Association between diuretic administration before diagnosis and incidence of acute kidney injury in patients with minimal change disease: A single-center observational study

We examined the association between diuretic administration before the diagnosis of minimal change disease and the incidence of acute kidney injury. Moreover, we examined whether the use of diuretics affected the time to complete remission in adults with such disease.The present study was a single-center, retrospective, observational cohort study. We included 107 patients with biopsy-proven minimal change disease who were treated at a tertiary referral center in Japan between January 1, 2000 and March 31, 2019. All biopsy specimens were examined by a board-certified renal pathologist. The patients were considered to have minimal change disease when the kidney biopsy specimen had no glomerular lesions or only mild focal mesangial prominence (not exceeding 3 or 4 cells per segment) by light microscopy and/or foot process effacement by electron microscopy. Logistic regression and Kaplan-Meier curve analyses were performed, comparing the data of patients who received diuretics or not.The median age was 47 (28-66) years, 52% of patients were women, and the median proteinuria dosage was 8.3 (5.3-11.2) g/d. When minimal change disease was diagnosed, 27% of patients were taking diuretics. Within 30 days after the diagnosis, acute kidney injury occurred in 27% of patients. On multivariable logistic regression analysis, the use of diuretics was significantly associated with a higher risk of acute kidney injury. The use of diuretics was also associated with a longer time to complete remission.Diuretic administration can be associated with an elevated acute kidney injury risk and longer remission time in adult patients with newly diagnosed minimal change disease.

Podocin and uPAR are good biomarkers in cases of Focal and segmental glomerulosclerosis in pediatric renal biopsies

There are controversies whether Minimal Change Disease (MCD) and Focal and Segmental Glomerulosclerosis (FSGS) are distinct glomerular lesions or different manifestations within the same spectrum of diseases. The uPAR (urokinase-type plasminogen activator receptor) and some slit diaphragm proteins may be altered in FSGS glomeruli and may function as biomarkers of the disease in renal biopsies. Thus, this study aims to evaluate the diagnostic potential of uPAR and glomerular proteins for differentiation between MCD and FSGS in renal pediatric biopsy. Renal biopsies from 50 children between 2 and 18 years old were selected, with diagnosis of MCD (n = 29) and FSGS (n = 21). Control group consisted of pediatric autopsies (n = 15) from patients younger than 18 years old, with no evidences of renal dysfunction. In situ expressions of WT1, nephrin, podocin and uPAR were evaluated by immunoperoxidase technique. Renal biopsy of patients with MCD and FSGS expressed fewer WT1 (p≤0.0001, F = 19.35) and nephrin (p<0.0001; H = 21.54) than patients in the control group. FSGS patients expressed fewer podocin than control (p<0.0359, H = 6.655). FSGS cases expressed more uPAR than each of control and MCD (p = 0.0019; H = 12.57) and there was a positive and significant correlation between nephrin and podocin (p = 0.0026, rS = 0.6502) in these cases. Podocin had sensitivity of 73.3% and specificity of 86.7% (p = 0.0068) and uPAR had sensitivity of 78.9% and specificity of 73.3% (p = 0.0040) for diagnosis of FSGS patients. The main limitation of the study is the limited number of cases due to the difficulty in performing biopsy in pediatric patients. Podocin and uPAR are good markers for FSGS and differentiate these cases from MCD, reinforcing the theory of distinct glomerular diseases. These findings suggest that podocin and uPAR can be used as biomarkers in the routine analysis of renal biopsies in cases of podocytopathies when the lesion (sclerosis) is not sampled.

