Late‐Onset Combined Immune Deficiency: A Subset of Common Variable Immunodeficiency with Severe T Cell Defect

Background. Common variable immunodeficiency (CVID) is a primary immune deficiency defined by defective antibody production. In most series, a small proportion of patients present with opportunistic infections (OIs). Methods.The French DEFI study has enrolled patients with primary hypogammaglobulinemia and allows a detailed clinical and immunologic description of patients with previous OIs and/or at risk for OIs. Results.Among 313 patients with CVID, 28 patients (8.9%) presented with late-onset combined immune deficiency (LOCID), defined by the occurrence of an OI and/or a CD4+T cell count < 200×106cells/L, and were compared with the remaining 285 patients with CVID. The patients with LOCID more frequently belonged to consanguineous families (29% vs 8%; P=.004). They differed from patients with CVID with a higher prevalence of splenomegaly (64% vs 31%), granuloma (43% vs 10%), gastrointestinal disease (75% vs 42%), and lymphoma (29% vs 4%). Even on immunoglobulin substitution, they required more frequent antibiotics administration and hospitalization. Lymphocyte counts were lower, with a marked decrease in CD4+T cell counts (158×106vs 604×106cells/L; P<.001) and a severe defect in naive CD45RA+CCR7+CD4+T cell counts (<20% of total CD4+T cells in 71% of patients with LOCID vs 37% of patients with CVID; P=.001). The CD19+B cell compartment was also significantly decreased (20×106vs 102×106cells/L; P<.001). Conclusions.LOCID differs from classic CVID in its clinical and immunologic characteristics. Systematic T cell phenotype may help to discriminate such patients from those with CVID. Identification of this phenotype should result in a more fitted diagnostic and therapeutic approach of infections and could provide insights for genetic diagnosis