Q20-45: Persistence of Cells

!Persistence of Cells and Genetically Modified Cell Therapy Products
This section pertains to the evaluation of persistence of a cellular product in the recipient and only applies to genetically modified cellular therapy products.

Question 20: Were tests performed to detect persistence of the cellular product?

Methods such as PCR assays (e.g. ExPeCT^TM), flow cytometry (immunophenotyping) or immunohistochemistry can be used to detect direct persistence of the cellular product in the recipient.

It is possible to use other testing methods, such as monitoring B cells, as a surrogate for ongoing cellular therapy persistence. Surrogate testing should not be reported here. Monitoring of B cells can be reported below.

Indicate Yes or No whether tests were performed to detect direct persistence of the cellular product in the current reporting period.

Question 21: Was persistence evaluated by molecular assay? (e.g., PCR)

Molecular assessment involves testing blood, bone marrow, tumor or other source for the presence of known molecular markers. Molecular assessments are the most sensitive test and involve amplifying regions of cellular DNA by polymerase chain reaction (PCR), typically using RNA to generate complementary DNA through reverse transcription (RT-PCR). The amplified DNA fragments are compared to a control, providing a method of quantifying log increase of genetic mutation transcripts. Each log increase is a 10-fold increase of gene transcript compared to control.

Indicate Yes or No whether molecular assay testing was performed to detect the persistence of the genetically modified cellular therapy product within the reporting period.

Question 22: Date Sample collected

Report the date the sample was collected for molecular assay. If multiple tests were performed in the reporting period and

• all tests were negative, report the date of the first negative test result
• there were positive and negative results, report the date of the last positive test (do not report negative results)

For more information regarding reporting partial or unknown dates, see General Instructions, General Guidelines for Completing Forms.

Questions 23-24: Specify the cell source (check all that apply)

Specify the cell source of the sample collected for evaluation by molecular assay. Select all that apply. If multiple cell sources were used and persistence was detected in some but not all the samples, report ONLY the cell sources that were positive. If Other cell source is selected, specify the source.

Question 25: Were the infused cells detected?

Indicate Yes or No if the infused cells were detected by molecular assay.

Question 26: Was persistence evaluated by flow cytometry testing? (immunophenotyping)

Flow cytometry is a technique that can be performed on blood, bone marrow, or tissue preparations where cell surface markers can be quantified on cellular material. The nature of flow cytometry is to detect cells based on a specific probe. To report flow cytometry results, the test must have been performed to specifically detect the genetically modified cellular therapy product.

Indicate Yes or No if flow cytometry testing was performed to detect the persistence of the genetically modified cellular therapy product within the reporting period.

Question 27: Date sample collected

Report the date the sample was collected for flow cytometry testing (immunophenotyping). If multiple tests were performed in the reporting period and

• all tests were negative, report the date of the first negative test result
• there were positive and negative results, report the date of the last positive test (do not report negative results)

For more information regarding reporting partial or unknown dates, see General Instructions, General Guidelines for Completing Forms.

Questions 28-29: Specify the cell source (check all that apply)

Specify the cell source of the sample collected for evaluation by flow cytometry. Select all that apply. If multiple cell sources were used and persistence was detected in some but not all the samples, report ONLY the cell sources that were positive. If Other cell source is selected, specify the source.

Question 30: Were the infused cells detected?

Indicate Yes or No if the infused cells were detected by flow cytometry.

Question 31: Was persistence evaluated by immunohistochemistry?

Immunohistochemistry is a process that uses antibodies to test for certain antigens (markers) in a sample. When the antibodies bind to the antigen in the tissue sample, the enzyme or dye is activated, and the antigen can then be seen under a microscope.

Indicate Yes or No if immunohistochemistry testing was performed to detect the persistence of the genetically modified cellular product within the reporting period.

Question 32: Date sample collected

Report the date the sample was collected for immunohistochemistry. If multiple tests were performed in the reporting period and

• all tests were negative, report the date of the first negative test result
• there were positive and negative results, report the date of the last positive test (do not report negative results)

For more information regarding reporting partial or unknown dates, see General Instructions, General Guidelines for Completing Forms.

