The role of immunohistochemistry in the assessment of classical Hodgkin lymphoma microenvironment.

Introduction: Classical Hodgkin lymphoma (CHL) has a unique cellular composition, containing a minority of neoplastic cells - Hodgkin and Reed-Sternberg (HRS) cells - in an inflammatory background. Investigations into this microenvironment have been given special importance in scientific hematopathology, playing an important role in elucidating its composition and its relationship to the prognosis of patients.

Objective: To investigate microenvironment tumor markers in CHL, in order to analyze their interactions with clinical-morphological aspects of interest in onco-hematopathology.

Methods: This retrospective study analyzed 184 patients with a pathologic diagnosis of CHL. Clinical data were reviewed from medical records. A morphological and immunophenotypic study with CD20, CD30, CD15, PAX-5, CD3, CD4, CD8, CD68, CD34, CD138 and PD-1 were performed. The data were tabulated and p value less than 0.05 was considered significant.

Results: The time-to-cure was shorter in CD20+ patients, especially in those with more than 25% positivity (P=0.0183). The time-to-cure (P=0.0309) and the death (P=0.016) rates were shorter in PD-1 negative patients. Among patients with the presence of plasma cells in the microenvironment, those with lower numbers tend to be cured earlier (P=0.0374). Higher vascular density is associated with lower frequency of B symptoms (P=0.036) and presence of disease recurrence (P=0.004).

Conclusions: The microenvironment is certainly the setting of increasingly robust studies and the findings of this work highlight non-neoplastic B lymphocytes, plasma cells, PD-1 lymphocytes, and vascular density, related to prognosis of CHL patients.