A Case Report of an Atypical Presentation of IgG4-Related Disease and Idiopathic CD4 Lymphocytopenia

The IgG4-related disease is a fibroinflammatory disease characterized by tumefactive lesions, a dense lymphoplasmacytic infiltraterich in IgG4-positive plasma cells, storiform fibrosis, and, often but not always, elevated serum levels of IgG4. IdiopathicCD4 lymphocytopenia is a heterogenic and rare syndrome characterized by the detection of a persistent absolute CD4 T cellscount <300 cells/mm3 (or <20% of total T cells) in more than one occasion and no evidence of HIV infection in absenceof immunodeficiency or therapy associated with depressed levels of CD4 T cells. We report the case of a 50-year-old manwith a multiorgan IgG4-related disease presenting in a temporal association with a profound and symptomatic idiopathic CD4lymphocytopenia. Both clinical pictures improved after steroid treatment. Idiopathic CD4 lymphocytopenia has been associatedwith a number of autoimmune conditions but, to the best of our knowledge, this is the first case in which an association with theIgG4-related disease is reported.