) of allograft biopsies with a higher prevalence of 1.4% during the period from 2012 to 2015. Out of 21 patients, 18 (85.71%) patients had undergone live donor and 3 (14.28%) patients had undergone deceased donor renal transplant. Hypertension was observed in 3 (14.28%) patients. The mean duration of diagnosis for CG was 1.85 ± 1.91 years. Urinalysis revealed microhematuria in 5 (23.8%) patients. The mean 24 h urinary protein excretion was 4.77 ± 5.3 g and serum creatinine was 2.12 ± 1.5 mg/dl. The predominant native kidney diseases in recipients were chronic glomerulonephritis of unknown etiology in 12 (57.14%) patients and hypertensive nephropathy in 3 (14.28%) patients. CG was associated with rejection in 9 (42.85%), calcineurin-inhibitor toxicity in 2 (9.5%), and BK virus nephropathy in 1 patient. All patients received standard triple immunosuppression. Eleven (52.38%) patients developed graft failure over a mean period of 2.2 ± 1.7 years and 6 (28.57%) patients recovered with stable graft function. CG can coexist with viral infection, drug toxicity, rejection, microvascular injury, etc. CG usually presents with moderate to severe proteinuria and may lead to rapid graft dysfunction and subsequent graft failure in most of the patients.

Viral-Associated GN: Hepatitis B and Other Viral Infections

By definition, viral-associated GN indicates the direct pathogenic relationship between active viral replication and the development of acute GN. This definition is in sharp contrast to the semantic label and pathophysiologic foundation behind postinfectious GN that uniquely develops only during a period of resolved and absent active infection. The primary example of postinfectious GN are the glomerular lesions described after a pharyngeal or cutaneous streptococcal infection and do not represent the clinical or immunologic pattern seen with viral-associated GN. Hepatitis B (HBV) is the most common chronic viral infection in the world affecting >400 million people which is more than double the prevalence of chronic HIV and hepatitis C carriers combined. In addition, 10%-20% of HBV patients may be coinfected with hepatitis C and 5%-10% will have coinfection with HIV. Being able to distinguish the different types of GN seen with each viral infection is essential for the practicing clinician as each virus requires its own specific antiviral therapy. HBV-induced immune complex disease with renal injury lies on one end of the spectrum of disorders that occurs after a prolonged chronic carrier state. On the opposite end of the spectrum are renal diseases that develop from acute or subacute viral infections. One important glomerular lesion in this category is the association of collapsing FSGS with acute active cytomegalovirus, Epstein-Barr virus, and parvovirus B19 infection. The data supporting or disproving this relationship for each of these viruses will be discussed. A second renal manifestation of acute viral infections often occurs with many different sporadic or epidemic infections such as dengue and hantavirus and can lead to a transient proliferative GN that resolves upon viral clearance. The complex interplay of HBV and all viruses with the immune system provides conceptual lessons on the pathophysiology of immune complex GN that can be applied to all infection-related renal disease and plays an integral role in developing an approach to therapeutic intervention.

Collapsing glomerulopathy, the Saudi Arabian scenario. A study of 31 cases and a review of literature

Objectives:

To compare the clinico-pathological features of collapsing glomerulopathy (CG) at a tertiary hospital in Saudi Arabia with the world literature.

Methods:

In a retrospective study, all biopsy-diagnosed cases of CG between 2004-2015 were identified and analyzed, at King Khalid University Hospital, King Saud University, Riyadh. The clinico-pathological findings along with prognosis were reviewed and compared with the reported literature.

Results:

Thirty-one CG patients were identified, most were adult males. All the CG cases were idiopathic, all Arabs, none HIV positive, none of African descent, and none with a history of drug abuse. The number of glomeruli with collapsing lesions per biopsy ranged from 1 to 9. Other types of FSGS lesions (not otherwise specified and perihilar) were also noted. There was extensive podocyte effacement. Upon treatment, remission (complete/partial) was noted in almost half the patients; around one fourth did not respond to treatment; and one fourth progressed to end stage kidney disease (ESKD). The median time taken to develop ESKD from the time of biopsy diagnosis was 23 months.

Conclusion:

The clinico-pathological and prognostic correlates of CG in Saudi Arabia are comparable with that of the world literature. The management protocol at our center is the same as that practiced in different parts of the world, and the prognosis is overall poor.

