title: Evidence for no relevance of anti-major histocompatibility complex class I-related chain a antibodies in liver transplantation.
abstract: The polymorphic major histocompatibility complex class I-related chain A (MICA) antigen is being increasingly recognized as a potential target molecule for immune cells during allograft rejection. Here we studied whether MICA is a target antigen for antibodies in liver transplant patients. Eighty-four patients were investigated for the presence of MICA antibodies before and after liver transplantation with MICA-transfected cells and flow cytometry. MICA typing was performed by polymerase chain reaction. Expression of MICA in liver cells was determined by reverse-transcription polymerase chain reaction, Western blotting, and flow cytometry. Liver biopsy specimens from liver transplant patients were examined for MICA expression. A total of 22 of 84 (26%) patients had MICA antibodies either pre-transplant (8/84, 9.5%) or post-transplant (14/84, 17%). No correlation between rejection frequencies (14/22, 63%) or other clinical parameters was observed in patients with MICA antibody versus those without MICA antibody (29/62, 47% P = not significant). We found weak messenger RNA expression for MICA in liver cells but no protein or cell surface expression. In addition, no MICA expression in liver biopsy sections from liver transplant patients was observed at any time point, including rejections. Thus, our preliminary results demonstrate no causal relationship between the presence of MICA antibodies and liver allograft rejections. Therefore, it is likely that MICA may not be an important target antigen during liver allograft rejections.
authors.affiliation: Division of Clinical Immunology, Huddinge University Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Uzunel
authors.forename: Haxiaobieke
authors.initials: H
authors.lastname: Kasimu
authors.forename: Meghnad
authors.initials: M
authors.lastname: Joshi
authors.forename: Xupeng
authors.initials: X
authors.lastname: Ge
authors.forename: Jining
authors.initials: J
authors.lastname: Liu
authors.forename: Bo
authors.initials: B
authors.lastname: Xu
authors.forename: Marie
authors.initials: M
authors.lastname: Jaksch
authors.forename: Carl
authors.initials: C
authors.lastname: Jorns
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Nowak
authors.forename: Suchitra
authors.initials: S
authors.lastname: Sumitran-Holgersson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D000906:Antibodies / Q000097:blood / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D005260:Female; D006084:Graft Rejection / Q000276:immunology*; D022781:Hepatocytes / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007223:Infant; D008099:Liver / Q000276:immunology*; D008107:Liver Diseases / Q000276:immunology / Q000473:pathology / Q000601:surgery*; D016031:Liver Transplantation / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D014019:Tissue Donors; D014162:Transfection; D055815:Young Adult
chemical_list: D000906:Antibodies; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A