BackgroundAlzheimer’s disease (AD) accounts for 60‐70% of dementia cases. It is a multi‐factorial process and not all factors that affect its appearance and development have been clarified. Several parasites have been correlated with dementia [1] and development of AD has been associated with Toxoplasma gondii parasitism [2].In the present study, IgG and IgM antibodies against Ascaris Lumbricoides (AL) antigens were detected in the serum of 60 patients with mild, medium and severe AD, 20 from each group.MethodsAntigens of AL were adhered to the bottom of ELISA plate (IBL International GMBH) in order to measure the level of IgG and IgM antibodies. Peroxidase labelled Protein A or goat anti‐human IgM were used to bind IgG and IgM antibodies, respectively.ResultsAccording to the results, 30% of patients with severe AD were positive to IgG antibodies (Ab) against AL antigens (Ab concentration > 9 U/µL) whereas none of the patients with mild and moderate AD was positive (Figures 1, 2). The mean IgG Ab concentration in this group was 2.1 times higher than the mean value of patients with mild and moderate AD (p = 0.001 according to t‐test). Additionally, 35% of patients with severe AD were positive to IgM Abs while 16.7% and 8% of IgM positive samples were found in patients with mild and moderate disease.ConclusionThe results present a potential correlation of Ascaris lumbricoides infection and antibodies development with Alzheimer’s Disease.References: [1] Gislaine Cristina Lopes Machado‐Porto etal., Reversible dementia due to neurocysticercosis: Improvement of the racemose type with antihistamines, Dement Neuropsychol, 2015; 9(1): 85‐90. [2] Hossein Mahmoudvand etal., Toxoplasma gondii Infection Potentiates Cognitive Impairments of Alzheimer’s Disease in the BALB/c Mice. J Parasitol (2016); 102 (6): 629‐635.