1Microbiology and ²Internal Medicine Departments, Faculty of Medicine, Menoufia University.

Tumor necrosis factor-a (TNF-a ) is a cytokine that has potent immune regulatory functions. Recently, it has been implicated in the pathogenesis of insulin dependent diabetes mellitus (IDDM), however, the role of TNF-a in occurrence of IDDM and the relation between it and control of the disease have not been well studied. This study was undertaken to evaluate TNF-a levels in IDDM and in non-insulin dependent diabetes mellitus (NIDDM) and to identify its relationship to laboratory features, complications and duration of the disease. The study included 40 IDDM and 23 NIDDM patients with varying durations of the disease. The results were compared to that of 26 age- and sex- matched healthy controls with no family history of diabetes. Sera were obtained from patients and controls and TNF-a was estimated by ELISA and C-peptide was estimated by radioimmunoassay. Results revealed that TNF-a levels were significantly elevated in patients with recent onset (P< 0.001) and long-standing (P<0.001) IDDM and in those with NIDDM compared to controls. C-peptide levels were significantly lower (P<0.001) in IDDM than in NIDDM patients, however, there was no significant correlation between the levels of TNF-a and that of C-peptide. A number (10/22) of IDDM patients with low TNF-a levels (£ 5 pg/ml) showed complications in the form of neuropathy, retinopathy and nephropathy, however, none of the patients with higher levels had any of these complications. It is concluded that TNF-a is increased in the early phase of IDDM and may have an important role in its pathogenesis. TNF-a may also have a role in occurrence of NIDDM by increasing resistance to insulin. However, it may have no direct role in occurrence of complications.