Increased soluble and platelet-associated CD40 ligand in essential thrombocythemia and reactive thrombocytosis.
CD40 ligand (CD40L) is expressed on activated CD4(+) T lymphocytes and at the activated platelet surface. A circulating soluble form of CD40L (sCD40L) is generated by the way of a proteolytic cleavage. We measured sCD40L in the plasma of either healthy subjects; patients with inflammatory disorders and low, normal, or high platelet count (reactive thrombocytosis); or patients with essential thrombocythemia (ET). A tight correlation was found between the platelet count and plasma sCD40L. ET patients had the highest levels of sCD40L. Platelet-associated CD40L was increased in ET and reactive thrombocytosis, conditions associated with increased platelet regeneration. Platelet-associated CD40L was released upon platelet activation. In conclusion, platelets appear as a reservoir of CD40L that may be a major contributor to circulating sCD40L. Platelet-associated CD40L may be a potential marker of platelet regeneration.
Viallard
Jean-François
JF
Department of Internal Medicine, Hôpital Haut-Lévêque, 5 avenue Magellan, 33604 Pessac, France. jean-francois.viallard@chu-bordeaux.fr
Solanilla
Anne
A
Gauthier
Bruno
B
Contin
Cécile
C
Déchanet
Julie
J
Grosset
Christophe
C
Moreau
Jean-François
JF
Praloran
Vincent
V
Nurden
Paquita
P
Pellegrin
Jean-Luc
JL
Nurden
Alan T
AT
Ripoche
Jean
J
D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000737:chemistry / Q000502:physiology*; D023201:CD40 Ligand / Q000032:analysis*; D002462:Cell Membrane / Q000276:immunology; D005260:Female; D005602:France; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation / Q000187:drug effects; D010976:Platelet Count; D012044:Regression Analysis; D013601:T-Lymphocytes / Q000276:immunology; D013920:Thrombocythemia, Essential / Q000097:blood* / Q000209:etiology; D013922:Thrombocytosis / Q000097:blood* / Q000209:etiology; D044465:White People
D023201:CD40 Ligand