Relapse/Refractory Paediatric B-ALL Case with CD19⁻ Phenotype Switching Indicating the Importance of Appropriate Diagnostic Approach and Targeted Treatment Adjustment—Case Report

Round 1

Reviewer 1 Report

In this review, Prażmo et al. have highlighted CD19- B cells in pediatric acute lymphoblastic leukemia through a case report involving a 9-year-old patient, which addresses a highly significant issue. The nature of the disease indeed necessitates the utilization of more advanced and comprehensive diagnostic tools to delve into the disease's phenotype. The manuscript is overall well-written and thoroughly discussed. However, there are a few minor concerns that require attention.

Upon the patient's diagnosis with B-ALL, immunophenotyping revealed the expression of CD10, CD19, CD22, and CD79a. Regarding the immunophenotyping, it would be beneficial to ascertain the frequency of CD19⁺and CD19^- B cells based on CD10, CD22, and CD79a. This information could contribute to a better grasp of the concept that the treatment led to the selection of a CD19^- B cell clone.

For the initial and subsequent relapses in 2017 and 2018, it is crucial to understand the outcomes of immunophenotyping and the proportions of CD19⁺ and CD19^- B cells. This understanding is particularly vital for comparing the B cell phenotype before the administration of three courses of blinatumomab between April 13th and August 4th, 2018.

There are a few typos present in the manuscript that require correction. Additionally, it would enhance comprehension if complex treatments, such as chemotherapy, were briefly mentioned.

Author Response

Dear Reviewer,

Thank you for your comments and insights, and for taking the time to review this work. I will be uploading a revised manuscript with the following changes, which are marked in red:

1. Immunophenotyping profiles performed at diagnosis and subsequent relapses have been provided and are mentioned in the text (red) and presented sequentially on Figure 3. We do not have access to immunophenotyping performed in the German clinic, which is also stated in the text.
2. Immunophenotyping before and after administering blinatumomab is shown on Figure 3, with a visible decrease in CD19 expression. A subsequent result from German clinic is not known but was determined to be insufficient to qualify the patient for CAR T-cell therapy. Additionally, another reference article was added – Pillai et al. [12] (in red) to mention similar findings regarding blinatumomab treatment.
3. The manuscript was revised again, and some typos were corrected and are also marked in red. Newly added figure 3 shows the sequence of chemotherapy protocols introduced at each of the stages. Rationale for their introduction is mentioned in the text. References are added to publications detailing the procedures and medications included in each protocol ([6], [7]).

I hope the abovementioned changes make the manuscript more comprehensive. Thank you again for your input and do not hesitate to contact me with further comments.

Yours faithfully,

Anna Prażmo

Reviewer 2 Report

The manuscript presents a case of a child with leukemia and genetic, immunophenotype and molecular changes at the time of diagnosis and subsequent disease recurrences. The manuscript is properly prepared; especially the discussion explains the next stages of therapy.

In my opinion, for a better description of the changes in the course of treatment/ relapse in cytogenetic, molecular and immunophenotype changes, it would be to include a table (or figure) showing subsequent changes in the above parameters during treatment.

Author Response

Dear Reviewer,

Thank you for your comments and insights, and for taking the time to review this work. I will be uploading a revised manuscript with the following changes, which are marked in red:

A new Figure 3 was included in the manuscript, which shows the most important stages in diagnostic and treatment process. Subsequent changes in parameters such as immunophenotype and molecular analysis are shown sequentially in diagnosis and relapses. Applied treatment protocols are also included in the flowchart.

I hope the abovementioned changes make the manuscript more comprehensive. Thank you again for your input and do not hesitate to contact me with further comments.

Yours faithfully,

Anna Prażmo