Monitoring Kidney Dysfunction in Kugelberg-Welander Syndrome

BACKGROUND Kugelberg-Welander (K-W) syndrome is a type of spinal muscular atrophy that causes weakness of the hip-girdle muscles. If severe enough, this weakness can confine patients to a wheelchair in adult life. Proteinuria, a manifestation of kidney dysfunction, is associated with disorders of many organ systems. The evaluation of kidney function in the context of K-W syndrome is challenging. CASE REPORT A 45-year-old man with K-W syndrome first diagnosed at 5 years of age developed peripheral edema and was found to have proteinuria under 1 g/24 h. His past history was significant for hypertension for 7 years. He was managed conservatively initially, but over the next year the serum creatinine concentration increased from 18 to 32 µmol/L (0.2 to 0.36 mg/dL). A percutaneous kidney biopsy was performed in the fetal position due to an inability of the patient to lay prone or supine. Minimal change disease (MCD) was diagnosed. Treatment consisted of dietary salt restriction, ramipril, amiloride, and hydrochlorothiazide, while avoiding corticosteroids. The serum creatinine concentration initially returned to the 18-20 µmol/L (0.2-0.22 mg/dL) range with increased fluid intake, but then slowly declined to 6 µmol/L (0.07 mg/dL) over the next 14 years. Muscle strength remained poor. CONCLUSIONS K-W syndrome, when associated with proteinuria, presents novel diagnostic and therapeutic challenges to the latter. The serum creatinine concentration may be unhelpful in assessing kidney function in K-W syndrome. A conservative management approach to MCD is reasonable to minimize comorbidity.

Paraneoplastic relapsing minimal change disease associated with type A thymoma in an elderly patient: A case report and literature review

Thymoma is a rare mediastinal tumour that can be accompanied by different paraneoplastic syndromes. Here we report a case of Type A thymoma associated with relapsing minimal change disease (MCD). This case highlights: (1) The need to balance rapid prednisolone weaning against risk for relapse in an elderly patient at risk for steroid-induced complications. (2) The addition of calcineurin inhibitor in relapsed thymoma-related MCD, to achieve steroid sparing effects. Resection of the offending tumour and prompt immunosuppressive therapy are critical in getting best renal and overall outcomes in this rare entity.

The utility of urinary CD80 as a diagnostic marker in patients with renal diseases

CD80, which regulates T cell activation, may provide a differential diagnostic marker between minimal change disease (MCD) and other renal diseases, including focal segmental glomerular sclerosis (FSGS). However, recent reports show contrasting results. Therefore, we evaluated the utility of urinary CD80 as a diagnostic biomarker. We collected 65 urine samples from 55 patients with MCD (n = 31), FSGS (n = 4), inherited nephrotic syndrome (n = 4), Alport syndrome (n = 5) and other glomerular diseases (n = 11), and control samples (n = 30). We measured urinary CD80 levels by ELISA. Urinary CD80 (ng/gCr) (median, interquartile range) levels were significantly higher in patients with MCD in relapse (91.5, 31.1-356.0), FSGS (376.2, 62.7-1916.0), and inherited nephrotic syndrome (220.1, 62.9-865.3), than in patients with MCD in remission (29.5, 21.7-52.8) (p < 0.05). Elevation of urinary CD80 was observed, even in patients with inherited nephrotic syndrome unrelated to T cell activation. Additionally, urinary CD80 was positively correlated with urinary protein levels. Our results suggest that urinary CD80 is unreliable as a differential diagnostic marker between MCD in relapse and FSGS or inherited kidney diseases. Increased urinary CD80 excretion was present in all patients with active kidney disease.

Urinary CD80 as a Replacement for Renal Biopsy for Diagnosis of Pediatric Minimal Change Disease

INTRODUCTION

Early diagnosis of minimal change disease (MCD) is challenging in nephrotic children. CD80 is a protein expressed on the surface of podocytes associated with nephrotic syndrome and it is implicated in the induction of proteinuria. This study aimed to investigate the use of urinary CD80 for the diagnosis of MCD.

MATERIALS AND METHODS

Urinary CD80 levels were evaluated in 36 children with nephrotic syndrome and normal glomerular filtration rate. They were divided into three groups of MCD (n = 21), focal segmental glomerulosclerosis (n = 9), and other glomerulopathies (n = 6). The MCD group was subdivided into 2 of those with remission (n = 11) and those in the active stage (n = 10). Forty healthy children were included as controls.

