Human platelet antigen 1, 2 and 5 gene polymorphisms in Egyptians and their potential association with susceptibility to immune thrombocytopenic purpura in Egyptian patients

Figures & data

Table 1. Clinical and laboratory data of the 120 studied ITP patients.

Variable	Value
Sex, number (%)
• Male	44 (36.7%)
• Female	76 (63.3%)
Age, years
• Median, range	20.29 years (2–63)
Age groups
• Children ≤16 years	54 (45.0%)
• Adults >16 years	66 (55.0%)
Platelet at sampling, ×10^9/l
• Mean ± SD	59.15 (6–180)
Hemoglobin at sampling, g/dl
• Median, range	11.01 (8–14)
TLC at sampling, ×10^3/µl
• Mean ± SD	9.74 (4–88)
Phase
• Acute (newly diagnosed)	52 (43.3%)
• Persistent	20 (16.7%)
• Chronic^a	48 (40%)
Disease state at sampling
• Activity	98 (81.7%)
• Remission	22 (18.3%)
Severity at sampling
• Bleeder	25 (20.8%)
• Non-bleeder	95 (79.2%)
Treatment
• Steroids	103(85.8%)
• IV Ig	5 (4.2%)
• Cyclosporine	1(0.8%)
Quality of laboratory response at follow-up (FU)^b
• Complete response	6/77 (7.8%)
• Partial response	70/77 (90.9%)
• No response	1/77 (1.3%)
Quality of clinical response at FU^b
• Response	71/74 (95.9%)
• No response	3/74 (4.1%)

^aLong FU ≥ 1 year.

^bShort FU, (3–6 months after diagnosis).

Table 2. HPA1, 2 and 5 allele, allele phenotype and genotype frequencies in patients and controls.

HPA alleles	Allele frequency			Allele phenotype frequency			HPA genotypes	Genotype frequency
	Patients	control	P-value	Patients	control	P-value		Patients	control	P-value
HPA1-a	194 (80.8%)	189 (78.75%)	0.570	115 (95.8%)	114 (95%)	0.758	HPA1a/1a	79 (65.8%)	75 (62.5%)	0.736
HPA1-b	46 (19.2%)	51 (21.25%)		41 (34.2%)	45 (37.5%)	0.590	HPA1a/1b	36 (30%)	39 (32.5%)
							HPA1b/1b	5 (4.2%)	6 (5%)
HPA2-a	179 (74.6%)	207 (86.25%)	0.001^a	112 (93.3%)	117 (97.5%)	0.123	HPA2a/2a	67 (55.8%)	91 (75.8%)	0.005^a
HPA2-b	61 (25.4%)	33 (13.75%)		53 (44.2%)	30 (25%)	0.002^a	HPA2a/2b	45 (37.5%)	26 (21.7%)
							HPA2b/2b	8 (6.7%)	3 (2.5%)
HPA5-a	204 (85%)	210 (87.5%)	0.426	115 (95.8%)	116 (96.7%)	0.734	HPA5a/5a	88 (73.3%)	92 (76.7%)	0.828
HPA5-b	36 (15%)	30 (12.5%)		32 (26.7%)	28 (23.3%)	0.551	HPA5a/5b	27 (22.5%)	24 (20%)
							HPA5b/5b	5 (4.2%)	4 (3.3%)

^aStatistically significant.

Table 3. OR of HPA1, 2 and 5 genotypes in patients and controls and in relation to the presence of chronic disease in patients group.

Allele phenotype	Patients		Controls		OR	95% CI OR
	Allele present	Allele absent	Allele present	Allele absent		Lower	Upper
HPA1a	115	5	114	6	1.21	0.36	4.08
HPA1b	41	79	45	75	0.87	0.51	1.47
HPA2a	112	8	117	3	0.36	0.09	1.39
HPA2b	53	67	30	90	2.37^a	1.37	4.11
HPA5a	115	5	116	4	0.79	0.21	3.03
HPA5b	32	88	28	92	1.20	0.67	2.15
	Chronic		Non-Chronic			95% CI OR
Allele phenotype	Allele present	Allele absent	Allele present	Allele absent	OR	Lower	Upper
HPA1a	46	4	4	0	1.14	0.05	24.93
HPA1b	19	31	0	4	5.57	0.28	109.24
HPA2a	47	3	4	0	1.51	0.07	34.05
HPA2b	17	33	1	3	1.22	0.17	8.99
HPA5a	48	2	4	0	2.16	0.09	52.16
HPA5b	12	38	2	2	0.33	0.05	2.20

^aStatistically significant.

Table 4. Hardy Weinberg comparison of HPA1, 2 and 5 observed frequencies versus expected frequencies.

Group	Gene	Observed genotype frequency			Total	Expected genotype frequency			P-value
		a/a	a/b	b/b		a/a	a/b	b/b
Patients	HPA1	79	36	5	120	78.4	37.2	4.4	0.73
	HPA2	67	45	8	120	66.8	45.5	7.8	0.91
	HPA5	88	27	5	120	85.9	31.3	2.9	0.13
Controls	HPA1	75	39	6	120	74.4	40.2	5.4	0.75
	HPA2	90	26	3	119	89.2	27.7	2.2	0.50
	HPA5	92	24	4	120	90.1	27.7	2.1	0.14

Table 5. HPA allele/genotype frequencies in our population compared to other populations.

