Donor-specific transfusions. Donor-recipient HLA compatibility, recipient HLA haplotype, and antibody production

HLA profiles of 25 donor-specific transfusion (DST) kidney donor-recipient pairs were analyzed for HLA antigen compatibility. Serum samples collected during and after DST were tested for cytotoxic antibodies against T and B lymphocytes of the donors and 30 normal individuals. Eleven recipients did not produce cytotoxic antibodies to the antigens of their DST donors, and eight produced cold and/or warm, broadly reactive B-cell antibodies. Six patients (24%) produced HLA-A, B, C, and/or DR antibodies. Three of these individuals produced antibodies after two immunizations, while others required three immunizations. Three of the 11 antibody nonproducers (17%) had not received previous transfusions, as compared to three of the eight antibody producers (43%). Comparison of HLA profiles revealed 22 percent of the HLA-A, B, DR identities between the transfusion donor and recipient in antibody nonproducers as compared to 9 percent of the HLA-A, B, DR identities in antibody producers. The HLA-A2, B40, DR4 haplotype and HLA-DRW6 antigen were more common among antibody producers than among nonproducers, who had an excess of the HLA-B8, DR3 haplotype. These results are consistent with the hypothesis that there may be high- and low-responder HLA haplotypes that control immunologic responsiveness to histocompatibility antigens.     

Antibodies against double-stranded DNA and development of polymyositis during treatment with interferon

Alpha interferons have become effective palliative treatments for patients with neuroendocrine tumours such as carcinoids and endocrine pancreatic tumours. However, several reports indicate an increased incidence of both autoantibodies and autoimmune diseases in patients treated with interferon-alpha (IFN-alpha). We studied the development of antibodies against double-stranded DNA (dsDNA) and clinical signs of autoimmune disease in 214 patients with malignant carcinoids or endocrine pancreatic tumours consecutively admitted for treatment with IFN-alpha. Seventeen patients (8%) developed antibodies against dsDNA, predominantly females (12 females and 5 males). One patient had clinical and laboratory signs of polymyositis. Among the other 16 patients, three developed hypothyroidism and in six patients the anti- dsDNA autoantibodies normalized despite continuing therapy. Although a significant number of patients developed autoantibodies against dsDNA, overt autoimmune disease related to these antibodies is a rare event and many patients spontaneously normalize these titres despite continuing IFN-alpha treatment.      

Improved prediction of fibrosis in chronic hepatitis C using measures of insulin resistance in a probability index

We sought to develop a clinically useful index comprising standard and physiologically relevant variables to predict the probability of significant hepatic fibrosis in subjects with chronic hepatitis C virus (HCV) infection. Fibrosis was graded as mild (stages F0 or F1) or significant (stages F2-F4). Thirty-five clinical and laboratory parameters were analyzed initially in 176 patients with detectable HCV RNA to derive a fibrosis probability index (FPI) to predict significant fibrosis. This index then was validated in a second group of 126 subjects. Among 18 variables associated with severe fibrosis on univariate analysis, multiple logistic regression analysis identified age, aspartate aminotransferase (AST), total cholesterol level, insulin resistance (by homeostasis model), and past alcohol intake as independent predictors of significant fibrosis. The area under the receiver operating characteristic (ROC) curves was 0.84 for the initial cohort and 0.77 for the validation cohort. In the initial cohort, the sensitivity of the FPI based on these five predictors was 96%, and the negative predictive value was 93% at a score of >/=0.2. At scores >/=0.8, the FPI was 94% specific and had a positive predictive value of 87%. In conclusion, an FPI using routinely assessed markers and incorporating a measure of insulin resistance can reliably predict the probability of significant hepatic fibrosis in most patients with chronic HCV infection. Such an index should prove useful to guide decision making regarding the need for liver biopsy, and potentially for avoiding or deferring biopsy in a large proportion of patients with mild liver disease.     

Direct gene delivery to synovium: An evaluation of potential vectors in vitro and in vivo

Objective. To assess the abilities of various vectors to transfer genes to the synovial lining of joints. Methods. Vectors derived from retrovirus, adenovirus, and herpes simplex virus as well as cationic liposomes and naked plasmid DNA were evaluated. Each construct contained the lac Z marker gene; and one retroviral construct, and one plasmid also contained a gene encoding human interleukin-1 receptor antagonist. Gene expression was under the control of the human cytomegalovirus promoter in all vectors except the retrovirus, where the endogenous 5′ long terminal repeat was retained as the promoter. Cultures of rabbit synovial fibroblasts were exposed to these vectors and stained with X-gal to identify lac Z+ cells. Vectors were then injected directly into rabbits' knee joints, and gene transfer and expression were assessed by X-gal staining and polymerase chain reaction (PCR). Results. Adenovirus was a highly effective vector both in vitro and in vivo, with lac Z gene expression persisting for at least 28 days. However, an inflammatory response was noted in vivo. Cells infected in vitro and in vivo with herpes simplex virus also expressed the lac Z gene at high levels, but expression was limited by cytotoxicity. Retroviruses, in contrast, were effective only under in vitro conditions, permitting cell division. Liposomes gave variable in vitro results; when injected into joints in vivo, gene expression was low and was detectable for only a few days, even though a PCR signal persisted for at least 28 days. Unexpectedly, plasmid DNA was captured by the synoviocytes and expressed transiently following intraarticular injection. Conclusion. None of the vectors was ideal for in vivo gene delivery to synovium, although adenovirus was clearly the most effective of those tested. Retroviruses, although poor vectors for in vivo gene delivery, are well suited for ex vivo gene transfer to the synovial lining of joints.