RESULTS

The urinary CD80 level was significantly higher in the MCD group (3.5 ± 2.1 ng/mg creatinine) than in the focal segmental glomerulosclerosis group (1.2 ± 0.5 ng/mg creatinine, P < .001), the other glomerulopathies group (1.4 ± 0.7 ng/mg creatinine, P < .001), and the control group (0.7 ± 0.2 ng/mg creatinine, P < .001), while it showed no significant difference among the non-MCD groups. There was no significant difference between MCD in remission and MCD in relapse, either. A urinary CD80 cutoff value of 1.5 ng/gm creatinine showed a sensitivity of 100% and a specificity of 86% for diagnosis of MCD.

CONCLUSIONS

Urinary CD80 levels were significantly higher in the children with MCD than in the controls and patients with other causes of nephrotic syndrome.

Urine volatile organic compounds as biomarkers for minimal change type nephrotic syndrome

Urinary volatile organic compounds (VOCs) profiling has recently received considerable attention because it can be obtained noninvasively and conveniently while it can be successfully used in a variety of diseases and can provide unique biomarkers. The aim of current study was to investigate potential biomarkers between minimal change type nephrotic syndrome (MCNS) and normal. Urinary samples were collected from 38 minimal change type nephrotic syndrome patients and 15 healthy controls. Solid phase microextraction (SPME) and chromatography- mass spectrometry (GC-MS) were used to analysis the urinary metabolites. To deal with the final data, the statistical methods principal component analysis (PCA) and orthogonal partial least-squares discriminant analysis (OPLSDA) were performed. Six specific VOC biomarkers were present at abnormal levels in the urine of MCNS patients. These VOCs included trans-2,2-dimethyl-4-decene; pyrrole; carbamic acid, monoammonium salt; 1-butyne, 3,3-dimethyl-; diisopropylamine; and 4-heptanone. These biomarkers may be useful as a new diagnostic method and for monitoring the prognosis for MCNS patients.

Reduced INF2 expression in nephrotic syndrome is possibly related to clinical severity of steroid resistance in children

AIM

Mutations of the inverted formin 2 gene (INF2), which encodes a member of the formin family, cause autosomal dominant focal segmental glomerulosclerosis (FSGS) and Charcot-Marie-Tooth (CMT) disease-associated FSGS. However, their role in idiopathic FSGS remains unclear. This study investigated INF2 localization in the normal adult kidney and its expression in children with idiopathic nephrotic syndrome.

METHODS

We generated a rabbit polyclonal antibody against the conjugated peptide from human INF2 and studied the glomerular expression of INF2 and synaptopodin using normal human adult kidney tissues and tissues from children with glomerular diseases such as minimal change disease (MCD), FSGS, IgA nephropathy (IgAN), non-IgA mesangial proliferative glomerulonephritis (non-IgAN), and Henoch-Schönlein purpura nephritis (HSPN).

RESULTS

The anti-INF2 antibody detected an approximately 140-kD fragment isolated from adult mature glomeruli by western blotting. Immunohistochemically, INF2 was detected in podocytes and renal arteries. Among 56 patients, INF2 in glomeruli was expressed at a similar level in patients with MCD, IgAN, non-IgAN, or HSPN and controls. In FSGS patients, INF2 expression in glomeruli was either decreased or absent. There was a relationship between decreased INF2 expression and the clinical severity of steroid resistant nephrotic syndrome (SRNS).

CONCLUSION

We propose that examination of INF2 expression may help to differentiate MCD from FSGS and evaluate the clinical severity of SRNS in children.

