Abstract • 94
A 9 year old boy was first admitted for evaluation of neutropenia and cervical lymphadenopathy. A low serum IgG with non detectable IgG2, IgG4 and IgE, low IgA and increased IgM were found, findings consistent with the diagnosis of Hyper-IgM syndrome. Chest X-ray and cell mediated immunity evaluation were normal. By that time lymph node biopsy showed reactive hyperplasia. The child was doing well on supportive therapy with IVIG every 21 days and GSCF during neutropenic periods. Mild episodes of reccurent upper respiratory tract infections, wheezing and mild diarrhea were the consequences of his immunodeficiency. Three years following initial admission, the boy presented with a rapid progression of his organomegaly (spleen 12cm, liver 8cm below margins), cervical, mediastinal, axillary, abdominal and inguinal lymphadenopathy with a concomitant polyclonal increase in IgM serum levels (as high as 4500mg/dl) and increased serum a-FP. Extensive investigation for infectious agents, as cause of the lymphoproliferation did not yield positive results. Biopsies obtained from liver, spleen abdominal and inguinal lymph nodes showed a polyclonal B-cell hyperplasia with intact secondary follicles and presence of germinal centers. Analysis of the expression of CD40L in peripheral blood lymphocytes was normal, most likely excluding the diagnosis of Hyper-IgM syndrome. At the age of four, he started having cerebellar ataxia and occular telangiectasies, symptoms and findings, which were progressively more prominent. By that time an MRI showed cortical cerebellar degeneration, while karyotype with bleomycin for evaluation of chromosomal instability and radiosensitivity test, by flow-cytometric analysis, performed in peripheral blood lymphocytes, were consistent with Ataxia-Telangiectasia. The case represents a typical AT with massive persistent lymphoproliferation and high polyclonal IgM serum levels.
