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Published on: November 3, 2018
Immunohistochemical evaluation of bone marrow lymphoid nodules in chronic myeloproliferative disorders
V Franco1, A M Florena, F Aragona
1Institute of Pathological Anatomy, University of Palermo, Italy.
Insights
Lymphoid nodules (LNs) in bone marrow biopsies are common in chronic myeloproliferative disorders (CMPDs). These reactive T- and B-lymphocyte aggregates suggest a potential immune response within the bone marrow microenvironment.
Area of Science:
- Hematology
- Immunology
- Oncology
Background:
- Chronic myeloproliferative disorders (CMPDs) are a group of clonal hematopoietic stem cell diseases.
- Bone marrow microenvironment alterations are increasingly recognized in CMPDs.
- The presence and significance of lymphoid nodules (LNs) in CMPDs require further investigation.
Purpose of the Study:
- To investigate the prevalence and characteristics of lymphoid nodules (LNs) in bone marrow biopsies from patients with CMPDs.
- To determine the immunological composition of LNs using immunohistochemistry.
- To explore the potential implications of LNs as a reactive phenomenon in CMPDs.
Main Methods:
- Evaluation of 170 bone marrow biopsies from patients diagnosed with CMPDs.
- Immunohistochemical staining of LNs using monoclonal antibodies (UCHL1, 4KB5, L26) targeting lymphocyte antigens.
- Analysis of LN presence and cellular composition (T- and B-lymphocytes).
Main Results:
- Lymphoid nodules (LNs) were detected in a significant percentage of CMPD cases: idiopathic thrombocythaemia (35%), myelofibrosis/osteomyelosclerosis (24.6%), polycythaemia vera (18.2%), chronic myeloid leukaemia (12.1%), and borderline cases (19.2%).
- Immunohistochemical analysis revealed varying proportions of T- and B-lymphocytes within the LNs.
- T-cells consistently showed a prevalence over B-cells in the observed lymphoid nodules.
Conclusions:
- Bone marrow lymphoid nodules (LNs) are frequently observed in patients with chronic myeloproliferative disorders (CMPDs).
- The composition of LNs, with a T-cell predominance, suggests they represent a reactive process rather than a neoplastic infiltrate.
- These findings indicate that LNs in CMPDs may reflect an immune response within the bone marrow.
Abstract:
One hundred and seventy bone marrow biopsies from patients with chronic myeloproliferative disorders (CMPDs) were evaluated for the presence of lymphoid nodules (LNs) and were immunostained using a panel of monoclonal antibodies (UCHL1, 4KB5 and L26) recognizing different lymphocyte antigens. LNs were found in 35% of cases of idiopathic thrombocythaemia, 24.6% of myelofibrosis/osteomyelosclerosis, 18.2% of polycythaemia vera 12.1% of chronic myeloid leukaemia and 19.2% of borderline cases. Varying degrees of immunohistochemical positivity for the three antibodies tested were found. LNs were always made up of variable proportions of both T- and B-lymphocytes with a prevalence of T-cells. This latter observation suggests that bone marrow LNs in CMPDs could be an expression of reactivity.
