STUDY OF THE KINETICS OF HAEMOLYSIS IN SICKLE CELL

TRAIT: ITS IMPLICATION IN TRANSFUSION

YM Sekongo *; S Kouamenan; A Abisse; S Konate; I Sanogo; S Konan; KD Yao;Centre National de Transfusion Sanguine, Abidjan, Côte d'Ivoire

INTRODUCTION

Sickle cell haemoglobinopathy: anomaly of the β chain of haemoglobin.

Glutamic acid at position 6 replaced by valine.

crystallization of haemoglobin,

Sickle cells formed

accentuation of physiological haemolysis

PO2 is lowered

Several haemoglobin phenotypes

Anaemic forms (SSFA2 et SFA2)

Non-anaemic forms (SAFA2 et SC).

Sickle cell trait AS is generally asymptomatic and detected by chance.

No treatment needed for Sickle Cell Trait, diagnosed during blood donations.

Legbedji (2009): 28% of sickle cell trait AS among blood donors

Cabannes et al: 12% of Ivory Coast population HbS carriers

INTRODUCTION

Sekongo Y.M. (2012) abnormal Hb : 15,06%; HbS 9,51%

Little is known of blood donation by heterozygous sickle cell trait AS persons.

Except in pathological conditions, haemolysis in subjects with sickle cell trait AS is not important

Normal red blood cells have a lifespan of 120 days

Kinetics of hemolysis undefined in heterozygous sickle cell trait AS

Ould A. (Trans Med 2006): 8% of sickle cell trait AS donors in Martinique; AS donors deferred

Bryant (Trans 2008) : variable in the US, depending on centres. If detected, red cell concentrate from AS donor contraindicated in neonates and in sickle cell disease recipients

Noizay-Pyrene (EFS site Mondor) 3.5% of donors with sickle cell trait

INTRODUCTION

Question : Is the level of haemolysis in a deoxygenated environment in bags that contain sickle cell trait AS phenotype blood significant, to the extent that residual haemoglobin becomes insufficient for transfusion?

Aim : determine the duration of storage of a bag that contains sickle cell trait AS blood

INTRODUCTION

GENERAL OBJECTIVECompare the kinetics of haemolysis in blood from AA and AS persons

SPECIFIC OBJECTIVES

1- determine potassium and haemoglobin level in each donor (AA and AS) at D0; D10; D20; D30

2- Estimate the haemoglobin weight in blood bags from AS and AA donors at D0; D10; D20; D30

3- Specify the optimal shelf-life of bags containing AS phenotype blood, to ensure an effective transfusion

METHODComparative Cohort Study: horizontal prospective

NBTS of Abidjan-Treichville

Duration : 2 (two) months: October 2010 – November 2010

11 AS donors and 11 AA control donors in a population of regular blood donors.

Donor eligibility criteria for blood donation: age, weight, pre-donation haemoglobin, medical consultation.

Random systematic sampling

All blood tested for transfusion transmissible infections HIV, HCV, HBV and Syphillis (negative) by serology on Architec

Total of 450 ml blood drawn +/-50 ml in triple bags with SAGM anti-coagulant

Sedimentation with extraction of plasma, to obtain one standard bag of red cell concentrate preserved in SAG-mannitol between 4°and 6°C.

After stripping the tube, several aliquots made and kept for 30 days between 4°and 6°C.

Bag of red cell concentrate introduced for distribution.

METHOD

EDTA and plain tube samples taken to perform serological and immuno-haematology tests on donated blood

Full blood count and serum potassium levels performed at D0; D10; D20 and D30.

Full blood count performed on automated haematology analyser of SYSMEX type.

Serial serum potassium levels performed on biochemistry autoanalyser by colorimetric and spectrophotometric methods.

Levels compared between normal donors (AA) and sickle cell trait (AS).

METHOD

RESULTS

0

5

10

15

20

25

Hb D0 Hb D10 Hb D20 Hb D30

AA1

AA2

AA3

AA4

AA5

AA6

AA7

AA8

AA9

AA10

AA11

Haemoglobin level among AA donors

Mean Hb AA g/dl)

D0 18,76 D10 17,76 D20 16,66 D30 16

RESULTSHaemoglobin level among AS donors

02468

101214161820

Hb D0 Hb D10 Hb D20 Hb DJ30

AS

AS

AS

AS

AS

AS

AS

AS

AS

AS

AS

Mean Hb AS g/dl)

16,43 15,26 11,76 10,76

Mean haemoglobin level among AS donors

and control AA donors

RESULTS

D0 D10 D20 D30

HB weight (g) 78,871,9974,675,573,879,2178,6776,2273, 3173,6275,07

7466,472,9873,8671,7376,9976,4375,8971,4871,7273,11

73,260,9966,0167,1365,9270,1370,1969,7765,7165,9067,57

7255,9164,3765,2363,8467,9667,4667,5363,8163,8865,77

Mean 75.13 71.12 66.73 64.09

Percentage drop/ initial weight

X 5.33% 11.18% 14.69%

Haemoglobin weights in bags of AA donor blood and percentage drop relative to original weight