Collapsing glomerulopathy in systemic lupus erythematosus

Collapsing glomerulopathy (CG) is a rare disease that can be associated with multiple other disorders. It usually leads to poor prognosis with a high percentage of patients progressing to end-stage renal disease. In this article, we illustrate a clinical case of CG associated with systemic lupus erythematosus that had a prompt response to mycophenolate and prednisone. The condition started after sudden cessation of the already established mycophenolate treatment regimen. The patient then presented with acute kidney injury due to kidney biopsy-proven CG. In that circumstance, we hypothesised that mycophenolate may play a role in prevention and development of CG.

Idiopathic collapsing focal segmental glomerulosclerosis in an 81-year-old Japanese woman: a case report and review of the literature

Focal segmental glomerulosclerosis (FSGS) is classified into five variants, with the collapsing variant being the most rare. Collapsing FSGS is characterized by a black racial predominance and is often associated with human immunodeficiency virus-associated nephropathy. However, the number of idiopathic cases is increasing and the presentation of non-black patients becoming more routine. Our analysis of 15 previous reports investigating FSGS variants shows that the collapsing variant accounts for 10.6 % of FSGS cases and its average age of onset is 32 years old. The current case is one of the oldest cases of idiopathic collapsing FSGS identified, being an 81-year-old Japanese woman. She presented with severe renal insufficiency (serum creatinine 7.9 mg/dL, albumin 1.5 g/dL) and so underwent hemodialysis immediately. Urinalysis demonstrated 3+ proteinuria and 3+ hematuria and the serological work up was all negative. Renal biopsy showed wrinkling of capillary walls with collapse lumens in every glomerulus, without endothelial tubuloreticular inclusions. Combined treatment with steroids, cyclosporine and low-density lipoprotein apheresis increased urine output slightly but she was unable to withdraw from hemodialysis and died 3 months later. This variant is reported to have the highest rate of progression to end-stage renal disease, regardless of the therapeutic intervention. However, there are also examples of cases with partial or complete remission in the literature. Progressive cases, like the current case, seem to be difficult to induce remission in, so it is important to diagnose idiopathic collapsing FSGS at an early stage by performing a renal biopsy, even in elderly patients.

Collapsing glomerulopathy in a case of anti-neutrophil cytoplasmic antibody associated vasculitis

Collapsing glomerulopathy (CG) is a pathological entity characterized by collapse and wrinkling of glomerular tuft, podocyte dedifferentiation and hyperplasia. CG may be idiopathic or secondary to other diseases. CG has been described with IgA nephropathy, membranous glomerulopathy, diabetic nephropathy, and lupus nephritis. However, till date there is no report of CG in association with the anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV). Here, we present a case of CG that developed during follow-up in a case of AAV with biopsy proven pauci-immune glomerulonephritis.

Collapsing Glomerulopathy: A Single Centre Clinicopathologic Study of Seven Years

INTRODUCTION

Collapsing Glomerulopathy (CG) is recognized as distinct pattern of proliferative parenchymal injury with poor response to empirical therapy.

AIM

A single center retrospective study was carried out to find out clinicopathological features of idiopathic CG.

MATERIALS AND METHODS

A total of 3335 native renal biopsies were analyzed retrospectively which were performed from 2008 to 2014 with emphasis on clinicopathological correlation and histopathological presentation.

RESULTS

Idiopathic CG constituted 0.75% incidence (25 out of 3335 biopsies) of all biopsies, adults constituting major study part with 88%. The duration of the symptoms at the time of biopsy was 34.12±26.09 days and 35±22.91 days respectively in adults and children. Hypertension was noted in 9(40.9%) and oliguria in 8(36.4%) in adults. Urinalysis revealed microscopic haematuria 12(54.5%) in adults. Nephrotic range proteinuria was reported in 10 (45.5%) adult patients. Glomerular collapse with hyperplasia/ hypertrophy of podocytes was seen in 4.54±3.11 glomeruli. Tubular microcystic dilation was seen in 16(64%) patients. Tubular atrophy involving mild (t1) in 15(60%), moderate (t2) in 4(16%) and severe (t3) in 6(24%) patients. Interstitial fibrosis was mild (i1) in 17(68%), moderate (i2) in 2(8%) and severe (i3) in 6(24%) patients.

CONCLUSION

Idiopathic CG is a morphological pattern of grave podocyte injury with poor prognosis. However, there are chances of remission/ recovery if the tubular atrophy and interstitial fibrosis are of grades ≤ t1 i1.