Impact of acute kidney injury on coagulation in adult minimal change nephropathy

A hypercoagulable state exists in patients with nephrotic syndrome (NS), which more easily leads to venous thromboembolism (VTE). However, whether acute kidney injury (AKI), a common complication of NS, affects the hypercoagulable state and VTE has rarely been elucidated. In this study, we aimed to explore coagulation changes and analyze relevant influencing factors in NS-AKI patients.A total of 269 consecutive NS patients with minimal change disease (MCD) between 2011 and 2016 were included in this observational study. Ninety-one cases were in the AKI group and 178 cases in the non-AKI group. The 1:1 propensity score matching (PSM) method was applied to match the baseline information. The coagulation biomarkers were compared, and the thrombosis events were recorded. Linear correlation was performed to detect any relation between D-dimer and clinical data.The PSM method gave matched pairs of 88 MCD patients with AKI and non-AKI patients, resulting in no differences in baseline information. The D-dimer, fibrinogen, and thromboelastography parameters maximum amplitude (MA), G values of the MCD-AKI patients were significantly higher than the levels of the MCD patients without AKI (D-dimer: 1.8 [1.0, 3.3] vs 1.1 [0.6, 1.7] mg/L, P < 0.001; fibrinogen: 7.0±2.0 vs 6.5 ± 1.4 g/L, P = 0.036; MA: 74.6 ± 5.0 vs 70.5 ± 5.3 mm, P = 0.020; G: 15.7 ± 5.3 vs 12.5 ± 3.3, P = 0.034). For the MCD patients, the serum creatinine, white blood cell count, and interleukin-6 levels in the patients with D-dimers >1 mg/L were significantly higher than those of patients with D-dimers ≤1 mg/L. The correlation analysis showed that the D-dimer level was correlated with serum creatinine, white blood cell count, and interleukin-6 (r = 0.410, P =  < 0.001; r = 0.248, P =  < 0.001; r = 0.306, P =  < 0.001, respectively). Five deep vein thrombosis events occurred in the AKI group and 1 pulmonary embolism event occurred in the non-AKI group after adjusting the propensity score value. AKI appeared to have an association with higher incidence of VTE, but the difference was not statistically significant (RR: 4.9, 95% CI: 0.6-42.7, P = 0.154).The MCD-NS patients complicated with AKI had a more severe hypercoagulable state, which might be associated with the active inflammation of AKI that mediated activation of the coagulation system.

Minimal change disease in a patient with myasthenia gravis: A case report

BACKGROUND

Myasthenia gravis superimposed with proteinuria is a very rare disorder with only 39 cases reported so far. Of these cases, the most commonly associated disorder is minimal change disease. Myasthenia gravis and minimal change disease are both related to the dysfunction of T lymphocytes and hence the 2 disorders may be connected.

METHODS

Here we report the first case on a patient diagnosed with myasthenia gravis concurrently with the minimal change disease, and it was presented in the absence of thymoma or thymic hyperplasia.

RESULTS

Treatment for myasthenia gravis also lowered proteinuria of minimal change disease. He ever experienced good control for myasthenia gravis and minimal change disease. However, pneumonia related septic shock occurred to him and finally he was dead. Minimal change disease is generally considered to occur subsequent to the onset of myasthenia gravis with causal association. After extensive literature review, we noted only 47.8% minimal change disease had occurred after the onset of myasthenia gravis.

CONCLUSION

Minimal change disease mostly occurs in children and if diagnosed in adults, clinicians should search for a potential cause such as myasthenia gravis and other associated thymic disorders.

Predictors of Relapse in Adult-Onset Nephrotic Minimal Change Disease

Minimal change disease (MCD) is a well-known benign primary glomerulonephritis because of its distinct rare tendency to progress to end-stage renal disease. However, factors associated with relapse in adults are not well known. We aimed to identify predictors of relapse in adult-onset MCD patients.A retrospective cohort of 195 patients with adult-onset primary MCD with nephritic syndrome and disease onset between 1979 and 2013 was followed up for >12 months. The number of relapses was counted and predictors of relapse were analyzed.A total of 195 patients were included. Median age at diagnosis was 38 years (IQR, 23-53 years) and 113 (57.9%) were men. During 81 months (IQR, 44-153 months) of follow-up, 92% of patients achieved remission after initial treatment. However, only 60 (32.8%) did not experience a relapse and 11 patients failed to remit. Among the remaining 124 patients, 65 experienced a relapse once or twice and 59 experienced a relapse more than twice. Younger onset age, increased severity of nephrotic features such as lower serum albumin levels and higher cholesterol level were associated with relapse. Interestingly, the grade of mesangial proliferation was lower in patients who experienced a relapse. Initial combined treatment with corticosteroids (CS) and cyclophosphamide reduced the number of relapses. In addition, patients with shorter treatment duration tended to experience relapse more often. Multivariate analysis showed that younger onset age, combined mesangial proliferation, initial treatment regimen, and treatment duration were independent risk factors for relapse. Progression to end-stage renal disease was developed in only a patient.In conclusion, more than two-thirds of adult-onset nephrotic MCD patients experienced relapse, although their renal progression was rare. Younger onset age, CS without cyclophosphamide treatment, and shorter treatment duration were independent risk factors for relapse in adult-onset MCD patients.

