[Effect of cryopreservation method on islets specific T cell responses in type 1 diabetic patient].

Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences

PubMedID: 23456066

Yang L, Chao C, Tang W, Wang Z, Yu H, Cui Q, Zhou Z. [Effect of cryopreservation method on islets specific T cell responses in type 1 diabetic patient]. Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2013;38(2):169-75.
OBJECTIVE
To explore the better freezing protocol to preserve peripheral blood monuclear cells (PBMCs), islets antigen-specific T cells responses compared with freshly isolated samples in type 1 diabetic (T1D) patients.

METHODS
The T cell Workshop Committee of the Immunology of Diabetes Society (IDS-TCW) organized the Freezing Study I and we were one of the 9 centers in the world to participate in the study. According to the two standardized T cell freezing protocols (warm and cold) to freshly isolated PBMCs in terms of recovery, viability, cell subset composition (FACS) and performance in Enzyme-linked immunospot (ELISPOT) assays, we chose 5 newly onset T1D patients and 5 age and sex matched healthy controls. Besides the protocols, all the freezing reagents and antigens were also centralized. The antigens used in ELISPOT were labeled blindedly.

RESULTS
1) Although warm frozen-thawed (W) samples had a slightly higher recovery rate (61.2% vs 60.1%, P>0.05) and viability (77.5% vs 74.9%, P>0.05) as compared with the cold frozen ones (C), the difference was not significant. 2) Both protocols led to a relative loss in monocytes as compared with the fresh samples (F) [3.2±1.1% (C) and 3.0±0.9% (W) vs 7.0±1.1% (F), both P<0.05], while other subsets including CD4+T, CD8+T, B cells, NK cells and NKT cells didn't. 3) Freezing and fresh samples showed similar IFN-? secretion responses to polystimuli in ELISPOT. Irrespective of the freezing protocol, recall antigen Pediacel and islet antigen-reactive responses were both lower in the frozen cells compared with fresh PBMCs. The stimuli index (SI) of GADspecific T cell response in the fresh samples from T1D patients was 5.1, higher than that of frozen samples with either cold protocol (1.3) or warm one (1.4) (both P<0.05). Only fresh samples from T1D showed significantly higher GAD-specific T cell responses than the healthy controls no matter in SI (5.1 vs 0.9, P<0.05) or spot forming cells (8.1 vs 0.1, P<0.05), whereas the frozen samples did not show such difference.

CONCLUSION
More studies are needed to verify a freezing method to bring comparable islets antigen specific T cell responses in T1D patients to fresh PBMCs.