[History and clinical picture of lymphogranulomatosis X (including (angio)immunoblastic lymphadenopathy]

The term lymphogranulomatosis X (LgX) designates a clinicopathological entity of unknown etiology ("X"), which was first described by Forster and Moeschlin in 1954. LgX includes the "immunoblastic lymphadenopathy" of Lukes and to a large extent the "angioimmunoblastic lymphadenopathy" of Rappaport (except for the cases with active germinal centers), but in LgX there is another morphologic variant not mentioned either by Lukes or by Rappaport. To establish the morphologic diagnosis of LgX three typical changes of the affected lymph nodes are needed: effacement of the nodal architecture, absence of active germinal centers, and markedly increased proliferation of epithelioid venules. Cases with only partial effacement of nodal architecture, and especially with active germinal centers, were considered hyperimmune reactions (HR). This "hyperimmune reaction" may be an early stage of LgX: 4 of 39 cases showed later transformation into LgX. Based on cytologic aspects, five different variants of LgX are distinguished: immunoblastic predominance, plasma cell predominance, mixed cell type, epithelioid cell predominance and lymphocytic predominance. Case history and clinical picture of the five variants of LgX (172 patients) are reported and compared with HR (37 patients). In LgX the age peak is in the 7th decade; the youngest patient was 16 years old. HR are seen in children as well as in elderly people, the mean age being 49 years. In LgX males predominate and in HR females. In LgX the disorder is usually more generalized than in HR (80% versus 46% with generalized lymph node enlargement, 69% versus 24% with hepatomegaly and 62% versus 27% with splenomegaly). Skin involvement and high sedimentation rate are less frequent in HR. In LgX a Coombs-positive anemia is occasionally found; its origin is "aplastic" rather than hemolytic. Based on the data presented, some reflections relative to the etiology and pathogenesis of LgX are presented. Rubella virus should be considered a possible etiologic agent. In most cases with drug hypersensitivity, allergic reactions to drugs appear only in the course of the illness; in these cases drugs are ruled out as an etiologic factor. Occasionally, an augmented number of azurophil granulated lymphocytes (suppressor T-cells?) is observed in the blood, a fact that could be a pointer to the pathogenesis of LgX and possibly explain the high incidence of infections seen in this disorder.