SYSTEMIC CHANGES IN THE IMMUNE-SYSTEM OF PATIENTS WITH ALZHEIMERS-DISEASE

Objective: The etiology of Alzheimer's disease (AD) is still unknown. Recent investigations have shown that immune and inflammatory mechanis ms could be of importance in the pathophysiology of AD. In this study 10 different immune parameters were measured to further investigate im munological changes in AD. Patients and methods: In 30 randomized pati ents with AD (20 females and ten males aged 74.5 +/- 6.5 years) as wel l as in 13 controls aged 70.7 +/- 8.4 years, mostly relatives of the p atients, all free of acute infection, serum concentrations of IgA, IgG , IgM, C3, C4, circulating immune complexes, sCD23, cardiolipin and th e soluble cytokine receptors interleukin 2-receptor (sIL2-R) and tumor necrosis factor-receptor (sTNF-R) were measured. Diagnosis of AD was made according to NINCDS/ADRDA criteria. The degree of dementia was de termined by Mini-Mental-State-Examination (MMSE). Results: Compared to the control group, patients with AD had significantly increased IgA ( 369,3 +/- 160,9 mg/dl vs 253.5 +/- 101.8 mg/dl [P = 0.02]), sCD23 [207 .4 +/- 217.7 l. U./ml vs 80.6 +/- 35.5 l. U./ml [P = 0.004]), sIL2-R ( 829.6 +/- 742.1 l. U./ml vs 299.7 +/- 168.5 l. U./ml [P = 0.001]) and sTNF-R (4.6 +/- 2.0 l. U./ml vs 2.9 +/- 1.1 l. U./ml [P = 0.001]) leve ls. A negative correlation was seen between MMSE and sTNF-R (r = -0.34 ; P < 0.05). Conclusion: These findings indicate a chronic state of im mune activation in AD and support the hypothesis of immune mediated me chanisms as part of the pathogenesis of AD. Prospective studies of the effect of anti-inflammatory drugs on the progression of AD will be ne eded.