Image Morphometric Analysis of B Cells and Plasma Cells in Erythema Nodosum Leprosum With Clinicopathological Correlation

Abstract

Erythema nodosum leprosum (ENL) occurs as an immunological complication of multibacillary leprosy (MBL). The pathogenesis of ENL is long considered to be a T-cell-mediated process. The role of B cells and plasma cells in ENL is not well described in the literature. Therefore, we investigated the B-cell and plasma cell infiltrates in the skin biopsies of biopsy-proven cases of ENL by immunohistochemistry and image morphometry and compared the result with paucibacillary leprosy and MBL. Moreover, we sought a correlation of the B-cell and plasma cell infiltrates with different clinical, hematological, histopathological, and bacteriological parameters as well as the T-cell subsets in the skin biopsies. Our study highlighted a significant reduction in the number of B cells from paucibacillary leprosy to MBL to ENL, although there was no significant variation in the plasma cell infiltrate. The plasma cell infiltrate correlated with absolute neutrophilia in the blood and the presence of eosinophils in the ENL lesions. Both B cells and plasma cells positively correlated with CD4-positive T-helper cells and the CD8-positive cytotoxic T cells. Besides, the B cells also correlated positively with the CD3-positive pan T cells in the biopsy and negatively correlated with the T-regulatory:T-cell ratio. Our results suggested the role of B cells and plasma cells even at the tissue level in the pathobiogenesis of ENL.

Changes in B Cell Pool of Patients With Multibacillary Leprosy: Diminished Memory B Cell and Enhanced Mature B in Peripheral Blood

“…Here, we observed that there were no significant differences between patients and uninfected subjects in both transitional and plasmablast B cells, but a higher frequency of mature B cells was observed in both groups of patients with MB and ENL. We acknowledge that one limitation of the present study is the absence of functional analysis but a previous morphometric analysis of B cells and plasma cells in ENL demonstrated a positive correlation with CD3-positive pan T cells in the biopsy and a negative correlation with T regulatory -T cell ratio (32). In addition, CD27+CD21+ resting memory B cells were diminished in patients with MB leprosy, with only a slight significant increase in atypical memory B cells.…”

“…We acknowledge that one limitation of the present study is the absence of functional analysis but a previous morphometric analysis of B cells and plasma cells in ENL demonstrated a positive correlation with CD3-positive pan T cells in the biopsy and a negative correlation with T regulatory – T cell ratio ( 32 ).…”

T-Regulatory Cells in Erythema Nodosum Leprosum: An Immunohistochemical and Image Morphometric Study

“…In our earlier study involving the same cohort of patients, we could document a correlation of the dermal eosinophils with the dermal plasma cells in ENL. 7 We believe that the FoxP3:CD3 ratio is possibly related to the Th2 limb of the acquired immunity, both being characterized by their immunoregulatory functions. Thus, the Th2 limb recruits the eosinophils by the release of IL-4, 5, and 13.…”

“…The study population was similar to our previous published study. 7 The methodology is essentially similar to our previous study. 7 Routine hematoxylin and eosin stain was performed in all cases for the diagnosis, detailed histopathological assessment, and subtyping of all cases.…”

“…5,6 In a previous study, we have elucidated the role of B cells and plasma cells in ENL and compared the relative tissue preponderance of T cells in relation to the B cells and plasma cells. 7 We have used the same cohort to investigate the relative proportion and association of T-regulatory cells in ENL. We used immunohistochemistry for the assessment of the T-regs and objectivized the result by means of image morphometry.…”