Determination of islet cell surface antibodies in first-degree relatives of type 1 diabetic patients using rat insulinoma cells.
Titre of islet cell surface antibodies (ICSA) in 114 sera from healthy control probands and 177 sera from first-degree relatives of Type 1 diabetic patients was determined by indirect immunofluorescence using rat insulinoma (RIN) cells as target. All sera were tested at four dilutions (1/40-1/320). 10(5) RIN cells were incubated with 100 microliters diluted serum overnight at 4 degrees C followed by a 45 min-incubation with a FITC-labelled goat anti-human globulin. Titre curves were calculated by double logarithmic regression. ICSA titre was defined as the serum dilution producing cell surface fluorescence on 40% of RIN cells. Based on these data a serum is defined as ICSA positive when the ICSA titre calculated is higher than 1:142, quantil Q (0.97). Twenty-five out of 177 (14%) sera of first-degree relatives of Type 1 diabetes were ICSA positive with a mean titre of 1/393, range 1/145-1/1,740, while 2/114 (1.7%) control sera were weakly positive for ICSA. These data demonstrate the significantly increased ICSA prevalence in first-degree relatives of Type 1 diabetic patients. The present study suggests that RIN cells may represent a useful tool for standardization of ICSA assay.
Ziegler
B
B
Central Institute of Diabetes Gerhardt Katsch, Karlsburg, GDR.
Heinke
P
P
Schlosser
M
M
Rjasanowski
I
I
Michaelis
D
D
Ziegler
M
M
D000293:Adolescent; D000328:Adult; D000818:Animals; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007340:Insulinoma / Q000276:immunology; D007515:Islets of Langerhans / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000276:immunology; D051381:Rats; D014407:Tumor Cells, Cultured
D001323:Autoantibodies; C024211:islet cell antibody