Evidence is presented for the existence of a "switch" T cell derived from a patient with mycosis fungoides/Sezary's syndrome. The serum immunoglobulin profile in this patient revealed high IgG and IgA but no detectable IgM. Peripheral blood mononuclear cells from this patient secreted only IgG and IgA in the presence of pokeweed mitogen. T cells (Trac) co-cultured with normal allogeneic non-T c...

We report a 10-year-old boy with a severe form of immunodeficiency with hyper-IgM who underwent successful bone marrow transplantation with his HLA-matched sister as donor. Busulfan (20 mg/kg) and cyclophosphamide (200 mg/kg) were used as conditioning. The post-transplant course was uneventful. He is alive 25 months later with full hematological and immunological reconstitution. BORDIGONI, P, e...

To the Editor : Hyper-immunoglobulin M (IgM) syndromes are characterized by the presence of recurrent infections, low levels of IgG and IgA, and normal to high levels of IgM. The X-linked hyper-IgM (X-HIGM) syndrome is the most frequently observed subtype of hyperIgM syndromes (65–70%) and results from defects in the CD40L gene, which encodes for the CD40 ligand (CD154) (1–3). In this study, a ...

Background: Hyper-Immunoglobulin M (IgM) syndrome (HIGM) is a rare primary immunodeficiency in which defective B-cell isotype switching results in a phenotype characterized by elevated or normal serum IgM levels and low levels of other Ig classes, leading to an increased susceptibility to infection, neutropenia, autoimmune disorders, and malignancies. In this disease, a mutation occurs in the C...