Collapsing glomerulopathy associated with pulmonary tuberculosis

Collapsing glomerulopathy (CG) usually presents with reduced glomerular filtration rate, heavy proteinuria and has unfavorable prognosis. Numerous associations with CG are found. We encountered a case of CG associated with pulmonary tuberculosis presenting with proteinuria and dialysis-requiring severe renal failure. Our patient made partial recovery of his renal function and became dialysis-independent after antituberculous therapy and oral steroids. Long-term follow-up is needed to assess the progression of the disease.

Clinical problem solving: Itching for a diagnosis

A 58-year-old woman presented with a 2-week history of generalized pruritus. She also reported having fatigue, dizziness, and decreased appetite. A week before the onset of symptoms, a mild upper respiratory tract infection had developed.

Collapsing focal segmental glomerulosclerosis in a patient with systemic lupus erythematosus

We present a case of a 36-year-old female from Ghana who presented with atypical chest pain and shortness of breath and was found to have bilateral transudative pleural effusion and trivial pericardial effusion. Further work-up revealed serological markers consistent with active lupus and negative HIV. She developed rapid deterioration of her renal function requiring dialysis. Her renal biopsy showed collapsing focal segmental glomerulosclerosis with diffuse mesangial proliferative glomerulonephritis, consistent with lupus nephritis class II along with tubular degenerative changes. She was started on high dose steroids and later on mycophenolate mofetil. Her renal function slowly recovered to baseline.

Epithelial cell foot process effacement in podocytes in focal and segmental glomerulosclerosis: a quantitative analysis

BACKGROUND/AIM

Effacement of the epithelial cell foot processes of glomerular podocytes are thought to be diffuse in the primary form of focal and segmental glomerulosclerosis (FSGS). In contrast, effacements that occur in the secondary form of FSGS are thought to be focal. To evaluate this theory, the extent of epithelial cell foot process effacement was analyzed and compared in podocytes from cases of primary and secondary FSGS.

METHODS

Consecutive cases of adult primary and secondary FSGS that were diagnosed between January 1997 and December 2010 were retrospectively retrieved and analyzed. The electron microscopy materials of all specimens were reviewed. Glomerular podocytes from each sample were counted, recorded and analyzed for the percentage of diffuse versus focal epithelial foot process effacement.

RESULTS

Seventeen primary and 16 secondary FSGS specimens were reviewed. In the 17 primary FSGS cases, 35.1% of the podocytes were focally fused, and 64.9% were diffusely fused. In the 16 secondary FSGS cases, 72.1% of the podocytes were focally fused. There were significantly more focally fused podocytes in secondary FSGS than in primary FSGS. In contrast, significantly more diffusely fused podocytes were observed in primary FSGS than in secondary FSGS.

CONCLUSION

This is the first study to perform a quantitative analysis of the extent of epithelial cell foot process effacement in podocytes in primary and secondary FSGS. This study also confirms that the electron microscopic characteristics of the podocyte effacement process can be used to facilitate the diagnosis of primary versus secondary FSGS.

An analysis of transplant glomerulopathy and thrombotic microangiopathy in kidney transplant biopsies

Glomerular diseases of the transplanted kidney are the most important cause of poor long- term outcome. The estimation of the magnitude of this problem and an elucidation of pathogenic mechanism is essential for improvement of graft survival. This study from the Indian subcontinent aims (i) to determine the incidence of transplant glomerulopathy (TG) and thrombotic microangiopathy (TMA) in a large cohort of indicated renal transplant biopsies, (ii) to evaluate the histological and ultrastructural features of TG and TMA, and (iii) to assess the relationship between the two glomerular lesions. Of a total of 1792 indication renal transplant biopsies received over 5 years (2006-2010), 266 biopsies (of 249 patients) had significant glomerular pathology and were further analyzed along with immunofluorescence, electron microscopy (EM), and C4d immunohistochemistry. TG is the most common glomerular lesion followed by TMA seen in 5.97% and 5.08% of allograft biopsies, respectively, which constitutes 40.23% and 34.2% of biopsies with significant glomerular lesions. Pathologic antibody-mediated rejection (AMR) is associated with both TG and TMA in 71% and 46.5%, respectively. A coexistent TG was found in 18.4% of biopsies with TMA. Endothelial swelling with subendothelial widening, a feature of TMA, is also seen in early TG by EM. Our findings support the concept that TG evolves from a smoldering TMA of various causes.

