#5295 SECONDARY MEMBRANOUS NEPHROPATHY WITH IGA DEPOSITS IN A PATIENT WITH PRIMARY CILIARY DYSKINESIA
Authors: Costa Denise Maria Do Nascimento , Oliveira Camila , Vajgel Gisele , Claizone Thais , Valente Lucila 
Published: June 2023

Abstract

Background and Aims
Membranous nephropathy and IgA nephropathy are two types of common glomerulonephritis worldwide. There are reports of the coexistence of these glomerulopathies, mostly with mesangial expansion and IgA deposits. Furthermore, primary ciliary dyskinesia is rarely associated to glomerulopathy. Thus, we report a case of a patient with primary ciliary dyskinesia with renal biopsy demonstrating membranous glomerulopathy associated with IgA and IgG deposits exclusively in glomerular basement membrane, without complement deposition.

Method
Case report.

Results
A 18 years-old man was referred from the nephropediatric outpatient clinic with subnephrotic hematuria and proteinuria. His medical history included a clinical diagnosis of primary ciliary dyskinesia due to a history of several respiratory infections since birth, asthma, rhinitis and bronchiectasis and a 15 years-old brother with a similar history. He was diagnosed with idiopathic thrombocytopenic purpura at age of one year-old and received prednisone. At 3 years-old he presented with nephrotic syndrome, hematuria and hypertension, and was treated with intravenous methylprednisolone and oral cyclophosphamide for three months. Renal biopsy demonstrated mesangial expansion and thickening of the glomerular basement membrane (GBM), without adequate material for immunofluorescence. Because proteinuria and hematuria persisted, the prednisone dose was increased to 2 mg/kg/day and cyclosporine was started. After 5 years on these medications, persisting with proteinuria, a second biopsy was performed and showed 16 glomeruli, three globally sclerosed and the others with diffuse thickening of the GBM, without other alterations, focal interstitial fibrosis and tubular atrophy and diffuse granular deposits of IgA 1+ and IgG 2+ along the GBM. Cyclosporine and prednisone were discontinued. At age of 18 years-old, he was admitted to adult glomerulonephritis clinic with significant developmental delay (weight 28.6kg and height 1.29m2), no edema and normal arterial blood pressure with RAAS inhibition. Laboratory tests: Hb 8.9 g/dL, serum iron 12 mcg/dL, Creatinine 0.7 mg/dL, albumine 2.3 g/dL. Serologies were negative for syphilis, hepatitis B and C, HIV, ANA and anti-DNA, with normal complement C3, C4 and C1q. Urinalysis revealed proteinuria 1+, hematuria 16.000/mL and proteinuria 1.400 mg/d. CT scan showed symmetrical bronchiectasis in both lungs, with mucoid endobronchial impingement and diffuse bronchial parietal thickening; and chronic post-thrombotic changes with calcified thrombi in the left renal vein, extending into the inferior vena cava. A third renal biopsy was performed showing 38 of 45 (84%) globally sclerosed glomeruli without mesangial matrix changes or capsular adhesions. GBM was thickened with spicules and holes and reactive podocytes. The tubulointerstitial compartment showed moderate atrophy and fibrosis (40-50%). Immunofluorescence microscopy evidenced strong immunoreactivity of IgG 3+/3+, IgA 3+/3+, Kappa 3+/3+ and Lambda 2+/3+, in granular pattern exclusively in GBM, without C3. Electron microscopy showed four sclerosed glomeruli, without deposits. Immunohistochemistry staining for IgG1 2+/3+, and it was negative for PLA2R, NELL-1, THSD7A, Exostosin-1 and 2, IgG 2, IgG3 and IgG4. The patient was maintained with supportive treatment, with RAAS inhibition and SGLT2 inhibitors, without immunosuppression.

Conclusion
This case highlights the codominance of IgG1 and IgA deposits along the MBG, without proliferation or mesangial deposition and without complement activation, in a patient with membranous nephropathy and primary ciliary dyskinesia, a condition rarely associated with glomerulopathies. Although rare, such renal biopsy findings reinforce the need for a better understanding of the different mechanisms of membranous nephritis, in addition to better understanding and management of treatment in this situation.