P. Parkkonen et al., DEFECTIVE HLA CLASS-II EXPRESSION IN MONOCYTES OF TYPE-1 DIABETIC-PATIENTS, APMIS. Acta pathologica, microbiologica et immunologica Scandinavica, 101(5), 1993, pp. 395-402
Activation of T-helper cells is modulated by the intensity of HLA clas
s II expression on antigen-presenting cells. We evaluated whether any
abnormalities could be found in the expression of HLA-DR and -DQ molec
ules on monocytes in type 1 diabetic subjects. DR and DQ molecules wer
e induced by human recombinant interferon-gamma on cultured peripheral
blood monocytes obtained from children with type 1 diabetes (N = 28),
their siblings (N = 18) and unrelated healthy controls (N = 21). The
response in DQ induction varied considerably between different individ
uals, but the average responsiveness was significantly lower in patien
ts compared to siblings and unrelated controls. In addition to the dia
betic subjects deficient DQ induction was also observed in three sibli
ngs. One of them had high levels of islet cell antibodies and presente
d with diabetes 6 months later, and another had active rheumatoid arth
ritis. The response in DR induction was also slightly lower in patient
s than in siblings, but did not differ from that in unrelated controls
. The results suggest abnormalities in the regulation of HLA class II
expression in type 1 diabetic subjects possibly reflecting the ongoing
autoimmune process.