Impaired immune function in children and adults with Fanconi anemia.

Background: Fanconi anemia (FA) is a rare genetic disorder characterized by genome instability, bone marrow failure, and cancer predisposition. Previously, small studies have reported heterogeneous immune dysfunction in FA. Procedure: We performed a detailed immunologic assessment in a large FA cohort who have not undergone bone marrow transplantation or developed malignancies. Comprehensive quantitative and functional immunologic assessment of 29 FA individuals was compared to healthy age-matched controls. Results: Compared to non-FA persons of similar ages, FA individuals showed lower absolute total B cells (P < 0.001), lower memory B cells (P < 0.001), and decreased IgM (P < 0.001) but normal IgG. NK cells (P < 0.001) and NK cytotoxicity (P < 0.001) were decreased. CD4(+) T cells were decreased (P = 0.022), while CD8(+) T cell and absolute T-cell numbers were comparable. Cytotoxic T cells (P < 0.003), and antigen proliferation response to tetanus (P = 0.019) and candida (P = 0.019), were diminished in FA. Phytohemagglutinin responses and plasma cytokines were normal. Within FA subjects, adults and older children (10 years) exhibited higher CD8(+) T cells than younger children (P = 0.004). Documented atypical infections were infrequent, although oral human papilloma virus (HPV) prevalence was higher (31% positive) in FA. Conclusions: Overall, these results demonstrate a high rate of significant humoral and cellular immune dysfunction. Continued longitudinal study of immune function is critical to understand evolution with age, bone marrow failure, and cancer development.