Detection of HLA class I- and class II-specific antibodies by flow cytometry and PRA-STAT screening in renal transplant recipients.

BACKGROUND: Screening for HLA-specific antibodies has been performed by complement-dependent lymphocytotoxicity for many years. In recent years, methods involving the use of flow cytometry or ELISA have been developed. METHODS: This study has compared a flow cytometric screening technique for the detection of HLA class I- and class II-specific antibodies with a commercially available ELISA technique, PRA-STAT. RESULTS: A significant correlation was found between the two methods for the detection of antibodies in patients after transplantation (P<0.001). Specificity analysis confirmed that the PRA-STAT technique detected both HLA class I- and class II-specific antibodies. Screening of serum samples from patients who experienced graft loss by cytotoxic, flow cytometric, and PRA-STAT techniques showed that there was a significant correlation between all three methods for the detection of antibody, but that the best correlation for the panel-reactive antibody level was that between the flow cytometric and PRA-STAT techniques (r=0.86). This was principally due to the detection of both HLA class I- and class II-specific antibodies by these methods, whereas cytotoxic screening detected only class I-specific antibodies. CONCLUSIONS: These results suggest that PRA-STAT is a useful technique for the detection of both HLA class I- and class II-specific antibodies, rather than only class I-specific antibodies as previously described.

Ferritin content in human cancerous and noncancerous colonic tissue.

Tumor tissue samples from 25 patients with adenocarcinoma of the colon, twelve related samples of normal colons as well as five serum specimens from the same patients were analyzed for ferritin. The average ferritin content of the tumor tissue was 788 ng/mcp with a range of 47-1,745 ng/mcp. The average ferritin content of normal colon mucosa was 115 ng/mcp with a range of 32-230 ng/mcp. Two specimens of metastatic colon cancer taken from the retroperitoneal space and liver, respectively, contained 3,867 and 2,827 ng/mcp of ferritin. The ferritin content of the tumor tissue was higher than that of the normal colon in 8 of 9 patients who had specimens obtained from both sites. The amount of ferritin found in tumor tissue was independent of sex, age, and the site of the original tumor. This study shows that the ferritin content of colon neoplasms is elevated and indicates that the tumor tissue may be the direct source of elevated serum levels of ferritin previously observed in cancer patients.