Preproinsulin specific CD8+ T cells in subjects with latent autoimmune diabetes show lower frequency and different pathophysiological characteristics than those with type 1 diabetes.

Latent autoimmune diabetes in adults (LADA) resembles type 1 diabetes (T1D) in disease presentation except that its onset is slow. We compared pathophysiological characteristics of CD8+ T cells recognizing preproinsulin (PPI) derived epitopes in both disease groups using MHC-I dextramers (DMRs) in peripheral blood and after in-vitro stimulation with PPI. Subjects with T1D harbored higher frequency of DMR+ CD8+ T cells with relatively higher frequency of effector T cell subsets. Following stimulation with PPI, an increase in DMR+ CD8+ T cells, particularly the central-memory subset was observed in T1D group, whereas no significant change in DMR+ CD8+ T cell subsets was observed in LADA group. Intracellular expression of Granzyme-B and Perforin in DMR+ CD8+ T cells was comparable in both the groups. In conclusion, lower frequency and inferior proliferative potential on account of a relatively restrained central-memory subset of PPI specific CD8+ T cells are associated with slow rate of disease progression in LADA.