The chemokine CXCL12 (also known as stromal cell-derived factor 1, SDF-1) controls many aspects of bone marrow-derived stem cell functions and has been associated with neurogenesis as well with recruitment of brain resident and non-resident circulating cells towards sites of lesion in the central nervous system (CNS). Disrupting this line of chemokine-mediated intercellular communication may contribute to the pathogenesis of Alzheimer's disease (AD). In this study, decreased CXCL12 plasma levels in patients with early AD (p = 0.003) were found, which significantly inversely correlated with CSF tau protein levels (r = -0.373; p = 0.042) and positively with CXCL12 CSF levels (r = 0.429; p = 0.018) and with changes of cognitive functions over the time period of 15 months (r = 0.583; p = 0.009). Our findings indicate a lack of chemotactic activity in early AD and support the view of a deficient regenerative hematopoietic brain support in early AD with putative pathogenic and therapeutic relevance.