Histidine-rich protein 2 (HRP2): Difference between revisions
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P.falciparum parasites | ''P.falciparum'' parasites produce “histidine-rich” proteins (HRP). The HRP2 antigen is highly expressed and stable, and is therefore very useful in the detection of ''P.falciparum'' infection. Additionally, antibodies that detect HRP2 also cross react with the closely related HRP3 protein which can improve their sensitivity, particularly where HPR2 is not expressed. | ||
At a high parasitaemia the sensitivity of HRP2 (like LDH-based tests) will meet or exceed 90% detection for ''P.falciparum''. However, at lower parasite levels (<1000 parasites/μL) the sensitivity is significantly less (around 70% for HRP2, which may perform better than LDH at low parasite levels). | At a high parasitaemia the sensitivity of HRP2 (like LDH-based tests) will meet or exceed 90% detection for ''P.falciparum''. However, at lower parasite levels (<1000 parasites/μL) the sensitivity is significantly less (around 70% for HRP2, which may perform better than LDH at low parasite levels). | ||
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(1) Half-life: HRP2 has a long half-life ''in vivo'' and expression persists following successful treatment. It should not therefore be used to monitor disease resolution [[Clearance of parasite antigens from blood|see antigen clearance after successful resolution]].</br> | (1) Half-life: HRP2 has a long half-life ''in vivo'' and its expression persists following successful treatment. It should not therefore be used to monitor disease resolution since HRP2 protein persists for several weeks post-therapy [[Clearance of parasite antigens from blood|see antigen clearance after successful resolution]].</br> | ||
(2) HRP2 may be affected by the [[prozone effect]]</br> | (2) HRP2 may be affected by the [[prozone effect]]</br> | ||
(3) HRP2 is increasingly subject to [[HRP2 gene deletion|gene deletion]] in some geographical areas* which may cause false negative results.</br> | (3) HRP2 is increasingly subject to [[HRP2 gene deletion|gene deletion]] in some geographical areas* which may cause false negative results.</br> | ||
Revision as of 21:00, 28 August 2024
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| Use of HRP2 in diagnosis
At a high parasitaemia the sensitivity of HRP2 (like LDH-based tests) will meet or exceed 90% detection for P.falciparum. However, at lower parasite levels (<1000 parasites/μL) the sensitivity is significantly less (around 70% for HRP2, which may perform better than LDH at low parasite levels).
Characteristics of HRP2 to be aware of
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