Dr. Kathrin Luckner (Lübeck/ DE), Dr. Friederike Wortmann (Lübeck/ DE), Tina Bunge-Philipowski (Lübeck/ DE), Petra Glessing (Lübeck/ DE), Prof. Dr. Siegfried Görg (Lübeck/ DE), PD Dr. David Juhl (Lübeck/ DE)
Background
A 53 year old female patient with multiple myeloma (IgG-kappa) presented with unexpected positive reactions in the indirect antiglobulin test (IAT) after autologous stem cell transplantation (HSCT) 3 days prior to the blood draw. With enzyme treated test cells no reactions were noticed. The auto control was negative. Diagnostic tests with blood taken directly prior the HSCT had been negative. She had not received further therapy between the two samples, no blood products had been given before.
Methods
Blood samples that were obtained before and after HSCT were screened in the IAT with and without pre-treatment of test cells with the Fab-fragment of anti-CD38 (DaraEx®) assuming, that the recently given autologous stem cell product could have contained daratumumab.
Results
Samples taken during therapy with anti-CD38 (daratumumab) (last dose was given 3 weeks before stem cell collection) and the sample taken by the stem cell collection showed low- but panreactive antibody screening in IAT, negative auto control but negative antibody screening with DaraEx®.
The initial samples during the current hospitalization including a sample taken in the morning of the autologous stem cell transplantation were unremarkable.
The next sample sent in 3 days later was panreactive in IAT with a negative auto control but was negative with DaraEx® again.
The phenomenon was visible in three samples sent in during the next ten days, on day 13 the antibody screening in the IAT without DaraEx® was negative again.
Conclusion
This case shows a presumable transmission of daratumumab by HSCT which caused interferences in immunohematological diagnostic several months after last doses of daratumumab.
It had to be kept in mind that events which had taken place before a collection of stem cells for autologous transplantation might cause unexpected results in immunohematological diagnostic after the transplantation.
For further confirmation, measurement of anti-CD38 in archive samples is intended.
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