Pulsed high-dose dexamethasone improves interleukin 10 secretion by CD5+ B cells in patients with primary immune thrombocytopenia.
BACKGROUND
B cells expressing CD5 are potentially capable of producing interleukin 10 (IL-10) which contributes to the regulatory function of B cells. This study was aimed at exploring the alteration of numbers of CD5(+) B cells and their ability of producing IL-10 in patients with immune thrombocytopenia (ITP), and the effects of pulsed high-dose dexamethasone (HD-DXM) therapy on CD5(+) B cells.


METHODS
Peripheral blood mononuclear cells from 25 adult ITP patients were stained with PE-CD5/FITC-CD19 antibodies for flow cytometry analyses before and after HD-DXM therapy. The expression of IL-10 mRNA was measured by RT-PCR. After 24 h culture with or without dexamethasone in the presence of PMA, ionomycin and Brefeldin A, cells were permeabilized and stained with APC-IL-10 antibody to investigate intracellular IL-10 expression. Supernatant IL-10 concentration was detected by ELISA.


RESULTS
The number of CD5(+) B cells was elevated in patients with ITP. Expression of IL-10 mRNA, percentage of IL-10(+) cells and intracellular IL-10 in CD5(+) B cells from untreated patients were significantly higher than that in controls. In contrast, ITP patients showed lower IL-10 concentration in supernatants than controls. After HD-DXM therapy, the number of CD5(+) B cells decreased to normal level, while intracellular IL-10 expression in CD5(+) B cells was further enhanced and IL-10 concentration in supernatants was also increased. Similar results were observed when dexamethasone was administrated in vitro.


CONCLUSIONS
Increased number of CD5(+) B cells in which IL-10 is accumulated with decreased IL-10 concentration in supernatants suggests that the ability of CD5(+) B cells to secret IL-10 is impaired in ITP patients. Both the aberrant number and ability of IL-10 secretion of CD5(+) B cells could be corrected by HD-DXM.
Department of Haematology, Zhongshan Hospital, Fudan University, 180 Feng Lin Road, Shanghai, 200032, China.
Fanli
F
Hua
Lili
L
Ji
Yanxia
Y
Zhan
Feng
F
Li
Shanhua
S
Zou
Xiaoyun
X
Wang
Dongli
D
Song
Zhihui
Z
Min
Song
S
Gao
Yangjiong
Y
Wu
Hao
H
Chen
Yunfeng
Y
Cheng
D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001402:B-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000473:pathology; D018956:CD5 Antigens / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000188:drug therapy* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000276:immunology
D000893:Anti-Inflammatory Agents; D018956:CD5 Antigens; C508609:IL10 protein, human; D012333:RNA, Messenger; D016753:Interleukin-10; D003907:Dexamethasone