T-cell recognition and cytokine profile induced by melanocyte epitopes in patients with HLA-DRB1*0405-positive and -negative Vogt-Koyanagi-Harada uveitis.
OBJECTIVE
Vogt-Koyanagi-Harada disease (VKH), an autoimmune disease targeted against melanocytes, is associated with HLA-DRB1*0405. This study was undertaken to analyze T-cell recognition and the cytokine expression profile induced by melanocyte epitopes in HLA-DRB1*0405-positive and -negative patients with VKH uveitis.


METHODS
Peripheral blood mononuclear cells (PBMC) proliferation and Th1 (IFN-gamma) and Th2 (IL-4 and IL-5) cytokine production were analyzed in HLA-DRB1*0405-positive (n = 12) and -negative (n = 22) patients with VKH and HLA-DRB1*0405-positive (n = 9) and -negative (n = 8) control subjects in response to human melanoma cell line lysate (HMCLL) and 28 synthetic peptides derived from the human melanocyte differentiation proteins TYR, TRP1, TRP2, and Pmel17. The peptides were selected using the TEPITOPE algorithm, based on their predicted binding to HLA-DRB1*0405 and to the non-disease-related HLA-DRB1*15.


RESULTS
HMCLL was recognized exclusively by the patients' PBMC (44%) but not by those of the control subjects (P < 0.01). PBMC from patients with VKH recognized an increased breadth of melanocyte-derived peptides at lower peptide concentrations than in the control subjects (68% vs. 25%; P < 0.01, at 1 microM) and did not produce the Th2 cytokine IL-4 in response to disease-specific peptides (0% vs. 50%, P < 0.001). Five peptides were exclusively recognized in patients bearing HLA-DRB1*0405. Furthermore, HLA-DRB1*0405-bearing patients, but not those with HLA-DRB1*15, recognized an increased breadth of melanocyte epitopes in comparison to HLA-matched control subjects (60% vs. 28%; P < 0.05).


CONCLUSIONS
These data indicate that patients with VKH are sensitized to melanocyte epitopes and display a peptide-specific Th1 cytokine response. In addition, the data indicate that patients bearing HLA-DRB1*0405 recognize a broader melanocyte-derived peptide repertoire, reinforcing the importance of this allele in susceptibility to the development of VKH disease.
Department of Ophthalmology, University of São Paulo School of Medicine, São Paulo, Brazil.
Francisco Max
FM
Damico
Edecio
E
Cunha-Neto
Anna Carla
AC
Goldberg
Leo Kei
LK
Iwai
Maria Lucia
ML
Marin
Juergen
J
Hammer
Jorge
J
Kalil
Joyce Hisae
JH
Yamamoto
D000293:Adolescent; D000328:Adult; D002648:Child; D000939:Epitopes / Q000276:immunology*; D005260:Female; D006684:HLA-DR Antigens / Q000276:immunology*; D059811:HLA-DRB1 Chains; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D015847:Interleukin-4 / Q000378:metabolism; D015848:Interleukin-5 / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D008544:Melanocytes / Q000276:immunology*; D008545:Melanoma / Q000276:immunology; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000276:immunology; D010455:Peptides / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology; D014407:Tumor Cells, Cultured; D014607:Uveomeningoencephalitic Syndrome / Q000276:immunology*
D000939:Epitopes; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; C493960:HLA-DRB1*04:05 antigen; D015848:Interleukin-5; D009363:Neoplasm Proteins; D010455:Peptides; D015847:Interleukin-4; D007371:Interferon-gamma