Home About us Contact
|
Home About us Contact | ||
|
|
||
HLA Phenotypes (hla + phenotype)
Selected AbstractsHLA phenotypes and outcomes of hepatitis B virus infection in Taiwan,JOURNAL OF MEDICAL VIROLOGY, Issue 1 2004Ya-Fang Wu Abstract The relationship of HLA phenotype and outcome of hepatitis B virus (HBV) infection was studied in two ethnic groups of Taiwan: Han Chinese and Taiwanese Aborigines. In Han Chinese, the study groups consisted of 98 persons who tested both hepatitis B surface antigen (HBsAg) and anti-HBs negative (Uninfected Group), 324 persons who tested HBsAg negative and both anti-HBs and anti-HBc positive (Recovered Group), and 98 patients who tested HBsAg positive for at least 6 months (Chronically Infected Group). In Taiwanese Aborigines, the study groups consisted of 34 persons in Uninfected Group, 229 persons in the Recovered Group, and 138 patients in the Chronically Infected Group. All subjects were tested for HLA (A, B, DRB1) phenotypes by sequence-specific oligonucleotide probe hybridization (SSOPH). HLA-DR*0406 was significantly more frequent in the Recovered Group, compared with the Chronically Infected Group (P,<,0.001) in Han Chinese. There was a significant excess of HLA-B*4001 (P,=,0.045) in the Recovered Group, compared with the Chronically Infected Group in Taiwanese Aborigines. The observation that different HLA phenotypes associated with recovery from HBV infection in different racial groups implies that various HLA molecules could present different HBV epitopes to induce effective immune responses. J. Med. Virol. 72:17,25, 2004. © 2004 Wiley-Liss, Inc. [source] Fulminant hepatitis associated with hepatitis A virus superinfection in patients with chronic hepatitis CJOURNAL OF VIRAL HEPATITIS, Issue 2000S. Vento There have been conflicting reports of the clinical outcome of acute hepatitis A virus (HAV) infection in patients with chronic hepatitis C virus (HCV) infection. A prospective study evaluated 432 patients with chronic hepatitis C (183 with cirrhosis) over a 7-year period. Of the 17 patients with concurrent HAV infection, seven developed fulminant hepatitis and six died. None of these patients had cirrhosis; however, the HLA phenotype (A1; B8:DR3) appeared to be a significant factor in the development of fulminant hepatitis. Patients with this phenotype had high titres of antinuclear antibodies, antismooth muscle antibodies and antiasialoglycoprotein-receptor antibodies, possibly reflecting the induction of autoimmune hepatitis in this group. The high frequency of fulminant hepatitis in patients with HAV/HCV coinfection contrasts with other surveys, although a large Centers for Disease Control and Prevention (CDC) survey demonstrated that HAV infection in patients with pre-existing chronic liver disease (CLD) is associated with increased mortality. It is likely that CLD has some importance as an underlying factor in the development of fulminant hepatitis following HAV infection. Further prospective studies are needed to clarify this issue. [source] Recurrent autoimmune hepatitis after liver transplantation: Diagnostic criteria, risk factors, and outcomeLIVER TRANSPLANTATION, Issue 4 2001Stefan G. Hübscher MD Approximately 20% to 30% of patients undergoing liver transplantation for autoimmune hepatitis (AIH) develop features of recurrent disease. Diagnostic criteria for recurrent AIH are similar to those used in the nontransplanted liver and include, in varying combinations, biochemical, serological, and histological abnormalities and steroid dependency. However, these criteria are more difficult to apply in the liver allograft because of potential interactions between recurrent AIH and other complications of liver transplantation, particularly rejection, and the uncertain effects of long-term immunosuppression. In the absence of other reliable diagnostic markers, a number of studies have used the histological finding of chronic hepatitis as the main or sole criterion for diagnosing recurrent AIH. However, this also lacks diagnostic specificity because there are many other possible causes of chronic hepatitis in the liver allograft. In addition, approximately 20% to 40% of biopsies performed on patients as part of routine annual review have histological features of chronic hepatitis, for which no definite cause can be identified. Risk factors that have been associated with the development of recurrent AIH include suboptimal immunosuppression, HLA phenotype, disease type and severity in the native liver, and duration of follow up. In many cases in which recurrent AIH seems to be related to underimmunosuppression, biochemical and histological features rapidly resolve once adequate immunosuppression is restored. However, in other cases, recurrent AIH behaves more aggressively, with progression to cirrhosis and graft failure. Areas that require further study include developing uniform criteria for the diagnosis of recurrent AIH, identifying risk factors for severe recurrent disease, and determining optimal levels of immunosuppression that minimize the impact of disease recurrence without exposing patients to the risks of overimmunosuppression. [source] Autoantibodies in alcoholic liver diseaseADDICTION BIOLOGY, Issue 2 2000Ian G. McFarlane Despite many decades of research, the reasons why only a relatively small proportion of individuals who consume excessive quantities of alcohol develop clinically significant liver disease remain unknown. The association with features of autoimmune diseases, including hypergammaglobulinaemia, circulating autoantibodies, inheritance of certain immunogenetic (HLA) markers and response to corticosteroid therapy in some patients has led