The value of PLA2R antigen and IgG subclass staining relative to anti-PLA2R seropositivity in the differential diagnosis of membranous nephropathy.

BACKGROUND: The diagnostic performance of PLA2R and IgG subclass staining of kidney biopsies relative to anti-PLA2R seropositivity in the differentiation of primary and secondary membranous nephropathy (pMN, sMN) was examined. Besides PLA2R staining - which has a lower specificity than anti-PLA2R antibody serology - there is insufficient knowledge to decide which IgG1-4 subtype immunohistological patterns (IgG4-dominance, IgG4-dominance/IgG1-IgG4-codominance or IgG4-dominance/IgG4-codominance with any IgG subtype) could be used to distinguish between pMN and sMN. METHODS: 87 consecutive Hungarian patients (84 Caucasians, 3 Romas) with the biopsy diagnosis of MN were classified clinically as pMN (n = 63) or sMN (n = 24). The PLA2R and IgG subclass staining was part of the diagnostic protocol. Anti-PLA2R antibodies were determined by an indirect immunofluorescence test in 74 patients with disease activity. RESULTS: For pMN, the sensitivity of anti-PLA2R seropositivity was 61.1%, and the specificity was 90.0%; and similar values for PLA2R staining were 81.0%, and 66.7%, respectively. In all stages of pMN, IgG4-dominance was the dominant subclass pattern, while the second most frequent was IgG3/IgG4-codominance. The sensitivity and specificity scores were: IgG4-dominance 52.2% and 91.7%, IgG4-dominance/IgG3-IgG4-codominance 76.2% and 87.5%, IgG4-dominance/IgG1-IgG4-codominance 64.2% and 75%, and IgG4-dominance/codominance with any IgG subclass 92.1% and 70.8%, respectively. Anti-PLA2R seropositivity, glomerular PLA2R, and IgG4-dominance/codominance significantly correlated with each other. The IgG4 subclass was rarely encountered in sMN. CONCLUSION: In our series, IgG4-dominance had the highest specificity in the differentiation of MN, just as high as that for anti-PLA2R seropositivity. The specificity values of PLA2R staining and IgG4-dominance/codominance with any IgG subclass or IgG4-dominance/IgG1-IgG4 codominance were ≤ 75%. Apart from IgG4 dominance, IgG4-dominance/IgG3-IgG4-codominance also had good statistical value in differentiating pMN from sMN. As IgG subclass switching during the progression of pMN was not the feature of our cohort, pMN in Hungarian patients is presumed to be an IgG4-related disorder right from the start. Although anti-PLA2R seropositivity has become the cornerstone for diagnosing pMN, if a kidney biopsy evaluation is conducted, besides the staining of PLA2R antigen, the evaluation of IgG subclasses provides relevant information for a differential diagnosis. Even in cases with IgG4-dominance, however, malignancy should be thoroughly checked.

[Rapidly progressive proliferative glomerulonephritis with monoclonal immunoglobulin G deposits despite the mild histological changes. Case report]. / Enyhe szövettani eltérések ellenére gyors progressziójú proliferativ glomerulonephritis monoklonális immunglobulin-G-depozitumokkal.

Proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits is characterized by granular deposits of monoclonal IgG; histologically it has typically a membranoproliferative or endocapillary pattern, and seen electronmicroscopically there are dense deposits without substructure. Here, we present the case of a 62-year-old Caucasian woman who was admitted with rapidly progressive kidney failure. The patient's status, the laboratory and imaging examinations did not support prerenal, postrenal and - among the intrinsic causes - vascular and tubulointerstitial origin. The proteinuria and dysmorphic microhematuria suggested rapidly progressive glomerulonephritis. Tests for anti-neutrophil cytoplasmic antibodies, anti-glomerular basement membrane, antinuclear antibodies and cryoglobulins were negative, the C3 and C4 levels were normal. The biopsy evaluation diagnosed proliferative glomerulonephritis with monoclonal IgG deposits because of mesangial granular deposits of IgG3-kappa, C3, and C1q, and ultrastructurally electron-dense deposits (incidence in our adult native kidney biopsy series: 0.18%). 31 glomeruli were assessed histologically. 29 glomeruli displayed mild mesangial hypercellularity, 2 glomeruli were globally sclerotic. Crescents were not observed. Mild arteriolar hyalinosis, interstitial fibrosis and tubular atrophy accompanied the glomerular alterations. In the postbiopsy evaluation, paraprotein or multiple myeloma was not detected. Despite the mild histological findings, the kidney failure progressed, and hemodialysis had to be started two weeks after the biopsy. Steroids, cyclophosphamide and rituximab did not affect her kidney function, and she remained on hemodialysis during the follow-up of 39 months. This report presents for the first time proliferative glomerulonephritis with monoclonal IgG deposits as the possible cause of rapidly progressive nephritic syndrome in the absence of pronounced glomerular proliferative, sclerotic or tubulointerstitial lesions. Orv Hetil. 2018; 159(38): 1567-1572.

