Expression of la‐Like Antigen in Lymphatic Leukaemias and Non‐Hodgkin Lymphomas in Correlation with Other Surface Markers

Ia-like antigen, surface Ig, E-rosettes, mouse red blood cell rosettes and further surface markers were investigated in 88 specimens from 69 patients with various lymphocytic leukaemias and non-Hodgkin lymphomas. Ia-like antigen was detectable in all cases of sIg+ leukaemias and lymphomas. E-la+sIg- leukaemias, especially CLL and lymphomas were interpreted as s-cell neoplasias, which either did not produce sIg or expressed it in undetectable amounts. E+Ia+sIg+ malignant lymphocytes represented a s-cell population with antibody activity of sIg to SRBC. In the present series 9.5 % of all s-cell leukaemias and lymphomas demonstrated this phenotype. Whereas ALL may possess Ia-like antigen, the vast majority of mature T-cell lymphomas are lacking it. In the present series 2 T-cell lymphomas expressed Ia-like antigen and did not contain TdT (E+Ia+sIg-TdT-). These lymphomas are probably derived from a stimulated T-cell clone synthesizing Ia-like antigen.