Prevalence of islet cell antibodies and its correlation with glucose and insulin response to oral glucose tolerance test in 1st degree relatives of insulin dependent diabetes mellitus probands.

93 first degree relatives (1st DR) of insulin dependent diabetes mellitus (IDDM) patients were investigated for detection of islet cell antibodies (ICA) and beta cell functional status. ICA were detected in 26.9% Ist DR subjects (25/93), equally in parents, siblings and offspring. Normal (n = 16), impaired (n = 5) and diabetic (n = 4), glucose curves were seen in 1st DR. Low insulin levels were observed in parents and siblings with normal glucose tolerance test (N-GTT) at 90 min (p < 0.05), and (p < 0.0005) relatives with impaired glucose tolerance and diabetes. Insulin release to glucose (IRG-insulinogenic index) in control group was 352 +/- 42 mu U/mg. From the group of 25 ICA positive cases, 4 had mean IRG of 394 +/- 70 mu U/mg (group A) comparable to control, and had N-GTT; 12 had mean IRG of 107 +/- 15.9 mu U/mg (group B) significantly low (P < 0.005) compared to controls and group A and 9 showed IRG of 75 +/- 29.3 mu U/mg, lower than group B (NS) with abnormal response to glucose load. Loss of insulin secretory ability thus can precede hyperglycemia by years. The ICA positive relatives were grouped based on the immunological status with their probands. ICA status in probands does not give an idea about ICA status in their relatives. This indepth study leads to understand the correlation of genetic, metabolic and immunological parameters for early detection of IDDM in first degree relatives.

Prevalence of islet cell antibodies and B cell functional status in insulin dependent diabetes.

As autoimmunity is an important factor in the etiopathogenesis of IDDM, 85 ketosis prone i.e. insulin dependent diabetes (IDD) were evaluated for immunological and beta cell functional status. Islet cell antibodies (ICA) against purified islet cells used in Microwell ELISA Method, were detected in 27.1% of cases (23/85). There was a prevalence of 36.4% of ICA positivity in newly diagnosed cases and its prevalence declined with duration. The highest ICA positivity was observed in fourth decade of life. 17 of the 23 ICA positive cases (73.9%) had a mean duration of 2.1 years whereas the remaining 6/23 (26.1%) had a mean duration of 9 years. Females showed a younger age of onset of diabetes. Only one female with duration of 10 years tested positive for ICA.ICA positive males had later age of onset and longer duration of diabetes as compared to ICA positive females. Ten ICA positive cases studied were showing non-significant C-peptide (CP) release (after glucose load) in comparison to negative cases (14); p < 0.05, 8 of these cases were with < 3 months duration. Significantly low delta % C-peptide response implies a low residual beta-cell function and further loss of beta cell function earlier in ICA +ve cases. Thus this study leads to understand in depth the immune mechanism of IDDM.