scholarly journals False-Positive Plasmodium falciparum Histidine-Rich Protein 2 Immunocapture Assay Results for Acute Schistosomiasis Caused by Schistosoma mekongi: Table 1.

2011 ◽  
Vol 49 (6) ◽  
pp. 2331-2332 ◽  
Author(s):  
Eyal Leshem ◽  
Nathan Keller ◽  
Daphna Guthman ◽  
Tamar Grossman ◽  
Michal Solomon ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
False Positive ◽  
Schistosoma Mekongi

scholarly journals Immune Response against the Exp-1 Protein of Plasmodium falciparum Results in Antibodies That Cross-React with Human T-Cell Lymphotropic Virus Type 1 Proteins

1998 ◽  
Vol 5 (5) ◽  
pp. 721-724 ◽  
Author(s):  
Kevin R. Porter ◽  
Joao Aguiar ◽  
Allen Richards ◽  
B. Sandjaya ◽  
H. Ignatias ◽  
...  
Keyword(s):  
Immune Response ◽  
Plasmodium Falciparum ◽  
T Cell ◽  
Western Blot ◽  
Virus Type ◽  
False Positive ◽  
Type I ◽  
Human T Cell

ABSTRACT To examine the role of the Plasmodium falciparum Exp-1 blood-stage protein in producing antibodies that cross-react with human T-cell lymphotropic virus type I (HTLV-I) proteins, we studied sera from Indonesian volunteers who seroconverted to malaria after transmigrating to an area where malaria is hyperendemic. Samples from Philippine volunteers, that were used in a prior study that examined malaria antibodies that cross-react with HTLV-I proteins, were also used. Eighty-three percent of the Indonesian transmigrants developed antibodies against the malaria Exp-1 protein by 6 months postmigration. Of these malaria seroconverters, 27% developed false-positive HTLV-I enzyme immunoassay (EIA) immunoreactivity, as indicated by indeterminate HTLV-I Western blot banding patterns. Five of the six Philippine samples tested were HTLV-I EIA false positive and Western blot indeterminate. When a recombinant Exp-1 protein was used in blocking experiments, the HTLV-I Western blot immunoreactivity of sera from both groups was either completely eliminated or greatly reduced. No effect on the Western blot immunoreactivity of truly HTLV-I-positive sera was seen. To determine if immunization with the recombinant Exp-1 protein could elicit the production of HTLV-I antibodies, six mice were inoculated with the recombinant protein. Following administration of three 50-μg doses of the protein, four of the six mice developed antibodies that cross-reacted with HTLV-I proteins on Western blot. These results indicate that the immune response against the malaria Exp-1 protein may result in HTLV-I-cross-reacting antibodies that can lead to false-positive EIA and indeterminant Western blotting results.

scholarly journals Evaluation of a rapid dipstick test, Malar-CheckTM, for the diagnosis of Plasmodium falciparum malaria in Brazil

2002 ◽  
Vol 44 (5) ◽  
pp. 293-296 ◽  
Author(s):  
Priscilla Elisangela AVILA ◽  
Karin KIRCHGATTER ◽  
Karen Cristina S. BRUNIALTI ◽  
Alessandra M. OLIVEIRA ◽  
Rinaldo F. SICILIANO ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
False Positive ◽  
False Negative ◽  
Plasmodium Falciparum Malaria ◽  
Dipstick Test ◽  
True Negative ◽  
Disease Evolution ◽  
Negative Results ◽  
False Positive Test ◽  
Positive Results

The present study was carried out to evaluate the Malar-CheckTM Pf test, an immunochromatographic assay that detects Plasmodium falciparum Histidine Rich Protein II, does not require equipment, and is easy and rapid to perform. In dilution assays performed to test sensitivity against known parasite density, Malar-CheckTMwere compared with thick blood smear (TBS), the gold standard for diagnosis. Palo Alto isolate or P. falciparum blood from patients with different parasitemias was used. The average cut-off points for each technique in three independent experiments were 12 and 71 parasites/mm³ (TBS and Malar-CheckTM, respectively). In the field assays, samples were collected from patients with fever who visited endemic regions. Compared to TBS, Malar-CheckTMyielded true-positive results in 38 patients, false-positive results in 3, true-negative results in 23, and false-negative result in 1. Malar-CheckTMperformed with samples from falciparum-infected patients after treatment showed persistence of antigen up to 30 days. Malar-CheckTM should aid the diagnosis of P. falciparum in remote areas and improve routine diagnosis even when microscopy is available. Previous P. falciparum infection, which can determine a false-positive test in cured individuals, should be considered. The prompt results obtained with the Malar-CheckTM for early diagnosis could avoid disease evolution to severe cases.

Delayed diagnosis of Plasmodium falciparum in a soldier in Uganda: false-positive rapid diagnostic test associated with reduced repeats in pfhrp2

2013 ◽  
Vol 23 (2) ◽  
pp. 181-184
Author(s):  
N. Wurtz ◽  
S. Briolant ◽  
D. Lemarié ◽  
V. Pommier de Santi ◽  
A. Pascual ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
False Positive ◽  
Delayed Diagnosis

scholarly journals Plasmodium falciparum Histidine-Rich Protein 2-Based Immunocapture Diagnostic Assay for Malaria: Cross-Reactivity with Rheumatoid Factors

2000 ◽  
Vol 38 (3) ◽  
pp. 1184-1186 ◽  
Author(s):  
J. Iqbal ◽  
A. Sher ◽  
A. Rab
Keyword(s):  
Plasmodium Falciparum ◽  
Rheumatoid Factor ◽  
Positive Reaction ◽  
False Positive ◽  
Malaria Infection ◽  
Cross Reactivity ◽  
Rheumatoid Factors ◽  
Optimal Test ◽  
False Positive Reaction ◽  
Rheumatoid Factor Activity

Recently introduced rapid nonmicroscopic immunocapture assays for the diagnosis of malaria infection are being evaluated for their sensitivity and specificity in various epidemiological settings. APlasmodium falciparum histidine-rich protein 2 (PfHRP-2)-based assay (ICT) and a Plasmodium-specific lactate dehydrogenase test (OptiMAL) were evaluated for their specificities in different groups of patients who tested negative for malaria infection by microscopy. The patients were selected from different disease groups: rheumatoid arthritis, hepatitis C, toxoplasmosis, schistosomiasis, and hydatid disease. One hundred thirty-three of the 225 patients were positive for rheumatoid factor. Thirty-five of the 133 (26%) rheumatoid factor-positive patients gave a false-positive reaction with the ICT assay, but only 4 of these gave false-positive reactions with the OptiMAL test. Thirty-three of the 35 false-positive specimens became negative when repeat tested with the ICT assay after absorbing out the rheumatoid factor activity. Our study shows that the PfHRP-2-based ICT assay gave a false-positive reaction in 26% of the patients who had rheumatoid factors, but were negative for malaria by microscopy.

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

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