Rituximab associated neutropenia: description of three cases and an insight into the underlying pathogenesis.
BACKGROUND
To describe Rituximab associated neutropenia (RAN), and to explore its underlying mechanism.


METHODS
We describe three patients with RAN. The effect of patient's plasma on colony forming unit, Granulocyte-Monocyte (CFU-GM) was measured by the addition of plasma to the culture of a healthy bone-marrow. Repeated tests were performed after recovery of white count. In the leukopenic period the patient's plasma inhibited CFU growth completely. Control plasma did not have such an effect. Addition of patient's cell supernatant to bone marrow cells did not change the number of CFU. The same effect was demonstrated in normal control. After recovery the patient's plasma did not inhibit colony formation, similar to control.


CONCLUSIONS
RAN is a clinically significant side effect. It may take place during treatment or several months afterwards. Circulating antibodies in the plasma may be responsible for this unique BM toxicity.
Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, Tel Hashomer, Israel. alinabrenner@yahoo.com
Alina
A
Weissmann-Brenner
Baruch
B
Brenner
Inessa
I
Belyaeva
Meir
M
Lahav
Esther
E
Rabizadeh
D000328:Adult; D058846:Antibodies, Monoclonal, Murine-Derived / Q000009:adverse effects* / Q000627:therapeutic use; D001772:Blood Cell Count; D001774:Blood Chemical Analysis; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use*; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000188:drug therapy*; D008875:Middle Aged; D009503:Neutropenia / Q000139:chemically induced* / Q000188:drug therapy; D000069283:Rituximab
D058846:Antibodies, Monoclonal, Murine-Derived; D016179:Granulocyte Colony-Stimulating Factor; D000069283:Rituximab