Andrea Jox

HMGI-C, a member of the high mobility group family of proteins, is expressed in hematopoietic stem cells and in leukemic cells.

The human HMGI-C gene encoding a member of the high mobility group protein family normally is expressed only during embryonic/fetal development but in none of the adult tissues tested so far. Recently, the HMGI-C gene has attracted a lot of interest since its rearrangements seem to underlie the development of frequent benign mesenchymal tumors. We have therefore checked CD34 positive hematopoietic stem cells and their normal and malignant descendants for HMGI-C expression. CD34 positive stem cells from healthy donors and the leukemia samples tested were positive while all peripheral blood samples from healthy volunteers were negative. We have concluded that the expression of the HMGI-C gene in leukemia seems to be a secondary effect due to abnormal stem cell proliferation and might be a sensitive tumor marker for particular types of leukemia.

Detection of identical Hodgkin-Reed Sternberg cell specific immunoglobulin gene rearrangements in a patient with Hodgkin's disease of mixed cellularity subtype at primary diagnosis and in relapse two and a half years later

BACKGROUND The malignant nature of Hodgkin-Reed Sternberg (H-RS) cells has been questioned due to their scarcity in lymphoma tissues. Recently, using micromanipulation of H-RS cells and single cell PCR evidence was obtained that H-RS cells represent a clonal B-cell population. In these studies H-RS cells were isolated from each one lymph node for a given case. In classical Hodgkins disease (HD) it thus could not be ruled out that H-RS cell clonality reflected a locally restricted clonal proliferation. We analysed biopsy specimens from a patient suffering from HD for the presence of clonally related H-RS cells at primary diagnosis and during relapse of the disease. MATERIALS AND METHODS In 1994 the H-RS cell line L1236 was generated from the peripheral blood of a patient suffering from a disseminating relapse of HD of mixed cellularity subtype. The patient had relapsed despite intensive treatment including high dose chemotherapy and autologous bone marrow transplantation. The clonal identity of this cell line with H-RS cells in situ was proven by amplifying identical Ig gene rearrangements of the cell line as well as of single H-RS cells picked from the patients bone marrow. Primers covering the CDR3 region were chosen from the H-RS cell specific VH1 gene rearrangement to detect H-RS cells of the identical clone by amplifying the rearranged VH1 genes in tissue samples obtained during disseminating relapsing disease and at primary diagnosis of HD in 1991. RESULTS The H-RS cell specific DNA sequence was detected in all affected tissues analysed including the cervical lymph node which has been exstirpated at primary diagnosis. CONCLUSION This finding indicates the existence of a clonal H-RS cell population during the first manifestation of HD and persistence and dissemination of this clone despite aggressive treatment. Thus, in the described case the malignant nature of H-RS cells defined by dissemination and recurrence of the identical H-RS cell clone in relapsing disease is proven.

Morphologically normal, CD30-negative B-lymphocytes with chromosome aberrations in classical Hodgkin's disease: the progenitor cell of the malignant clone?

A recent study observed that numerical chromosome abnormalities in Hodgkins disease (HD) are detected not only in morphologically abnormal Hodgkin/Reed–Sternberg cells, but also in a fraction of morphologically normal cells. However, the phenotypic constitution of these genetically abnormal, morphologically normal cells and their relationship to the malignant Hodgkin/Reed–Sternberg cells could not be established in the earlier cases studied, because of the low frequency of these cells. The present study investigated two cases of classical Hodgkins disease containing a relatively large population of such apparently normal cells with aberrant chromosome copy numbers. The phenotype and their position within the developmental route of the malignant compartment were examined by a combined in situ hybridization and immunocytochemistry approach. Numerical abnormalities for chromosome 1 in one case and for chromosomes X, Y, and 1 in the other case were observed not only in CD30‐positive Hodgkin/Reed–Sternberg cells, but also in CD30‐negative, morphologically normal cells. It was shown that these genetically aberrant cells expressed the B‐cell antigen CD19, thus confirming their B‐cell nature. These studies indicate a relationship between the genome aberrations in these genetically abnormal, morphologically normal B‐cells and the Hodgkin/Reed–Sternberg cells, suggesting that they are progenitor cells of the malignant cell fraction. Copyright

Detection of a Hodgkin/Reed-Sternberg cell specific immunoglobulin gene rearrangement in the serum DNA of a patient with Hodgkin's disease

We analysed multiple serum samples from a patient with mixed cellularity Hodgkins disease for the Hodgkin/Reed‐Sternberg cell clone‐specific rearranged Ig gene sequence. The clone‐specific sequence could be detected in DNA extracted from a serum sample obtained during clinical relapse but not in serum samples obtained during or after treatment following relapse.

Integration of Epstein Barr virus near the breakpoint of a translocation 11;19 in a Burkitt's lymphoma cell line

The physical state of Epstein Barr virus (EBV) DNA was analyzed in the Burkitts lymphoma (BL) cell line BL60 and in the autologous EBV-immortalized lymphoblastoid cell line (LCL) IARC 277 by Gardella gel analysis, Southern blotting, and nonradioactive in situ hybridization to metaphase chromosomes. Although only episomal viral DNA was detected in the LCL, the 6-12 copies of EBV DNA in the BL cell line are integrated in one site of the host cell genome. The integration site is located near the breakpoint of a translocation 11;19 which is present in this cell line in addition to the BL-specific t(8;22).

Hodgkin's disease biology: recent advances

The cellular origin of H‐RS cells has been questioned for a long time. Recently, using single cell amplification of Ig genes evidence was obtained that H‐RS cells clonally arise from B‐cells. Sequence analysis of rearranged Ig genes demonstrated that H‐RS cells develop within the germinal centre. H‐RS cells in classical HD grow despite loss of function of their rearranged Ig genes. In contrast, the mutation pattern of rearranged Ig genes in L & H cells of lymphocyte‐predominant HD frequently shows ongoing mutations indicating that these cell are still antigen selected. These molecular differences show that LP HD genetically differs from classical HD. H‐RS cells escape from apoptosis within the germinal centre. However, the events leading to malignant transformation are still unknown. The association between EBV and HD has been repeatedly described, but the occurrence of EBV negative cases is hard to explain just by loss of EBV. The analysis of chromosomal aberrations in H‐RS cells did not result in the description of a specific ‘HD‐gene’. Also the role of the T‐lymphocytes surrounding the H‐RS cells has remained an open question.