to a persistent impression that altered immune regulation with a relative loss of self-tolerance underlies susceptibility to the development of the more severe forms of alcoholic liver disease (alcoholic hepatitis and/or cirrhosis). However, review of the data from the numerous studies that have been conducted over the past 30 years fails to reveal sufficiently convincing evidence that autoimmunity plays a primary role in alcohol-related liver damage. In particular, most of the wide range of circulating autoantibodies that have been reported in patients are found mainly at low titres, are not confined to those with severe liver injury, and are probably more likely to be a response to the hepatic insult than causally related to liver damage. Additionally, an association with various HLA phenotypes has not been confirmed by meta-analysis. Interpretation is complicated by evidence that alcohol may have direct effects on some components of the immune system but, if there is an immunogenetic basis for alcoholic liver disease, the present evidence suggests that this might be related more to cytokine gene polymorphisms than to a predisposition to autoimmunity per se. [source] Tumour immunology, vaccination and escape strategiesINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 3 2003A. García-Lora Summary Our increasing knowledge of the mechanisms by which tumour cells escape immune effector cells is helping to establish new approaches to therapeutic vaccination against tumour development. One of the escape mechanisms used by tumour cells is the generation of multiple variants with different HLA phenotypes. These MHC class I phenotypic alterations play a key role in the tumour,host scenario, as they are crucial molecules for antigen presentation to T cells and modulation of natural killer (NK) cell activity. This review presents evidence indicating that tumours develop sophisticated MHC phenotypes that allow them to escape immune surveillance. We evaluate the importance of these alterations in terms of the potential development of therapeutic approaches to immune vaccination. [source] HLA phenotypes and outcomes of hepatitis B virus infection in Taiwan,JOURNAL OF MEDICAL VIROLOGY, Issue 1 2004Ya-Fang Wu Abstract The relationship of HLA phenotype and outcome of hepatitis B virus (HBV) infection was studied in two ethnic groups of Taiwan: Han Chinese and Taiwanese Aborigines. In Han Chinese, the study groups consisted of 98 persons who tested both hepatitis B surface antigen (HBsAg) and anti-HBs negative (Uninfected Group), 324 persons who tested HBsAg negative and both anti-HBs and anti-HBc positive (Recovered Group), and 98 patients who tested HBsAg positive for at least 6 months (Chronically Infected Group). In Taiwanese Aborigines, the study groups consisted of 34 persons in Uninfected Group, 229 persons in the Recovered Group, and 138 patients in the Chronically Infected Group. All subjects were tested for HLA (A, B, DRB1) phenotypes by sequence-specific oligonucleotide probe hybridization (SSOPH). HLA-DR*0406 was significantly more frequent in the Recovered Group, compared with the Chronically Infected Group (P,<,0.001) in Han Chinese. There was a significant excess of HLA-B*4001 (P,=,0.045) in the Recovered Group, compared with the Chronically Infected Group in Taiwanese Aborigines. The observation that different HLA phenotypes associated with recovery from HBV infection in different racial groups implies that various HLA molecules could present different HBV epitopes to induce effective immune responses. J. Med. Virol. 72:17,25, 2004. © 2004 Wiley-Liss, Inc. [source] HLA typing in Taiwanese patients with oral submucous fibrosisJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 4 2004Hsin-Ming Chen Background:, A significant association of certain human leukocyte antigens (HLA) and haplotypic pairs with oral submucous fibrosis (OSF) has been reported. However, controversial result of no HLA association with OSF has also been reported. In this study, the phenotype and haplotype frequencies of HLA-A, -B, -C, -DRB1, and -DQB1 in 135 Taiwanese OSF patients were calculated and compared with those in 540 healthy control Taiwanese. Methods:, The analysis of HLA-A, -B, and -C antigens, and of HLA-DRB1 and -DQB1 alleles in OSF patients and healthy control subjects, was performed by serologic typing and DNA typing using polymerase chain reaction with sequence-specific primers (PCR-SSP), respectively. Results:, We found that the phenotype frequency of HLA-B76 (3.0%) in OSF patients was significantly greater than that (0%) in healthy control subjects (corrected P (Pc) = 0.000). In addition, the haplotype frequencies of HLA-B48/Cw7 (3.0%), -B51/Cw7 (6.7%), and -B62/Cw7 (8.2%) in OSF patients were significantly greater than the corresponding haplotype frequencies (0, 0.7, and 1.9%, respectively) in healthy control subjects (Pc = 0.000). The relative risk (RR) values of haplotypes B51/Cw7 (9.57) and B62/Cw7 (4.7) were greater than the RR values of phenotypes B51 (1.81), B62 (2.31), and Cw7 (1.91) in OSF patients. In addition, the etiologic fraction (EF) value of haplotype B51/Cw7 (0.63) was higher than the EF values of phenotypes B51 (0.2) and Cw7 (0.59). Conclusions:, We conclude that some Taiwanese areca quid (AQ) chewers with particular HLA phenotypes and haplotypes are prone to have OSF. In addition, some particular HLA haplotypes may play more important roles than the individual HLA phenotypes for the genetic susceptibility to OSF. However, the significantly increased HLA phenotype B76 and three of the common HLA haplotypes detected are present in only about 20% of incident cases of OSF. [source] | |||||||||||||