Observations of changes of blood pressure before and after neurosurgical decompression in hypertensive patients with different types of neurovascular compression of brain stem.

AIMS: The neurovascular pulsatile compression of the rostral ventrolateral medulla can be divided into different subtypes. The posterior inferior cerebellar artery and/or vertebral artery can compress either the rostral ventrolateral medulla or the cranial nerves IX and X or both and on left, right or both sides. METHODS: It was retrospectively investigated whether the types of neurovascular compression can influence blood pressure values. Data from 13 resistant hypertensive patients after decompression were investigated. RESULTS: Six patients had 2 compressions, two had only medulla compression, four had only nerve compression on the left side and one had 2 compressions on both sides. There was no correlation between the types of compression and the levels of blood pressure, either before or after the decompression. Both, systolic and diastolic blood pressures and pulse pressure also decreased in all cases after the decompression but the change was significant only in the group with 2 compressions on the left side. CONCLUSION: According to our data, in a severe hypertension not responding to conventional antihypertensive therapy, the surgical decompression of the brain stem independently of the types of neurovascular compression could guarantee a decrease of blood pressure and improved sensitivity to antihypertensive medication.

Investigation of cardiac autonomic and peripheral sensory neuropathy in diabetic and nondiabetic patients with hypertension.

Peripheral sensory function and cardiac autonomic neuropathy were studied in 18 nondiabetic and 10 type-2 diabetic hypertensives compared with 11 healthy controls. All the patients were treated with antihypertensive drugs. Cardiac autonomic neuropathy using Ewing method was detected in all patient groups. The current perception threshold values on peroneal nerve at 250 Hz in nondiabetic group and at 250 Hz and at 5 Hz in diabetic group were found increased compared with the controls. In conclusion, so-called typical complications of diabetes can be observed in nondiabetic hypertensives also. Our data might support the essential role of vascular factors in the development of neuropathy.

FHR-5 Serum Levels and CFHR5 Genetic Variations in Patients With Immune Complex-Mediated Membranoproliferative Glomerulonephritis and C3-Glomerulopathy.

Background: Factor H-related protein 5 (FHR-5) is a member of the complement Factor H protein family. Due to the homology to Factor H, the main complement regulator of the alternative pathway, it may also be implicated in the pathomechanism of kidney diseases where Factor H and alternative pathway dysregulation play a role. Here, we report the first observational study on CFHR5 variations along with serum FHR-5 levels in immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G) patients together with the clinical, genetic, complement, and follow-up data. Methods: A total of 120 patients with a histologically proven diagnosis of IC-MPGN/C3G were enrolled in the study. FHR-5 serum levels were measured in ELISA, the CFHR5 gene was analyzed by Sanger sequencing, and selected variants were studied as recombinant proteins in ELISA and surface plasmon resonance (SPR). Results: Eight exonic CFHR5 variations in 14 patients (12.6%) were observed. Serum FHR-5 levels were lower in patients compared to controls. Low serum FHR-5 concentration at presentation associated with better renal survival during the follow-up period; furthermore, it showed clear association with signs of complement overactivation and clinically meaningful clusters. Conclusions: Our observations raise the possibility that the FHR-5 protein plays a fine-tuning role in the pathogenesis of IC-MPGN/C3G.

Validation of distinct pathogenic patterns in a cohort of membranoproliferative glomerulonephritis patients by cluster analysis.

