The effect of cyclosporine-A on labeling blood cells with radiopharmaceuticals

The effect of cyclosporine-A (CsA) on the labeling efficiencies of red blood cells with reduced ^99mTcO₄^-; leukocytes and platelets with ¹¹¹In oxine was studied. Blood was used from rats treated with CsA (30 mg/kg body weight) for 28 consecutive days and from control rats. For ^99mTc labeling of RBCs, blood was obtained from individual rats and in vitro labeling technique was used. For leukocyte and platelet labeling, blood was pooled from 5 rats either treated with CsA or control. Leukocytes/platelets were labeled with ¹¹¹In oxine using routine techniques. The labeling efficiency for ^99mTc RBCs was 83.42 ± 0.83% (CsA treated) and 84.85 ± 0.62% (control); ¹¹¹In-oxine leukocytes was 38.5 ± 1.75% (CsA treated) and 42.5 ± 3.53% (control); and for ¹¹¹In-oxine platelets, it was 74.0 ± 2.5% (CsA treated) and 78.0 ± 1.41%( control). Comparison of the results indicate that there is no difference between the percent labeling efficiencies of ^99mTc RBCs, ¹¹¹In-oxine leukocytes, and ¹¹¹In-oxine platelets for CsA-treated and control rats. Hence, CsA does not interfere with the labeling process of blood cells with radiopharmaceuticals.