TRALI: It’s Not Just For Blood Bankers Anymore

2. TRALI: It’s Not Just For Blood Bankers Anymore Norman D. Means, MD, FCAP Blood Bank of Alaska

3. TRALI What is it?

5. Transfusion-Related Acute Lung Injury • First described by Popovsky , Abel and Moore in 1983 Am Rev RespDis 1983;128:185-9 • Acute Pulmonary Edema • Respiratory Distress • Hypoxemia • Hypotension • Fever • In the setting of a recent transfusion

6. History • Case reports as long ago as 1951 • “Noncardiogenic edema” • “Allergic pulmonary edema” • “Hypersensitivity reaction” • “Leukoagglutinin transfusion reaction”

7. History • TRALI is a difficult diagnosis to make, since there are often confounding underlying medical conditions that tend to obscure the diagnosis • TRALI is one subset of Acute Lung Injury • Spectrum of disorders

8. Acute Lung Injury • Spectrum of injury • Acute Respiratory Distress Syndrome (ARDS) is most severe form • Many potential causes, including many causes which are treated by transfusion • Up to 40% of acutely ill, actively bleeding patients will develop ALI • Pulmonary edema may develop simultaneously

9. ALI/ARDS Other possible causes of ALI/ARDS • Sepsis • Trauma • Aspiration • Shock • others

10. Acute Lung Injury • ARDS Mortality 30 – 40% • TRALI Mortality 6 – 12%

11. Consensus conferences • North American-European Consensus Conference on ARDS (1994) • NHLBI Working Group (2002) • Canadian Consensus Conference (2004)

12. North American European CC Acute Lung Injury definition: • Acute hypoxemia • PaO2/FiO2 <300 mm Hg • Pulmonary edema on frontal CXR • Pulmonary artery occlusion pressure <18 mm HG or no evidence of left atrial hypertension

13. NHLBI WG /Canadian CC Defined TRALI • Adopted NAECC definition of ALI • TRALI if 6 hours since transfusion • Risk factors for ALI • Canadian: “possible TRALI” • NHLBI: interpret time course

14. Why is TRALI suddenly so important?

15. Transfusion-associated fatalities reported to the FDA 1990-1998 Source: Lee, JH Workshop on Bacterial Contamination of Platelets, 9/24/99; adapted from Menitove, JE Complications of Transfusion (p 1617), in Clinical Laboratory Medicine, 2nd Ed. (2001) , McClatchey, KD, ed.

16. Transfusion-associated fatalities reported to the FDA 2005-2006 • Cases • 6 Source: Fatalities reported to the FDA following blood collection and transfusion (2005-2006); from http://www.fda.gov/cber/blood/fatal0506.htm

17. Differential Diagnosis of TRALI

18. TACO Transfusion-Associated Circulatory Overload

19. TACO • The most common transfusion reaction • 1-8% of post surgical patients requiring transfusion • Age > 60 may develop with only a single unit of pRBC • Dyspnea, orthopnea, elevated BP, pedal edema, crackles, tachycardia, infiltrates • Elevated BNP

20. Anaphylactic Reactions • Bronchospasm • Wheezing • Laryngeal edema • Urticaria/Erythema • Hypotension • Rapid onset after start of transfusion • IgA deficiency

21. Transfusion-Associated Sepsis • Fever • Hypotension • Shock • Rapid onset • Bacteria present • Platelets most at risk

22. Pathophysiology of TRALI • Traditional model (antibody transfer) • Transfer of biologic response modifiers

23. Traditional Model • Passive transfer of antibody via transfusion • HLA Class II, HNA, HLA Class I antibodies • Sensitized donors • Multiparous women • Organ and tissue transplant recipients • Previously transfused blood donors

24. Traditional Model • Bray, et al (2004) • 308 randomly selected units of plts, pRBC, FFP, cryoprecipitate • Overall 22% of units had HLA antibodies • FFP 29% • Cryo 24% Hum Immunol 2004;65:240-4

25. Traditional Model • Why don’t we see more TRALI? • Antigen-antibody pairing • Threshold concentration of antibodies • Preexisting endothelial “priming” may potentiate response

26. Bioactive Response Modifier Model • Accumulation of IL-6, IL-8, PAF, IFN-γ, TNF-α, NO, bioactive lipids • Transfusion leads to activation of inflammatory cascade (NO→vasoconstriction) • Damage to alveolar capillaries or increased hydrostatic pressure • Pulmonary Edema

27. Bioactive Response Modifier Model • These bioactive agents have been shown to accumulate in stored blood products over time. • Levels may rise high enough to “prime” neutrophils or endothelial cells • Some evidence that these may rarely trigger TRALI directly.

