Neutrophil antigen 5b is carried by a protein, migrating from 70 to 95 kDa, and may be involved in neonatal alloimmune neutropenia.
BACKGROUND
Neutrophil antigen 5b has been described as involved in transfusion reactions and not in neonatal alloimmune neutropenia.


METHODS
Anti-5b was found in the serum of a mother of a persistently neutropenic newborn, who had several bacterial infections. The neutropenia responded to treatment with recombinant human granulocyte-colony-stimulating factor. Immunoprecipitation experiments performed with this and three other 5b antisera identified a protein, migrating from 70 to 95 kDa, as carrier of 5b. The observed pattern of migration may point to heavy glycosylation of this protein.


RESULTS
Six 5b-negative donors were identified among 54 screened white donors, for a 5b gene frequency of 0.66.


CONCLUSIONS
Alloimmunization to 5b in pregnancy is rare. In the patients with neonatal neutropenia analyzed in the last decade, this was the first case discovered.
de Haas
M
M
Central Laboratory of the Netherlands Red Cross, Amsterdam. M_de_Haas@clb.nl
Muniz-Diaz
E
E
Alonso
L G
LG
van der Kolk
K
K
Kos
M
M
Buddelmeijer
L
L
Porcelijn
L
L
von dem Borne
A E
AE
D000941:Antigens / Q000097:blood; D001782:Blood Donors; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use; D006801:Humans; D007154:Immune System Diseases / Q000097:blood; D016130:Immunophenotyping; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000276:immunology*; D008297:Male; D009503:Neutropenia / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D011233:Precipitin Tests; D011247:Pregnancy; D013290:Streptococcal Infections / Q000097:blood
D000941:Antigens; D016179:Granulocyte Colony-Stimulating Factor