Oral direct-acting antiviral therapy for hepatitis C virus infection in X-linked agammaglobulinemia

Oral direct-acting antiviral therapy of hepatitis C virus infection was successful and safe in 3 unrelated adult patients with X-linked agammaglobulinemia. In X-linked agammaglobulinemia (XLA), a mutation in the gene coding for Bruton's tyrosine kinase (btk), which is involved in signaling through the B-cell antigen receptor, leads to absence of mature B cells and lack of antibodies of all immunoglobulin isotypes.1 Replacement therapy with human immunoglobulin derived from plasma donations has to be started as early as possible after diagnosis to prevent life-threatening infections and long-term disability. Infection with the hepatitis C virus (HCV) through contaminated immunoglobulin products has been described in the 1980s in patients with primary antibody deficiency, before blood and plasma donor screening became possible through the discovery of the HCV in 1989.2 Permanent cure of chronic HCV infection in 95% or more of treated patients has become possible through the introduction of direct-acting orally available antiviral (DAA) drugs.3 However, experience about this therapy in the different immunocompromised, difficult-to-treat patient populations is limited to hemodialysis and HIV-infected patients, as well as liver transplant recipients.4 The present study is, to our knowledge, the first to describe DAA HCV therapy in patients with primary antibody deficiency.