Abstract
Common variable immune deficiency (CVID) is the most common symptomatic immunodeficiency in adults, but it remains rare. It is characterized by its extremely heterogeneous phenotypic spectrum. We here report the case of a 39-year-old patient presenting with chronic diarrhoea with anal fistula. Laboratory tests showed inflammatory syndrome and malabsorption syndrome, hypogammaglobulinemia on serum protein electrophoresis, global hypogammaglobulinemia in weight-based assignments for immunoglobulin and a low level of lymphocytes in the analysis of lymphocyte subpopulations, thus confirming the diagnosis of common variable immune deficiency (CVID) complicated by systemic AA amyloidosis identified by amyloid deposits in the biopsies. This study highlights the importance of paying attention to common gastrointestinal symptoms of immune deficiency and to suspect it in patients with treatment-resistant symptoms.