What is the meaning of "leukemic cell recovery" in an abstract?
TL;DR: Yes, it's just percentage of cells that survived. With the caveat that the assay doesn't give information on how much the number of cells is influenced by survival, dying, or growth rate.
&quot;Recovery&quot; in this context means &quot;cells found after X amount of culture time&quot;. Generally speaking, recovery often refers to putting something in a program/dish/liquid/organism and seeing how much is still left after some processing/treatment/culture. For example, if I give a 1-year-old child 10 porcellain plates to play with, I might be interested in what percentage I can recover after 2h of play time. Of course in the context of cell culture, that percentage can be above 100% if the cells multiplied in the meantime.
As the methods of the article describe, the culture assay consists of first growing a single layer of stromal cells (HS-5 cells) on a culture plate for 24h. These cells provide support for the actual cells of interest. The researchers then spread 5.0 × 105 viable T-ALL lymphoblasts isolated from a patient sample on the stromal cell layer. They do this twice* for each sample, in one case collecting the cells after 1h (which isn't usually enough time for human cells to do anything), in the other case collecting them after 72h of culture (which is enough for healthy cells to grow substantially). Then they use flow cytometry to quantify how many T-ALL cells are now in the culture after that time has elapsed.
This helpful graphic is from the paper. The word &quot;cells&quot; in the formula refers to T-ALL cells.

The percentage of recovered T-ALL cells (RTC) was calculated by:


Essentially, what the authors here studied is whether the likelihood of a T-ALL patient to relapse might be related to the ability of their cancerous cells to survive or grow in a culture dish coated with stromal cells.
The quote from your colleague would mean that the T cells were surviving/growing less or dying more if they were transduced with the receptor.
*rather, four times. Twice for 1h and twice for 72h collection. At least this is what &quot;in duplicate&quot; implies.