Hodgkin's disease, lymphocyte predominance type, nodular--further evidence for a B cell derivation. L & H variants of Reed-Sternberg cells express L26, a pan B cell marker.

Immunoreactivity for L26, a highly effective pan B cell marker that can be detected in paraffin sections, was evaluated in 72 cases of Hodgkin's disease of various histologic types. In all cases of nodular lymphocyte predominance type of Hodgkin's disease, L & H variants of Reed-Sternberg cells uniformly exhibited strong immunoreactivity for L26. Other variants of Reed-Sternberg cells, eg, lacunar, mononuclear, and diagnostic forms, present in nodular sclerosis, mixed cellularity, and lymphocyte depletion types of Hodgkin's disease, infrequently expressed L26 reactivity. In 55 of 63 cases (87%) of these combined types, less than 5% of Reed-Sternberg cells or variants were L26 positive. In the remaining cases, a larger proportion of these cells expressed L26. Topographic patterns of immunoreactivity for small lymphocytes in these different types of Hodgkin's disease also varied. In nodular lymphocyte predominance type, L26 positive lymphocytes (presumptive B cells) were mainly localized to nodular areas of the proliferation. In other types of Hodgkin's disease, L26 positive cells occurred in small or large aggregates and generally represented a minor proportion of the population of lymphoid cells. These studies further support a B cell derivation for L & H variants of Reed-Sternberg cells and provide additional evidence that nodular lymphocyte predominance type Hodgkin's disease may represent a distinct entity, possibly an unusual low grade B cell lymphoma. These data also suggest that some Reed-Sternberg cells and variants present in other histologic types of Hodgkin's disease may be of B cell derivation, and precludes the use of L26 as a diagnostic discriminant in cases in which the distinction between Hodgkin's disease and non-Hodgkin's lymphoma is unclear.