[Immunoglobulins in periapical lesion with special reference to qualitative and quantitative analysis of IgG]

Immunoglobulins in periapical lesions (including 34 radicular cysts and 11 radicular granulomas) were investigated through extracts of the lesions and cystic fluids. The extracts of dental sacs and sera were used as a control. For a qualitative analysis, the immunoglobulins (especially IgG) of each sample were investigated by agarose gel electrophoresis and agarose gel isoelectric focusing. For quantitative analysis, single radial immunodiffusion was employed for determining the concentration of IgG, IgG subclasses, IgA and IgM in the extracts, cystic fluids and autologous sera, also IgE in cystic fluids. In agarose gel electrophoresis, homogeneous bands that were regarded as monoclonal or oligoclonal patterns in gamma region were identified with IgG by immunofixation. These bands were detected in 65% of the radicular cysts, 73% of the radicular cysts obtained cystic fluid, and 73% of the radicular granulomas, but were not detected in any of the autologous sera and dental sacs. In cases that these homogeneous bands were found in extract of cyst, the same bands were found in fluid of same radicular cyst. These results strongly suggested that a part of IgG in periapical lesions was locally produced. By agarose gel isoelectric focusing, immunoglobulins in the extract, cystic fluid and serum were investigated. Many clearly detectable bands were found in extracts of periapical lesions and cystic fluids in the range of pH 6-9 and identified with IgG by immunofixation. These findings revealed restricted heterogeneity of IgG. These IgG bands were found randomly in the range of pH 6-9 and no specific inclination of arrangement. These results suggested that IgG in periapical lesions seem to have different specificities in immunological reaction. Furthermore, in isoelectric focusing pattern of IgG, similar bands were identified in the extract of the cystic wall and fluid of same radicular cyst in 82% of the cases. These bands were detected in some of the dental sacs but not in the serum. Therefore it means that a quantities of IgG in periapical lesions and cystic fluids were locally produced. By quantitative analysis, no statistically significant differences were found in the concentration of IgG, IgG subclasses, IgA and IgM in sera between periapical lesion group and control group.