111In-platelets dynamic study in chronic immune thrombocytopenic purpura.
BACKGROUND
The aim of this work was to estimate the significance of a dynamic study performed during the first 20 minutes after autologous (111)In-oxinate-platelets injection in patients with chronic immune thrombocytopenic purpura (ITP). Two hypotheses were tested: a) dynamic study indicates the place of platelet sequestration; b) dynamic study reflects the quality of platelet separation and labelling procedure.


METHODS
Thirty-nine persons were investigated: 25 with shortened platelet life span (ITP), and 14 with normal platelet life span (6 healthy subjects and eight patients with myelodysplastic syndrome--MDS). Platelet blood count on the day of platelet labelling, general yield of platelet labelling (GYL), differential yield of platelet labelling (DYL), platelet life span, dynamic study with initial platelet accumulation in the liver (IPAL), sequential static study for determining the platelet sequestration index (SI) and platelet sequestration site (SS) were investigated.


RESULTS
Two types of labelled platelet kinetics were determined in both groups of patients: IPAL < 20% and IPAL > 20%. A statistically significant difference in GYL and DYL was noted between the patients with IPAL < 20% and IPAL > 20%. No significant difference was registered in platelet blood count, life span, SS and SI between the two groups of patients. Both yields of platelet labelling were higher in the group with IPAL < 20%. There was no correlation between IPAL and platelet SI, or between IPAL and platelet SS.


CONCLUSIONS
Dynamic study with (111)In-platelets cannot predict platelet sequestration site in ITP patients, but it is a useful and sensitive method of platelet labelling procedure quality control.
Nuclear Medicine Institute Clinical Centre Of Serbia, Belgrade, Yugoslavia. mila.todorovic@kcs.ac.yu
Mila V
MV
Todorović-Tirnanić
Vladimir B
VB
Obradović
Smiljana V
SV
Pavlović
Nada D
ND
Suvajdzić
Ivo V
IV
Elezović
Milica D
MD
Colović
Vladimir B
VB
Bosnjaković