CD34 and amyotrophic lateral sclerosis: In addition, proliferating microglia at 12 m upregulated the stem cell marker Cd34, which identifies a subset of proliferating microglia associated with degenerating neurons in ALS (Kovacs et al., 2019) and which is upregulated in early-activated microglia after facial nerve axotomy (Ladeby et al., 2005).