CD30 distribution. Immunohistochemical study on formaldehyde-fixed, paraffin-embedded Hodgkin's and non-Hodgkin's...

Two hundred Hodgkin's and non-Hodgkin's lymphomas were immunohistochemically studied for the presence of the CD30 (Ki-1) activation antigen using a monoclonal antibody BerH2 on paraffin-embedded, formaldehyde-fixed tissue. Immunohistochemistry was performed by using the avidin-biotin complex technique and was preceded by enzymatic digestion with pepsin (0.05% for 20 minutes). Ninety percent (56/64) of cases of Hodgkin's disease, other than lymphocyte predominance type, showed positive tumor cells, although the positivity was often focal. In contrast, lymphocyte predominance type showed CD30 in only two of nine cases. CD30 was commonly seen in non-Hodgkin's lymphomas. Five of 37 large-cell lymphomas showed extensive CD30 positivity and morphologically represented large-cell anaplastic lymphomas ("Ki-1 lymphomas"). Apart from this, occasional CD30-positive cells were seen in nine of 32 large-cell non-Hodgkin's lymphomas. About half of the nodular small cleaved-cell lymphomas contained CD30-positive cells, two of them showing large numbers of positive cells both within and outside the nodules. Lymphocytic lymphoma sometimes (6/17) showed a few CD30-positive cells. Peripheral T-cell lymphomas showed positive cells in three of eight cases. The positive cases were one lymphoma with small groups of epithelioid cells (Lennert's lymphoma) and two immunoblastic lymphadenopathylike peripheral T-cell lymphomas. The results show that CD30 is more widespread than originally thought in non-Hodgkin's lymphomas and that especially nodular small cleaved-cell lymphomas often contain positive cells. These findings have to be considered in the immunohistochemical differential diagnosis of lymphomas. Obviously, CD30 alone cannot be used to differentiate between Hodgkin's and non-Hodgkin's lymphomas. The CD30-positive cells in non-Hodgkin's lymphoma may represent a link between Hodgkin's and non-Hodgkin's lymphomas.