Immunohistochemical characterisation and quantitative evaluation of lymphomononuclear cells in dilated cardiomyopathy-an endomyocardial biopsy study.

ABSTRACT

Endomyocardial biopsies (EMB) from patients of dilated cardiomyopathy (DCM) and normal hearts were evaluated for infiltration by lymphomononuclear cells. Cryostat sections from cases of DCM were stained with antisera against leucocyte common antigen (LCA), Pan T lymphocytes and macrophages. Paraffin sections from patients of DCM and normal hearts were also stained with a panel of antisera against LCA, and macrophage markers namely, lysozyme, alpha-1-antitrypsin (AAT) and alpha-1-antichymotrypsin (ACT). The stained cells were quantitated and expressed as number of cells/mm2. Comparisons were made between the number of lymphomononuclear cells in hematoxylin and eosin stained sections and those stained by various markers. Light microscopic evaluation of paraffin sections of EMB in all cases of DCM showed mild to moderate hypertrophy of the myocardium in 20 and 10 patients respectively. Only mild focal myonecrosis was observed in 14 patients. These foci showed minimal infiltration by lymphomononuclear cells. In normal hearts, occasional small foci of lymphomononuclear cells were seen within the interstitium. The number of LCA positive cells in the frozen section from cases of DCM were more (7.03 +/- 3.15/mm2) than the number of cells in the corresponding paraffin sections (5.26 +/- 1.14/mm2), thus indicating that antigens are possibly better preserved in frozen sections. In normal hearts, the number of cells staining positively with LCA were almost identical (4.81 +/- 1.14/mm2) to those seen in paraffin sections of cases of DCM (5.26 +/- 1.61/mm2).(ABSTRACT TRUNCATED AT 250 WORDS)