Key Points

  • The mechanisms of anti-GPIbα antibody-induced thrombocytopenia and thrombopoietin response differ in relation to antibody dose.

  • Megakaryocytes targeted by anti-GPIbα antibody generate platelets with reduced surface GPIbα expression.

Abstract

Immune thrombocytopenia (ITP) is an acquired bleeding disorder characterized by antibody-mediated platelet destruction. Different mechanisms have been suggested to explain accelerated platelet clearance and impaired thrombopoiesis, but the pathophysiology of ITP has yet to be fully delineated. In this study, we tested 2 mouse models of immune-mediated thrombocytopenia using the rat anti-mouse GPIbα monoclonal antibody 5A7, generated in our laboratory. After a single IV administration of high-dose (2 mg/kg) 5A7, opsonized platelets were rapidly cleared from the circulation into the spleen and liver; this was associated with rapid upregulation of thrombopoietin (TPO) messenger RNA. In contrast, subcutaneous administration of low-dose 5A7 (0.08-0.16 mg/kg) every 3 days gradually lowered the platelet count; in this case, opsonized platelets were observed only in the spleen, and TPO levels remained unaltered. Interestingly, in both models, the 5A7 antibody was found on the surface of, as well as internalized to, bone marrow megakaryocytes. Consequently, platelets generated in the chronic phase of repeated subcutaneous 5A7 administration model showed reduced GPIbα membrane expression on their surface. Our findings indicate that evaluation of platelet surface GPIbα relative to platelet size may be a useful marker to support the diagnosis of anti-GPIbα antibody–induced ITP.

