Blockage of CD72 reduces B cell proliferation in immune thrombocytopenic purpura, involving interleukin 1 and macrophage migration inhibitory factor secretion

Figures & data

Table 1. The status of ITP patients at recruitment and tests underwent.

No.	Gender	Age (years)	Diagnosis	Platelet count (×10^9/l)	Tests
1	Male	51	pITP	9	eCD72
2	Female	20	nITP	16	eCD72
3	Male	44	pITP	7	eCD72
4	Female	56	pITP	13	eCD72
5	Female	30	nITP	5	eCD72
6	Female	29	PITP	28	eCD72
7	Male	61	nITP	1	eCD72
8	Female	47	pITP	5	eCD72
9	Female	21	nITP	21	eCD72
10	Male	68	nITP	32	eCD72
11	Female	18	nITP	36	eCD72
12	Female	39	ITPr	112	eCD72
13	Male	79	ITPr	98	eCD72
14	Female	43	ITPr	89	eCD72
15	Male	18	ITPr	103	eCD72
16	Male	77	ITPr	85	eCD72
17	Female	47	ITPr	217	eCD72
18	Female	21	ITPr	233	eCD72
19	Male	21	pITP	7	BCP+HPA+cytokines
20	Female	23	pITP	2	BCP+HPA+cytokines
21	Male	61	nITP	25	BCP+HPA+cytokines
22	Female	36	nITP	23	BCP+HPA+cytokines
23	Female	20	nITP	30	BCP+HPA+cytokines
24	Female	22	nITP	7	BCP+HPA+cytokines
25	Female	70	nITP	4	BCP+HPA+cytokines
26	Male	16	pITP	2	BCP+HPA+cytokines
27	Female	15	pITP	22	BCP+HPA+cytokines
28	Female	17	pITP	48	BCP+HPA+cytokines
29	Female	14	nITP	12	BCP+cytokines
30	Male	26	pITP	10	BCP
31	Female	20	ITPr	123	BCP+HPA
32	Female	28	ITPr	97	BCP+HPA
33	Female	20	ITPr	143	BCP+HPA
34	Female	32	ITPr	59	BCP+cytokines
35	Female	46	ITPr	66	BCP

Note: nITP, newly diagnosed ITP; pITP, persistent ITP; ITPr, ITP in remission; eCD72, CD72 expression; BCP, B cell proliferation; HPA, human platelet antibody.

Figure 1. Flow cytometry analysis of ITP and control peripheral lymphocytes. (a,b) The percentage and absolute count of B cells in ITP patients were significantly increased compared with that in control (P = 0.021 and 0.032, respectively, bars at median with interquartile range). (c) CD72 expression in B cells was significantly different between npITP, ITPr, and control with median of 87.35%, 78.19%, and 83.72%, respectively (P = 0.049, bars at median with interquartile range). (d) The percentage of CD72-positive B cells of npITP was significantly higher than that of ITPr (P = 0.018, bars at median with interquartile range). (e) There is no significant difference in CD72-positive B cell percentages between npITP and control (P = 0.18, bars at median with interquartile range).

Figure 2. The effect of anti-CD72 on B cell proliferation during in vitro culture of ITP patients’ mononuclear cells. (a) Histograms represent CD72 antibody cultured cells (red line) or isotype antibody cultured cells (green-filled histogram). (b) Anti-CD72 significantly decreased B cell proliferation of ITP patients in vitro (**P = 0.009). (c) Anti-CD72 decreased B cell proliferation from control in culture (*P = 0.021).

Figure 3. The effect of anti-CD72 on the levels of platelet antibody, interleukin 1(IL-1), and macrophage migration inhibitory factor (MIF) during in vitro culture. (a) Platelet antibody levels were not significantly different between CD72 and isotype antibody-added cultures in ITP. B. IL-1 was significantly elevated by the addition of CD72 antibody in the group of ITP (*P = 0.014). (c) IL-1 levels were not significantly different between CD72 and isotype antibody-added cultures in control group. (d) MIF was significantly increased in CD72 added culture compared with isotype antibody in ITP group (**P = 0.002). (e) MIF was not obviously different between CD72 and isotype antibody-added cultures in control group.

Data availability statement

All data generated or used during the study appeared in the submitted article.