Glomerular Immune Deposits Are Predictive of Poor Long-Term Outcome in Patients with Adult Biopsy-Proven Minimal Change Disease: A Cohort Study in Korea

Background and Objectives

There has been little published information on risk factors for poor long-term outcome in adult biopsy-proven minimal change disease (MCD).

Methods

Data from sixty-three adult, biopsy-proven primary MCD patients treated at a tertiary university hospital between 2003 and 2013 were analyzed. Baseline clinical and pathologic factors were assessed for the associations with composite outcome of creatinine doubling, end stage renal disease, or all-cause mortality.

Results

During a median (interquartile) 5.0 (2.8–5.0) years, the composite outcome occurred in 11.1% (7/63) of patients. The rate of glomerular immune deposits was 23.8% (15/63). Patients with glomerular immune deposits showed a significantly lower urine protein creatinine ratio than those without deposits (P = 0.033). The rate of non-responders was significantly higher in patients with glomerular immune deposits than in those without deposits (P = 0.033). In patients with deposits, 26.7% (4/15) developed the composite outcome, while only 6.3% (3/48) developed the composite outcome among those without deposits (P = 0.049). In multivariate Cox proportional hazards regression analysis, the presence of glomerular immune deposits was the only factor associated with development of the composite outcome (hazard ratio: 2.310, 95% confidence interval: 1.031–98.579, P = 0.047).

Conclusion

Glomerular immune deposits were associated with increased risk of a composite outcome in adult MCD patients. The higher rate of non-responders in patients with deposits might be related to the poor outcome. Future study is needed.

Spectrum of steroid-resistant and congenital nephrotic syndrome in children: the PodoNet registry cohort

BACKGROUND AND OBJECTIVES

Steroid-resistant nephrotic syndrome is a rare kidney disease involving either immune-mediated or genetic alterations of podocyte structure and function. The rare nature, heterogeneity, and slow evolution of the disorder are major obstacles to systematic genotype-phenotype, intervention, and outcome studies, hampering the development of evidence-based diagnostic and therapeutic concepts. To overcome these limitations, the PodoNet Consortium has created an international registry for congenital nephrotic syndrome and childhood-onset steroid-resistant nephrotic syndrome.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Since August of 2009, clinical, biochemical, genetic, and histopathologic information was collected both retrospectively and prospectively from 1655 patients with childhood-onset steroid-resistant nephrotic syndrome, congenital nephrotic syndrome, or persistent subnephrotic proteinuria of likely genetic origin at 67 centers in 21 countries through an online portal.

RESULTS

Steroid-resistant nephrotic syndrome manifested in the first 5 years of life in 64% of the patients. Congenital nephrotic syndrome accounted for 6% of all patients. Extrarenal abnormalities were reported in 17% of patients. The most common histopathologic diagnoses were FSGS (56%), minimal change nephropathy (21%), and mesangioproliferative GN (12%). Mutation screening was performed in 1174 patients, and a genetic disease cause was identified in 23.6% of the screened patients. Among 14 genes with reported mutations, abnormalities in NPHS2 (n=138), WT1 (n=48), and NPHS1 (n=41) were most commonly identified. The proportion of patients with a genetic disease cause decreased with increasing manifestation age: from 66% in congenital nephrotic syndrome to 15%-16% in schoolchildren and adolescents. Among various intensified immunosuppressive therapy protocols, calcineurin inhibitors and rituximab yielded consistently high response rates, with 40%-45% of patients achieving complete remission. Confirmation of a genetic diagnosis but not the histopathologic disease type was strongly predictive of intensified immunosuppressive therapy responsiveness. Post-transplant disease recurrence was noted in 25.8% of patients without compared with 4.5% (n=4) of patients with a genetic diagnosis.

CONCLUSIONS

The PodoNet cohort may serve as a source of reference for future clinical and genetic research in this rare but significant kidney disease.

