Clinical Outcome of Acquired Post-Immunosuppressive-Therapy Aplastic Anemia in Pediatric Patients: A 13-Year Experience in Two Southern China Tertiary Care Centers

Figures & data

Table 1 Characteristics and Events of AA Patients

Number of patients	130
Gender (male: female)	65: 65
Age in years, median (range)	6.5 (1.0–15.5)
Diagnostic category, count (percentage)
VSAA	41 (31.54%)
SAA	64 (49.23%)
NSAA	25 (19.23%)
Peripheral blood, median (range)
WBC (×10^9/L)	3.15 (0.47–11.90)
NEUT#(×10^9/L)	0.39 (0.01–2.82)
LY#(×10^9/L)	2.50 (0.11–11.34)
NEUT% (%)	14.2 (0.70–71.90)
LY% (%)	79.3 (9.0–99.30)
RBC (×10^12/L)	2.50 (0.96–4.37)
Hb (g/L)	76 (28–135)
PLT (×10^9/L)	12.5 (2–303)
RET# (10^9/L)	18.00 (0–146.30)
RET% (%)	0.71 (0–4.17)
Corrected RET# (10^9/L)	7.64 (0–71.05)
Corrected RET%	0.30 (0–2.47)
Bone marrow, median (range)
Granulocyte linkage (G) %	21.0 (0–61.0)
Erythrocyte linkage (E) %	15.5 (0–53.3)
G:E	1.24 (0–127.00)
Hematopoietic tissue ratio (%)	10 (3–30)
Flow cytometry before treatment (Peripheral blood), median (range)
NK cell/Lymphocyte (%)	5.6 (0.2–32.6)
B cell/Lymphocyte (%)	20.3 (2.8–50.8)
T cell/Lymphocyte (%)	72.4 (43.0–93.4)
CD8^+ T cell/Lymphocyte (%)	27.8 (10.1–51.9)
CD4^+ T cell/Lymphocyte (%)	35.7 (7.4–64.4)
CD4^+T cell/CD8^+ T cell	1.34 (0.17–3.41)
Treg/Lymphocyte (%)	1.45 (0.68–5.68)
Treg/CD4^+T cell (%)	4.62 (1.60–12.33)
Treatment, count (percentage)
IST only	117 (90.0%)
IST→Transplant	13 (10.0%)
Overall survival, percentage	85.7±4.0%
EFS, percentage	71.5±5.0%
Death, count (percentage)	11 (8.46%)
Adverse reactions, count (percentage)
Infection	72 (55.38%)
Serum sickness	87 (66.92%)
Hyperglycemia	7 (5.38%)
Hypertension	1 (0.77%)

Notes: ￡ due to the long period of follow up and technological limitation, only 56 patients eligible for these flow cytometry parameters.

Abbreviations: VSAA, very severe aplastic anemia; SAA, severe aplastic anemia; NSAA, nonsevere aplastic anemia; WBC, white blood cell; NEUT, neutrophil granulocyte; LY, lymphocyte; RBC, red blood cell; Hb, hemoglobin; PLT, platelet; G:E, ratio of granulocyte and erythrocyte; NK, natural killer cells; Treg, regulatory T cells; IST, immunosuppressive therapy; CR, complete response; PR, partial response; NR, no response; EFS, event-free survival.

Figure 1 (A) 5-year OS was 85.7% ± 4.0% in all patients who underwent IST; and (B) the event-free survival rate was 76.0% ± 4.6% in the medium 50.6-month follow up.

Figure 2 (A) The 5-year OS rates in patients with NSAA, SAA, and VSAA were 100%, 90.5% ± 4.1%, and 84.0% ± 6.0%, respectively; and (B) the event-free survival rates in patients with NSAA, SAA, and VSAA were 94.4% ± 5.4%, 71.2% ± 7.1%, and 71.0% ± 9.6%, respectively.

Table 2 Different Time Point for Evaluation of IST

Follow-up Time		Response, Count (Percentage)			x^2 value	p value
	All Patients (n=117)	NSAA (n=24)	SAA (n=55)	VSAA (n=38)
3 month	40 (34.19%)	15 (62.50%)	14 (25.45%)	11 (28.95%)	x^2=10.878	p =0.004
6 month	46 (39.32%)	14 (58.33%)	21 (38.18%)	11 (28.95%)	x^2=5.380	p =0.068
9 month	58 (49.57%)	13 (54.17%)	29 (52.73%)	16 (42.11%)	x^2=1.269	p =0.530
12 month	78 (66.67%)	18 (75.00%)	35 (63.64%)	25 (65.79%)	x^2=0.990	p =0.609
Total response	80 (68.38%)	19 (79.17%)	36 (65.45%)	25 (65.79%)	x^2=1.627	p =0.443

