Altered red blood cell e antigen expression in variant RHCE*ce alleles. Is it worth doing a molecular analysis?

Transcription

1 Altered red bld cell e antigen expressin in variant RHCE*ce alleles. Is it wrth ding a mlecular analysis? Mingmar Sherpa, MLS, SBB (ASCP) cm Mississippi Valley Reginal Bld Center

2 Objectives Understand the basics f RHCE gene and RhCE prteins. Understand hw a variant RHCE*ce allele can have altered expressin f e antigen. Understand the imprtance f differentiating between an aut anti-e (RH5) versus an all anti-e (RH5) due t partial e expressin. Understand the imprtance f mlecular analysis in prper identificatin f clinically significant antibdy.

3 Case Study 22 year ld female presented t the ER due t sickle cell crisis. Chief cmplaint Pain lcated in her arms and legs, mre severe in wrists with assciated chills and intermittent dizziness. Patient histry Sickle cell anemia, asthma, and migraines. Patient has n primary r hematlgist

4 Additinal Histry Transfusin/Pregnancy: N recrd f transfusin r pregnancy at the current hspital. 11/3/2017- transfused 1 unit f prbc at a different facility Febrile transfusin reactin after first unit n 11/3/ /5/2017- transfused 1 unit f prbc (same hspital- previus) Medicatins: Aleve t manage pain 0.9% NaCl infusin Oxycdne and acetaminphen Ondansetrn Mrphine Ketrlac Flic acid

5 Labs: CBC

6 Labs: CMP

7 Labs: Urinalysis

8 Bld Bank Type and Crss rdered fr transfusin f 1 prbc unit Hspital perfrmed a type and screen pan reactive (including aut cntrl) Sample referred t reference lab

9 ABO/Rh Anti-A Anti-B Anti-D Rh cntrl A1 cell A2 cell B cell Aut ABO Interp NT 4+ NT 4+ NT O psitive DAT Result Methd IgG 2+ Gel C3 Neg Tube

10 Plasma Eluate D C c E e Cw K k Kpb Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lub Gel Gel TC AC

11 Adsrbed Plasma- R D C c E e Cw K k Kpb Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lub Gel TC

12 Adsrbed Plasma- R D C c E e Cw K k Kpb Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lub Gel TC sel cell

13 Adsrbed Plasma- R D C c E e Cw K k Kpb Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lub Gel TC sel cell

14 Adsrbed Plasma- rr D C c E e Cw K k Kpb Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lub Gel TC AC

15 Adsrbed plasma- rr D C c E e Cw K k Kpb Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lub Gel TC AC

16 Phentype (with sickle separated cells) C c E e K Fya Fyb Jka Jkb S s Hmm e+?? But the patient has anti-e Maybe it s aut anti-e Let s find ut.

17 Adsrbed Plasma- R2R D C c E e Cw K k Kpb Jsb Fya Fyb Jka Jkb Lea Leb P1 M N S s Lub Gel TC AC (tested with sickle separated DAT negative patient cells) 0

18 Is This e Variant?

19 HEA Mlecular Patient was referred fr RHCE variant testing

20 RHCE Gene and RhCE Prteins RH lcus is the mst plymrphic f thse encding the antigens f the 30 BGS antigens in the Rh BGS are the mst immungenic Tw hmlgus genes RHD and RHCE, each spanning 10 exns, encde, respectively, the RhD and RhCE prteins D, C, E, c, and e are the 5 majr Rh antigens encded by these genes

21 RHCE Gene and RhCE Prteins Alteratin in RHD and RHCE genes due t nucletide changes Cause gene rearrangement May encde altered expressin f antigens, aka partial antigens present technical challenges Mutatins in RHCE result in quantitative and qualitative changes in C/c r E/e antigen expressin, Patient antigen type as C+ and/r e+, but prduce anti-c and/r anti-e. Altered C and e encuntered in African Americans mst frequently.

22 Gentyping Numerus partial e antigens have been described Several partial e encded by RHCE*ce alleles Many were classified as autantibdies- prir t RH gentyping. Serlgic methds d nt detect variant C r e RH gentyping can identify thse patients wh are at risk fr allimmunizatin if expsed t cnventinal C/c and E/e antigens.

23 Diagram f sme altered RHD and RHCE alleles cmmn in African Black ethnic grups that cmplicate transfusin in patients with sickle cell disease.

24 Back t0 ur patient: Gentype Reprt

25 Hw D I Interpret That?? RHCE*cE/*ce(733G), with a predicted C-c+E+ and e+(partial) phentype, Partial e because f E in trans n the ther allele. Risk fr all anti-c and all anti-e Recmmended phen-matched and e- units C- e- K- Fya- Jkb- S- SDN unit

26 High-Thrughput Gentyping Mlecular DNA-based genetic methds prvide an invaluable tl fr imprved transfusin therapy fr patients with SCD. Limitatins: Multiple genetic variatins will be fund May, r may nt, be immungenic r affect the phentype. The cmplexity f alleles encding RBC antigens is cmplicated by gegraphy, ppulatin diversity, and ethnicity, and new alleles cntinue t be fund.

27 What des this all mean? Cmbine the mlecular and serlgical methds t prvide cmpatible bld and t avid additinal allimmunizatin. High-thrughput mlecular methds may be cst-effective when screening large # f dnr units.

28 References Flegel WA. Mlecular genetics and clinical applicatins fr RH. Transfusin and apheresis science : fficial jurnal f the Wrld Apheresis Assciatin : fficial jurnal f the Eurpean Sciety fr Haemapheresis. 2011;44(1): di: /j.transci Flegel WA. The genetics f the Rhesus bld grup system. Bld Transfusin. 2007;5(2): di: / Gaspardi AC, Sippert EA, de Maced MD, Pellegrin J, Csta FF, Castilh L. Clinically relevant RHD-CE gentypes in patients with sickle cell disease and in African Brazilian dnrs. Bld Transfusin. 2016;14(5): di: / Westhff CM, Vege S, Hipsky CH, et al. RHCE*ceAG(254C>G, Ala85Gly) is prevalent in blacks, encdes a partial ce-phentype, and is assciated with discrdantrhdzygsity. Transfusin. 2015;55(11): di: /trf Chu ST, Jacksn T, Vege S, Smith-Whitley K, Friedman DF, Westhff CM. High prevalence f red bld cell allimmunizatin in sickle cell disease despite transfusin frm Rh-matched minrity dnrs. Bld. 2013;122(6): di: /bld

29