Membranoproliferative Glomerulonephritis and X-Linked Agammaglobulinemia: An Uncommon Association

Introduction. X-linked agammaglobulinemia (XLA) is a primary immunodeficiency characterized by agammaglobulinemia requiring replacement treatment with immunoglobulin. The association of XLA and membranoproliferative glomerulonephritis (MPGN) is unexpected and, to our knowledge, only one case was previously published. Case Report. The authors report the case of a 10-year-old boy with family history and prenatal diagnosis of XLA, treated from birth with intravenous immunoglobulin replacement therapy. He presented with pneumonia, macroscopic hematuria, nephrotic proteinuria, hypoalbuminemia, and hypercholesterolemia with normal renal function and serum complement levels. Renal histology showed immune complex mediated MPGN. He was started on high dose prednisolone and ramipril and switched to weekly subcutaneous immunoglobulin. After a 4-month treatment, hematuria and proteinuria significantly improved and prednisolone was gradually tapered without relapse. Conclusion. The pathogenic process underlying MPGN development in this patient is unknown but residual humoral immunity might play an important role. Thus, this case highlights the risk of autoimmune disorders among patients with XLA. 1. Introduction Membranoproliferative glomerulonephritis (MPGN) is an uncommon cause of chronic nephritis that occurs primarily in children and young adults. In most cases, complement activation is prominent and immune complex formation and deposition in the glomeruli play an important role [1–3]. On the other hand, patients with X-linked agammaglobulinemia (XLA, MIM number 300755), also known as Bruton agammaglobulinemia, have a profound defect in B-lymphocyte development resulting in severe hypogammaglobulinemia. Bruton tyrosine kinase (BTK) gene mutation on the X chromosome has been identified as responsible for this disease. Replacement therapy with regular administration of intravenous (IVIG) or subcutaneous (SCIG) immunoglobulin is the only effective treatment, preventing severe infections, which are the hallmark of the untreated disease [4]. The authors report the case of a patient with XLA who developed MPGN during treatment with IVIG. The association of XLA and MPGN is unusual and, to our knowledge, only one case was previously reported [5], although other cases with renal immune complex deposition were also described [6] and are listed in Table 1. Table 1: Patients with XLA and renal disease due to immune complex deposition. 2. Case Presentation The patient in this report has a family history of XLA with two affected siblings, with their mother being a carrier of