Glycosylphosphatidylinositol-specific, CD1d-restricted T cells in paroxysmal nocturnal hemoglobinuria.
The mechanism of bone marrow failure (BMF) in paroxysmal nocturnal hemoglobinuria (PNH) is not yet known. Because in PNH the biosynthesis of the glycolipid molecule glycosylphosphatidylinositol (GPI) is disrupted in hematopoietic stem and progenitor cells by a somatic mutation in the PIG-A gene, BMF might result from an autoimmune attack, whereby T cells target GPI in normal cells, whereas PIG-A mutant GPI-negative cells are spared. In a deliberate test of this hypothesis, we have demonstrated in PNH patients the presence of CD8(+) T cells reactive against antigen-presenting cells (APCs) loaded with GPI. These T cells were significantly more abundant in PNH patients than in healthy controls; their reactivity depended on CD1d expression and they increased upon coculture with CD1d-expressing, GPI-positive APCs. In GPI-specific T cells captured by CD1d dimer technology, we identified, through global T-cell receptor α (TCRα) analysis, an invariant TCRVα21 sequence, which was then found at frequencies higher than background in the TCR repertoire of 6 of 11 PNH patients. Thus, a novel, autoreactive, CD1d-restricted, GPI-specific T-cell population, enriched in an invariant TCRα chain, is expanded in PNH patients and may be responsible for BMF in PNH.
Centre for Haematology, Department of Medicine, Hammersmith Hospital, Imperial College London, London, United Kingdom.
Lucia
L
Gargiulo
Maria
M
Papaioannou
Michela
M
Sica
Giulia
G
Talini
Aristeidis
A
Chaidos
Barbara
B
Richichi
Andrei V
AV
Nikolaev
Cristina
C
Nativi
Mark
M
Layton
Josu
J
de la Fuente
Irene
I
Roberts
Lucio
L
Luzzatto
Rosario
R
Notaro
Anastasios
A
Karadimitris
D000328:Adult; D000368:Aged; D000741:Anemia, Aplastic; D000938:Antigen-Presenting Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D055610:Antigens, CD1d / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D001855:Bone Marrow Diseases; D000080983:Bone Marrow Failure Disorders; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D018920:Coculture Techniques; D019281:Dimerization; D005260:Female; D005434:Flow Cytometry; D015723:Gene Library; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D006457:Hemoglobinuria, Paroxysmal / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D055815:Young Adult
D055610:Antigens, CD1d; C526877:CD1D protein, human; D017261:Glycosylphosphatidylinositols; D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta