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Detection of aberrant transcription of major histocompatibility complex class II antigen presentation genes in chronic lymphocytic leukaemia identifies HLA‐DOA mRNA as a prognostic factor for survival
Author(s) -
Souwer Yuri,
Chamuleau Martine E. D.,
Van De Loosdrecht Arjan A.,
Tolosa Eva,
Jorritsma Tineke,
Muris Jettie J. F.,
Dinnissenvan Poppel Marion J.,
Snel Sander N.,
Van De Corput Lisette,
Ossenkoppele Gert J.,
Meijer Chris J. L. M.,
Neefjes Jacques J.,
Marieke van Ham S.
Publication year - 2009
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.2009.07625.x
Subject(s) - ciita , biology , mhc class ii , major histocompatibility complex , cd74 , antigen processing , antigen presentation , human leukocyte antigen , immunology , antigen , messenger rna , cancer research , microbiology and biotechnology , mhc class i , immune system , gene , t cell , genetics
Summary In human B cells, effective major histocompatibility complex (MHC) class II‐antigen presentation depends not only on MHC class II, but also on the invariant chain (CD74 or Ii), HLA‐DM (DM) and HLA‐DO (DO), the chaperones regulating the antigen loading process of MHC class II molecules. We analysed immediate ex vivo expression of HLA‐DR (DR), CD74, DM and DO in B cell chronic lymphocytic leukaemia (B‐CLL). Real‐time reverse transcription polymerase chain reaction demonstrated a highly significant upregulation of DRA , CD74 , DMB , DOA and DOB mRNA in purified malignant cells compared to B cells from healthy donors. The increased mRNA levels were not translated into enhanced protein levels but could reflect aberrant transcriptional regulation. Indeed, upregulation of DRA , DMB , DOA and DOB mRNA correlated with enhanced expression of class II transactivator ( CIITA ). In‐depth analysis of the various CIITA transcripts demonstrated a significant increased activity of the interferon‐γ‐inducible promoter CIITA‐PIV in B‐CLL. Comparison of the aberrant mRNA levels with clinical outcome identified DOA mRNA as a prognostic indicator for survival. Multivariate analysis revealed that the prognostic value of DOA mRNA was independent of the mutational status of the IGHV genes. Thus, aberrant transcription of DOA forms a novel and additional prognostic indicator for survival in B‐CLL.