Effect of Cytokine Gene Polymorphisms on Eltrombopag Reactivity in Japanese Patients with Immune Thrombocytopenia

Figures & data

Figure 1 Presumed mechanism of anti-platelet antibody and platelet destruction in ITP. A. Anti-GPIIb/IIIa antibody-coated platelets are trapped by the Fc receptors of activated macrophages, following which the platelets are destroyed. B. Activated macrophages present GPIIb/IIIa-derived antigen to T cells. C. These T cells interact with autoreactive B cells and present the GPIIb/III-derived antigen. D. Th1 cytokines such as IL-2 and IFNγ promote the activation of B cells. E. Anti-GPIIb/IIIa antibodies are produced by activated B cells. F. T-reg’s control is weakened.

Abbreviations: PLT, platelet; CD40L, CD40 ligand; MHCII, major histocompatibility complex II.

Table 1 Baseline Characteristics of the Patients with ITP and Healthy Controls

	ITP	Control
Number	153	70
Age, years, mean±SD	49.2±13.1	41.3±7.8
Age range	19–86	24–62
Gender, F/M	98/55	39/31
First platelet count ×10^9/L (range)	26 (3–91)
Severe thrombocytopenia*^a
No. of cases (%)	54 (35.3)
Bleeding symptoms
No. of cases (%), Yes	94 (61.4)
No	59 (38.6)
Treatment, No. of cases (%)
Steroid, prednisolone	135 (88.2)
TRA, eltrombopag	62 (40.5)
Eradication of H. pylori	19 (12.4)
Splenectomy	5 (3.3)
IVIG	18 (11.8)
Other, rituximab etc.	22 (14.4)
Observation	18 (11.8)
Response to steroid treatment
Responsive, PR & CR (%)	73/135 (54.1)
Unresponsive (%)	62/135 (45.9)
Complications
Cardiovascular, no. of cases (%)	14 (9.2)
Diabetes, no. of cases (%)	8 (5.2)
Malignancy, no. of cases (%)	3 (2.0)

Notes: *^aPlatelet count <30 ×10⁹/L. Bold letters/numbers represent statistical significance (p < 0.05).

Abbreviations: ITP, immune thrombocytopenia; TRA, thrombopoietin receptor agonist; IVIG, intravenous-immunoglobulin therapy; PR, partial response; CR, complete response.

Table 2 Frequencies of Cytokine Gene Polymorphisms in ITP and Normal Controls

Polymorphism	Genotype	150 Patients N (%)	70 Controls N (%)	χ^2 Value	P value	OR	95% CI
IL-10-592	C/C	24 (16.0)	17 (24.3)	1.4468	0.22904	1.518	0.767–3.005
	A/A	66 (44.0)	28 (40.0)	0.1265	0.72206	0.909	0.538–1.537
	C/A	60 (40.0)	25 (35.7)	0.1656	0.68409	0.893	0.517–1.541
IL-10-819	C/C	24 (16.0)	17 (24.3)	1.4468	0.22904	1.518	0.767–3.005
	T/T	66 (44.0)	28 (40.0)	0.1265	0.72206	0.909	0.538–1.537
	C/T	60 (40.0)	25 (35.7)	0.1656	0.68409	0.893	0.517–1.541
IL-10-1082	G/G	0 (0)	0 (0)	–	–	–	–
	A/A	143 (95.3)	66 (94.3)	0.0028	0.95755	0.989	0.658–1.486
	G/A	7 (4.7)	4 (5.7)	0.0994	0.75253	1.224	0.347–4.320
TNF-α-308	G/G	149 (99.3)	70 (100)	0.0011	0.97395	1.007	0.674–1.504
	A/A	0 (0)	0 (0)	–	–	–	–
	G/A	1 (0.7)	0 (0)	0.4657	0.49498	–	–
TGF-β1 +869	T/T	56 (37.3)	18 (25.7)	1.4827	0.22335	0.689	0.377–1.258
	C/C	14 (9.3)	16 (22.9)	5.4154	0.01996	0.408	0.189–0.883
	T/C	80 (53.4)	36 (51.4)	0.0216	0.88315	0.964	0.594–1.566
IFN-γ +874	T/T	7 (4.7)	4 (5.7)	0.0994	0.75253	1.224	0.347–4.320
	A/A	121 (80.6)	55 (78.6)	0.0146	0.90378	0.974	0.636–1.492
	T/A	22 (14.7)	11 (15.7)	0.0303	0.86189	1.071	0.492–2.331

Note: Bold letters/numbers represent statistical significance (p < 0.05).

Abbreviations: N, absolute number; OR, odds ratio; CI, confidence interval; TNF, tumor necrosis factor; TGF, transforming growth factor; IL-10, interleukin-10; IFN, interferon.

Table 3 Distribution of Cytokine Genotypes in Prednisolone (PSL) Responder and Nonresponder Patients with ITP

