Cognitive impairment in remitted late-life depression is not associated with Alzheimer's disease-related CSF biomarkers

•AD-related CSF biomarkers were determined for all four diagnostic groups: amnestic MCI, early-onset remitted-LLD with MCI, late-onset remitted-LLD with MCI, and healthy controls.•Amnestic MCI subjects displayed significantly lower CSF Aβ1-42, and higher p-Tau mean values than remitted-LLD elders with cognitive impairment.•Pearson's χ2 test showed statistically significant differences between amnestic MCI and MDD groups for CSF Aβ1-42, p-Tau, and Aβ1-42/p-Tau profiles.•Patients with MCI in the context of LLD did not display a pattern of CSF biomarkers indicative of AD pathology.•The neurobiological burden of depression per se seems to contribute to cognitive impairment in LLD, independently of the presence of AD pathology. Cognitive impairment is a common feature of late-life depression (LLD). Early studies using Alzheimer's disease (AD) biomarkers inferred a biological link between AD pathology and LLD, but recent findings have challenged this association. The aim of this investigation was to determine a panel of AD-related cerebrospinal fluid (CSF) biomarkers in a cross-section of elders with mild cognitive impairment (MCI) with and without LLD. Subjects comprised 102 older adults: 27 with ‘pure' amnestic MCI (aMCI), 53 with major depression and cognitive impairment – encompassing 22 late-onset (LOD) and 31 early-onset depression (EOD), and 22 euthymic elders without cognitive impairment (controls). Participants underwent lumbar puncture for determination of CSF concentrations of Aβ1-42, T-tau, and P-tau. Cut-off scores for suspected AD were: Aβ1-42 36.1 pg/mL and Aβ/P-tau ratio