CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 46, 177- 185 (1988) Clinical and Immunological Findings in Large B-Cell Chronic Lymphocytic Leukemia ALBERTO~RFAO,* MARCOSGONZALEZ,*JESUS FERNANDO SANMIGUEL,* MARIA CONSUELO CA~ZO,* PURIFICACION GALINDo,t MARIADOLORESCABALLERO,SRAMIROJIMENEZ,§ AND ANTONIO LOPEZBORRASCA* *Servicio de Hematologia, Hospital Vniversitario, Salamanca; fVnidad docente de Bioestadistica, Facultad de Biologia, Vniversidad de Salamanca; SServicio de Hematologia, Hospital Virgen Blanca, Leon; $Servicio de Hematologia, Hospital Virgen de la Vega, Salamanca, Spain In order to define the characteristics of B-CLL cases in which the predominant cell population is composed of large lymphocytes, we studied 97 patients with B-CLL, com- paring the cell morphological features with the clinical and biological findings and the immunological phenotype of the proliferating cells. Multivariant analysis showed that there were three significantly different morphological groups: Typical CLL, large lym- phocyte CLL (LLL), and CLL with prolymphocytes (CLL/PL). The LLL group showed a greater incidence of lymphadenopathies (P < 0.05) and higher percentages of both p,+6+ cells (P < 0.01) and Fmc/7 + cells (P < 0.001) than in typical CLL. The main differences between LLL and CLL/PL were the peripheral blood lymphocyte count and the percentage of Fmc/7+ cells (P < 0.002)-both higher in the CLL/PL group-and the percentage of mouse rosette-forming cells (P < O.Ol)-lower in CLU PL. Further studies including functional assays and survival analyses could contribute to elucidating whether these groups are different entities or a single disease with marked heterogeneity. 0 1988 Academic Press. Inc. INTRODUCTION For many years the term chronic lymphocytic leukemia (CLL) has included several different lymphoproliferative disorders such as B-CLL, prolymphocytic- leukemia (PLL), and hairy cell leukemia (HCL) (1, 2). Currently, these diseases are well differentiated from B-CLL. However, within this latter group of patients there continues to be considerable clinical and biological heterogeneity (3, 4). Accordingly, although in most cases the morphological appearance of the cells is that of typical small lymphocytes with clumped chromatin and scanty cytoplasm, it is not uncommon to find cases in which the predominant cell population is represented by large lymphocytes with abundant cytoplasm and mature clumped chromatin without a nucleolus (5, 6). These findings pose the question of consid- ering whether one is dealing with a single disease with a certain heterogeneity or whether there might be different disorders. In this sense, recently Melo er al. (7) suggested the possibility that some cases of B-CLL in prolymphocytic transfor- mation might correspond to a clinical, morphological, and immunological entity different from both B-CLL and B-PLL, whereas other cases would correspond to the intermediate form described by Enno et a/. (8). Immunological markers consistitute an additional tool for elucidating these 177 0090-1229/88 $1.50 Copyright 0 1988 by Academic Press. Inc. All nghts of reproduction in any form reserved.