REFERENCES

REFERENCES
1.
Lambert
MP
,
Gernsheimer
TB
.
Clinical updates in adult immune thrombocytopenia
.
Blood
.
2017
;
129
(
21
):
2829
-
2835
.
2.
Li
J
,
Sullivan
JA
,
Ni
H
.
Pathophysiology of immune thrombocytopenia
.
Curr Opin Hematol
.
2018
;
25
(
5
):
373
-
381
.
3.
Webster
ML
,
Sayeh
E
,
Crow
M
, et al
.
Relative efficacy of intravenous immunoglobulin G in ameliorating thrombocytopenia induced by antiplatelet GPIIbIIIa versus GPIbalpha antibodies
.
Blood
.
2006
;
108
(
3
):
943
-
946
.
4.
Peng
J
,
Ma
S-H
,
Liu
J
, et al
.
Association of autoantibody specificity and response to intravenous immunoglobulin G therapy in immune thrombocytopenia: a multicenter cohort study
.
J Thromb Haemost
.
2014
;
12
(
4
):
497
-
504
.
5.
Go
RS
,
Johnston
KL
,
Bruden
KC
.
The association between platelet autoantibody specificity and response to intravenous immunoglobulin G in the treatment of patients with immune thrombocytopenia
.
Haematologica
.
2007
;
92
(
2
):
283
-
284
.
6.
Grozovsky
R
,
Begonja
AJ
,
Liu
K
, et al
.
The Ashwell-Morell receptor regulates hepatic thrombopoietin production via JAK2-STAT3 signaling
.
Nat Med
.
2015
;
21
(
1
):
47
-
54
.
7.
Li
J
,
van der Wal
DE
,
Zhu
G
, et al
.
Desialylation is a mechanism of Fc-independent platelet clearance and a therapeutic target in immune thrombocytopenia
.
Nat Commun
.
2015
;
6
(
1
):
7737
.
8.
Xu
M
,
Li
J
,
Neves
MAD
, et al
.
GPIbα is required for platelet-mediated hepatic thrombopoietin generation
.
Blood
.
2018
;
132
(
6
):
622
-
634
.
9.
Poujol
C
,
Bergmeier
W
,
Nurden
P
,
Nieswandt
B
,
Nurden
A
.
Effect of infusing rat monoclonal antibodies to the murine GPIb-IX-V complex on platelet and megakaryocyte morphology in mice
.
Platelets
.
2003
;
14
(
1
):
35
-
45
.
10.
Quach
ME
,
Chen
W
,
Li
R
.
Mechanisms of platelet clearance and translation to improve platelet storage
.
Blood
.
2018
;
131
(
14
):
1512
-
1521
.
11.
Kawamoto
T
,
Kawamoto
K
.
Preparation of thin frozen sections from nonfixed and undecalcified hard tissues using Kawamot’s film method (2012)
.
Methods Mol Biol
.
2014
;
1130
:
149
-
164
.
12.
Morodomi
Y
,
Kanaji
S
,
Won
E
,
Kawamoto
T
,
Kanaji
T
.
Modified application of Kawamoto’s film method for super-resolution imaging of megakaryocytes in undecalcified bone marrow
.
Res Pract Thromb Haemost
.
2019
;
4
(
1
):
86
-
91
.
13.
Kanaji
T
,
Vo
MN
,
Kanaji
S
, et al
.
Tyrosyl-tRNA synthetase stimulates thrombopoietin-independent hematopoiesis accelerating recovery from thrombocytopenia
.
Proc Natl Acad Sci USA
.
2018
;
115
(
35
):
E8228
-
E8235
.
14.
Fox
JE
,
Aggerbeck
LP
,
Berndt
MC
.
Structure of the glycoprotein Ib.IX complex from platelet membranes
.
J Biol Chem
.
1988
;
263
(
10
):
4882
-
4890
.
15.
Carrell
NA
,
Fitzgerald
LA
,
Steiner
B
,
Erickson
HP
,
Phillips
DR
.
Structure of human platelet membrane glycoproteins IIb and IIIa as determined by electron microscopy
.
J Biol Chem
.
1985
;
260
(
3
):
1743
-
1749
.
16.
Quach
ME
,
Dragovich
MA
,
Chen
W
, et al
.
Fc-independent immune thrombocytopenia via mechanomolecular signaling in platelets
.
Blood
.
2018
;
131
(
7
):
787
-
796
.
17.
Bergmeier
W
,
Rackebrandt
K
,
Schröder
W
,
Zirngibl
H
,
Nieswandt
B
.
Structural and functional characterization of the mouse von Willebrand factor receptor GPIb-IX with novel monoclonal antibodies
.
Blood
.
2000
;
95
(
3
):
886
-
893
.
18.
Kitajima
K
,
Minehata
K
,
Sakimura
K
,
Nakano
T
,
Hara
T
.
In vitro generation of HSC-like cells from murine ESCs/iPSCs by enforced expression of LIM-homeobox transcription factor Lhx2
.
Blood
.
2011
;
117
(
14
):
3748
-
3758
.
19.
Chang
M
,
Nakagawa
PA
,
Williams
SA
, et al
.
Immune thrombocytopenic purpura (ITP) plasma and purified ITP monoclonal autoantibodies inhibit megakaryocytopoiesis in vitro
.
Blood
.
2003
;
102
(
3
):
887
-
895
.
20.
Nishimura
S
,
Nagasaki
M
,
Kunishima
S
, et al
.
IL-1α induces thrombopoiesis through megakaryocyte rupture in response to acute platelet needs
.
J Cell Biol
.
2015
;
209
(
3
):
453
-
466
.
21.
Hawkins
J
,
Aster
RH
,
Curtis
BR
.
Post-Transfusion Purpura: Current Perspectives
.
J Blood Med
.
2019
;
10
:
405
-
415
.
22.
Warren
A
,
Le Couteur
DG
,
Fraser
R
,
Bowen
DG
,
McCaughan
GW
,
Bertolino
P
.
T lymphocytes interact with hepatocytes through fenestrations in murine liver sinusoidal endothelial cells
.
Hepatology
.
2006
;
44
(
5
):
1182
-
1190
.
23.
Li
Y
,
Fu
J
,
Ling
Y
, et al
.
Sialylation on O-glycans protects platelets from clearance by liver Kupffer cells
.
Proc Natl Acad Sci USA
.
2017
;
114
(
31
):
8360
-
8365
.
24.
Ward
SE
,
O’Sullivan
JM
,
Drakeford
C
, et al
.
A novel role for the macrophage galactose-type lectin receptor in mediating von Willebrand factor clearance
.
Blood
.
2018
;
131
(
8
):
911
-
916
.
25.
Cantoni
S
,
Carpenedo
M
,
Nichelatti
M
, et al
.
Clinical relevance of antiplatelet antibodies and the hepatic clearance of platelets in patients with immune thrombocytopenia
.
Blood
.
2016
;
128
(
17
):
2183
-
2185
.
26.
Vrbensky
JR
,
Moore
JE
,
Arnold
DM
,
Smith
JW
,
Kelton
JG
,
Nazy
I
.
The sensitivity and specificity of platelet autoantibody testing in immune thrombocytopenia: a systematic review and meta-analysis of a diagnostic test
.
J Thromb Haemost
.
2019
;
17
(
5
):
787
-
794
.
27.
Tomiyama
Y
,
Take
H
,
Honda
S
, et al
.
Demonstration of platelet antigens that bind platelet-associated autoantibodies in chronic ITP by direct immunoprecipitation procedure
.
Br J Haematol
.
1990
;
75
(
1
):
92
-
98
.
28.
Kuwana
M
,
Okazaki
Y
,
Ikeda
Y
.
Detection of circulating B cells producing anti-GPIb autoantibodies in patients with immune thrombocytopenia
.
PLoS One
.
2014
;
9
(
1
):
e86943
.
29.
Arnold
DM
,
Nazy
I
,
Clare
R
, et al
.
Misdiagnosis of primary immune thrombocytopenia and frequency of bleeding: lessons from the McMaster ITP Registry
.
Blood Adv
.
2017
;
1
(
25
):
2414
-
2420
.
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