IgA nephropathy associated with axial spondyloarthritis responding to treatment by etanercept: A case report

Introduction: Immunoglobulin A (IgA) nephropathy may be associated with spondyloarthritis (SpA). This association raises the possibility of a common pathogenesis. Tumor necrosis factor alpha (TNF alpha) blockers showed good efficiency in SpA and may be efficient in IgA nephropathy. Case report: A case of a 28-year-old man diagnosed with axial SpA is reported. The patient's Bath ankylosing spondylitis disease activity index (BASDAI) was 7 and functional index (BASFI) 9. Laboratory investigations revealed: erythrocyte sedimentation rate (ESR) 38 mm/1st hour, C-reactive protein (CRP) 6 mg/L, serum creatinine 72 lmol/L with a clearance of 108 ml/min; proteinuria 1.55 g/24 h, leucocyturia at 60,000 cells/ml and haematuria 80,000 red cells/ml. The serum IgA level was normal (238.8 mg/dL). Salivary gland and subcutaneous fat biopsies were normal. The renal biopsy showed moderate focal interstitial fibrosis. The glomerular basement membranes were not thickened while the mesangium was slightly thickened. There was no vascular damage. Congo red staining was negative. By immunofluorescent microscopy, there were mesangial deposits of IgA mainly; leading to the diagnosis of IgA nephropathy. Infliximab was initially given with limited efficacy and the patient was switched to etanercept which was effective especially in the osteoarticular symptoms. Leucocyturia, haematuria and proteinuria decreased but did not disappear, and the renal function and blood pressure remained normal. After 2 years there remained a persistent efficacy and good profile of tolerance (BASDAI = 2.2, BASFI = 4, CRP = 2, ESR = 21, proteinurua = 0.5 g/24 h). Conclusion: Etanercept may be a potentially effective option for treating IgA nephropathy associated with axial SpA. (C) 2019 Egyptian Society of Rheumatic Diseases. Publishing services provided by Elsevier B.V.