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New approaches with different types of circulating cathodic antigen for the diagnosis of patients with low Schistosoma mansoni load.

Grenfell R, Harn DA, Tundup S, Da'dara A, Siqueira L, Coelho PM - PLoS Negl Trop Dis (2013)

Bottom Line: In our previous investigations, the use of crude antigens led to false-positive results.Recently, focus has been given to highly purified Schistosoma mansoni antigens, especially to circulating antigens.Interestingly, the "crude antigen" worked as a good marker for control of cure after praziquantel treatment.

View Article: PubMed Central - PubMed

Affiliation: Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, Brazil.

ABSTRACT

Background: Schistosomiasis mansoni is a debilitating and sometimes fatal disease. Accurate diagnosis plays a key role in patient management and infection control. However, currently available parasitological methods are laborious and lack sensitivity. The selection of target antigen candidates has turned out to be a promising tool for the development of more sensitive diagnostic methods. In our previous investigations, the use of crude antigens led to false-positive results. Recently, focus has been given to highly purified Schistosoma mansoni antigens, especially to circulating antigens.

Method: Thus, our main goal was to test different types of circulating cathodic antigen glycoprotein (CCA), as "crude antigen," the protein chain of recombinant CCA and two individual peptides. These schistosome proteins/peptides were tested in a new diagnostic method employing immunomagnetic separation based on the improvement of antigen-antibody binding.

Principal findings: Use of recombinant CCA as a diagnostic antigen allowed us to develop a diagnostic assay with high sensitivity and specificity with no false-negative results. Interestingly, the "crude antigen" worked as a good marker for control of cure after praziquantel treatment.

Conclusions/significance: Our new diagnostic method was superior to enzyme-linked immunosorbent assay in diagnosing low endemicity patients.

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Related in: MedlinePlus

Individual analysis of IgG titer in 30 days after praziquantel administration by IMS protocols.Each OD value is representative for the mean of four absorbance values. Cut-off values are represented by bars. In: (a) IMS-crude Ag; (b) IMS-CCAr; (c) IMS-CCApep1; and (d) IMS-CCApep2. Artwork created by Prism 5.0 software.
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pntd-0002054-g005: Individual analysis of IgG titer in 30 days after praziquantel administration by IMS protocols.Each OD value is representative for the mean of four absorbance values. Cut-off values are represented by bars. In: (a) IMS-crude Ag; (b) IMS-CCAr; (c) IMS-CCApep1; and (d) IMS-CCApep2. Artwork created by Prism 5.0 software.

Mentions: Not all the infected patients showed an adequate post treatment follow-up, since no eggs were found in any patient stools 30 days after drug administration. Forty-two of the 50 praziquantel-treated patients agreed to donate serum samples once more. Diagnostic results obtained by the four IMS protocols from both time points were compared with the purpose of detecting any differences in IgG antibody titers. From the observations in each period, 98% of the patients became negative via IMS-crude Ag (41/42), whereas 81% became negative via IMS-CCApep1 (34/42) and 93% via IMS-CCApep2 (39/42). IMS using CCAr identified 55% of the patients as negative for S. mansoni 30 days after treatment (23/42), as shown in Figure 5.


New approaches with different types of circulating cathodic antigen for the diagnosis of patients with low Schistosoma mansoni load.

Grenfell R, Harn DA, Tundup S, Da'dara A, Siqueira L, Coelho PM - PLoS Negl Trop Dis (2013)

Individual analysis of IgG titer in 30 days after praziquantel administration by IMS protocols.Each OD value is representative for the mean of four absorbance values. Cut-off values are represented by bars. In: (a) IMS-crude Ag; (b) IMS-CCAr; (c) IMS-CCApep1; and (d) IMS-CCApep2. Artwork created by Prism 5.0 software.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585039&req=5

pntd-0002054-g005: Individual analysis of IgG titer in 30 days after praziquantel administration by IMS protocols.Each OD value is representative for the mean of four absorbance values. Cut-off values are represented by bars. In: (a) IMS-crude Ag; (b) IMS-CCAr; (c) IMS-CCApep1; and (d) IMS-CCApep2. Artwork created by Prism 5.0 software.
Mentions: Not all the infected patients showed an adequate post treatment follow-up, since no eggs were found in any patient stools 30 days after drug administration. Forty-two of the 50 praziquantel-treated patients agreed to donate serum samples once more. Diagnostic results obtained by the four IMS protocols from both time points were compared with the purpose of detecting any differences in IgG antibody titers. From the observations in each period, 98% of the patients became negative via IMS-crude Ag (41/42), whereas 81% became negative via IMS-CCApep1 (34/42) and 93% via IMS-CCApep2 (39/42). IMS using CCAr identified 55% of the patients as negative for S. mansoni 30 days after treatment (23/42), as shown in Figure 5.

Bottom Line: In our previous investigations, the use of crude antigens led to false-positive results.Recently, focus has been given to highly purified Schistosoma mansoni antigens, especially to circulating antigens.Interestingly, the "crude antigen" worked as a good marker for control of cure after praziquantel treatment.

View Article: PubMed Central - PubMed

Affiliation: Schistosomiasis Laboratory, Rene Rachou Research Center, Oswaldo Cruz Foundation (Fiocruz), Belo Horizonte, Minas Gerais, Brazil.

ABSTRACT

Background: Schistosomiasis mansoni is a debilitating and sometimes fatal disease. Accurate diagnosis plays a key role in patient management and infection control. However, currently available parasitological methods are laborious and lack sensitivity. The selection of target antigen candidates has turned out to be a promising tool for the development of more sensitive diagnostic methods. In our previous investigations, the use of crude antigens led to false-positive results. Recently, focus has been given to highly purified Schistosoma mansoni antigens, especially to circulating antigens.

Method: Thus, our main goal was to test different types of circulating cathodic antigen glycoprotein (CCA), as "crude antigen," the protein chain of recombinant CCA and two individual peptides. These schistosome proteins/peptides were tested in a new diagnostic method employing immunomagnetic separation based on the improvement of antigen-antibody binding.

Principal findings: Use of recombinant CCA as a diagnostic antigen allowed us to develop a diagnostic assay with high sensitivity and specificity with no false-negative results. Interestingly, the "crude antigen" worked as a good marker for control of cure after praziquantel treatment.

Conclusions/significance: Our new diagnostic method was superior to enzyme-linked immunosorbent assay in diagnosing low endemicity patients.

Show MeSH
Related in: MedlinePlus