Angiotensin II and canonical transient receptor potential-6 activation stimulate release of a signal transducer and activator of transcription 3-activating factor from mouse podocytes

Previous studies have shown that the transcription factor signal transducer and activator of transcription-3 (STAT3) in podocytes plays an important role in progression of HIV nephropathy and in collapsing forms of glomerulonephritis. Here, we have observed that application of 100 nM angiotensin II (Ang II) to cultured podocytes for 6-24 hours causes a marked increase in the phosphorylation of STAT3 on tyrosine Y705 but has no effect on phosphorylation at serine S727. By contrast, Ang II treatment of short periods (20-60 minutes) caused a small but consistent suppression of tyrosine phosphylation of STAT3. A similar biphasic effect was seen after treatment with the diacylglycerol analog 1-oleoyl-2-acetyl-sn-glycerol (OAG), an agent that causes activation of Ca(2+)-permeable canonical transient receptor potential-6 (TRPC6) channels in podocytes. The stimulatory effects of Ang II on STAT3 phosphorylation were abolished by small-interfering RNA knockdown of TRPC6 and also by inhibitors of the Ca(2+)-dependent downstream enzymes calcineurin and Ca(2+)-calmodulin-dependent protein kinase II. The stimulatory effects of Ang II appear to be mediated by secretion and accumulation of an unknown factor into the surrounding medium, as they are no longer detected when medium is replaced every 2 hours even if Ang II is continuously present. By contrast, the inhibitory effect of Ang II on STAT3 phosphorylation persists with frequent medium changes. Experiments with neutralizing and inhibitory antibodies suggest that the STAT3 stimulatory factor secreted from podocytes is not interleukin-6, but also suggest that this factor exerts its actions through a receptor system that requires glycoprotein 130.

Successful treatment of adult-onset collapsing focal segmental glomerulosclerosis with rituximab

Collapsing focal segmental glomerulosclerosis (FSGS), or collapsing glomerulopathy (CG), responds poorly to commonly employed therapies, with a high proportion of patients progressing to end-stage renal disease. We report an adult in a nephrotic state, diagnosed with minimal-change disease on biopsy, who failed to respond to steroids, calcineurin inhibitors (CNIs), mycophenolate mofetil and cyclophosphamide. Repeat biopsy showed CG. Treatment with 4 weekly doses of rituximab led to sustained remission of his nephrotic state. This is the first report of adult-onset CG that has responded favourably to rituximab. Rituximab could be a treatment option for patients with this difficult-to-treat condition.

Prospective 5-year follow-up of cyclosporine treatment in children with steroid-resistant nephrosis

BACKGROUND

Cyclosporine has improved remission rates in children with steroid-resistant nephrotic syndrome (SRNS). However, little prospective long-term follow-up data is available.

METHODS

We prospectively followed and analyzed 5-year outcomes of all 35 patients enrolled in our previous prospective multicenter trial with cyclosporine and steroids in children with SRNS. At enrollment, 23 cases were classified as minimal change (MC), five as diffuse mesangial proliferation (DMP), and seven as focal segmental glomerulosclerosis (FSGS).

RESULTS

Renal survival at 5 years (median 7.7 years) was 94.3 %. Patient status was complete remission (CR) in 31 (88.6 %) (MC/DMP, 25; FSGS, 6); partial remission in one (FSGS); and non-remission in three (MC/DMP), including chronic kidney disease and end-stage kidney disease in one each. Among 31 patients with CR, 22 (71.0 %) were receiving treatment with immunosuppressants at 5 years, including cyclosporine in 19, and seven of these 22 continued to show frequent relapse. Response to cyclosporine at 4 months predicted 5-year outcome in 31 of 35 patients.

CONCLUSIONS

Although SRNS treatment with cyclosporine provides high renal survival and remission rates, many children require ongoing immunosuppression. Management has advanced from the prevention of end-stage kidney disease to the long-term maintenance of remission and management of relapse after induction therapy.

