Rheological red blood cell behaviour in minor α-thalassaemia carriers

Article type: Research Article

Authors: Vayá, Amparo | Suescun, Marta | Hernández, Jose Luis | Pérez, María Luz | Palanca, Sarai | Laiz, Begoña

Affiliations: Hemorheology and Haemostasis Unit, Service of Clinical Pathology, La Fe University Hospital, Valencia, Spain | Hematology Service, La Fe University Hospital, Valencia, Spain

Note: [] Corresponding author: Amparo Vayá, MD, PhD, Hemorheology and Hemostasis Unit, Service of Clinical Pathology, La Fe University Hospital, Avda. de Campanar, 21, 46009, Valencia, Spain. Tel. and Fax: +34 963862714; E-mail: [email protected]

Abstract: Although several studies have been published regarding rheological behaviour of red blood cells in beta and delta-beta thalassaemia traits, little information about erythrocyte deformability in alpha-thalassaemia carriers is available. We aimed to determine erythrocyte deformability in heterozygous (silent, -α/αα) and homozygous (minor alpha-thalassaemia, -α/-α) carriers of the alpha-thalassaemia trait for the alpha 3.7 deletion, the most common in our geographical area. We evaluated erythrocyte deformability by means of the elongation index (EI) in a Rheodyn SSD at 12, 30 and 60 Pa, along with basic haematological cell count, erythrocyte indices, reticulocytes, plasma lipids and iron metabolism parameters in 36 (18 women, 18 men) alpha-thalassaemia carriers (17 heterozygous, 19 homozygous) and 36 healthy subjects (23 women, 13 men). The molecular diagnosis of the alpha 3.7 deletion was evaluated by a PCR-based method. Alpha-thalassaemia carriers presented higher red blood cell counts, RDW-CV (p < 0.001) and lower haemoglobin, MCV, MCH and MCHC (p < 0.001) than controls. EI was statistically lower at 12, 30 and 60 Pa in cases than in controls (p = 0.001, p = 0.002, p = 0.010, respectively). No differences in either elongation indices or haematimetric values were observed when comparing silent heterozygous and minor homozygous alpha-thalassaemia carriers (p > 0.05). Pearson's bivariate correlation showed that EI60 correlated positively with haemoglobin and MCV, MCH, MCHC (p < 0.01), but negatively with ferritin (p< 0.05) and RDW-CV (p< 0.01). In the multivariate regression analysis, MCV (p = 0.001) and haemoglobin (p < 0.001) predicted EI60, with this model accounting for around 43% of variation in EI60 (R2 = 0.427). Alpha-thalassaemia carriers phenotypically showed mild microcytosis and hypochromia, irrespectively of them being silent heterozygous or minor homozygous alpha-thalassaemia carriers, which is associated with decreased erythrocyte deformability.

Keywords: Erythrocyte deformability, alpha-thalassaemia, silent heterozygous alpha-thalassaemia (-α/αα), minor homozygous alpha-thalassaemia (-α/-α)

DOI: 10.3233/CH-2011-1416

Journal: Clinical Hemorheology and Microcirculation, vol. 48, no. 4, pp. 241-246, 2011