Review Reports - Clonal B-Cell Lymphocytosis of Marginal Zone Origin: Presenting Features, Clinical Evolution and Prognostic Factors

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study retrospectively examined 98 consecutive cases of CD5(-) clonal B-cell lymphocytosis of marginal origin. The authors showed that the vast majority of cases either remained stable or developed increasing lymphocytosis, indicating that this entity may represent a pre-malignant state rather than a frank lymphoma; furthermore, evolution to splenic marginal zone lymphoma was a rare event

Please note the following:

-authors should specify why in cases with a marrow lymphoplasmacytic population greater than 10%, myd88 mutation and paraproteinemia the diagnosis of lymphoplasmacytic lymphoma was not made.

Minor:

- line 185: specify in how many cases a monotypic lambda restriction was present

- line 302: change “low lount” in “low count”

Author Response

-authors should specify why in cases with a marrow lymphoplasmacytic population greater than 10%, myd88 mutation and paraproteinemia the diagnosis of lymphoplasmacytic lymphoma was not made.

Minor:

- line 185: specify in how many cases a monotypic lambda restriction was present

- line 302: change “low lount” in “low count”

Response:We would like to thank the reviewer for this constructive comment. We fully agree with the observation that these patients exhibit overlapping features with LPL patients and may indeed represent this subgroup. Consequently, we have addressed this point in the Discussion section (lines 415–421) as well as in the Conclusions (lines 488–490).Regarding your query about the percentage of patients with λ (lambda) clonality, these accounted for 34 out of 98 patients (35%). Additionally, the typographical error in paragraph 3.8 has been corrected

Reviewer 2 Report

Comments and Suggestions for Authors

This study addressed a difficult problem of diagnosing marginal zone (MZ) lymphoma or MZ-like peripheral blood lymphocytosis. As the authors rightly discussed, the diagnosis of MZ lymphoma or MZ-like lymphocytosis is a matter of excluding other small B-cell proliferations. Though the authors admirably included only CD5-negative cases in the study (thus excluding CD5+ CLL and mantle cell lymphoma), and excluding others by a constellation of clinical, perpheral blood, bone marrow involvement patterns, a more positive approach is to include the more modern MZ cell IRTA1) and MZL (MNDA) markers in the flow cytometry panel. Not having included these two markers render the diagnosis of "MZ-like" doubtful and throws the study into incedibility.

Despite the well worked out remaining parts of the study, omission of modern MZ markers is a very significant omission.

Author Response

Despite the well worked out remaining parts of the study, omission of modern MZ markers is a very significant omission.

Response:We highly appreciate your valuable comment, which greatly contributes to improving the quality of our data. Fortunately, an immunohistochemical analysis for both antigens was performed on all bone marrow samples, and both were found to be negative in all cases. We have now included the description of this technique in the Immunophenotypic and Immunohistochemical Methodology section, as well as the evaluation findings in the Results section (pages 105–109 and 210–211, respectively

Reviewer 3 Report

Comments and Suggestions for Authors

I believe the manuscript addresses an important and underexplored issue in mature B-cell neoplasia. The cohort is relatively large for such an uncommon and poorly standardized condition, and the long follow-up adds value. However, I have some suggestions/comments as follows:

1. Abstract: I suggest moderating some of the conclusion language. In particular, “may represent a pre-lymphoma state and not a frank lymphoma entity,” “these cases should probably be called primary BM MZL,” and “may represent a separate LPL-like MBL”

2. Introduction: One suggestion is to clarify earlier that the study uses the term CBL-MZ operationally, while recognizing that the true biologic derivation may not always be fully proven without tissue histology.

3. Materials and Methods: I think several points need clarification:

- Definition of consecutive cases: Please clarify how referral and case ascertainment were performed across the participating centers and whether referral bias may have influenced the spectrum of cases seen.

- Bone marrow availability: Since BM studies were available in 83/98, please clarify how the remaining 15 were classified and followed.

- Immunophenotyping completeness: It would be helpful to summarize in a small supplemental table exactly how many cases were tested for each marker.

- Progression definition: I suggest separating biologic progression from treatment-triggering events more clearly.