Detection of activated parietal epithelial cells on the glomerular tuft distinguishes early focal segmental glomerulosclerosis from minimal change disease

In rodents, parietal epithelial cells (PECs) migrating onto the glomerular tuft participate in the formation of focal segmental glomerulosclerosis (FSGS) lesions. We investigated whether immunohistologic detection of PEC markers in the initial biopsies of human patients with first manifestation of idiopathic nephrotic syndrome with no immune complexes can improve the sensitivity to detect sclerotic lesions compared with standard methods. Ninety-five renal biopsies were stained for claudin-1 (PEC marker), CD44 (activated PECs), and LKIV69 (PEC matrix); 38 had been diagnosed as early primary FSGS and 57 as minimal change disease. PEC markers were detected on the tuft in 87% of the biopsies of patients diagnosed as primary FSGS. PEC markers were detected in FSGS lesions from the earliest stages of disease. In minimal change disease, no PEC activation was observed by immunohistology. However, in 25% of biopsies originally diagnosed as minimal change disease the presence of small lesions indicative of a sclerosing process were detected, which were undetectable on standard periodic acid-Schiff staining, even though only a single histologic section for each PEC marker was evaluated. Staining for LKIV69 detected lesions with the highest sensitivity. Two novel PEC markers A-kinase anchor protein 12 and annexin A3 exhibited similar sensitivity. In summary, detection of PECs on the glomerular tuft by immunostaining improves the differentiation between minimal change disease and primary FSGS and may serve to guide clinical decision making.

Comparison of characteristics of chronic kidney diseases between Tibet plateau and plain areas

BACKGROUND

The purpose of the current study was to investigate the pathological characteristics of chronic kidney diseases in the Tibet plateau and the plain.

METHODS

77 cases from the Tibet plateau and 154 cases from the plain of renal biopsied patients with chronic kidney diseases were compared in a randomized, and parallel controlled manner. Pathological characteristics were defined according to the standards of WHO and associated classifications.

RESULTS

The ration of sex was shown that most of patients in the plateau region were female, whereas those in the plain were male. The characteristics of pathological types were shown that the patients in the plateau region were primarily minimal change disease, but IgA nephropathy was rare; meanwhile, the proportional lupus nephritis (LN) ratio of the secondary glomerulonephritis in the plateau region was significantly lower than those in the plain region.

CONCLUSIONS

The current data demonstrated that the most common kidney disease in the Tibet Plateau region is still the primary glomerulonephritis as the same as those in the plain region. However, the primary glomerular disease in the plateau region is minimal change disease, and the most common clinical manifestations are the nephrotic syndrome. The IgA nephropathy in the plain is the most frequent disease. In terms of the secondary renal diseases, Henoch-Schnolein purpura nephritis are dominated in the plateau region, whereas LN-based diseases are frequently found in the plain. There is a statistical significance existed between those two groups.

CD80 and suPAR in patients with minimal change disease and focal segmental glomerulosclerosis: diagnostic and pathogenic significance

BACKGROUND

Minimal change disease (MCD) is characterized by increased urinary excretion of CD80, whereas focal segmental glomerulosclerosis (FSGS) is associated with increased serum soluble urokinase-type plasminogen activator receptor (suPAR). The aim of the study was to assess whether the simultaneous measurement of urinary CD80 and serum suPAR helps differentiate MCD and FSGS.

METHODS

Urine and sera were collected from patients with MCD in relapse or in remission, from FSGS patients with nephrotic syndrome, and from healthy individuals. CD80 and suPAR were measured by ELISA.

RESULTS

Urinary CD80 was significantly increased in MCD patients in relapse compared with those in remission and with FSGS patients and control individuals. Serum suPAR levels were significantly higher in patients with FSGS when compared with MCD patients in relapse. Urinary suPAR showed a positive correlation with proteinuria in MCD in relapse and FSGS patients, whereas urinary CD80 correlated with proteinuria only in MCD patients in relapse.

CONCLUSION

Urinary CD80 is elevated in MCD patients in relapse compared with FSGS patients. In contrast, serum suPAR is significantly elevated in FSGS patients. The consistent pattern of these two biomarkers in MCD and FSGS suggests that these two conditions represent different entities rather than a continuum spectrum of one disease.

