Differential gene expression profile of lymphomononuclear cells of recently diagnosed type 1 diabetes mellitus patients

INTRODUCTION: Insulin-dependent diabetes mellitus (IDDM) or type 1 diabetes mellitus (DM-1) is an organ-specific auto-immune disease caused by the selective destruction of the pancreatic b cells by inflammatory cells, especially auto-reactive CD8+ T lymphocytes. DM-1 is one of the commonest chronic disease among young children and teenagers. The etiology of DM-1 is considered to be multifactorial, involving the participation of genetic, immunologic and environmental factors. Background: Our knowledge about the molecular and genomic background of diseases has expanded dramatically in the recent past and cDNA microarray now provide the opportunity to simultaneously analyses the expression of thousands of genes. METHODS: To study the pathogenesis IDDM a total of 6 recently diagnosed patients with IDDM and 6 normal individuals matched to patients in terms of sex and age have also be studied. Total RNA was extracted using Trizolaa reagent. The cDNA microarrays were constructed with 4500 clones (in replicates) from human cDNA library (IMAGE consortium) in the form of PCR products using an Array Spotter Amersham Generation III (Amersham Biosciences). The cDNA complex probes were prepared by RT using 10 mg of total RNA in the presence Cy3 and Cy5 fluorochromes (CySribe Post labeling Kit). The microarrays were washed using an ASP system (Automated Slide Wash). The generation III laser Scanner was used for image acquisition. Normalization and centralization were applied to minimize differences between distinct hybridizations. Statistical analysis was performed using the SAM (Significance Analysis of Microarrays) and Cluster software. RESULTS: These preliminary results showed 21 genes induced and 9 repressed in the IDDM patients when compared with healthy controls. CONCLUSION: Although preliminary, the findings obtained in this study showed several genes potentially implicated in the pathogenesis of IDDM.