28. Pathophysiology of TRALI • Probably all of these models have some role to play in the causation of TRALI • Other causes may emerge

29. Pathophysiology of TRALI • End result is damage to the pulmonary capillary endothelium • Neutrophil-induced damage • Activated neutrophils • express HLA Class II and HNA antigens • Activated pulmonary endothelium • express HLA Class II antigens

30. Pathophysiology of TRALI • Activated neutrophils • Response to various priming agents • PAF, TNF-α, IL-8, GM-CSF, IFN-γ, LPS, infectious agents • Anatomic and physiologic changes • Stiffening (actin polymerization) • Adhesivity (β2integrins, selectins) • Clustering of surface receptors (FcγRIIa, β2integrins) • Release of toxic granule enzymes • Formation of NADPH oxidase → Reactive oxygen species

31. Pathophysiology of TRALI • Activated neutrophils • Activation may be triggered by a number of events • Infection • Cardiovascular disease • Leukemia • Recent surgery • Others (trauma?, hemorrhage?) • Mechanical sequestration and aggregation in pulmonary microvasculature

32. Pathophysiology of TRALI • Activated endothelium • Increased adhesivity (selectins, ICAM-1) • Promotes priming of “captured” neutrophils • Interaction of activated endothelium and neutrophils leads to endothelial damage/TRALI • Platelet activation • Increased neutrophil aggregation • Complement activation • Role unclear

33. Pathophysiology of TRALI • Neutrophil specific antibodies • HNA, HLA Class II, and HLA Class I • Some are strong enough to trigger TRALI alone • Presence of leukoagglutinins is especially worrisome • Leukoagglutinins may stimulate active neutrophil aggregation

34. Pathophysiology of TRALI • Activated neutrophils are sequestered in the microvasculature of the lungs • Production of bioactive products • ROS • Enzymes • Endothelial damage • Exudation of fluid and neutrophils into alveoli • Respiratory compromise

35. Pathophysiology of TRALI • Exudative (high protein) fluid in alveoli • TACO has transudative (low protein) protein in alveoli • Damage to the pulmonary capillary endothelium leads to leakage into alveoli • Due to activated neutrophils damaging endothelium

36. Pathophysiology of TRALI • Presence of HLA-antibodies and HNA antibodies in a blood product does not necessarily mean that these antibodies will cause TRALI • Cognate antigens in recipient may be necessary

37. HLA and HNA antibodies • HLA antibodies identified in 70-75% of all TRALI cases • 85-90% antibody in transfused product • 10% in recipient • Rare inter-donor cases • antibody in transfused product directed against antigen in other transfused product • HNA antibodies 10-15% • 10-15% ? ?

38. HLA and HNA antibodies Reil A, et al. VoxSanguinis 2008;95(4):313-317

39. HLA and HNA antibodies • HNA-3a antibodies in 6 of 10 fatal cases in this study • Remainder were HLA Class II and HNA-2a

40. HLA testing • All test rely on the AHG test • Plasma or serum is reacted to test antigens • Wash unbound antibody away • Incubate with anti-IgG • Wash unbound anti-IgG away • Detection

41. HLA testing • Complement Dependent Cytotoxicity • Live cells • Mix with complement • Count living cells (dye exclusion) • Very labor intensive • Least sensitive • Cellular test • Not specific for HLA antibodies

42. HLA testing • ELISA • Full range of antigens bound to test wells • Usually one well for Class I and one well for Class II • Less sensitive • Manual testing currently • automation under development • Acellular (specific for HLA antibodies) • No indeterminant tests: cutoff value

43. HLA testing • Flow Cytometry • Latex microparticle beads with antigen • Complex test that is labor intensive • Indeterminate results possible • Acellular • Can distinguish between class I and class II due to differences in luminescence markers • Single run tests for both

44. HLA testing • Luminex • Similar to Flow cytometry • Antigen coated microbeads • Fluorescent-tagged antibodies • Simpler chemiluminescence test • Instrument is smaller • Less expertise to operate • Both class I and class II can be simultaneously tested • Manual test, but automation looks easiest • No indeterminate tests…cutoff value

45. HNA testing • Expensive ($200-300) , few labs doing this at the moment • Generally tests are labor-intensive and require high level of expertise to perform

46. HNA testing • Granulocyte agglutination testing • Serum incubated for 4-6 hours with fresh neutrophils • Presence of antibodies cause clumping of neutrophils • Least sensitive of tests

47. HNA testing • Granulocyte immunofluorescence (GIF) • Similar to AHG test • Pretreatment with 1% paraformaldehyde to prevent antibody binding to Fc portion of neutrophil receptor • Microscopy: Can have high background fluorescence making it difficult to read weak results • Flow cytometer is most often used now

48. I got a TRALI case! What do I do now?

49. Tenth Law of the House of God IF YOU DON’T TAKE A TEMPERATURE, YOU CAN’T FIND A FEVER. -- Samuel Shem (1978)

50. Investigation of Suspected TRALI • Increased numbers of reported TRALI fatalities in past few years is due in large part to increased awareness on part of the folks at the bedside • Education of clinical personnel about TRALI recognition is critical. • CCC criteria • NHLBI WG criteria