Abstract:
Background: Even though research on the pathophysiology of RHD has much advanced than before, little is known about the underlying mechanisms that lead to severe valve malfunction. The histopathological examination of dis eased mitral valvular tissues, search for intralesional regulatory T cells, B cells and macrophages by immunohisto chemical study and observing their association can contribute toward a better understanding of the immunopatho genesis of RHD, and help in developing a more precise targeted therapy.
Objectives: The aim of this study is to evaluate the association between histopathological changes in diseased mitral heart valves in RHD cases by Haematoxylin & eosin and Masson’s trichrome staining and immunohistochemical expression of CD3, CD20 & CD68 in those tissues to identify the morphological changes and underlying immune mechanism responsible for the disease progression.
Method: A cross-sectional study was carried out in the collaboration of Department of Cardiac surgery and Depart ment of Pathology, Bangabandhu Sheikh Mujib Medical University, Dhaka, from July 2022 to June 2024. A total of 55 patients aged between 18 and 65 years with rheumatic mitral valvular disease were included in this study. The excised mitral valves were histopathologically analyzed and immunohistochemical study was done.
Result: In gross morphological study, fibrous stenotic valve was 44%, elastic insufficient valve 40% and calcific stenotic mitral valve was 16%. In microscopic examination, pattern of inflammation was focal 25% and diffuse 75% cases. Fibrosis was mild in 24%, moderate in 40% and severe in 36%. Calcification was present as mild in 2%, moderate in 5% and severe in 9% (focal in 7% and diffuse in 9%). In immunohistochemical examination, for calcifi cation, CD3 infiltration- occasional 44.5% and several groups 55.5% which was not statistically significant (P- value 0.581ns). CD20 infiltration- absent 22.2%, occasional 33.3%, several groups 33.3% and many groups 11.2% which was not statistically significant (P- value 0. 3945ns).CD68 infiltration- absent 11.1%, focal 55.6% and multifocal 33.3% which was statistically significant (P- value 0. 0036s). In case of fibrosis, CD3 infiltration- occasional 61.5% (mild), 45.5% (moderate), 10% (severe) and several groups 38.5%(mild), 54.5% (moderate), 90% (severe) which was statistically significant (P- value 0. 0056s). CD20 infiltration- absent 7.7% (mild), 22.8% (moderate), 5% (severe); occasional 61.5% (mild), 54.5% (moderate),5% (severe); several groups 15.4% (mild), 18.2% (moderate), 25% (severe) and many groups 15.4% (mild), 4.5% (moderate),65% (severe) which was statistically significant (P- value 0. 00015s). CD68 infiltration- absent 61.5% (mild), 27.3% (moderate), 5% (severe); focal 23.1% (mild), 68.2% (mod erate),90% (severe) and multifocal 15.4% (mild), 4.5% (moderate), 5% (severe) which was statistically significant (P- value 0. 0027s).
Conclusion: The significant association between immunohistochemical examination and histopathological changes observed in this study can provide new insight to disease presentation and hence can contribute to the development of more specific targeted therapy to halt disease progression.
