[Common ALL-associated antigen on cells and in the serum of common ALL patients: clinical relevance and biochemical characterization (author's transl)]. 
The clinical application of an antiserum recognizing common ALL associated antigen (cALL-AG) is very useful in classifying leukemias and diagnosing bone marrow relapse as well as CNS-leukemia.  We could demonstrate that sera of common ALL (cALL) patients contain cALL-AG; its partial biochemical characterization is described.  The anti cALL serum (cALL-AS) was raised in rabbits with cALL-cells precoated with rabbit antiserum against normal human lymphocytes.  After appropriate absorbtion the cALL-AS was highly specific for cALL cells.  The isolation of serum cALL-AG was performed by ammoniumsulfat precipitation, gel chromatography and affinity chromatography on agarose lens culinaris hemagglutinin A (lentil lectin).  The apparent molecular-weight of the serum glycoprotein is 125 000.  Two cALL-AG active structures could be solubilized from cALL cell membrane.  The apparent molecular-weights were calculated to be 55 000 and 110 000.