Interesting Cases Conference Blood Bank Ariana Beck, M.D. PGY1 11/30/2012

Interesting Case Conference: Pt CS Patient CS is a 23 year old G3P2 female who presented to Maternal Fetal Medicine Clinic at 37 WGA with a history of children with neonatal complications. In 2008, her first child had a seizure in the nursery and was found to have a platelet count of 20k. The infant had negative MRI, LP, and brain US and was treated with platelet transfusions x3.

Interesting Case Conference In 2010, her second child was found to have a platelet count of 3k and bruising in the shape of the physician’s hands following delivery. Testing at that time revealed a maternal platelet genotype of homozygote HPA-1b and a fetal platelet genotype of HPA-1a/1b and the diagnosis of NAIT (neonatal alloimmune thrombocytopenia was made

Interesting Case Conference: Neonatal Alloimmune thrombocytopenia NAIT is the most common cause of moderate to severe thrombocytopenia in an otherwise healthy neonate. Relatively rare occurrence, recent publications report an incidence of 86 per 100,000 live births Result after maternal alloimmunization to paternally inherited incompatible fetal human platelet antigens (HPAs) Maternal IgG crosses the placenta and coats fetal platelets which are then removed by the fetus’s reticuloendothelial system. [1,2]

Interesting Case Conference: Background Information on Platelet HPAs There are 28 completely categorized HPAs HPAs are found on platelet glycoproteins that are involved in activation (primarily GPIIb/IIIa) HPAs are expressed as early as 16 WGA Alleles differ based on single nucleotide polymorphisms that encode different amino acids Incompatibility in HPA-1 is responsible for 80% of all cases of NAIT NAIT due to HPA-1a is rare in other races 2% of the Caucasian population is negative for HPA-1a and 10% of HPA-1a negative women will become immunized during or after pregnancy HPA-5b (~15%) and HPA-3a (~2%) alloimmunization accounts for the remaining cases of NAIT in Caucasians (milder bleeding) In the Japanese population, HPA-4b alloimmunization is the predominate cause of NAIT Alloimmunization to other HPAs is rare [1,5]

Interesting Case Conference: Neonatal Alloimmune Thrombocytopenia Can occur in a first pregnancy Although fetal platelets can be found in maternal circulation as early as 16 WGA, this is not thought to cause alloimmunization because HPA-1a positive platelet transfusions rarely cause an antibody response Alloimmunization may occur when microparticles that express HPA-1a are shed from cytotrophoblasts during pregnancy Recent prospective studies have shown that 75% of immunization occurs in relation delivery [1,3,5]

Gastrointestinal bleeding is not uncommon Interesting Case Conference: Neonatal Alloimmune Thrombocytopenia Presentation Presenting symptoms may be as mild as incidental thrombocytopenia with no bleeding Petechiae and hematomas are common symptoms occurring in 66%- 90% of cases Gastrointestinal bleeding is not uncommon Hematuria, hemoptysis, and retinal hemorrhages are fairly rare The most severe consequence is postnatal or in-utero intracranial hemorrhage [5]

Interesting Case Conference: Neonatal Alloimmune Thrombocytopenia Testing algorithm Tests maternal serum against 2 types screening platelets to detect maternal antibodies [1]

Interesting Case Conference Treatment Maternal IVIG at a dose and duration dependent on the likely severity of the fetal thrombocytopenia (as assessed by previous history) with or without steroids IVIG: 1-2 g/kg/week for 10-25 weeks Intrauterine transfusion of HPA-1a-negative platelets is rarely performed Neonatal treatment includes platelet transfusions (HPA-1a-negative platelets if available) and IVIG. In patient’s with ICH, a platelet count of >100k is generally recomended Patients with platelet counts above 50k and no active bleeding may be observed [2]

Interesting Case Conference: the PROFNAIT project There is no current FNAIT prevention…However, the PROFNAIT project aims to create and test an anti-HPA-1a IgG to prevent maternal alloimmunization similar to RhIG in the prevention of HDFN The EU’s 7th Framework Programme is funding the endeavor [2,3]

Interesting Case Conference: NAIT Diagnostic methods: interesting developments in non-invasive prenatal testing Published online by Transfusion in November, 2012 Authors were able to use cell free DNA of fetal origin found in maternal blood and allele-specific real time PCR to reliably determine fetal HPA-1 genotype as early as 15 WGA [4]

Interesting Case Conference: Patient CS Prior to delivery, the maternal and paternal genotypes were unknown, but based on history, the current pregnancy was treated as affected. IVIG was not given due to late presentation A caesarian section was scheduled and performed at 38 weeks gestational age [1]

Interesting Case Conference Hospital Course and Treatment Baby Girl S was born via cesarean section with truncal and extremity petechiae and a platelet count of 15k A head US on day of life 1 showed an area of suggested calcification lateral to the frontal horn of the lateral left ventricle but no acute IVH A follow up MRI on day of life 3 showed scattered areas of punctate intraparenchymal and intrachoroidal old hemorrhages, possibly secondary to the patient’s thrombocytopenia

