Poor in vitro induction of FOXP3 and ICOS in type 1 cytokine environment activated T-cells from children with type 1 diabetes.
BACKGROUND
Type 1 diabetes (T1D) is characterised by loss of tolerance to beta-cell antigens, and the insulin-producing beta-cells in the pancreatic islets are destroyed by the host's own immune system. Immunological risk factors associated with T1D are related to the defects in the polarization of T-cells and in the function of regulatory T (Treg)-cells. We set out to study whether an impaired induction of regulatory mechanisms during the generation of T-cell responses upon stimulation is associated with T1D.


METHODS
Naive T-cells were isolated from 18 children with recent T1D (0-14days from diagnosis; mean age 9.3 years), 11 children who had had T1D for at least 1 year (mean age 10.6) and 14 non-diabetic children (mean age 8.1). CD45RA+ T-cells were stimulated with PHA for 72 h in type 1 cytokine [interleukin (IL)-12 and anti-IL-4] or type 2 cytokine (IL-4 and anti-IL-12) environment. T-cell polarization and regulation related markers were analysed by quantitative reverse transcription polymerase chain reaction (QRT-PCR) (Th1 promoting T-bet, Th2 promoting GATA-3 and regulation related FOXP3, ICOS and NFATc2).


RESULTS
Children with recently diagnosed T1D showed decreased induction of FOXP3, ICOS and NFATc2 in T-cells activated in type 1 cytokine milieu (p = 0.007, p = 0.001, and p = 0.02), whereas no differences between the diabetic and healthy children were seen in the up-regulation of activation markers, T-bet and GATA-3.


CONCLUSIONS
The poor induction of factors that mediate down-modulation of T-cell responses upon stimulation in type 1 cytokine environment may contribute to the development of autoreactive type 1 responses in T1D.
Honkanen
Jarno
J
Department of Viral Diseases and Immunology, National Public Health Institute, Helsinki, Finland. jarno.honkanen@ktl.fi <jarno.honkanen@ktl.fi>
Skarsvik
Susanne
S
Knip
Mikael
M
Vaarala
Outi
O
D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics*; D002648:Child; D016207:Cytokines / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology*; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000235:genetics*; D006801:Humans; D060889:Inducible T-Cell Co-Stimulator Protein; D018664:Interleukin-12 / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D008213:Lymphocyte Activation; D050778:NFATC Transcription Factors / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D016207:Cytokines; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C556692:ICOS protein, human; D060889:Inducible T-Cell Co-Stimulator Protein; D050778:NFATC Transcription Factors; C494003:NFATC1 protein, human; D012333:RNA, Messenger; D018664:Interleukin-12; D015847:Interleukin-4