Interestingly, CD34+DNAM-1− cells from HD PBMC did not express CXCR4 (Fig. 8a), thus suggesting that under normal conditions Lin−CD34+DNAM-1brightCXCR4+ precursors are barely detectable in PB, and may be released from BM in case of need such as during chronic inflammation. The gene discussed is CD34; the disease is Huntington disease.