Transfusion medicine

• Apheresis procedure wherein the buffy coat is removed and treated with psoralen and UV light, which leads to apoptosis and immune modulation of treated cells (J Clin Apher 2019;34:171)

• Therakos UVAR XTS machine operates using a discontinuous flow; thus, it only requires single needle venous access (J Clin Apher 2017;32:462)
• Therakos CellEx machine operates using a continuous flow; thus, either single or double venous access can be used (J Clin Apher 2017;32:462)
• ECP can be performed either with peripheral IV access or with a central venous catheter (CVC)
• For patients undergoing chronic ECP, a CVC is often used to ensure adequate venous access
• Emergent procedures are not performed since numerous ECP procedures are often needed before there is evidence of clinical benefit

• ECP is a chronic treatment and not generally used as an acute intervention
• American Society for Apheresis (ASFA) has expanded their indications for ECP in recent years (J Clin Apher 2023;38:77)

Current indications for ECP according to ASFA 2023 guidelines (J Clin Apher 2023;38:77)

Disease	Indication	Category	Grade
Atopic (neuro) dermatitis (atopic eczema), recalcitrant		III	2B
Cutaneous T cell lymphoma (CTCL); mycosis fungoides; Sézary syndrome	Erythrodermic	I	1B
	Nonerythrodermic	III	2B
Graft versus host disease (GVHD)	Acute	II	1B
	Chronic	II	1B
Inflammatory bowel disease	Crohn's disease	III	2C
Nephrogenic systemic fibrosis		III	2C
Pemphigus vulgaris	Severe	III	2C
Psoriasis	Disseminated pustular	III	2B
Systemic sclerosis		III	2A
Transplantation, cardiac	Cellular / recurrent rejection	II	1B
	Rejection prophylaxis	II	2A
Transplantation, liver	Antibody mediated rejection / immune suppression withdrawal	III	2B
	Desensitization, ABOi	III	2C
Transplantation, lung	Chronic lung allograft dysfunction / bronchiolitis obliterans syndrome	II	1C

• ECP is a safe and well tolerated procedure
• ECP does not require exposure to blood / blood products
• Patients may require blood transfusion prior to ECP to maintain a safe extracorporeal blood volume
• Minor adverse events
  • Low grade fevers may occur within 2 to 12 hours post infusion of mononuclear cells (Front Immunol 2023;14:1086006)
  • Temporary increase in pruritis or erythema may be seen in patients with CTCL
  • Psoralen medications can remain in the peripheral circulation following ECP therapy; patients may be photosensitive and should avoid UV exposure
  • Recommended to avoid a high fat meal at least 7 hours prior to ECP, as plasma opacity from triglycerides could interfere with the separation as well as the photoactivation process
  • Similar difficulty in the interface detection can occur in patients with high bilirubin levels
  • Some patients may experience a foul taste with psoralen infusion
  • Patients with limited or compromised cardiopulmonary reserve or impaired kidney function should be closely monitored for any significant changes in fluid shifts
• Contraindications
  • Psoralen compounds are contraindicated in patients with aphakia or with a photosensitive disease (e.g., porphyria cutanea tarda)
  • Patients with psoralen allergies should avoid ECP; additionally, patients allergic to common sources of psoralens like figs or celery should be evaluated by an allergist prior to initiation of therapy
  • Heparin is often used as an anticoagulant in ECP; thus, it is contraindicated in patients with a history of heparin induced thrombocytopenia

• Diagnosis of CTCL is based on history, physical, flow cytometry and biopsy assessment (Clin Lab Med 2017;37:527)
• Diagnosis of cardiac rejection can be made by biopsy assessment as well as clinical status changes
• Diagnosis of lung transplant rejection can be made by biopsy as well as followed by pulmonary lung function testing (PFT)
• Graft versus host disease can be assessed clinically (skin involvement, GI involvement [diarrhea], lung [PFT]) and by biopsy)

• Prior to initiating ECP, both the patient and laboratory values should be assessed
• Try to limit the amount of blood outside of a patient to < 15%
• For patients with low HCT, preprocedure transfusion may be required
• Additionally, there can be small platelet losses from ECP; therefore, a patient must be assessed for bleeding risk prior to ECP initiation
• Hemoglobin value of 10 g/dL and a platelet count of 20 x 10⁹/L is recommended (Asian J Transfus Sci 2017;11:81)

• 29 year old man with a history of metastatic melanoma who was managed with checkpoint inhibitor therapy and subsequently developed colitis (N Engl J Med 2020;382:294)
• 49 year old woman with checkpoint inhibitor associated systemic sclerosis who was managed with ECP (Clin Exp Rheumatol 2022;40:2004)
• 63 year old man with hepatitis B cirrhosis who developed GVHD after liver transplant and was successfully treated with ECP (Transfusion 2022;62:2409)

• Shaz: Transfusion Medicine and Hemostasis - Clinical and Laboratory Aspects, 2nd Edition, 2013

Which of the following is an ASFA category I indication for extracorporeal photopheresis (ECP)?

1. Erythrodermic cutaneous T cell lymphoma
2. Graft versus host disease (GVHD)
3. Inflammatory bowel disease (Crohn's disease)
4. Pemphigus vulgaris

A. Erythrodermic cutaneous T cell lymphoma. All other indications are noncategory I indications. Answers B - D are incorrect because these answers are category II or III indications.

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Reference: Photopheresis

Which of the following is a side effect of extracorporeal photopheresis (ECP)?

1. Allergy to psoralen
2. Dysgeusia
3. Feeling of impending doom
4. Slight increase in platelet count

B. Dysgeusia. Though ECP is well tolerated, dysgeusia (or abnormal taste) has been reported with psoralen infusion. Answer A is incorrect because patients allergic to psoralens should avoid ECP, thus this is a contraindication not a side effect. Answer C is incorrect because a feeling of impending doom may be a sign of a hemolytic transfusion reaction but has not been described with ECP. Answer D is incorrect because there is a slight loss of platelets within the machine during the procedure so a slight decrease in platelet count would be observed.

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Reference: Photopheresis