Population	No.	HPA 1 allele %		PV	HPA 1 genotype %			PV	No.	HPA 2 allele %		PV	HPA 2 genotype %			PV	No.	HPA 5 allele %		PV	HPA 5 genotype %			PV
		1a	1b		1a/1a	1a/1b	1b/1b			2a	2b		2a/2a	2a/2b	2b/2b			5a	5b		5a/5a	5a/5b	5b/5b
Egyptian (current study)	120	0.79	0.21	–	62.5	32.5	5.0	–	120	0.86	0.14	–	75.8	21.6	2.5	–	120	0.88	0.12	–	76.7	20.0	3.3	–
Egyptian [11]	206	0.77	0.23	0.59	59.2	35.0	5.83	0.72	206	–	–	–	–	–	–	–	206	–	–	–	–	–	–	–
Egyptian [12]	6974	0.79	0.20	0.93	62	34.2	3.8	0.76	376	0.87	0.13	0.78	75.5	22.8	1.7	0.96	376	0.84	0.16	0.19	70.6	26.9	2.6	0.31
Egyptian [13]	206	0.77	0.23	0.59	59.2	35.0	5.83	0.72	218	0.76	0.24	0.00	56.0	39.9	4.13	0.00	230	0.73	0.27	0.00	56.5	32.6	10.9	0.00
ARABS
Bahraini [17]	194	0.76	0.24	0.46	56.8	38.5	4.7	0.58	194	0.77	0.23	0.00	60.1	33.1	6.8	0.01	194	0.86	0.13	0.66	75.7	20.9	2.7	0.93
Moroccan [18]	107	0.74	0.25	0.28	57.9	33.7	8.41	0.40	107	0.82	0.18	0.15	66.36	30.80	2.80	0.31	112	0.86	0.14	0.57	73.22	25.89	0.89	0.53
Algerian [19]	485	0.83	0.17	0.09	–	–	–	–	485	0.83	0.17	027	–	–	–	–	485	0.84	0.16	0.19	–	–	–	–
Tunisian [20]	90	0.75	0.25	0.30	–	–	–	–	–	–	–	–	–	–	–	–	90	0.78	0.22	0.01	–	–	–	–
Saudi Arabian [21]	100	0.80	0.20	0.75	75	23	2	0.11	100	0.71	0.29	0.00	62	32	6	0.08	100	0.80	0.20	0.03	76.50	23.50	0	0.46
EUROPE
Southern (Mediterranean) Europe
Italian [22]	144	0.85	0.15	0.15	–	–	–	–	144	0.89	0.11	0.07	–	–	–	–	144	0.9	0.10	0.45	–	–	–	–
Macedonian [23]	122	0.87	0.13	0.01	75.40	22.10	2.50	0.12	132	0.85	0.15	0.66	72.00	26.50	1.50	0.78	126	0.91	0.09	0.29	82.5	16.70	0.80	0.51
Spanish [24]	727	0.81	0.19	0.41	–	–	–	–	462	0.9	0.1	0.09	–	–	–	–	454	0.88	0.11	0.87	–	–	–	–
Eastern Europe
Slovenian [25]	152	0.83	0.17	0.22	–	–	–	–	152	0.90	0.10	0.25	–	–	–	–	152	0.89	0.11	0.64	–	–	–	–
Polish [26]	135	0.82	0.18	0.32	75.55	23.70	0.75	0.09	211	0.90	0.10	0.14	81.04	17.54	1.42	0.57	166	0.94	0.06	0.00	87.35	12.65	0%	0.03
Northern Europe
Norwegian [27]	105	0.86	0.13	0.02	81.0	20.0	4.0	0.06	105	0.94	0.06	0.00	94.0	10.0	1.0	0.03	105	0.93	0.07	0.09	91.0	13.0	1.0	0.13
Swiss [28]	500	0.80	0.19	0.47	70.40	26.0	3.60	0.24	500	0.92	0.11	0.00	81.20	17.40	1.40	0.34	500	0.93	0.07	0.00	79.6	19.2	1.2	0.24
Western Europe
British [29]	134	0.84	0.16	0.16	–	–	–	–	134	0.93	0.08	0.85	–	–	–	–	134	0.91	0.09	0.20	–	–	–	–
German [30]	1583	0.84	0.16	0.04	–	–	–	–	1576	0.93	0.07	0.00	–	–	–	–	1643	0.92	0.08	0.01	–	–	–	–
AFRICA
Cameroonian [31]	118	0.91	0.09	0.00	82.2	16.9	0.80	0.01	118	0.76	0.24	0.00	60.20	32.20	7.60	0.02	118	0.75	0.25	0.00	56.8	35.6	7.63	0.01
Central African [31]	110	1.0	0	0.00	100	0	0	0.00	110	0.61	0.39	0.00	35.10	53.20	11.7	0.00	110	0.60	0.41	0.00	37.0	45.0	18.0	0.00
AMERICA
Argentinean [32]	192	0.88	0.12	0.00	76.6	22.4	1	0.00	192	0.86	0.13	0.65	77.10	20.8	2.1	0.95	192	0.93	0.07	0.05	86.5	12.5	1	0.06
Brazilian [33]	100	0.93	0.08	0.00	86.0	13.0	1.0	0.0	100	0.85	0.15	0.71	73	24	3	0.90	100	0.92	0.08	0.12	85.0	14.0	1.0	0.23
ASIA
Pakistan [34]	593	0.89	0.12	0.00	79.4	19.0	2.0	0.01	593	0.92	0.08	0.01	85	13.5	1.2	0.00	593	0.90	0.10	0.24	82.0	16.0	2.5	0.00
Han Chinese [35]	1000	0.99	0.01	0.00	98.9	1.2	0	0.00	1000	0.95	0.05	0.00	90.4	9.5	0.1	0.00	1000	0.99	0.01	0.00	97.3	2.6	0.1	0.00

Note: Bold-italic represents statistically significant values.

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