Influence of Allergy on Immunoglobulins and Amyloid-β in the Cerebrospinal Fluid of Patients with Alzheimer’s Disease

Article type: Research Article

Authors: Sarlus, Heela^{a; *} | Eyjolfsdottir, Helga^{b; c} | Eriksdotter, Maria^{b; c} | Oprica, Mircea^{a; d} | Schultzberg, Marianne^a

Affiliations: [a] Karolinska Institutet, Department of Neurobiology, Care Sciences and Society, Center for Alzheimer research, Section for Neurodegeneration, Novum, Huddinge, Sweden | [b] Karolinska Institutet, Department of Neurobiology, Care Sciences and Society, Center for Alzheimer research, Section for Clinical Geriatrics, Novum, Huddinge, Sweden | [c] Department of Geriatric Medicine, Karolinska University Hospital, Stockholm, Sweden | [d] Department of Neurology, Karolinska University Hospital, Stockholm, Sweden

Correspondence: [*] Correspondence to: Heela Sarlus, Karolinska Institutet, Department of Neurobiology, Care Sciences and Society, Section for Neurodegeneration, Center for Alzheimer Research, Novum, Floor 5, SE-141 57 Stockholm, Sweden. Tel.: +46 8 585 83881; Fax: +46 8 585 83610; Heela.Sarlus@ki.se

Abstract: Background: Peripheral inflammation has been suggested to influence the development of Alzheimer’s disease (AD). Elevated levels of pro-inflammatory markers in the plasma of patients with AD indicate that a systemic pro-inflammatory status occurs concomitantly with inflammatory changes in the brain. Objective: To investigate whether allergy influences the levels of immunoglobulins (Ig) and of pro- and anti-inflammatory cytokines in the serum and cerebrospinal fluid (CSF) from patients with AD, mild cognitive impairment (MCI), and subjective cognitive impairment (SCI). Methods: IgA, IgG, and its subclasses, IgM, and cytokines were analyzed in CSF and serum from patients with SCI, MCI, and AD, with or without allergy. The relation between allergy and Mini-Mental State Examination (MMSE) scores, and between allergy and CSF biomarkers for AD (phosphorylated (p)-tau, total (t)-tau, amyloid-β 42 (Aβ42), were analyzed. Results: In MCI, the CSF levels of IgG2 were lower in allergic patients, and in AD, the levels of IgA and the IgG1/total IgG ratio were lower in allergic patients, compared to patients without allergy. MCI subjects with allergy had higher serum IgM levels compared to those without allergy. CSF levels of Aβ42 were lower and MMSE scores were higher in AD patients with allergy than in those without allergy. Conclusions: The presence of allergy was associated with seemingly beneficial effects on AD as suggested by higher Aβ42 levels in CSF, and higher MMSE scores. Higher IgM levels and lower other Ig classes suggest that allergy may influence senescence of the immune response.

Keywords: Cerebrospinal fluid, cytokines, mild cognitive impairment, Mini-Mental State Examination, serum, subjective cognitive impairment, systemic inflammation, tau

DOI: 10.3233/JAD-143147

Journal: Journal of Alzheimer's Disease, vol. 48, no. 2, pp. 495-505, 2015