4. Results: The description of two broad subcategories, one more lymphoplasmacytic/paraproteinemic/MYD88-linked and one more leukemic/CD11c/LDH-linked, is one of the strongest parts of the paper. However, I recommend presenting this more systematically, perhaps with a summary table listing the defining features and actual denominators for each variable.

5. Discussion: The terminology arguments should be presented more tentatively, the assertion that BM infiltration >50% identifies a distinct “primary BM MZL” entity should be framed as a proposal rather than a conclusion and the MYD88/paraproteinemic subgroup should be discussed as potentially overlapping with LPL-like biology rather than as a clearly defined separate category. I also suggest expanding the limitations section to include retrospective design, incomplete testing across cases, possible referral bias, lack of central pathology review language (if not performed) and low event numbers for multivariable survival models.

6. Conclusions: I suggest revising them to say that the study supports the hypothesis that CBL-MZ is heterogeneous and may include subgroups with different biological relationships to marginal zone lymphoma and lymphoplasmacytic disorders.

7. Minor comments:

- In section 3.8, “low-lount” should be corrected to low-count.

- The institutional review statement contains a typographical error: “Institutional Review Board StatementL:” should be corrected.

- There are a few small inconsistencies in notation, such as MYD-88L275P in Table 3 instead of MYD88 L265P. This should be corrected carefully.

Author Response

3. Materials and Methods: I think several points need clarification:

- Bone marrow availability: Since BM studies were available in 83/98, please clarify how the remaining 15 were classified and followed.

- Immunophenotyping completeness: It would be helpful to summarize in a small supplemental table exactly how many cases were tested for each marker.

- Progression definition: I suggest separating biologic progression from treatment-triggering events more clearly.

7. Minor comments:

- In section 3.8, “low-lount” should be corrected to low-count.

- The institutional review statement contains a typographical error: “Institutional Review Board StatementL:” should be corrected.

There are a few small inconsistencies in notation, such as MYD-88L275P in Table 3 instead of MYD88 L265P. This should be corrected carefully.

RESPONSE:

In the Abstract section: The sentences you pointed out have been removed (lines 54–56).
Introduction: We have made the necessary change according to your recommendation (lines 76–78).
Material and Methods
We have rephrased this section (lines 89–91) and have explicitly acknowledged the potential issue of bias within the study's limitations.(lines 480-482)
The remaining 15 patients refused to undergo a bone marrow biopsy; however, they all presented with an inverted white blood cell differential without cytopenias or symptoms, and remained stable without requiring treatment (lines 163–166)
We have added the number of patients and the corresponding percentages for characteristic immunophenotypic markers to Table 1.
This section has been rephrased according to your comment, and we now explicitly emphasize that a distinction exists between biological progression and the need for treatment (lines 141–143).

Results:We would like to thank you for your suggestion. We have created a new table outlining the baseline characteristics of each category, which has been added as Table 2
Discussion, Conclusions:We have taken your recommendations into account and adjusted the Discussion section to address the key issues (lines 415–424), as well as the Conclusion section(488-490). Additionally, as you very accurately pointed out, we have now included the limitations of our study in the revised manuscript(480-482)
Minor comments: We have made all the correction as you pointed out

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

the authors have adequately addressed the points highlighted in the first review;

Reviewer 2 Report

Comments and Suggestions for Authors

The most important starting point of any study is CORRECT case selection. despite repeating the term "MZ" feautures/derivation/origin, these have not been defined in the entire manuscript. The staining of infiltrated BM with IRTA1 and MNDA was universally NEGATIVE, further NOT supporting the assertion that the cases included have MZ features or are of MZ derivation/origin. The other markers used are non-specific for MZ, and DBA-44 and FMC-7 are more for Hairy Cell Leukemia.
Though the authors acknowledged the possibility of LP lymphoma, they insisted on classifying these cases as subcategory 1 CBCL-MZ. The positivity for CD38, detected MYD88 mutation and LP morphology are in fact strong strong evidence of LP lymphoma.

Reviewer 3 Report

Comments and Suggestions for Authors

All comments have properly been addressed.