Apolipoprotein L1 risk variants associate with systemic lupus erythematosus-associated collapsing glomerulopathy

Collapsing glomerulopathy is a devastating renal disease that primarily affects African Americans and associates with numerous etiologies, such as HIV and autoimmune disease. The presence of APOL1 risk alleles associates with HIV-associated collapsing glomerulopathy, but it is unknown whether these risk alleles also associate with systemic lupus erythematosus (SLE) -associated collapsing glomerulopathy. Here, re-examination of 546 renal biopsies from African-American patients with SLE identified 26 cases of collapsing glomerulopathy, which we genotyped for APOL1 risk alleles using DNA extracted from archived biopsy tissue. APOL1 strongly associated with SLE-associated collapsing glomerulopathy (P<0.001). In a recessive model, two APOL1 risk alleles conferred 5.4-fold (95% CI=2.4 to 12.1) higher odds of developing SLE-associated collapsing glomerulopathy (P<0.001). In conclusion, APOL1 genotyping of African-American patients with SLE might help identify patients at risk for collapsing glomerulopathy, an entity with a poor prognosis that is often resistant to treatment.

Cytomegalovirus-induced collapsing focal segmental glomerulosclerosis

Collapsing glomerulopathy is an aggressive morphologic variant of focal segmental glomerulosclerosis which typically presents with nephrotic syndrome and rapidly progressive renal failure. Most cases of collapsing glomerulopathy are associated with human immunodeficiency virus infection. We present a rare case of collapsing glomerulopathy associated with acute cytomegalovirus (CMV) infection in an immunocompetent host with improvement in renal function after the treatment of CMV with ganciclovir. CMV may be an under-recognized cause of collapsing glomerulopathy which may respond to antiviral treatment.

Collapsing glomerulopathy and hemolytic uremic syndrome associated with falciparum malaria: completely reversible acute kidney injury

Acute kidney injury (AKI) is one of the most dreaded complications of severe malaria. Herein, we report a case of spontaneous resolution of AKI due to collapsing glomerulopathy (CG) and hemolytic-uremic syndrome (HUS) associated with P. falciparum malaria. Our case report highlights the fact that early intervention on the triggering cause of CG without a long course of steroids may obtain a remission of this severe subset of CG and may obtain a remission of HUS without therapeutic plasmapheresis The etiologic treatment of CG and HUS may avoid progression to end-stage renal disease.

Collapsing focal segmental glomerulosclerosis: Increasing the awareness

Collapsing focal segmental glomerulosclerosis (cFSGS), also known as collapsing glomerulopathy (CG) is of considerable interest for a variety of reasons. Its incidence is on the rise, and in many parts of the world, it has emerged as one of the leading causes of end-stage renal disease (ESRD). There is currently no specific treatment and the response to standard immunotherapeutic agents is poor. Majority of the cases have been reported from the western countries, but the lesion is also being increasingly recognized in the tropical regions. It is imperative to increase the awareness of the lesion among the pathologists and the nephrologists from the developing countries for its accurate diagnosis and appropriate prognostication.

Collapsing focal segmental glomerulosclerosis: Current concepts

Collapsing focal segmental glomerulosclerosis (cFSGS), also known as collapsing glomerulopathy is currently classified under the rubric of FSGS. However, its defining morphological features are in stark contrast to those observed in most other variants of FSGS. During the early stage of the disease, the lesion is characterized pathologically by an implosive segmental and/or global collapse of the glomerular capillary tufts, marked hypertrophy and hyperplasia of podocytes, and severe tubulointerstitial disease. With advancement of the disease, segmental and/or global glomerulosclerosis is also observed in association with the collapsing lesions. The etiology of this enigmatic disorder is still elusive, but a growing list of diseases/conditions is being reported in association with this morphological pattern of renal parenchymal injury. The pathogenesis of cFSGS involves discreet epithelial cell injury leading to cell cycle dysregulation and a proliferative cellular phenotype. From the clinical perspective, cFSGS is notorious for its propensity to affect black people, a high incidence and severity of nephrotic syndrome, marked resistance to empirical therapy, and rapid progression to end-stage renal disease. The lesion has also been reported in transplanted kidneys either as recurrent or de novo disease, frequently leading to graft loss. Most cases have been reported in western countries, but the lesion is also being increasingly recognized in the tropical regions. The recent increase in reporting of cFSGS partly reflects a true increase in the incidence and partly a detection bias. There is no specific treatment for the disorder at present. Newer insights into the pathogenesis may lead to the development of targeted and specific therapy in near future. There is an urgent need to increase awareness of the lesion among pathologists and nephrologists, especially those from developing countries, to ensure accurate diagnosis and appropriate managment. With the accumulation of more and more data, it is hoped that the prevailing confusion about the nosological identity of the lesion will also be resolved in a more logical way.

