The present invention relates to the use of L-.alpha.-lysophosphatidylcholine and/or an equivalent compound for the differentiation of monocytes into mature denditric cell.The present invention also relates to a method for differentiation monocytes into mature denditric cells according to which monocytes are provided in a medium suitable for their differentiation and L-.alpha.-lysophosphatidylcholine and/or an equivalent compound is added to said medium.