Abstract
Disorders of the long arm of chromosome 11 (11q) are rare and involve various chromosomal regions. Patients with 11q-disorders, including Jacobsen syndrome, often present with a susceptibility for bacterial, prolonged viral and fungal infections partially explained by hypogammaglobulinemia. Additional T-lymphocyte or granular neutrophil dysfunction may also be present. In order to evaluate infectious burden and immunological function in patients with 11q-disorders, we prospectively studied a cohort of 14 patients with various 11q aberrations. Clinically, 12 patients exhibited prolonged and repetitive respiratory tract infections, frequently requiring (prophylactic) antibiotic treatment (n=7), ear-tube placement (n=9) or use of inhalers (n=5). Complicated varicella infections (n=5), chronic eczema (n=6), warts and chronic fungal infections (n=4) were reported. Six patients were on immunoglobulin replacement therapy. We observed a high prevalence of low B-lymphocyte counts (n=8), decreased T-lymphocyte counts (n=5) and abnormal T-lymphocyte function (n=12). Granulocyte function was abnormal in 29% without an aberrant clinical phenotype. Immunodeficiency was found in patients with terminal and interstitial 11q-deletions and in one patient with 11q trisomy. Genetically, FLI1 and ETS1 are seen as causative for the immunodeficiency, but these genes were deleted nor duplicated in 5 of our 14 patients. Alternative candidate genes on 11q such as ATM, CD3-cluster, CBL and THYN1 may have a role in immune dysregulation in our patients. In conclusion, we present evidence that a combined primary immune deficiency may be present in patients with 11q-disorders leading to clinically relevant infections. Therefore, broad immunological screening and necessary treatment is of importance in this patient group.