Expression of Ro/SS-A and La/SS-B determined by immunohistochemistry in healthy, inflamed and autoimmune diseased human tissues: a generalized phenomenon.

OBJECTIVE: Autoantibodies to the ribonucleoproteins Ro/SS-A and La/SS-B are found in autoimmune diseases such as primary Sjögren's syndrome (pSS), systemic lupus erythematousus and rheumatoid arthritis. Increased and aberrant expression of Ro/SS-A and La/SS-B in target organs, which have been reported in the recent literature, might contribute to their antigenicity. However, data on the expression of Ro/SS-A and La/SS-B in other inflammatory conditions are scarce. MATERIALS AND METHODS: Using monoclonal antibodies against Ro/SS-A and La/SS-B, we studied the expression of these antigens in paraffin-embedded healthy tissue, aspecific inflamed tissue, the neonatal and adult cardiac conduction systems and labial salivary gland tissues of patients suspected of having pSS. RESULTS: In healthy tissues, the nuclei expressed both Ro/SS-A and La/SS-B. This expression was stronger in inflamed tissues. Nucleoli were negative and cytoplasmic expression was weaker than nuclear expression. No increased or aberrant expression of Ro/SS-A or La/SS-B was observed in either neonatal or adult atrioventricular nodes and bundle branches. More pSS patients showed high La/SS-B immunoreactivity levels in their labial salivary gland ductal cell nuclei than non-Sjögren's syndrome sicca patients. CONCLUSIONS: Ro/SS-A and La/SS-B expression is a generalized cell biological phenomenon and may be upregulated by increased cell activation both in aspecific and autoimmune-mediated inflammation. In pSS the high expression of La/SS-B in labial salivary, gland ductal cell nuclei might contribute to the local immune response.

c-Src protein expression is increased in human breast cancer. An immunohistochemical and biochemical analysis.

In human breast cancer, c-Src activity is elevated compared to normal breast tissue. It is not yet known whether this increase in c-Src activity is accompanied by an increase in c-Src protein expression. In this study, c-Src activity and protein expression were determined in a series of human breast cancers and in normal breast tissue, using immune complex kinase assays and immunoblotting. As the heterogeneity of breast cancer is not taken into account in these biochemical experiments, immunohistochemistry was also used to distinguish between normal and malignant cells. In human breast cancers, the c-Src activity is increased 4- to 30-fold, compared with normal breast tissue. This enhanced activity is accompanied by an increase in c-Src protein expression, as shown by both immunoblotting and immunohistochemistry. Immunohistochemistry indicates that the majority of c-Src appears to be concentrated around the nucleus in malignant cells, whereas in normal cells, it is distributed more evenly in the cytoplasm. These data confirm that c-Src activity is increased in human breast cancer. In addition, this study provides strong immunohistochemical evidence that the c-Src protein is also overexpressed, enabling a distinction to be made between normal and malignant cells.

Implantation of cultured thymic fragments in congenitally athymic nude rats: ignorance of thymic epithelial haplotype in generation of alloreactivity.

We studied the development of thymus-dependent immunity in congenitally athymic nude rats after implantation of cultured thymic fragments (CTF), particularly the development of in vitro alloreactivity in allogeneic combinations. CTF of DA (RT1a), PVG (RT1c), and RP (RT1p(u,1] origin were implanted in nude rats of WAG (RT1u) origin. In analysis 14 to 18 wk later, all recipients exhibited thymus-dependent immunocompetence assessed by (immuno)-histology of lymphoid organs and responsiveness to in vitro concanavalin A stimulation and in vivo ovalbumin immunization. Control nude animals were unresponsive. Also, in vitro alloreactivity was observed, measured by mixed lymphocyte reaction and cell-mediated lympholysis. The alloresponse to the allogeneic CTF donor haplotype was as to a third party, but that to the recipient was negative. The CTF before implantation were devoid of lymphoid elements and revealed epithelial-like cells as the major component. Cells in CTF showed expression of RT1 class I and class II antigens. CTF at autopsy had the architecture of a normal thymus. In immunohistochemistry using haplotype-specific antibodies, lymphocytes showed RT1u class I expression as in the normal WAG thymus. In the cortex-like area of CTF, stromal cells revealed class I and class II haplotype expression of the donor thymus, but in the medulla-like area, class II haplotype expression was that of the recipient WAG rat. These data indicate that after implantation in nude rats, CTF become populated not only with lymphoid elements, but also with stromal components from the recipient. In induction of thymus-dependent immunity, these acceptor-derived stromal (dendritic) cells may be involved in generation of allospecificity; class I and class II haplotype expression by the donor cortex (epithelial) compartment is ignored in this process.

Monotypic immunoglobulin E plasma cells in an allogeneic bone marrow transplant recipient.

A patient with acute lymphoblastic leukaemia in first remission received a bone marrow transplant from his HLA-identical brother. The patient had a remote history of asthma and the bone marrow donor had allergic asthma. The patient developed acute graft-versus-host disease and died 2 months after transplantation. At autopsy there were high numbers of plasma cells in lymphoid tissues. The majority of this cell population was of polytypic IgG, IgM or IgA origin, but there was a significant contribution by monotypic IgE-lambda-containing cells, varying from 10% in the appendix to 35% in lymph node. The serum IgE level in the patient was less than 0.5 IU/ml before transplantation, and 8.5 IU/ml 1 month thereafter. In the donor the value was about 400 IU/ml. In the donor only, specific IgE antibodies to various allergens were detectable. The bone marrow of the donor contained 0.4% plasma cells, of which 36% were IgE positive (chi/lambda ratio 1/11). These findings are compatible with literature data on elevations in serum IgE level following bone marrow transplantation. We suggest that the IgE-lambda plasma cell population is of donor origin.