Table 3 Comparison of Clinical Features and Lab Data Between Response and Non-Response Groups

	Response Group (n=80)	Nonsponse Group (n=37)		p value
Age (years)	6.78±3.40	7.30±3.69	t = −0.744	p = 0.115
Gender (male:female)	41: 39	15: 22	X^2=1.163	p = 0.281
Diagnostic category
NSAA (n=24)	19 (79.17%)	5 (20.83)	X^2=1.627	p =0.443
SAA (n=55)	36 (65.45%)	19 (34.55%)
VSAA (n=38)	25 (65.79%)	13 (34.21%)
Year of diagnosis
≤ 2010	39	23	X^2=1.827	p =0.176
>2010	41	14
Treatment
Time from diagnosis to ATG application (d)	76.96±328.84	98.32±362.84	t=−0.316	p = 0.115
Peripheral blood before treatment
WBC (×10^9/L)	3.30±0.21	3.17±0.23	t =0.360	p =0.720
NEUT#(×10^9/L)	0.60±0.07	0.45±0.09	t =1.287	p =0.201
LY#(×10^9/L)	2.53±0.18	2.54±0.22	t =−0.042	p =0.967
NEUT%	17.91±1.60	14.35±2.31	t =1.236	p =0.219
LY%	76.38±1.89	79.75±2.89	t =−0.969	p =0.335
RBC (×10^12/L)	2.63±0.08	2.19±0.12	t =2.924	p =0.004
Hb (g/L)	77.75±2.39	67.54±3.72	t =0.774	p =0.023
PLT (×10^9/L)	19.56±1.75	12.67±1.29	t =2.427	p =0.017
RET# (10^9/L)	28.76±3.23	21.18±4.02	t =1.352	p =0.180
RET%	1.07±0.11	0.93±0.16	t =0.721	p =0.473
Corrected RET# (10^9/L)	15.94±2.02	10.61±2.48	t =1.536	p =0.128
Corrected RET%	0.58±0.06	0.0.43±0.08	t =1.332	p =0.186
Flow cytometry before treatment (Peripheral blood)￡
NK cell/Lymphocyte (%)	7.26±0.84	5.66±0.87	t =1.101	p =0.275
B cell/Lymphocyte (%)	20.54±1.35	17.92±2.11	t =1.037	p =0.303
T cell/Lymphocyte (%)	70.85±1.50	75.44±2.32	t =−1.639	p =0.106
CD8^+ T cell/Lymphocyte (%)	27.66±1.25	30.86±1.88	t =−1.382	p =0.171
CD4^+ T cell/Lymphocyte (%)	35.62±1.50	38.12±1.63	t =−0.948	p =0.346
CD4^+T cell/CD8^+ T cell	1.47±0.10	1.44±0.15	t =0.153	p =0.879
Treg/Lymphocyte(%)	2.95±1.823	1.20±0.46	t =3.395	p =0.004
Treg/CD4^+T cell(%)	4.79±3.30	3.07±1.50	t =0.871	p =0.395
Bone marrow
Granulocyte series (G) %	22.92±1.71	17.42±2.19	t =1.611	p =0.111
Erythocyte series (E) %	17.63±1.30	15.83±2.70	t =0.536	p =0.593
G:E	4.28±2.04	3.10±01.22	t =0.321	p =0.749
Hematopoietic tissue ratio %	15.05±2.24	17.43±4.33	t =−0.512	p =0.612
Adverse reactions
Yes	70	28	X^2=0.143	p=0.706

Notes: ￡ due to the long period of follow up and technological limitation, only 56 patients eligible for these flow cytometry parameters.

Table 4 Receiver Operating Characteristic Curve Analysis, Optimum Cutoff Value and Predict Performance for Factors Affecting Overall Response to IST

Test Result Variable(s)	Area	p value	Youden’s Index	Threshold
RBC	0.658	0.007	0.251	2.735×10^12/L
Hb(g/L)	0.632	0.024	0.228	77.5g/L
PLT	0.626	0.03	0.253	18.5×10^9/L

Figure 3 The ROC curve analyzed the correlations of the RBC count, Hb level, and PLT count with the patient IST response.

Table 5 Contributing Factors for Overall Response to IST: Univariate Analysis

Variable	Wald	p value	OR(95% CI)
RBC	8.021	0.005	2.45 (1.318,4.554)
Hb	5.153	0.017	1.025 (1.004,1.046)
PLT	6.185	0.013	1.054 (1.011,1.099)

Table 6 Contributing Factors for Overall Response to IST: Multivariate Logistic Regression Analysis (Backward, Wald, α = 0.05)

Variable	β	Wald	p value	OR(95% CI)
RBC	0.749	5.04	0.025	2.11 (1.1, 4.066)
PLT	0.044	3.853	0.05	1.045 (1, 1.092)
α	−1.674	4.123	0.042