Importance of methodological standardization for the ektacytometric measures of red blood cell deformability in sickle cell anemia

Article type: Research Article

Authors: Renoux, Céline^{a; b; f} | Parrow, Nermi^{c; 1} | Faes, Camille^{a; f; 1} | Joly, Philippe^{a; b; f} | Hardeman, Max^d | Tisdale, John^c | Levine, Mark^c | Garnier, Nathalie^e | Bertrand, Yves^e | Kebaili, Kamila^e | Cuzzubbo, Daniela^e | Cannas, Giovanna^g | Martin, Cyril^{a; f} | Connes, Philippe^{a; f; h; *}

Affiliations: [a] Laboratoire CRIS EA647, Team “Vascular Biology and Red Blood Cell”, Université Lyon 1, Université de Lyon, Lyon, France | [b] Laboratoire de Biochimie et de Biologie Moléculatire, Hôpital Edouard Herriot, Lyon, France | [c] National Institutes of Health, Washington, DC, USA | [d] Academic Medical Center, Amsterdam, The Netherlands | [e] Institut d’Hématologie et d’Oncologie Pédiatrique, Lyon, France | [f] Laboratoired’Excellence GR-Ex « The red cell: from genesis to death », Paris, France | [g] Service de Médecine Interne, Hôpital Edouard Herriot, Lyon, France | [h] Institut Universitaire de France, Paris, France

Correspondence: [*] Corresponding author: Philippe Connes, PhD, CRIS EA 647 Laboratory, Team « Vascular Biology and Red Blood Cell », University Claude Bernard Lyon 1, Villeurbanne, France. Tel.: +33 472 43 16 25; E-mails: [email protected]; [email protected].

Note: [1] Equivalent position.

Abstract: Red blood cell (RBC) deformability is severely decreased in patients with sickle cell anemia (SCA), which plays a role in the pathophysiology of the disease. However, investigation of RBC deformability from SCA patients demands careful methodological considerations. We assessed RBC deformability by ektacytometry (LORRCA MaxSis, Mechatronics, The Netherlands) in 6 healthy individuals and 49 SCA patients and tested the effects of different heights of the RBC diffraction patterns, obtained by altering the camera gain of the LORRCA, on the result of RBC deformability measurements, expressed as Elongation Index (EI). Results indicate that the pattern of RBCs from control subjects adopts an elliptical shape under shear stress, whereas the pattern of RBCs from individuals with SCA adopts a diamond shape arising from the superposition of elliptical and circular patterns. The latter represent rigid RBCs. While the EI measures did not change with the variations of the RBC diffraction pattern heights in the control subjects, we observed a decrease of EI when the RBC diffraction pattern height is increased in the SCA group. The differences in SCA EI values measured at 5 Pa between the different diffraction pattern heights correlated with the percent of hemoglobin S and the percent of sickled RBC observed by microscopy. Our study confirms that the camera gain or aperture of the ektacytometer should be used to standardize the size of the RBC diffraction pattern height when measuring RBC deformability in sickle cell patients and underscores the potential clinical utility of this technique.

Keywords: Ektacytometry, sickle cell disease, red blood cell deformability, standardization, clinical relevance

DOI: 10.3233/CH-151979

Journal: Clinical Hemorheology and Microcirculation, vol. 62, no. 2, pp. 173-179, 2016