Coexistence of IgA nephropathy and membranous nephropathy

Concurrent IgA Nephropathy and Membranous Nephropathy, Is It an Overlap Syndrome?

IgA nephropathy (IgAN) and membranous nephropathy (MN) are common glomerulonephritis, the presence of which in the same patient– concurrent of IgAN and MN (cIgAN/MN) has been described occasionally. This study aims to show clinical-pathological features of cIgAN/MN and attempts to suggest underlying pathogenesis using disease-specific biomarkers and a genomics approach. This retrospective cohort study described the clinical and pathological data from 137 patients with cIgAN/MN diagnosed in Peking University First Hospital from 2005 to 2019. One hundred primary IgAN and 100 MN cases were randomly selected as disease controls between the same time interval. Moreover, disease-specific biomarkers and polygenic risk score models were conducted to reveal the underlying pathogenesis. The median age of the cIgAN/MN cases was 45-year-old, and 46% were women. Compared to IgAN, patients with cIgAN/MN had a higher level of 24-hour proteinuria excretion but lower microscopic hematuria. They had a lower median level of galactose-deficient IgA1 (Gd-IgA1, 4.00 versus 5.45 μg/ml, P=0.002) as well as the standardized genetic risk scores of developing IgAN (GRSs: 0.05 versus 0.68, P<0.001). Compared to MN, patients with cIgAN/MN had a lower proportion of nephrotic syndrome and a lower level of albumin-to-creatinine ratio. However, the 24-hour proteinuria levels, serum lipid profiles, proportion of hypertension, and pathology classification were similar. Patients with cIgAN/MN had lower levels of plasma autoantibodies against the M-type transmembrane phospholipase A2 receptor (PLA2R) (11.23 versus 36.59 U/ml, P=0.005). Intriguingly, there were no statistical differences in standardized GRSs of developing MN between them (2.77 versus 3.02, P=0.326). Compared to IgAN, cIgAN/MN may lean towards MN more according to clinical-pathological features, disease-specific biomarker levels, and disease-specific genetic risk scores.

Analysis of Clinical, Pathological and Prognostic Features of Coexistent Membranous and IgA Nephropathy in a Series of 13 Patients at a Tertiary Care Hospital

Background Membranous nephropathy (MN) and immunoglobulin A nephropathy (IgAN) are although two different entities, yet can rarely coexist. There is not much data available on this coexistent disorder, specifically with regard to the treatment modality and outcome. Here, we analyse in detail, retrospectively, 13 cases of coexistent IgA and membranous nephropathy (IgA-MN). Methods Renal biopsy data of 1084 diagnosed cases of either membranous or IgA nephropathy was obtained from March 2015 till March 2021. Out of 1084 patients, 19 diagnosed cases of the coexistent disorder were identified. Six out of 19 patients were excluded because of their unwillingness. From remaining 13 patients, data regarding clinical presentation, investigations, management and treatment response was collected from hospital database, files and via telephonic interview. Results The overall prevalence noted was 1.75%. Among them, 53.8% were females and 46.2% were males. Their median age was 40 years (range: 14-71 years). On workup, mean serum albumin was 2.64 g/dl (range: 1.6-3.8 g/dl), mean proteinuria was 5.5 g/24 hours (range: 1.55-11.48 g/24 hours) and mean creatinine was 0.98 mg/dl (range: 0.5-2.8 mg/dl). Anti-phospholipase A2 receptor antibody positivity was only 14.2%. The renal biopsy of all patients showed thickening of the glomerular basement membrane with granular IgG deposits and mesangial expansion with granular IgA deposits. A total of 80% patients showed complete remission with steroids, calcineurin inhibitors (CNIs) and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEi/ARBs). Conclusion IgA-MN is probably a separate disorder that can only be confirmed on immunofluorescence microscopy. The response to the combination of steroids, CNIs and ACEi/ARBs is found to be the most effective; hence, this combination must often be used for the management of this coexistent disorder.

