1. COMPARATIVE PERFORMANCE OF THE 2B2t RECOMBINANT ANTIGEN AND HYDATID FLUID IN ELISA AND IMMUNOSTRIPS FOR THE DIAGNOSIS OF CYSTIC ECHINOCOCCOSIS
I would like to thank organisers for the kind invitation to come here, a very nice chance to knwo china, and also the invitation to give this talk about the serology for the diagnosis and follow-up of patients with cystic echinococcosis. Are we in a good time and knowledge point to guide people towards a consensus?

2. THE RECOMBINANT ANTIGEN 2B2t
Antígen B2 (U15001) Ovine genotype (G1)
Truncated antigen B2 (B2t). ~ 7 kDa
Head-to-tail tandem repeated B2t = 2B2t ~ 14 kDa
SIGNAL PEPTIDE
1 MRTYILLSLA LVAFVAVVQA KDEPKAHMGQ VVKKRWGELR DFFRNDPLGQ
51 RLVALGNDLT AICQKLQLKI REVLKKYVKN LVEEKDDDSK 90
35-
25-
15-
kDa
B2t 2B2t
195 sera CE patients, 120 sera donors, 75 sera other parasitic diseases
ANTIGEN
SENS
SPEC
ELISA B2t
79%
90.4%
ELISA 2B2t
86.2%
80.9%
ELISA HF
82.1%
80.4%
22/57 (38.6%)
7/7 (100%)
ELISA HF
21/57 (36.8%)
1/7 (14.3%)
ELISA 2B2t
11/57 (19.3%)
3/7 (42.8%)
ELISA B2t
NCC PERU AE
ANTIGEN
Hernández-González et al., CVI 2008
Hernández-González et al., PLoS NTD 2012

3. CLINICAL VARIABLES AFFECTING THE SEROLOGICAL OUTCOME
BINARY LOGISTIC REGRESSION ANALYSIS
ELISA-HF
ELISA-2B2t
B-OR
M-OR
Cyst number
Single 1
Multiple
3.5 ( )
3.1 ( )
2.4 ( )
2.2 ( )
Cyst location
Liver -
Others
2.6 ( )
WHO classification
CE4-5
CE1-2-3
5.7 ( )
3.9 ( )
7.4 ( )
6.4 ( )
Serum collection date
Before tr.
After tr.
13.3 ( )
10.2 ( )
2.8 ( )
2.3 ( )
The outcome of serological tests is heavily influenced by clinical variables
The usefulness of each single test has to be evaluated in patients grouped by defined clinical variables

4. THE 2B2t-ELISA: THE GROUND FOR THE DEVELOPMENT OF
AN IMPROVED ROUTINE TEST FOR THE DIAGNOSIS OF CE
Can we keep the diagnostic performance of the 2B2t-ELISA in a easy-to-use, unexpensive technique?
The patented 2B2t antigen in immunostrips
Strip containing the antigens l serum
10 minutes
Interpretation
Control
line
IgG
α-2B2t

5. Overall specificity, n=240
COMPARISON OF HF (IMMUNOSTRIPS)
AND 2B2t (IMMUNOSTRIPS AND ELISA)
383 SERA FROM CE PATIENTS -ITALY, GERMANY-
86 SERA FROM DONORS -SPAIN, PERU-
SERA FROM AE + NCC PATIENTS -SWITZERLAND, PERU-
IMMUNOSTRIPS HF
n+ (%)
IMMUNOSTRIPS 2B2t
ELISA 2B2t
CE, n=385
(Sensitivity)
334 (86.8%)
321 (83.4%)
220 (57.1%)
DONORS, n=86
2 (94.4%)
0 (100%)
1 (97.2%)
AE, n=50
33 (34%)
16 (68%)
8 (84%)
NCC, n=104
17 (83.6%)
50 (51.9%)
2 (1.9%)
Overall specificity, n=240
38 (78.3%)
17 (72.5%)
11 (95.3%)

6. CLINICAL VARIABLES AFFECTING THE SEROLOGICAL OUTCOME
BINARY LOGISTIC REGRESSION ANALYSIS
IMMUNOSTRIPS HF
IMMUNOSTRIPS 2B2t

7. WHO CLASSIFICATION AND SEROLOGICAL OUTCOME
CE1
CE2
CE3a
CE3b
Act+Tran
CE4
CE5
Inact N 25 23 51
140
239
107 39
146
IMMUNOSTRIPS HF + 24 21
132
228 80 26
106 %
96.0
91.3
100.0
94.3
95.4
74.8
66.7
72.6
IMMUNOSTRIPS 2B2t 49
134
227 75 19 94
92.0
96.1
95.7
95.0
70.1
48.7
64.5 20 40 60 80
100
CE1
CE2
CE3a
CE3b
CE4
CE5
IMMUNOSTRIPS HF
IMMUNOSTRIPS 2B2t
% positive

8. THE 2B2t RECOMBINANT ANTIGEN IN IMMUNOSTRIPS
-Better than 2B2t in ELISA
-Similar sensitivity than HF for active and transitional cysts (95%)
Better differentiation of active/transitional cyst from inactive cysts than HF
Better differentiation of AE and CE patients than HF
BUT
-A percentage of patients with active/transitional cysts are 2B2t negative
-Specificity problems with NCC (and some AE) patients
COMBINATION OF RECOMBINANT ANTIGENS
EPITOPE SELECTION
LARGER PANEL OF WELL CHARACTERIZED SERA

9. A MULTICENTER STUDY IS PLANNED IN THE FRAME OF THE EUROPEAN PROJECT HEALTH-F3-2013-602051-2
“Human cystic Echinococcosis ReseArch in CentraL and Eastern Societies” (HERACLES)