[Detection of carboxypeptidase H specific T cells in peripheral blood of latent autoimmune diabetic patients with carboxypeptidase antibody positivity by ELISPOT assay].
OBJECTIVE
To explore the characteristics of T cell immunity in peripheral blood of patients with carboxypeptidase-H antibody (CPH-Ab).


METHODS
Forty-two latent autoimmune diabetes in adults (LADA) patients with CPH-Ab(+) alone, 20 Type 2 diabetes mellitus patients (T2DM), and 22 healthy controls were selected and their peripheral blood mononuclear cells were isolated. Human recombinant carboxypeptidase (CPH) protein was expressed and further used as a stimulant in Enzyme-linked immunospot (ELISPOT) assay to detect IFN-gamma-Th1 and IL-4-Th2 cells in the 3 groups. Th1/Th2 ratios were also calculated. CPH-Ab and glutamic acid decarboxylase antibody (GAD-Ab) were determined by radioligand assay.


RESULTS
Compared with healthy controls and T2DM, IFN-gamma-Th1 and IL-4-Th2 numbers did not increase significantly in CPH-Ab(+) group, nor did the Th1/Th2 ratios (P>0.05). We further divided the CPH-Ab(+) patients into a short duration group (n=22) and a long duration subgroup (n=20) according to the duration of 3 years. CPH-IL-4-T in the short duration subgroup was significantly higher than that in T2DM and healthy controls (1.8 vs. 0.2 and 0.3, both P<0.05) and we did not find any factor that was significantly correlated with the IL-4 spots number. There were not any significant differences in T cell responses to phaseolus vulgaris agglutinin (PHA) among all groups (P>0.05).


CONCLUSIONS
CPH does not directly involve in the cellular pathological mechanism of LADA. Anti-CPH immunity may be associated with more slowly aggressive beta cell autoimmunity.
Yang
Lin
L
Department of Endocrinology, Institute of Metabolism and Endocrinology, Diabetes Center, Second Xiangya Hospital, Central South University, Changsha, China.
Zhou
Zhiguang
Z
DU
Tao
T
Tan
Shaozhen
S
Zhnag
Yi
Y
Jin
Ping
P
D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D043423:Carboxypeptidase H / Q000276:immunology*; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000276:immunology*
D001323:Autoantibodies; D043423:Carboxypeptidase H; D005968:Glutamate Decarboxylase