Interesting Case Conference: Maternal and Paternal testing Shortly after delivery, testing confirms diagnosis Serologic screening on maternal plasma against paternal platelets and one of the screening platelets is positive Confirmatory genotyping is done by PCR with fluorescent probes specific for the a and b alleles of HPA-1-6, 9 and 15

Interesting Case Conference: Hospital Course and treatment IVIG given BGS received 1 transfusion of HPA 1a negative platelets at a dose of 13 ml/kg with a good response and 1 dose of IVIG at 1g/kg She was discharged after a 1 week stay with a platelet count of 115k. Follow up includes platelet counts twice a week and neurodevelopment referral

Interesting Case Conference Case 2: NAIT? Baby Boy M is an ex 39 WGA neonate born via spontaneous vaginal delivery to a 24 year old Caucasian female through meconium stained amniotic fluid. The patient’s mother was also treated for gonorrhea/ trichomonas/ chlamydia during pregnancy. 14 hours after delivery, he developed jaundice and was treated with photo-therapy. Upon excess bleeding at heel stick, he was found to have a platelet count of 13k. Maternal platelet count was normal. The patient’s father is African American. A sepsis workup was started at the outside hospital. He was treated with 2 platelet transfusion and transferred to VUMC. His admission platelet count was 31k. We were notified by the team during transport that a possible NAIT case was coming and HPA-1a negative platelets were requested.

Interesting Case Conference Case 2: NAIT? Differential diagnosis for neonatal thrombocytopenia [6]

Interesting Case Conference Case 2: NAIT? Further workup included a normal head ultrasound and a normal abdominal and liver ultrasound. Maternal blood type is O+ and a maternal antibody screen is negative (BBS’s blood type is also O+). Viral cultures for HSV 1, HSV 2 and CMV were negative. Bacterial blood cultures from the OSH remain negative but CRP on admission was elevated at 64.

Interesting Case Conference Case 2: NAIT? Date Time Platelet count 11/28/2012 16:10 55 10:25 38 4:30 99 11/27/2012 22:15 35 84 6:10 40 0:45 70 11/26/2012 15:35 16 11:10 60 5:40 126 0:05 44 11/25/2012 18:30 11:40 33 4:45 103 11/24/2012 22:55 43 17:15 101 11:50 8:30 49 2:20 107 11/23/2012 23:30 147 18:35 14:00 23 7:35 47 3:00 11/22/2012 21:00 28 15:15 9:00 69 3:02 36 0:35 19:30 31 Transfusion history Guide: HPA-1a negative platelets Non typed platelet units IVIG

Interesting Case Conference Case 2: NAIT? Poor response to HPA-1a negative platelets NAIT due to non-HPA 1a alloimmunization? possible especially since the neonate is of mixed ethnicities Other cause of thrombocytopenia Sepsis/ TORCH infections is still on the differential despite negative testing We are no longer issuing HPA-1a negative platelets to this patient Maternal serology/ platelet genotype testing pending (sent 11/27/2012)

Mistransfusions: Several potential sources of error Error zone 1: mislabeled samples ( frequency of 1/165), mis-collected samples (wrong blood in tube, frequency of 1/1987) Error zone 2: the decision to transfuse Error zone 3: giving the right blood to the right patient [7]

Mistransfusions Mistransfusion is the most frequent error that results in ABO-incompatible transfusions and is a leading cause of morbidity and mortality from transfusion. The bedside check which verifies that the identity of the patient to be transfused matches the identity of the intended recipient is critical to prevent mistransfusions. However, CAP audits performed in 2000 found that in 25% of transfusions, there was a failure to match wristband identification to compatibility label. Serious hazards of transfusion [7]

Case 4: HDFN XXX is a YY year old G4P3 female who presented October 26 2012 at 30 WGA with concern of fetal anemia in the setting of Rhesus alloimmunization. Her blood type is B-. She reports that while pregnant with her first child, she received rhogam, but after she delivered, testing revealed Rh antibodies. Thus, she was told she would not benefit from additional rhogam injections. With her 2 subsequent pregnancies, her children were both Rh negative. Due to concern of her positive Rh-alloantibody status, on 10/5/12 she underwent fetal genotyping and the fetus was found to be Rh positive. At that point, she was referred to an MFM group to undergo further evaluation. On 10/26/12, an ultrasound found that the fetus had elevated MCA dopplers with an MoM of 1.81. She was sent to VUMC to be evaluated for possible percutaneous umbilical cord blood sampling procedure with fetal transfusion.