Questions 33-34: Specify the cell source (check all that apply)

Specify the cell source of the sample collected for evaluation by immunohistochemistry. Select all that apply. If multiple cell sources were used and persistence was detected in some but not all the samples, report ONLY the cell sources that were positive. If Other cell source is selected, specify the source.

Question 35: Were the infused cells detected?

Indicate Yes or No if the infused cells were detected by immunohistochemistry testing.

Questions 36-37: Was persistence evaluated by other method?

Indicate Yes or No if persistence of cells was tested by a method not listed above. If Yes, specify the other method used to evaluate persistence of cells.

Question 38: Date sample collected

Report the date the sample was collected for the other method. If multiple tests were performed in the reporting period and

• all tests were negative, report the date of the first negative test result
• there were positive and negative results, report the date of the last positive test (do not report negative results)

For more information regarding reporting partial or unknown dates, see General Instructions, General Guidelines for Completing Forms.

Questions 39-40: Specify the cell source (check all that apply)

Specify the cell source of the sample collected for evaluation by other method. Select all that apply. If multiple cell sources were used and persistence was detected in some but not all the samples, report ONLY the cell sources that were positive. If Other cell source is selected, specify the source.

Question 41: Were the infused cells detected?

Indicate Yes or No if the infused cells were detected by the other method being reported in these questions.

!B-cell monitoring
These questions will only enable for the CAR-T products that target CD19+ cells (Aucatzyl®, Breyanzi®, Carteyva®, Kymriah®, Tecartus®, Yescarta®, rapcabtagene autoleucel or zamtocabtagene autoleucel).

Question 42: Were B-cell counts monitored after infusion?

CAR-T cells that target antigens (e.g., CD19) on B-cells do not distinguish between cancerous and normal B-cells. As result, the recipient can develop B-cell aplasia (low number or absence of B-cells). B-cell aplasia can be used as a surrogate to track persistence of the product. If the recipient has B-cell aplasia, then the product may still be present.

Examples of applicable tests that will show B-cell populations include (but not limited to) “cellular immunology report”, “lymphocyte subsets”, or “B-cell panel”. Some of these tests might be performed using flow cytometry, but it is distinct from the flow cytometry path report for disease evaluation.

Indicate Yes or No if B-cell counts were monitored during the current reporting period. If it was not known whether B-cell counts were monitored during the current reporting period, select Unknown

Question 43: Was there B-cell recovery?

A guideline for B-cell aplasia is a B-cell count of < 50 cells/µL of blood (applicable for both adult and pediatric). Use the following guidelines when reporting B-cell recovery:

• Yes: B-cell aplasia was identified (< 50 cells/µL) and B-cells subsequently recovered (>50 cells/uL). Confirmatory testing may or may not be done. It is acceptable to report Yes with only one test value.
• No: B-cell aphasia was identified but B-cells never recovered (>50 cells/uL)
• Previously reported: B-cell aplasia was identified, and the initial B-cell recovery was reported in a prior reporting period.
• Unknown: B-cell aplasia was identified but B-cell recovery is not documented.

If B-cell counts were monitored but never dropped below the threshold of 50 cells/µL, then leave the question blank and override the error using the code “Unable to Answer.”

B-cell counts in the blood do vary with age, and children have much higher counts than adults. The younger the child, the higher the concentration.

Question 44: Date of initial B-cell recovery

Report the date the flow cytometry report showed initial (the first) B-cell recovery.

For more information regarding reporting partial or unknown dates, see General Instructions, General Guidelines for Completing Forms.

Question 45: Did the recipient receive a subsequent infusion for loss of B-cell aplasia?

Indicate if a subsequent infusion was given for the indication of loss of B-cell aplasia. If Yes, the number of infusions reported on the Cellular Therapy Product (4003) Form should be updated and a new Cellular Therapy Infusion (4006) Form must be completed. A new Pre-CTED (4000) Form is not required for the subsequent infusion.

Section Updates:

Question Number	Date of Change	Add/Remove/Modify	Description	Reasoning (If applicable)
.	.	.	.	.

Copyright © 2004-2026 The Medical College of Wisconsin, Inc. and NMDP. All Rights Reserved.
CIBMTR® (Center for International Blood and Marrow Transplant Research) is a research collaboration between the Medical College of Wisconsin and NMDP.