BACKGROUND: A novel data-driven cluster analysis identified distinct pathogenic patterns in C3-glomerulopathies and immune complex-mediated membranoproliferative glomerulonephritis. Our aim was to replicate these observations in an independent cohort and elucidate disease pathophysiology with detailed analysis of functional complement markers. METHODS: A total of 92 patients with clinical, histological, complement and genetic data were involved in the study, and hierarchical cluster analysis was done by Ward method, where four clusters were generated. RESULTS: High levels of sC5b-9 (soluble membrane attack complex), low serum C3 levels and young age at onset (13 years) were characteristic for Cluster 1 with a high prevalence of likely pathogenic variations (LPVs) and C3 nephritic factor, whereas for Cluster 2-which is not reliable because of the small number of cases-strong immunoglobulin G staining, low C3 levels and high prevalence of nephritic syndrome at disease onset were observed. Low plasma sC5b-9 levels, decreased C3 levels and high prevalence of LPV and sclerotic glomeruli were present in Cluster 3, and patients with late onset of the disease (median: 39.5 years) and near-normal C3 levels in Cluster 4. A significant difference was observed in the incidence of end-stage renal disease during follow-up between the different clusters. Patients in Clusters 3-4 had worse renal survival than patients in Clusters 1-2. CONCLUSIONS: Our results confirm the main findings of the original cluster analysis and indicate that the observed, distinct pathogenic patterns are replicated in our cohort. Further investigations are necessary to analyse the distinct biological and pathogenic processes in these patient groups.

C4 nephritic factor in patients with immune-complex-mediated membranoproliferative glomerulonephritis and C3-glomerulopathy.

BACKGROUND: Acquired or genetic abnormalities of the complement alternative pathway are the primary cause of C3glomerulopathy(C3G) but may occur in immune-complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) as well. Less is known about the presence and role of C4nephritic factor(C4NeF) which may stabilize the classical pathway C3-convertase. Our aim was to examine the presence of C4NeF and its connection with clinical features and with other pathogenic factors. RESULTS: One hunfe IC-MPGN/C3G patients were enrolled in the study. C4NeF activity was determined by hemolytic assay utilizing sensitized sheep erythrocytes. Seventeen patients were positive for C4NeF with lower prevalence of renal impairment and lower C4d level, and higher C3 nephritic factor (C3NeF) prevalence at time of diagnosis compared to C4NeF negative patients. Patients positive for both C3NeF and C4NeF had the lowest C3 levels and highest terminal pathway activation. End-stage renal disease did not develop in any of the C4NeF positive patients during follow-up period. Positivity to other complement autoantibodies (anti-C1q, anti-C3) was also linked to the presence of nephritic factors. Unsupervised, data-driven cluster analysis identified a group of patients with high prevalence of multiple complement autoantibodies, including C4NeF. CONCLUSIONS: In conclusion, C4NeF may be a possible cause of complement dysregulation in approximately 10-15% of IC-MPGN/C3G patients.

Neurovascular pulsatile compression and neurosurgical decompression of the rostral ventrolateral medulla in medically resistant hypertensive patients.

BACKGROUND/AIMS: In cases of severe primary hypertension not responding to conventional medical therapy, neurovascular pulsatile compression of the rostral ventrolateral medulla on the left side may be considered as an etiological factor in the hypertension. Through neurosurgical decompression, the blood pressure can be reduced in these cases, and the conventional medication can also become more effective. METHODS: The authors retrospectively analysed the changes in the blood pressure and therapy of patients with or without neurosurgical decompression over a 2-year period. The 2-year data were available for 9 operated and 7 non-operated patients with neurovascular compression. The data of control examinations performed 1, 3, 6, 12 and 24 months after the intervention (or after MR-angiography in the non-operated cases) were analysed. RESULTS: After the decompression, both the systolic and diastolic blood pressure decreased significantly and permanently in all cases, and there was an improved response to the medication. In the non-operated group, the blood pressure did not change significantly during the 2 years. CONCLUSION: In severe hypertension that does not respond to conventional therapy, neurosurgical decompression of the brain stem on the left side can guarantee a long-lasting blood pressure reduction and a better response to antihypertensive medication.