Immunohistochemical study on the labial salivary glands of the Sjögren's syndrome patients

Abstract

Sjögren's Syndrome (SS) is an organ specific autoimmune disease in which exocrine glands, mainly salivary and lacrimal glands, become heavily infiltrated with lymphocytes leading to decreased production of saliva and tears, i.e. sicca complex. However, its etiology remained to be determined. We have been doing SS patients clinical and pathological research and searching for the correlation between these two factors. And we realized that it is important to retrieve lymphocyte subsets which are infiltrating in the salivary gland. In this study, monoclonal antibodies which recognize lymphoid-associated antigens on paraffin sections were used for retrospective study.
We studied 101 cases of SS (6 male cases, 95 female cases). 87 patients had “definite” and 14 had “probable” SS according to the criteria by the SS committee of the ministry of health and welfare. The distribution of the degree of lymphocytic infiltration which was evaluated according to the Ishikawa and Komori classification was as follows;(-): 5, (±): 26, (+): 34, (++): 22, (+++): 14. Paraffin sections of minor salivary glands were stained with UCHL 1, LN-1, LN-2, LN-3, and L 26 by the ABC technique.
A relationship between the degree of lymphocytic infiltration according to the Ishikawa and Komori classification and T cell/B cell ratio was detected. The more extensive lymphocytic infiltration became, the higher the percentage of occupied B cells. There was also a relationship between the number of lymphocytes infiltrating and the T cell/B cell ratio, In small foci of the lesion, the infiltrating lymphocytes were mainly T cells. As the foci became larger, the percentage of B cell became higher.
In 5 cases germinal center was detected in foci. In these foci, the high percentage of B cells were seen, especially LN-1 positive B cells gathered and formed the germinal center. Compaired with those who did not have LN-1 positive B cells, rheumatoid factor was detected more frequently in the patients who had LN-1 positive B cells. The infiltrated LN-1 positive B cells seemed to play an important role in producing the rheumatoid factor.
These data showed that T cells infiltrate first in the salivary glands, and B cells appear and get activated as the focus gets larger. Thus, T cells are likely to play an important role in the initiation of SS and B cells play in the further process of SS.