Double Glomerulonephritis in a Patient with Ankylosing Spondylitis Treated with Biologic Agent: Extrarticolar Involvement or Anti-Tumor Necrosis Factor Alpha Injury? A Case-Based Review

With the widespreading use of biologic drugs, reports of renal injury are increasing, most of which belong to the spectrum of secondary autoimmune syndromes. We present the case of a young man affected by Ankylosing Spondylitis, treated with tumor necrosis factor alpha inhibitors (Anti-TNF) that develop a peculiar renal damage: a coexistence of 2 glomerulonephritis due to different noxae, an IgA nephropaty with a Membranous nephropathy. The first one probably related to the rheumatologic disease, the second one related to Anti-TNF. Despite the underlying mechanisms, the renal involvement both related to Ankylosing Spondylitis and secondary to biologic treatment are currently rare and not predictable. Regular control of renal function and urinalysis during treatment with anti-TNF is mandatory. A concomitant treatment with Disease Modifying Anti Rheumatic Drugs or eventually a low dose of steroids may prevent the formation of anti-drug antibodies and could limit the renal damage related to this phenomenon.

Focal and Segmental Glomerulosclerosis and Membranous Nephropathy overlapping in a patient with Nephrotic Syndrome: a case report

Introduction:

Some cases of membranous nephropathy (MGN) present focal segmental glomerulosclerosis (FSGS) typically associated with disease progression. However, we report a case of a patient who seemed to have MGN and FSGS, both primary.

Case presentation:

A 17-year-old female, Caucasian, presenting lower extremity edema associated with episodes of foamy urine and high blood pressure, had physical and laboratorial exams indicating nephrotic syndrome. A renal biopsy was performed and focal and segmental glomerulosclerosis were observed under light microscopy in some glomeruli presented as tip lesion, and in others it was accompanied by podocyte hypertrophy and podocyte detachment in urinary space, compatible with podocytopathy FSGS. Besides, there were thickened capillary loops with basement membrane irregularities due to "spikes" compatible with MGN stage II. Immunofluorescence showed finely granular IgG, IgG4, and PLA2R deposits in capillary loops and, in electron microscopy, subepithelial deposits and foot process effacement. These morphological findings are compatible with FSGS and MGN stage II.

Conclusions:

In the present case, clinical and morphological characteristics showed a possible overlap of primary FSGS and MGN as focal and segmental glomerulosclerosis does not seem to be related with MGN progression but with the podocytopathy FSGS.

Characteristics of patients with coexisting IgA nephropathy and membranous nephropathy

BACKGROUND

Coexistence of IgA nephropathy (IgAN) and membranous nephropathy (MN) in the same patient is rare. Few studies have reported the clinical and pathological features of patients with combined IgAN and MN (IgAN-MN).

METHODS

The clinico-pathological features, levels of galactose-deficient IgA1 (Gd-IgA1) and autoantibodies against M-type transmembrane phospholipase A₂ receptor (anti-PLA₂R) in sera were compared among IgAN-MN, IgAN, and MN patients.

RESULTS

Twenty-six patients with biopsy-proven IgAN-MN were enrolled. The mean age at biopsy was 43.6 ± 15.9 years, and 65.4% were male. Proteinuria and estimated glomerular filtration rate (eGFR) levels in patients with IgAN-MN were similar to that of MN patients. Compared with the IgAN patients, IgAN-MN patients showed a higher median proteinuria level (4.3 vs. 1.2 g/day, p < .001), and a higher mean eGFR level (101.8 ± 25.4 vs. 78.6 ± 26.9 mL/min/1.73 m², p < .001). IgAN-MN patients presented with milder pathological lesions than IgAN patients according to the Oxford Classification. IgAN-MN patients had comparable serum levels of Gd-IgA1 with those of IgAN patients (353.4 ± 95.5 vs. 347.0 ± 109.6 U/mL, p = .801). Percentage of IgAN-MN patients with detectable serum levels of anti-PLA₂R was lower than that of MN patients (38.5% vs. 68.6%, p = .011).

CONCLUSIONS

IgAN-MN patients display similar clinical features to MN patients and milder pathological lesions than IgAN patients. IgAN-MN patients have similar levels of Gd-IgA1 to those of IgAN patients, and a lower proportion of anti-PLA₂R than MN patients.