Anti-Ge2 Antibodies (RCI)

An urgent Investigation of a pan-reactive antibody From referral, testing, appraisal of results and application of clinical significance in the provision of blood for transfusion Candice Davison BMS Education Day NHSBT Tooting 15/02/17 Referral to RCI • Urgent requests are telephoned – Patient ID, serological investigation results, urgency, recent Tx status, Hb, Report or XM? – Sent via urgent transport • Sample booked in and grouped by Automation – Triage patient (review history on NHSBT LIMS/ Hematos/1A request form) • Careful appraisal of all information enables efficient and formative investigation of the antibody Candice Davison BMS Education Day NHSBT Tooting 15/02/17 Previous Results • Full Red Cell Phenotype (FCT) – k+ Kp(a-b+) M+N+S+s+ P1-Lu(a-b+) Le(a-b-) Fy(a+b+) Jk(a+b+), In(b+), Ge-2 • Referred to the IBGRL in 2002 – Patient’s red cells express the Ge: -2, -3, 4 (Gerbich phenotype) – Anti-Ge2 detected, reacting at moderate strength by IAT with untreated cells but NOT with papainised test cells. – The presence of additional alloantibody specificities were excluded Candice Davison BMS Education Day NHSBT Tooting 15/02/17 Panel 1: Antibody Investigation worksheet: BD 12.10.16 KCH Rh M N S s P1 Lua K k 1 R1wR1 0 + 0 + 4 0 0 + 0 + 0 + 2 R1R1 + 0 + 0 0 0 + + 0 0 + 3 R2R2 0 + 0 + 0 0 0 + 0 0 4 r’r + 0 0 + 0 0 0 + 0 5 r”r + 0 + 0 2 0 0 + 6 rr 0 + 0 + 3 0 + 7 rr 0 + + 0 2 0 8 rr + 0 0 + 3 9 rr 0 + 0 + 10 rr + 0 + 0 Kpa Lea Leb Fya Fyb Jka Jkb A B C 0 + 0 3 0 0 0 + 0 + 3 0 0 + 0 + 0 + 3 0 0 0 + 0 + + 0 3 0 0 0 + 0 + 0 + 0 3 0 0 0 0 0 + + 0 + 0 3 0 0 0 + 0 0 0 0 + 0 + / / 0 0 0 + + 0 + 0 + + 0 / / 0 3 + 0 + 0 + 0 0 + 0 + / / 0 1 0 0 + 0 0 + + 0 0 + / / 0 0 / 0 A/C A Bio-Rad gel IAT B Bio-Rad gel enzyme IAT C LISS tube IAT 370C B, RhD positive Candice Davison BMS Education Day NHSBT Tooting 15/02/17 C+c-E-e+ K- Further Investigations • Rare test cell panel • Comprised of a selection of rare HFA negative liquid or frozen donor test red cells – E.g Yt(a-), Ch-, Rg-, Kna-, U- Yk(a-), JMH-, Fy(a-b-), Lan- etc. • DTT treatment of plasma – Dirupts the J chain of IgM antibodies, enables IgG antbody strength to be determined. • The haemolytic potential of the IgG antibody can be estimated by the strength of the anti-IgG antibody detected. • Can be helpful to infer clinical significance where in vivo RBC survival data is either unknown or dubious. Candice Davison BMS Education Day NHSBT Tooting 15/02/17 Report Candice Davison BMS Education Day NHSBT Tooting 15/02/17 Gerbich: Anti-Ge2 • 12 antigens located on either or both sialoglycoproteins (GPC and GPD). – Produced by GYPC • Population Frequency (Ge+) – >99.9% – 3 rare Ge negative phenotypes 1. Ge: -2, 3, 4 (Yus) 2. Ge: -2, -3, 4 (Gerbich) 50% Melanesian Population 3. Ge: -2, -3, -4 (Leach) Candice Davison BMS Education Day NHSBT Tooting 15/02/17 Carrier Molecule Ge2 antigen GPD NH2 1 Ge2 (not expressed on GPC). 19 27 RBC Lipid Bilayer 71 107 COOH Image courtesy of M.Needs adapted from The Antigen Facts Book 2004 Candice Davison BMS Education Day NHSBT Tooting 15/02/17 Clinical Significance • Transfusion Reaction – No to moderate/immediate/delayed • However there is no FIRM evidence that this antibody has caused a HTR (SPN214) – Anti-Ge2 (IgG1) – The antibody strength is considered moderate by Bio-Rad IAT, undetectable by LISS tube IAT. – NHSBT recommendation • Select ABO compatible D+ E- c- K- for crossmatching and select the least incompatible by IAT. Candice Davison BMS Education Day NHSBT Tooting 15/02/17 Summary • Effective communication is vital in resolving complex antibody cases in a timely manner • Review of historical and current results enables a more efficient investigation process • Anti-Ge2 is a rare antibody • Understanding the clinical significance is not always straightforward – Antigen negative blood is not always indicated Candice Davison BMS Education Day NHSBT Tooting 15/02/17 References • Daniels G (2013) Gerbich Blood Group System in Human Blood Groups 3rd Edition. Oxford: Blackwell Publishing Limited 182-207. • Reid ME and Lomas-Francis C (2004). The Blood Group Antigen Facts Book 2nd Edition. London: Elsevier Ltd. • Daniels G (2015) NHSBT SPN214/3: The clinical significance of Blood Group alloantibodies and the Supply of Blood for Transfusion. Candice Davison BMS Education Day NHSBT Tooting 15/02/17