The expression of CD23 and CD40 in primary cutaneous B-cell lymphomas.

BACKGROUND: CD23 expression in normal B lymphocytes is limited to autoreactive B cells, naïve B cells and mature B cells manifesting an activated phenotype. As a marker of hematologic dyscrasia/malignancy, expression of CD23 is associated with small lymphocytic lymphoma/chronic lymphocytic leukemia. An absence of CD23 expression within small lymphocytes is typically seen in marginal zone lymphoma and mantle cell lymphoma. Positive CD23 expression amidst neoplastic cells in primary cutaneous B-cell lymphoma is not a reported phenomenon.

METHODS: This paper reports nine patients with cutaneous B-cell lymphoma manifesting CD23 expression.

RESULTS: In seven of the nine cases CD23 expression was observed in the setting of recurrent disease, being present in both large and small lymphocytes. CD23 expression paralleled staining for CD40 in all but one case.

CONCLUSIONS: A potential mechanism of CD23 upregulation may involve the anti-apoptotic nuclear kappa beta CD40-CD40 ligand pathway. Neoplastic B cells manifesting CD23 expression could have a survival advantage, predisposing to recurrent disease and or oncogenic events permissive to disease progression.