Correspondence Regarding the Study by Chen-Lu Yang et al. Published in the Chinese Medical Journal, 129(18):2258-9.

To the Editor: We read with interest the case report by Chen-Lu Yang et al.[1] of an elderly Chinese male diagnosed with an autoimmune disease (Wegener's granulomatosis) and an incidental diagnosis of monoclonal B lymphocytosis.

Considering the immunophenotype, three types of monoclonal B lymphocytosis have been described: chronic lymphocytic leukemia (CLL), atypical CLL, and non-CLL (CD5−). The patient described in Chen-Lu Yang et al.'s study showed a small clonal B-lymphocyte population in the bone marrow, which was CD5−.

It could be interesting to clarify to readers the patient's clinical aspects that led his doctors to require a bone marrow examination since there was no peripheral lymphocytosis. In case the medical staff considered it worthwhile to search for monoclonality for specific reasons, why didn't they first perform a flow cytometry of the peripheral blood?

As the immunophenotype found was not CLL, the case report discussion should have been based more specifically on the association of non-CLL MBL (CD5−) and the progression to other malignant lymphoproliferative diseases.

The term chronic B-cell lymphocytosis - marginal zone (CBL-MZ)[23] has been proposed for denominating cases with peripheral monoclonal B-cell lymphocytosis, resembling marginal zone lymphoma phenotype and no other clinical features such as splenomegaly or lymphadenopathy. The 2016 revision of the World Health Organization classification of lymphoid neoplasms has cited CBL-MZ as a provisional entity to be considered.[4] The patient in Yang's study could not be classified as CBL-MZ as no flow cytometry was performed on peripheral blood (and there was no clinical indication either). Therefore, would such a close follow-up with computed tomography and flow cytometry really be necessary? If the medical staff really considers it necessary, would flow cytometry of the peripheral blood be sufficient?

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