Large cell lymphomas and Hodgkin disease may develop during the course of chronic lymphocytic leukemia (CLL). In some cases the transformed cells are Epstein-Barr virus (EBV)–positive and not clonally related to the CLL cells. In other cases the transformed cells have the same clonal rearrangements as the CLL cells. Here we describe a composite lymphoma in a patient with CLL that exhibits a combination of CLL/small lymphocytic lymphoma, large cell lymphoma with anaplastic morphology, and Hodgkin lymphoma (HL). Although the large cell lymphoma cells are CD45R0 and TIA-1–positive, suggesting a T- or 0-cell anaplastic large cell lymphoma (ALCL), the genetic analysis demonstrates immunoglobulin heavy chain (IgH) gene rearrangements for both alleles, carrying the same somatic mutations as observed in the CLL component. The Reed-Sternberg (R-S) cells in the Hodgkin component also strongly express TIA-1 but differ from the anaplastic large cells by the expression of CD15 and TARC and the presence of a prominent lymphocytic infiltrate. The ALCL and HL components both are EBV negative. Analysis of the IgH gene rearrangements in micromanipulated R-S cells revealed identical Ig gene rearrangements carrying the same somatic mutations as the CLL and the large cell components. The findings indicate transformation of the CLL cells into a large cell lymphoma with anaplastic morphology and a Hodgkin component.

Langerhans cell histiocytosis (LCH) is a neoplastic disorder that results in clonal proliferation of cells with a Langerhans cell (LC) phenotype. The pathogenesis of LCH is still poorly understood. In the present study, serial analysis of gene expression (SAGE) was applied to LCs generated from umbilical cord blood CD34+ progenitor cells to identify LC-specific genes and the expression of these genes in LCH was investigated. Besides the expression of several genes known to be highly expressed in LCs and LCH such as CD1a, LYZ, and CD207, high expression of genes not previously reported to be expressed in LCs, such as GSN, MMP12, CCL17, and CCL22, was also identified. Further analysis of these genes by quantitative RT-PCR revealed high expression of FSCN1 and GSN in all 12 LCH cases analysed; of CD207, MMP12, CCL22, and CD1a in the majority of these cases; and CCL17 in three of the 12 cases. Immunohistochemistry confirmed protein expression in the majority of cases. The expression of MMP12 was most abundant in multi-system LCH, which is the LCH type with the worst prognosis. This suggests that expression of MMP12 may play a role in the progression of LCH. These data reveal new insight into the pathology of LCH and provide new starting points for further investigation of this clonal proliferative disorder.

Aim: To gain more insight into the genes involved in the aetiology and pathogenesis of anaplastic large cell lymphoma (ALCL). Methods: Serial analysis of gene expression (SAGE) was undertaken on the CD4+ALK+ (anaplastic lymphoma kinase positive) ALCL derived cell line Karpas299 and as comparison on CD4+ T cells. Quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were performed on five ALCL derived cell lines and 32 tissue samples to confirm the SAGE data. Results: High expression of Mcl-1 was seen in the Karpas299 cell line, whereas the two other antiapoptotic Bcl-2 family members, Bcl-2 and Bcl-X L , were not detected in the SAGE library. Quantitative RT-PCR confirmed the high expression of Mcl-1 mRNA and low expression of Bcl-2 and Bcl-X L in Karpas299 and in four other ALCL cell lines. To expand on these initial observations, primary tissue samples were analysed for Mcl-1, Bcl-X L , and Bcl-2 by immunohistochemistry. All 23 ALK+ and nine ALK2 ALCL cases were positive for Mcl-1. Bcl-2 and Bcl-X L were expressed infrequently in ALK+ ALCL cases, but were present in a higher proportion of ALK2 ALCL cases. Conclusion:The consistent high expression of Mcl-1 in ALK+ and ALK2 ALCL suggests that Mcl-1 is the main antiapoptotic protein in this disease. The high frequency of Mcl-1, Bcl-2, and Bcl-X L positive ALCL cases in the ALK2 group compared with the ALK+ group indicates that ALK induced STAT3 activation is not the main regulatory pathway in ALCL.