Table 3.

GMP-grade Treg product characteristics and details of indium tropolonate labelling of GMP-Tregs prior to infusion.

	Patient 1*	Patient 2	Patient 3	Patient 4	Patient 5
A) GMP-grade Treg product characteristics
Total GMP-Tregs	32.9 x 106	8.9 x 106	86 x 106	26.1 x 106	21.5 x 106
CD8 x 106	0.01	0.019	0.28	0.017	0.015
CD20 x 106	0.006	0.044	0.66	0.003	0.006
Treg viability, %	99.53	99.7	99.02	99.56	99.43
B) Details of indium tropolonate labelling of GMP-Tregs prior to infusion
Initial activity of indium, Mbq	108	88	125	116	116
Post- labelled Treg viability, %	98	95	96.5	96.2	98.5
Mbq labelled GMP-Tregs, Mbq	0	6.8	20.6	19.8	15.4

(A) GMP-grade Treg product characteristics. GMP-grade Tregs frequency, purity (log reduction of CD8 and CD19 along with purity of CD4positive CD25high GMP-grade Tregs) and viability following CliniMACS isolation. All products were negative for bacterial, fungal and blood borne viruses (HIV, HTLV, HCV, HBV). *Treg product from patient 1 was not reinfused as a result of poor indium labelling. (B) Details of indium tropolonate labelling of GMP-Tregs prior to infusion. Treg product from patient 1* was not reinfused as a result of poor indium labelling thus, only 4 of the 5 patients were evaluated. Once ¹¹¹indium tropolonate labelling was completed, the labelling efficiency was calculated and the numbers of labelled GMP-Tregs to be infused were adjusted, aiming for a dose of up to 20 Mbq. Indium-labelled GMP-Tregs were assessed for viability (≫90%) before being infused immediately into the same patient via a peripheral vein injection on the same day of labelling. All infused patients has indium labelling efficiency of more than 90%. Labelling efficiency was calculated by activity of indium-labelled Tregs divided by indium activity in supernatant.

GMP, Good Manufacturing Practice; Treg, regulatory T cell.