Coeliac sprue-associated membranoproliferative glomerulonephritis (MPGN)

Coeliac sprue (CS) may occur in association with immune complex-mediated diseases, including IgA nephropathy, dermatitis herpetiformis and thyroiditis. An association of CS with membranoproliferative glomerulonephritis (MPGN) type 1 is rare, with only two prior cases reported. Here we describe a 45-year-old man with no prior medical history who presented initially with microhaematuria, subnephrotic proteinuria and hypocomplementaemia. A renal biopsy revealed MPGN type 1 with negative serologic workup for secondary causes. The patient was treated conservatively with angiotensin-converting enzyme inhibitors. Several months later, he developed daily non-bloody diarrhoea and was found to have worsening hypoalbuminaemia, hypophosphataemia and severe iron deficiency anaemia. A diagnosis of CS was established based on elevated tTGA (IgA anti-tissue transglutaminase) antibody and positive IgA antiendomysial antibody titres. Proteinuria resolved completely following the initiation of a gluten-free diet, without the use of immunosuppressive therapy and despite tapering of angiotensin-converting enzyme inhibitor. This case illustrates that CS-associated MPGN may precede overt clinical evidence of coeliac disease and may respond to gluten-free diet, without resort to immunosuppressive therapy.