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IMMUNOBIOLOGY
From the Department of Pediatric Oncology, Institute of
Development, Aging and Cancer, Tohoku University, Sendai, Japan;
Department of Human Genome and Multifactorial Disease, Instituto di
Tecnologie Biomediche Avanzate, Consiglio Nazionale delle Ricerche,
Milano, Italy; Miyagi Red Cross Blood Center, Sendai, Japan; and
Division of Transfusion, Tohoku University Hospital, Sendai, Japan.
Mutations of the RAG1 or RAG2 protein that eliminate their
recombination activity result in T-B-severe combined immunodeficiency (SCID), whereas mutations retaining partial recombination activity lead
to Omenn syndrome, a peculiar SCID characterized by increased host T
cells and absence of circulating B cells. The prognosis of this disease
is fatal, unless hematopoietic stem cell transplantation is performed.
This study reports a case of atypical SCID, carrying RAG1 mutations.
The patient survived for 6 years without hematopoietic stem cell
transplantation. The missense mutation, tested by in vivo recombination
assay, revealed residual recombination activity. By the age of 5 years,
the patient developed host B cells, but not T cells, possibly
due to engrafted maternal T cells. In addition, the host B cells were
able to produce antibodies, including anti-herpes simplex
virus-antibodies. The fact that host B cells could produce antibodies
in this patient could explain not only the mild phenotype observed but
also, at least in part, how patients with Omenn syndrome produce
immunoglobulin E and sometimes immunoglobulin M, as the same missense
mutation of RAG1 gene has been reported in a patient with
Omenn syndrome. This article has been cited by other articles:
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| Copyright © 2001 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