Early posttransplant nephrotic range proteinuria as a presenting feature of minimal change disease and acute T cell-mediated rejection

Early-onset nephrotic range proteinuria is an extremely rare presentation of an acute rejection episode. Herein, we have reported a patient who developed nephrotic range proteinuria 7 days after receiving a renal allograft from his sister despite minor changes in serum creatinine levels. A kidney biopsy spcimen revealed a T cell-mediated acute rejection process concomitant with minimal change disease (MCD). Proteinuria and renal dysfunction improved dramatically in response to corticosteroids. The possibility of acute cellular rejection and coexisting MCD should be considered in patients with early posttransplantation nephrosis and normal serum creatinine levels. The coexistence of these entities provides support for the role of T cells in the pathogenesis of MCD.

The spectrum of glomerular diseases as studied by immunofluorescence microscopy a single center study in Iraq

INTRODUCTION

Immunofluorescence (IF) microscopy is an important tool for the diagnosis of glomerular diseases. In this study, we focused on using IF technique together with light microscopy (LM) and clinical features in the diagnosis of different types of glomerulonephritis (GN). We aimed to evaluate the spectrum of glomerular diseases in our center and compare it with other centers in Iraq as well as in other countries.

METHODS

We studied a total of 58 kidney biopsies taken between June 2010 and June 2012. All biopsies were examined by LM and 56 of them were examined by IF technique. Clinical information was recorded in a predesigned form before taking the biopsy.

RESULTS

Nephrotic syndrome was the predominant clinical presentation in this study (75.9%). Focal segmental glomerulosclerosis (FSGS) was the commonest GN in this study (29.3%) followed by minimal change disease (20.7%) and membranous glomerulonephritis (13.8%). Immune deposition was observed in 37.5% of cases and the predominant deposit was immunoglobulin G (IgG). In all cases but one, deposition was granular and was found in the glomerular basement membrane (GBM) and/ or in the mesangium. In one case, IF showed dominant positive staining (3+) for complement factor 1q (C1q) in the glomerular mesangium and slightly positive staining for complement factor 3 (C3) in the same mesangeal areas. Two cases (3.4%) fulfilled the clinical, serological and histopathological criteria of lupus nephritis (LN).

CONCLUSION

Nephrotic syndrome was the predominant clinical presentation and FSGS was the most commonly diagnosed GN in this study. Using IF technique and correlating it with LM, clinical, biochemical and serological markers was very useful for the correct diagnosis of glomerular diseases.

Low birthweight and premature birth are risk factors for podocytopenia and focal segmental glomerulosclerosis

BACKGROUND

Recent reports suggest that low birthweight (LBW) is a risk factor for kidney diseases, including focal segmental glomerulosclerosis (FSGS), although the underlying pathological mechanism remains unknown. Podocyte loss triggers glomerulosclerosis; however, whether FSGS in LBW children is associated with podocytopenia is unclear.

METHODS

We reviewed the birthweights and gestational age of all patients who underwent renal biopsies from 1995 to 2011 at our Institute. Sixteen patients had FSGS, of which 6 (37.5%) had LBW; this LBW rate was significantly higher than the overall LBW rate in Japan (9.7%). The incidence of LBW was also high in patients with minimal change nephrotic syndrome (MCNS; 12.5%). The glomerular cell numbers in biopsy sections were calculated using computer image analysis and compared with FSGS of normal birthweight (NBW-FSGS). Biopsy specimens from age-matched patients with MCNS were also compared. Wilms' tumor-1 (WT1) immunohistochemistry was performed to enumerate the podocytes.

RESULTS

All patients in the LBW-FSGS group were also preterm, with an average gestational age of 25.8 weeks. The number of podocytes per glomerulus in the LBW-FSGS patients was 34 and 24% lower as compared to that in the MCNS patients (p < 0.01) and the NBW-FSGS patients (p < 0.05), respectively. Similar results were observed for the WT1-positive glomerular cell number.

CONCLUSION

LBW and premature birth were associated with FSGS development. The possibility that LBW and premature birth may be predisposing factors for severe podocytopenia in children with FSGS warrants further investigation.