D0 D10 D20 D30

HB weight(g)

5668,869,859,762,460,3166,6358,3465,3561,3263,27

4866,8

66,6954,8

58,7859,0262,4756,7861,1359,5761,94

46,847,261,2352,3547,5950,9752,7251,0555,0150,7653,41

41,3841,258,8947,2143,2145,4347,4246,7450,7841,4746,09

Mean 64.86 60.49 51.74 47.15

percentage drop / initial weight

X 6.7% 20.22% 27.3%

Haemoglobin weights in bags of AS donor blood and percentage drop relative to original weight

AA0

20

40

60

80

D0 D10 D20 D30

AA

AS

Comparison of mean haemoglobin weights of blood bag s obtained from AS and AA donors

Comparison of drop in haemoglobin weight in blood b ags from AS and AA donors relative to initial weight

DO D10 D20 D30

percentage drop /initial

weightAS subjects

X 6.7% 20.22% 27.3%

Percentage drop / initial weight

AA subjects

X 5.33% 11.18% 14.69%

Evolution of serum potassium levels among AA donors

0

5

10

15

20

25

30

35

K+ D0 K+ D10 K+ D20 K+ D30

AA1

AA2

AA3

AA4

AA5

AA6

AA7

AA8

AA9

AA10

AA11

0

5

10

15

20

25

30

35

K+ D0 K+ D10 K+ D20 K+ D30

AA1

AA2

AA3

AA4

AA5

AA6

AA7

AA8

AA9

AA10

AA11

Evolution of potassium levels (Kaliémie) among AS donors

DISCUSSION

Mean haemoglobin levels in our donors prior to donation greater or equal to 12g/dl

Haemoglobin levels drop as from D10 among AS donors;

Brief drop at D10, then stable level among AA donors

Mean haemoglobin weight of blood bags from AS phenotype donors close to red cell concentrate production norms at D0 and D10

The weight drops as from D20.

Weight of blood bags from AS donors lower than those from AA donors.

Variation in weight among different AS donors; probably linked to endogenous or exogenous factors that need to be identified

DISCUSSION

Percentage of HbS in the blood bag?

Drop in haemoglobin weight as from D10: blood units from AS donations may be proposed for transfusion only in the 10-days following the date of donation.

Bryant USA: red cell concentrate contra-indicated in neonates and sickle cell disease patients

ACKLEY: After deglycerolisation of blood bags from AS donors, these retain their viability up to six (6) days

Difference in the drop of haemoglobin weight between AA subject and AS subject. Drop is more pronounced among AS subjects

DISCUSSION

Noizat-Pyrene (EFS ile de France site Mondor): Problems caused A/S red cell concentrate

Clogging of filters during leukodepletion

AS red cell concentrate: filter blocked within 7 min

AA red cell concentrate: filtration in 12 minMechanism

During blood donation: Anticoagulant

-hyperosmolarity, Acid with lowering of SaO2 levels

During storage:

-temperature, duration

« sickling » of AS red cells with increased adherenceExclusion of AS subjects from blood donations

DISCUSSION

Serum potassium levels increase with time: indirect marker of haemolysis

More marked increase in AA donor than in AS donor

Noizat-Pyrene: Increase in serum potassium level during storage of red cell concentrate

Higher serum potassium levels in AA subject than in AS subject: paradoxical

Distribute freshest possible blood to patients in critical condition.

DISCUSSION

CONCLUSIONHaemolysis is observed in both AA donors and AS donors, however it is increased in AS donors.

Mean haemoglobin weight in blood bags from AS donors is within quality norms for up to 10 days.

Given our conditions for distribution of blood products (few blood donors), AS donors cannot be excluded from giving blood.Transfusion of red cell concentrate from AS donors must be within 10 days post-donation

AS red cell concentrate contra-indicated in neonates and sickle cell disease patients

CONCLUSION

PERFORM HAEMOGLOBIN ELECTROPHORESIS IN BLOOD DONORS?

�YES

� NO

SICKLING TEST AN ALTERNATIVE?

ACKNOWLEDGEMENTPr Sanogo DG of CHU Treichville

Dr Kouamenan Sidonie Hémovigilence NBTS

Personnel from Consultation site NBTS Treichville

Dr Tchimou, Dr Konan S Distribution

Dr Yao D. RAQ NBTS

Quality Control Laboratory NBTS

QB laboratory of NBTS

Mr AKA Jules GIMED laboratory

Dr KONATE Seidou: Director NBTS