Elevated Semaphorin 5A correlated with Th1 polarization in patients with chronic immune thrombocytopenia.
BACKGROUND
Primary immune thrombocytopenia (ITP) is an immune-mediated disorder in which cellular immunity deficiency and disturbed cytokine profiles have been found. Semaphorin 5A (Sema5A) has been showed to be implicated in cellular immune response. We aimed to evaluate the role of Sema5A in patients with chronic ITP.


METHODS
Plasma levels of Sema5A, T helper (Th) cytokines (interferon [IFN] -γ,interleukin [IL]-4,IL-17A) were determined by enzyme-linked immunosorbent assay (ELISA) in ITP patients and healthy controls. Using real-time quantitative polymerase chain reaction (RT-PCR), mRNA levels of Sema5A and its receptor plexin-B3, plexin-A1 in peripheral blood mononuclear cells(PBMCs)were studied in all subjects. Specific anti-platelet autoantibodies were measured by the Pak Auto method. The dynamic change of plasma Sema5A and mRNA levels of its receptors was measured in 9 patients after effective therapy.


RESULTS
Plasma Sema5A levels were significantly increased in active patients with chronic ITP compared to patients in remission and healthy controls. Elevated levels of Sema5A were found positively correlated with higher levels of plasma IFN-γ, IFN-γ/IL-4 ratio and negatively correlated with lower levels of plasma IL-4, platelet counts in ITP patients. The mRNA plexin-B3 was decreased in active ITP patients and inversely correlated with plasma Sema5A levels. Additionally, plasma levels of Sema5A and IFN-γ were reduced with up-regulation of plexin-B3 expression after effective treatment.


CONCLUSIONS
Our data demonstrated elevated plasma Sema5A in chronic ITP patients might be involved in Th1 polarization by down-regulating receptor plexin-B3 expression and correlated with disease activity.
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Mingen
M
Lyu
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Yang
Y
Li
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Yating
Y
Hao
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Tiantian
T
Sun
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Wenjie
W
Liu
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Cuicui
C
Lyu
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Rongfeng
R
Fu
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Huiyuan
H
Li
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Feng
F
Xue
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Xiaofan
X
Liu
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China.
Lei
L
Zhang
State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China. Electronic address: rcyang65@163.com.
Renchi
R
Yang
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002908:Chronic Disease; D016207:Cytokines / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000097:blood*; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000097:blood*; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000097:blood*; D039961:Semaphorins; D055815:Young Adult
D016207:Cytokines; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C491228:SEMA5A protein, human; D039961:Semaphorins
Cytokines; Immune thrombocytopenia; Semaphorin 5A; Th1; Treatment