Polymorphism	Genotype	PSL-res. 73 Patients N (%)	PSL-non. 62 Patients N (%)	χ^2 Value	P value	OR	95% CI
IL-10-592	C/C	19 (26.0)	2 (3.2)	9.9532	0.00161	0.124	0.028–0.553
	A/A	23 (31.5)	37 (59.7)	4.1178	0.04243	1.894	1.018–3.524
	C/A	31 (42.5)	23 (37.1)	0.1732	0.67730	0.874	0.462–1.651
IL-10-819	C/C	19 (26.0)	2 (3.2)	9.9532	0.00161	0.124	0.028–0.553
	T/T	23 (31.5)	10 (59.7)	4.1178	0.04243	1.894	1.018–3.524
	C/T	31 (42.5)	11 (37.1)	0.1732	0.67730	0.874	0.462–1.651
IL-10-1082	G/G	0 (0)	0 (0)	–	–	–	–
	A/A	69 (94.5)	60 (96.8)	0.00091	0.92399	1.024	0.631–1.661
	G/A	4 (5.5)	2 (3.2)	0.3675	0.54437	0.589	0.104–3.323
TNF-α-308	G/G	73 (100)	61 (98.4)	0.0044	0.94704	0.984	0.609–1.590
	A/A	0 (0)	0 (0)	–	–	–	–
	G/A	0 (0)	1 (1.6)	1.1673	0.28000	–	–
TGF-β1 +869	T/T	23 (31.5)	27 (43.6)	0.9528	0.32901	1.382	0.721–2.650
	C/C	5 (6.8)	9 (14.5)	1.7141	0.19051	2.119	0.688–6.524
	T/C	45 (61.7)	26 (41.9)	1.6468	0.19942	0.680	0.378–1.225
IFN-γ +874	T/T	4 (5.5)	1 (1.6)	1.3094	0.25251	0.294	0.036–2.391
	A/A	58 (79.5)	52 (83.9)	0.0442	0.83354	1.056	0.637–1.749
	T/A	11 (15.0)	9 (14.5)	0.0060	0.93820	0.963	0.375–2.475

Note: Bold letters/numbers represent statistical significance (p < 0.05).

Abbreviations: PSL-res., prednisolone responder; PSL-non., prednisolone nonresponder; other abbreviations: see Table 2.

Table 4 Distribution of Cytokine Genotypes in Eltrombopag Responder and Nonresponder Patients with ITP

Polymorphism	Genotype	Elt-res. 32 Patients N (%)	Elt-non. 30 Patients N (%)	χ^2 Value	P value	OR	95% CI
IL-10-592	C/C	1 (3.1)	1 (3.3)	0.7381	0.96421	1.067	0.064–17.820
	A/A	13 (40.6)	24 (80.0)	2.5376	0.11122	1.970	0.855–4.533
	C/A	18 (56.3)	5 (16.7)	4.9185	0.02657	0.296	0.098–0.898
IL-10-819	C/C	1 (3.1)	1 (3.3)	0.7381	0.96421	1.067	0.064–17.820
	T/T	13 (40.6)	24 (80.0)	2.5376	0.11122	1.970	0.855–4.533
	C/T	18 (56.3)	5 (16.7)	4.9185	0.02657	0.296	0.098–0.898
IL-10-1082	G/G	0 (0)	0 (0)	–	–	–	–
	A/A	32 (100)	28 (93.3)	0.0362	0.84913	0.933	0.458–1.900
	G/A	0 (0)	2 (6.7)	2.0645	0.15080	–	–
TNF-α-308	G/G	32 (100)	29 (96.7)	0.0088	0.92521	0.967	0.476–1.961
	A/A	0 (0)	0 (0)	–	–	–	–
	G/A	0 (0)	1 (3.3)	1.0489	0.49212	–	–
TGF-β1 +869	T/T	6 (18.8)	21 (70.0)	6.6407	0.00997	3.733	1.326–10.510
	C/C	4 (12.5)	5 (16.7)	0.1616	0.68772	1.333	0.328–5.422
	T/C	22 (68.7)	4 (13.3)	8.4153	0.00372	0.194	0.060–0.629
IFN-γ +874	T/T	0 (0)	1 (3.3)	1.0489	0.49212	–	–
	A/A	28 (87.5)	24 (80.0)	0.0566	0.81203	0.914	0.437–1.913
	T/A	4 (12.5)	5 (16.7)	0.1616	0.68772	1.333	0.328–5.422

Note: Bold letters/numbers represent statistical significance (p < 0.05).

Abbreviations: Elt-res., eltrombopag responder; Elt-non., eltrombopag nonresponder; other abbreviations: see Table 2.

Table 5 Individual IL-10 Haplotype Frequencies and Genotypes in Prednisolone (PSL) or Eltrombopag (Elt) Responders and Nonresponder Patients with ITP

IL-10 HT & GT	PSL-res. 73 Patients N (%)	PSL-non. 62 Patients N (%)	χ^2, p value	Elt-res. 32 Patients N (%)	Elt-non. 30 Patients N (%)	χ^2, p value
Haplotype
ACC	65 (44.5)	25 (20.2)	0.00247	20 (31.2)	5 (8.3)	0.00903
ATA	77 (52.8)	97 (78.2)	0.04333	44 (68.8)	53 (88.4)	0.35616
GCC	4 (2.7)	2 (1.6)	0.54022	0 (0)	2 (3.3)	0.14751
Genotype
ACC/ACC	19 (26.0)	2 (3.2)	0.00161	1 (3.1)	1 (3.3)	0.96417
ACC/ATA	27 (37.0)	21 (33.9)	0.79480	18 (56.3)	3 (10.0)	0.00578
ATA/ATA	23 (31.5)	37 (59.7)	0.04243	13 (40.6)	24 (80.0)	0.11117
GCC/ACC	0 (0)	0 (0)	–	0 (0)	0 (0)	–
GCC/ATA	4 (5.5)	2 (2.2)	0.54437	0 (0)	2 (6.7)	0.15076
GCC/GCC	0 (0)	0 (0)	–	0 (0)	0 (0)	–

Note: Bold letters/numbers represent statistical significance (p < 0.05).

Abbreviations: PSL-res., prednisolone responder; PSL-non., prednisolone nonresponders; Elt-res., eltrombopag responder; Elt-non., eltrombopag nonresponder; other abbreviations: see Table 2.