Submitted May 17, 2006
Accepted July 31, 2006
Monoclonal immunoglobulin with anti-transferrin activity:
a rare cause of hypersideremia with increased transferrin
saturation
Marie-Alexandra Alyanakian, Youri Taes, Mimouna Bensaid, Berta Segovia, Pierre Aucouturier, Jean-Didier Rain, Joris Delanghe, Bruno Varet, and Carole Beaumont*
AP-HP, Hopital Necker, Laboratoire d'Immunologie; Universite Paris 5 Rene Descartes
Department of Clinical Chemistry, Ghent University Hospital
AP-HP, Service de medecine nucleaire, Hopital Saint Louis
AP-HP, Hopital Necker, Service d'Hematologie adultes; Universite paris 5 Rene Descartes
INSERM U773, Centre de Recherche Biomedicale Bichat Beaujon; Universite Paris 7 Denis Diderot
* Corresponding author; email: beaumont{at}bichat.inserm.fr.
Two unusual but similar cases of very high serum iron,
extremely high transferrin concentrations (5.4 - 6.5
g/l) and increased transferrin saturation are reported. No
anemia or microcytosis were observed. The ferritin
concentration remained within the normal range and no iron
overload was observed. In one case, the in vivo half-life
of 59Fe-labelled transferrin was shown to be
prolonged (206 min vs 75 min for controls). In both
patients, a monoclonal IgG was observed in the serum. The
association between serum transferrin and monoclonal IgG
was demonstrated by Western blot analysis and affinity
chromatography.
We suggest that the transferrin bound to the monoclonal
IgG molecule has a prolonged half-life in the circulation,
leading to high transferrin concentrations, and that the
increased serum iron values prevent the onset of anemia.
The anti-transferrin activity of monoclonal antibody
should be added to the list of situations accounting for
elevated serum iron with elevated transferrin saturation.