Familial collapsing focal segmental glomerulosclerosis

The majority of patients with non-HIV-related collapsing focal segmental glomerular sclerosis (FSGS) have idiopathic disease. Only a few genetic forms associated with rare syndromes have been described in families. Here we report two families with multiple members who have collapsing FSGS with no clear associated secondary etiology. Genetic analysis revealed a defect in the TRPC6 gene in one family, but excluded all known common inherited podocyte defects in the other family. The course and response to treatment differed dramatically among members of the same family.

De Novo Collapsing Glomerulopathy: An Unusual Cause of Early Graft Failure following Kidney Transplantation

Collapsing glomerulopathy (CG) is a variant of focal segmental glomerulosclerosis (FSGS) characterized histologically by prominent glomerular capillary tuft collapse with hypertrophy and hyperplasia of podocytes and tubulointerstitial damage. Patients usually present with heavy proteinuria and rapidly progressive renal failure. We report a patient who developed de novo CG with severe clinical manifestations including worsening renal failure and nephrotic syndrome within six months of receiving deceased donor kidney transplant. Secondary work-up was negative, and despite therapy with high-dose steroids and plasmapheresis, allograft function rapidly deteriorated with the need for dialysis. Theories about the pathogenesis of this entity as well as treatment modalities are discussed.

Collapsing glomerulopathy in sickle cell disease: a case report

Introduction

Sickle cell disease has been associated with many renal structural and functional abnormalities. Collapsing glomerulopathy or the collapsing variant of focal segmental glomerulosclerosis is a rare clinicopathologic entity in patients with sickle cell disease that requires timely diagnosis and aggressive management.

Case presentation

In this case report we describe a 21-year-old African-American woman with a medical history of significant sickle cell disease and asthma. She was admitted for pain, decreased urine output, bilateral leg swelling and reported weight gain. During her period of hospitalisation she developed acute renal failure requiring dialysis. Further investigation revealed the collapsing variant of focal segmental glomerulosclerosis.

Conclusions

Although focal segmental glomerulosclerosis is a common feature of sickle cell nephropathy, the collapsing variant of focal segmental glomerulosclerosis or collapsing glomerulopathy has been rarely documented. Even when other risk factors are controlled, collapsing glomerulopathy has a very poor prognosis. This is a rare case of a patient with massive proteinuria presenting as acute renal failure with a very poor response to corticosteroids and a much faster rate of progression to end-stage renal disease.

Collapsing glomerulopathy in Portugal: a review of the histological and clinical findings in HIV and non-HIV patients

BACKGROUND

Collapsing glomerulopathy (CG) is a glomerulonephritis seen in association with human immunodeficiency virus (HIV) infection, known as HIV-associated nephropathy (HIVAN), and less frequently observed in non-HIV-infected patients. Method. The aim of this study was to review the histological and clinical findings of all CG diagnosed since 1981 in our laboratory. Result. Since 1981, 18 kidney biopsies with collapsing features were diagnosed among 6130 biopsies performed: 72.2% (n = 13) males, mean age 33.8 ± 9.7 years, 61.1% (n = 11) of black ethnic origin. HIV infection was present in 10 patients. Mean serum creatinine (Scr) was 4.7 ± 2.5 mg/dL, and mean proteinuria was 6.1 ± 5 g/24 h. Both HIVAN and non-HIVAN patients were similar in terms of age, gender and dialysis requirement. In the HIVAN population, African origin was predominant and more frequent than in the non-HIVAN population, Scr was higher and proteinuria was less severe. Interstitial infiltrate, interstitial fibrosis and tubular atrophy were severe, and the presence of microcystic dilatation of renal tubules was more common. Immunofluorescence was positive in six patients. In the non-HIVAN population, this histological lesion was related to an infectious illness in 6/8 patients and to the use of illegal oral drugs in one patient. Interstitial infiltrate, interstitial fibrosis and tubular atrophy presented as moderate to severe, and tubular atrophy correlated with dialysis requirement. Mesangial proliferation was present in 3/8 patients, with C3 and IgA deposits.

CONCLUSION

CG is a rare podocytopathy. In this study, the association between infection and CG is evident, and we may suggest that infections could, in a direct or indirect manner, be a trigger of podocyte injury.