HLA-DR expression in B-cell non-Hodgkin's malignant lymphomas: a multiparameter flow cytometry study

Fully human antibody exhibits pan-human leukocyte antigen-DR recognition and high in vitro/vivo efficacy against human leukocyte antigen-DR-positive lymphomas

HD8, a fully human monoclonal antibody specific for human leukocyte antigen-DR (HLA-DR), was generated by using the transchromosome mouse that bears the human immunoglobulin genes. HD8 could bind to all 13 tested HLA-DR-positive cell lines and 35 B-cells from healthy donors. Epitope mapping revealed that while the antibody recognizes the most polymorphic region of the HLA-DRB chain, its critical epitope residues are conserved in the major alleles. Indeed, HD8 could recognize 99.2% of HLA-DRB alleles. Since its essential epitope residues are also largely conserved in HLA-DP and HLA-DQ, HD8 could recognize 100% and 66% of the HLA-DP and HLA-DQ alleles tested, respectively. HD8 exerted strong antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro, and significantly extended the life span of immunocompromised mice inoculated with non-Hodgkin lymphoma cell lines. The HD8 antibody may be highly useful in HLA-DR-targeted immunotherapy as it is likely to evoke similarly strong responses in individuals carrying different HLA-DR alleles.

Practical applications of immunohistochemistry in hematolymphoid neoplasms

Immunohistochemistry plays a key role in the diagnosis and classification of hematolymphoid neoplasms. New cell and lineage markers are constantly being discovered and added to the existing long list of antibodies. In this review article we provide general information and new applications of the commonly used hematolymphoid markers. We also discuss the features and applications of some newly discovered markers, such as ALK, fascin, granzyme/perforin, and tryptase. There is no universal "panel" for the diagnosis of hematolymphoid neoplasms. However, in this review article, we provide suggested panels for a given hematolymphoid neoplasm that is based on our experience and that reported in the literature.

Flow cytometric analysis of cell-surface antigen expressions on acute myeloid leukemia cell populations according to their cell-size

Acute myeloid leukemia (AML) cells which expanded from a single leukemic cell show certain degrees of morphological and biological heterogeneity. In the present study, we determined cell-surface antigen expressions (CD13, 33, 34 and 38, and HLA-DR) on AML cells based on their cell-size (large vs small cells) by flow cytometry. We found that the cell-surface antigens were more strongly expressed on the large leukemic cells than the small cells, regardless of FAB subtypes. Furthermore, our preliminary study demonstrated that AML patients who showed a relatively small difference in antigen expression between large and small leukemic cells had longer remission durations and survival periods, compared with those with a more prominent difference in antigen expression. Thus, the heterogeneity of AML cells determined by the combination of cell-surface antigen expressions and cell-size may be associated with clinically important biological behaviors.