Hyper-IgM syndrome type 4 with a B lymphocyte-intrinsic selective deficiency in Ig class-switch recombination

Kohsuke Imai, Nadia Catalan, Alessandro Plebani, L. Máródi, Özden Sanal, Satoru Kumaki, Vasantha Nagendran, Philip Wood, Catherine Glastre, Françoise Sarrot-Reynauld, Olivier Hermine, Monique Forveille, Patrick Revy, Alain Fischer, Anne Durandy

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Abstract

Hyper-IgM syndrome (HIGM) is a heterogeneous condition characterized by impaired Ig class-switch recombination (CSR). The molecular defects that have so far been associated with this syndrome -which affect the CD40 ligand in HIGM type 1 (HIGM1), CD40 in HIGM3, and activation-induced cytidine deaminase (AID) in HIGM2 - do not account for all cases. We investigated the clinical and immunological characteristics of 15 patients with an unidentified form of HIGM. Although the clinical manifestations were similar to those observed in HIGM2, these patients exhibited a slightly milder HIGM syndrome with residual IgG production. We found that B cell CSR was intrinsically impaired. However, the generation of somatic hypermutations was observed in the variable region of the Ig heavy chain gene, as in control B lymphocytes. In vitro studies showed that the molecular defect responsible for this new HIGM entity (HIGM4) occurs downstream of the AID activity, as the AID gene was induced normally and AID-induced DNA double-strand breaks in the switch μ region of the Ig heavy chain locus were detected during CSR as normal. Thus, HIGM4 is probably the consequence of a selective defect either in a CSR-specific factor of the DNA repair machinery or in survival signals delivered to switched B cells.

Original languageEnglish
Pages (from-to)136-142
Number of pages7
JournalJournal of Clinical Investigation
Volume112
Issue number1
DOIs
Publication statusPublished - Jul 2003

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ASJC Scopus subject areas

  • Medicine(all)

Cite this

Imai, K., Catalan, N., Plebani, A., Máródi, L., Sanal, Ö., Kumaki, S., Nagendran, V., Wood, P., Glastre, C., Sarrot-Reynauld, F., Hermine, O., Forveille, M., Revy, P., Fischer, A., & Durandy, A. (2003). Hyper-IgM syndrome type 4 with a B lymphocyte-intrinsic selective deficiency in Ig class-switch recombination. Journal of Clinical Investigation, 112(1), 136-142. https://doi.org/10.1172/JCI200318161