Case 4: HDFN Doppler ultrasound measurement of peak systolic velocity blood flow in the middle cerebral artery has been shown to be more sensitive and specific than amniotic-fluid DOD450 in predicting fetal anemia. High blood velocities indicate decreased viscosity (decreased RBCs) and increased cardiac output. Values above 1.5 MoM are concerning for severe anemia [8]

Case 4: HDFN Testing at Vanderbilt confirmed maternal blood type of B- An antibody panel was positive for anti-D (1:256) and C alloantibodies (1:64) 6/2012 anti-D titer 1:16 In anticipation of possible fetal transfusion, a crossmatch compatible RBC product with a hematocrit of 80% was prepared However MCA doppler done at that time was not concerning for severe anemia (PSV= 1.2 MoM)

Case 4: HDFN Titers were stable on 11/6/2012 On 11/7/2012, the procedure was performed after a concerning MCA doppler (PSV>1.8 MoM) 30 ml of RBCs were transfused Hematocrit 88%, crossmatch compatible with maternal serum, Amniotic bilirubin scan value is high at 0.126 OD A post transfusion MCA doppler showed decreased PSV at 1.6 MoM

Case 4: HDFN On 11/16/2012 another IUT was scheduled after MCA doppler showed PSV of 1.9 MoM During the procedure, just prior to the transfusion, the needle dislodged from the cord and fetal heart rate decreased An emergent Cesarean section was performed Baby Girl St was born a

Case 4: HDFN Interestingly, in addition to anti-D and C alloantibodies, an antibody screen performed 11/16/2012 showed a new anti-Jka alloantibody with a titer of 1:4. Anti-D titer 1: 16,384 Anti C titer 1:128

Case 4:HDFN Upon delivery the infant had no respiratory effort and was pale and cyanotic with a HR <60. She was intubated at ~2mins of age. In the first 24 hours of life, she underwent a double volume exchange transfusion, IVIG and phototherapy Tbili 10.6, cbili 0.5 On 11/26/2012, the infant’s anti-D titer was 1:1024, her tbili has trended down and she has not required blood products since her exchange transfusion Interestingly, her reticulocyte count has been persistently low (0.3 on 11/26/2012)

Interesting Case Conference Case 5: Positive antibody screen Pt EM is a 72 year old female with severe mitral regurgitation, coronary artery disease (s/p CABG at Centennial in 2007), type II diabetes mellitus and chronic kidney disease who was transferred to VUMC 11/26/2012 with symptoms of heart failure exacerbation. A mitral valve replacement was scheduled for 11/27/2012 and a type and screen was sent to the blood bank. She has not been previously transfused at Vanderbilt and her last in house type and screen was done in 1999 and was negative for antibodies.

Interesting Case Conference Case 5: Positive antibody screen Forward and reverse typing are consistent with blood type A+ The antibody screen was positive a follow up antibody panel revealed the presence of anti-C, ant-K, anti-Fya, anti-Jka and anti-S in her plasma. For her surgery, 4 units negative for these antigens are acquired from the red cross. In our note, we stated that obtaining antigen negative crossmatch compatible units is exceedingly difficult and strongly recommended a transfusion free approach: 25,000 units EPO subcutaneous twice per week, Fe, folate and B12. We also asked that if RBCs are needed, please give the blood bank at least 48 hours of advanced notice.

Interesting Case Conference Case 5: Positive antibody screen What is the frequency of red blood cells negative for C, K, Jka, Fya, and S in the Caucasian population? Prevalence of C (Rh): 70% Prevalence of K (Kell): 9% Prevalence of Jka (Kidd): 77% Prevalence of Fya (Duffy): 65% Prevalence of S (MNS): 55% Calculation: (1-.7)(1-.09)(1-.77)(1-.65)(1-.55) x 100%= 0.99% In order to supply 4 units of RBC’s 404 units need to be tested.

References [1] Arinsburg SA, Shaz BH, Westhoff C, Cushing MM. Determination of human platelet antigen typing by molecular methods: Importance in diagnosis and early treatment of neonatal alloimmune thrombocytopenia. Am J Hematol. 2012 May;87(5):525-8. [2] Kumpel BM. Would it be possible to prevent HPA-1a alloimmunization to reduce the incidence of fetal and neonatal alloimmune thrombocytopenia? Transfusion. 2012 Jul;52(7):1393-7. [3] Kjeldsen-Kragh J, Ni H, Skogen B. Towards a prophylactic treatment of HPA-related foetal and neonatal alloimmune thrombocytopenia. Curr Opin Hematol. 2012 Nov;19(6):469-74. [4] Le Toriellec E, Chenet C, Kaplan C. Safe fetal platelet genotyping: new developments. Transfusion. 2012 Nov 12. [5] Risson DC, Davies MW, Williams BA. Review of neonatal alloimmune thrombocytopenia. J Paediatr Child Health. 2012 Sep;48(9):816-22. [6] Chakravorty S, Roberts I. How I manage neonatal thrombocytopenia. Br J Haematol. 2012 Jan;156(2):155-62. [7] Dzik WH. New technology for transfusion safety. Br J Haematol. 2007 Jan;136(2):181-90. [8] Oepkes D, Seaward PG, Vandenbussche FP, Windrim R, Kingdom J, Beyene J, Kanhai HH, Ohlsson A, Ryan G; DIAMOND Study Group. Doppler ultrasonography versus amniocentesis to predict fetal anemia. N Engl J Med. 2006 Jul 13;355(2):156-64.