The pink intranuclear inclusions in the erythroid precursors seen here are characteristic for parvovirus infection .
核内可见粉红色包含体是病毒感染的典型特征。
Other factors that affect erythropoiesis are the supply of nutrients ( eg , iron , folate , or vitamin b12 ) and cell-cell interactions between erythroid precursors , lymphoid cells , and other components of the hematopoietic microenvironment .