Asosiasi dan Disosiasi Insulin-Antibodi Insulin pada pasien Sindrom Autoimun Insulin. - Yunus Tanggo (Fakultas Kedokteran Universitas Kristen Indonesia, 2010)
Abstrak Sindrom autoimun insulin (SAI) ditandai oleh pembentukan autoantibodi pada pasien yang sebelumnya tidakpernah menggunakan insulin. Pasien SAI biasanya mengalami hiperglikemia diikuti dengan hipoglikemiasesudah makan, yang terjadi karena asosiasi dan disosiasi insulin dari kompleks antibodi insulin-insulin. Studi inidilakukan untuk mengevaluasi perubahan konsentrasi insulin imunoreaktif bebas (IIB), insulin imunoreaktif total(IIT), antibodi anti insulin dan gula darah pada saat uji toleransi glukosa oral 75 g (TTGO). Pada fase pertama,setelah dimulai uji toleransi, konsentrasi antibodi insulin turun dari 54% ke 45%, selama 120 menit. Hal itumenunjukkan terjadi ikatan insulin dengan antibodi hingga menyebabkan kenaikan insulin terikat (IIT) padawaktu bersamaan. Gula darah naik sampai 200 mg% dalam 60 menit karena IIB relatif tidak cukup untukmenekan kenaikan gula darah sesudah uji toleransi glukosa. Fase kedua, 120 menit sesudah TTGO, konsentrasiIIT dan antibodi insulin kembali ketingkat basal. Perubahan itu menunjukkan disosiasi insulin dengan kompleksinsulin-antibodi. Gula darah turun menjadi 33 mg% pada waktu 240 menit, mungkin karena ekses IIB yangdihasilkan kompleks insulin-insulin antibodi. Hal itu menunjukkan bahwa asosiasi insulin terhadap antibodimenyebabkan hiperglikemia 60 menit setelah TTGO dan disosiasi dari kompleks insulin-insulin antibodimenyebabkan hipoglikemia 240 menit setelah TTGO. Kata kunci: antibodi insulin, glukosa darah, asosiasi, disosiasi. Abstract The insulin autoimmune syndrome ( IAS ) is characterized by the autoantibodies formation in patient withoutprevious insulin usage. Patient affected by IAS usually developed hyperglycemia followed by hypoglycemiaafter meal due to association of insulin to its antibody and dissociation of insulin from insulin-insulin antibodiescomplexes. This study was carried out by evaluation of the changes of the free immunoreactive insulin (FIRI)concentration and the total immunoreactive insulin (TIRI) concentration. Insulin antibody and blood sugar during75 g oral glucose tolerance test (75 g OGTT) also evaluated. There were two distinct time courses could beidentified during the OGTT. The insulin antibody concentration gradually decreased from 54% to 45% at 120minutes. That change indicates consumption of the antibody or association of the insulin to its antibody, results inthe increase of bound insulin or TIRI at the same time. The blood sugar increased to 200 mg% in 60 minutes dueto relativity insufficient of FIRI to supress blood sugar elevation after OGTT. After 120 minutes of OGTT theconcentrations of TIRI and the insulin antibodies were returned to the basal level and these changes were stronglyindicated the dissociation of the insulin–insulin antibodies complexes. Blood sugar was decreased to 33 mg% at240 minutes, may be due to the relativity excess of FIRI released from insulin-insulin antibodies complexes.These data indicated that association of the insulin to its antibody result in hyperglycemia 60 minutes after OGTTand dissociation of the insulin-insulin antibodies complexes result in hypoglycemia 240 minutes after OGTT. Keywords: insulin antibody, blood glucose, association, dissociation.