Indirect allorecognition of major histocompatibility complex allopeptides in human renal transplant recipients with chronic graft dysfunction.
BACKGROUND
It has been suggested that T cells primed by processed donor major histocompatibility complex antigen (the "indirect" pathway of allorecognition) may be responsible for mediating chronic allograft rejection. The purpose of this study was to develop a clinically useful assay to study the occurrence of indirect allorecognition during chronic rejection in humans.


METHODS
A panel of 20 mer peptides corresponding to the hypervariable regions of HLA-DRB1*0101, DRB1*1501, and DRB1*0301 were synthesized. Lymphocytes obtained from renal allograft recipients were cocultured with these peptides. Proliferation was assayed by DNA incorporation of [3H]thymidine, and positive proliferation was defined by a statistically significant increase in counts per minute over background with a minimum stimulation index of 2. The precursor frequency of allopeptide reactive T cells was determined by limiting dilution analysis.


RESULTS
Lymphocytes from 82% of patients who were mismatched for at least one of the three DR molecules and had chronic allograft dysfunction specifically proliferated to the mismatched allopeptides (n=11). Proliferation was seen in only 6% of control subjects (2/33, P<0.0001). The proliferative response was low grade and was best detected on day 7-8 of culture in vitro. The precursor frequency of peptide-specific T cells was more than 10-fold higher compared with controls (P<0.001).


CONCLUSIONS
These data demonstrate for the first time that T cells of patients with chronic graft dysfunction are primed to recognize and respond to specific donor-derived major histocompatibility complex allopeptides. Our results support the hypothesis that T cells primed via the indirect pathway of allorecognition may be important mediators of chronic rejection and provide the rationale to develop specific therapeutic strategies to prevent or interrupt this process.
Vella
J P
JP
Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
Spadafora-Ferreira
M
M
Murphy
B
B
Alexander
S I
SI
Harmon
W
W
Carpenter
C B
CB
Sayegh
M H
MH
D000328:Adult; D000595:Amino Acid Sequence; D002478:Cells, Cultured; D018920:Coculture Techniques; D003404:Creatinine / Q000097:blood; D004247:DNA / Q000096:biosynthesis; D004359:Drug Therapy, Combination; D005260:Female; D006084:Graft Rejection / Q000276:immunology*; D006684:HLA-DR Antigens / Q000737:chemistry* / Q000276:immunology; D059811:HLA-DRB1 Chains; D006801:Humans; D007108:Immune Tolerance; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007519:Isoantigens / Q000276:immunology*; D016030:Kidney Transplantation / Q000276:immunology* / Q000502:physiology; D008213:Lymphocyte Activation / Q000187:drug effects; D008285:Major Histocompatibility Complex; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*
D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; C553502:HLA-DRB1*03:01 antigen; D007166:Immunosuppressive Agents; D007519:Isoantigens; D010446:Peptide Fragments; D004247:DNA; D003404:Creatinine