1. Interesting Case Conference
Brian C. Radlinski, MD
January 27, 2015

2. Clinical History 43 y/o white F with SLE ESRD on HD
CAD: MI and stents x 2
MR s/p MVR in 7/2013
AICD placement in 9/2014
Met. Multifocal PTC s/p thyroid resection in 10/2014
Chronic anemia: PCV 20-30% past 5+ yrs.
2 children, born in 2000 and 2002
Stents in 2002 and ‘12
50 LN mets

3. Clinical History
MSSA bacteremia in Nov.; removal of Vascath; tx. With cefazolin x 4 weeks; new tunneled L. subclavian line on 12/5
Presented to OSH on 12/10 with fever; MSSA bacteremia again; transferred to VUH on 12/12
AICD extracted on 12/15 and cefazolin restarted x 6 weeks; removal of tunneled line on 12/16; discharged on 12/23

4. Prior Tx. Hx. and Blood Bank Reports
Positive DAT for IgG fixation with negative eluate since 2009
Never evidence of immune hemolysis
2 RBC units 7/2010
2 RBC units 8/2010; last negative Ab screen
3/2013: Fya Ab (plus DAT+); 2 RBC units thereafter
7/2013: E Ab (plus Fya Ab and DAT+); partial phenotype: C Ag+, E Ag-, Jka Ag-; 2 RBC units thereafter
1 RBC unit 10/9/14
11/15/14: Jka Ab (plus E Ab, Fya Ab, and DAT+); partial phenotype: Jka Ag-; 1 RBC unit thereafter
negative eluate (including on LISS)
DAT always 2+
3/2013: prior to L. knee I and D (infected hardware)
7/2013: prior to MVR
10/14: 3 days post-op thyroidectomy
11/2014: first adm. For MSSA bac.

5. Blood Bank Report – 12/15/14
H/o alloantibodies against Fya, E, and Jka; rec’d RBC tx.’s on 10/9/14 and 11/5/14
ABO type: A+
Ab Screen+, DAT 2+ for IgG and negative for complement
Anti-s Ab identified in patient's plasma and the eluate
Pt.'s RBCs previously tested by ARC and found to be s Ag-
New clinically significant IgG antibody directed against the s antigen. This is consistent with a delayed serologic transfusion reaction

6. Delayed Transfusion Rxn. (DTR)
Delayed hemolytic transfusion reaction (DHTR)
Hemolysis occurs 24 hours to 28 days after transfusion (CDC)
Anamnestic response:
Exposure to non-self RBC Ag  Ab formation but fades over time (if pt. not retested after tx., might never be known)  re-exposure to Ag in future tx. (because Ab screen is negative)  Anamnestic rapid production of IgG Ab vs. target Ag
IgG Ab remove RBC in the liver/spleen = extravascular hemolysis
NB: DHTRs due to Jk Ab may be intravascular and severe (can fix complement)

7. Delayed Transfusion Rxn. (DTR)
Sg/sx: fever, mild jaundice/scleral icterus, back pain, hypotension, etc.
Lab findings: anemia, elevated LDH and (indirect±direct) bilirubin, decreased haptoglobin (even though extravascular), (micro)spherocytes on peripheral smear, DAT+ (classically “mixed field”), newly identified allo-Ab
Treatment: Often unnecessary (unless severe and intravascular, then treat as for an acute HTR)

8. Delayed Transfusion Rxn. (DTR)
Delayed serologic transfusion reaction (DSTR)
Presence of a new, clinically significant RBC Ab in a patient transfused between 24 hours and 28 days ago without evidence of that Ab at time of tx., AND
Complete lack of evidence of hemolysis
Don’t diagnose DSTR without studying the patient carefully
i.e., repeat Ab screen on pretransfusion sample if possible, evaluate bilirubin, haptoglobin, LDH, peripheral smear, etc.
Blood group Ab associated with DTRs include Kidd, Duffy, Kell, and MNS, in order of decreasing frequency

9. Antigens of Pt.’s Alloantibodies
Prev.
Chrom.
System
HDFN?
HTR?
Dosage
Enzyme modifi-cation
Fya
65% (W)
10% (B) 1
Duffy
yes ↓ E
30% (W)
21% (B) Rh
Rare, mild ↑
Jka
77% (W)
91% (B) 18
Kidd
s (little)
89% (W)
97% (B) 4
MNS
Modern BB and Tx. practices

10. Donor Unit Compatibility
This pt. has acquired Ab against Jka, E, Fya, and s. The probability of finding a donor unit negative for these Ag:
0.35 x 0.70 x 0.23 x 0.11 x 100 = 0.62%
But pt. is A+, so can only receive A or O blood, which is 40% + 45% = 85% of donor population
This decreases donor population to 85% of 0.62%, or 0.53% (or just 0.25% if matched for type A)
Thus, number of units to crossmatch to find compatible unit:
1/ = 190 units, or 1/ = 403 units
Pt.’s RBCs have been phenotyped at ARC; clinicians aware that if transfusion anticipated, as much advance notice as possible is needed

11. Questions/Comments

12. References
Centers for Disease Control and Prevention. National Healthcare Safety Network: Biovigilance Component Protocol. August
Chaffin, J. Blood Bank Guy. Last updated
Harmening, DM. Modern Blood Banking and Transfusion Practices. 5th ed. Philadelphia: F.A. Davis Company, 2005.
Roback, JD et al. Technical Manual. 17th ed. AABB, 2011.