Cellular and molecular characterisation of the hyper immunoglobulin M syndrome associated with congenital rubella infection.

INTRODUCTION

The hyper-immunoglobulin M syndrome (HIM) is a rare group of immune deficiency disorders characterised by normal or increased serum IgM with normal or reduced IgG, IgA and IgE.

MATERIALS AND

METHODS

We have undertaken detailed cellular and molecular studies in a 53-year-old man with HIM as a result of congenital rubella.

RESULTS

No mutations were detected in the CD40 ligand, activation-induced cytidine deaminase and uracil DNA glycosylase. His T-cell responses to lectins and antigens were normal. Flow cytometry confirmed the presence of CD40 ligand on activated T cells. Most CD40-dependent functions that were tested, including B-cell proliferation, isotype switching and production of memory B cells, were normal. CD40/IL4 dependent rescue from anti-IgM-induced apoptosis was impaired.

CONCLUSION

The detection of cell-surface IgG but lack of serum IgG indicated that he may have an antibody secretion defect.