Quantitative Flow Cytometric Assessment of CD36 (Platelet Glycoprotein IV) Expression on Monocytes and Platelets: Assay Development, Role in Plasmodium falciparum Risk Assessment, and Relationship to Sickle Hemoglobin.
Notice bibliographique
Résumé
Abstract Background: CD36 (platelet glycoprotein IV) is a known binding site for red cells infected with Plasmodium falciparum (iRBC). The pathologic adhesion of iRBC to CD36 accounts for much of the endothelial sequestration and platelet rosetting observed. Deficient expression of CD36 is hypothesized to be another adaptation to P. falciparum malaria, because a 10-fold higher prevalence of deficiency (3–12%) exists in malaria-endemic areas. Purpose: A technique to quantitatively assess CD36 expression was developed for a future study on factors affecting P. falciparum malaria severity. In this pilot, CD36 levels were assessed in African-Americans (AA), non-African-Americans (non-AA), and a cohort of patients screened for sickle hemoglobin (HbS), in order to determine the prevalence and types of CD36 deficiency, and deficiency co-inheritance with HbS, a known malaria-adaptive mutation. Method: EDTA-anticoagulated blood was retrieved from clinical specimens. Antibody-conjugated fluorochromes (CD36-PE, CD14-FITC/− APC, CD61-PerCP, and CD54-FITC) were used. Effects of different assay conditions were investigated on samples from AA (N=57), non-AA (N=36), and those screened for HbS (N=27). FacsLyse lysis was used in the AA and non-AA subjects, but NH4Cl was selected in HbSS samples because of its unique ability to lyse otherwise lysisresistant sickle cells. After washing, samples were analysed by flow cytometry (FACSCalibur). Monocytes and platelets were identified by light-scatter and CD14- and CD61-expression respectively, and analyzed for CD36 at different storage times. Viability was assessed in 2 non-AA controls with 7-AAD. The median fluorescence intensity (MFI) of CD36 expression was log transformed. Results: Monocyte CD36 MFI follows a log-normal distribution: number tested mean SD *5% of AA were type I CD36-deficient (logMFI <1.5; MFI<32.) AA* 57 2.42 .45 non-AA 36 2.58 .22 HbS-pos 15 2.51 .35 HbS-neg 12 2.73 .28 Monocyte CD36 MFI at day 4 of room temperature storage was not significantly different from day 1 [N=28; mean MFI 96% of fresh, mean Δ = 65±241, p=NS, paired t-test], despite reduced monocyte viability and CD14 expression after 3 days. Results of platelet CD36 paralleled monocyte CD36. Platelet-monocyte aggregates gave spuriously high CD36, occurring commonly in citrated, heparinized, and ACD anticoagulants, but were rare in EDTA. Sample size was insufficient to detect an association between reduced CD36 and HbS+ (p=0.23, Fisher’s exact test). Conclusions: Flow cytometry using EDTA blood can quantify CD36 expression on monocytes and platelets. NH4Cl lysis is preferred for Hb SS specimens. Monocyte CD36 follows a log-normal distribution with 5% of AA deficient in CD36. Monocyte CD36 appears stable during room temperature storage for 4 days. This assay should be useful in studies of malaria and CD36-expression. Further work is required to assess if the reduced expression of CD36 is associated with adaptations to malaria.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».