HLA associations, microsatellite instability and epigenetic changes in thyroid lymphoma in Chinese.

In Chinese, autoimmune thyroid disease (AITD) is very common but lymphoma of the thyroid is a rare disease. Southern Chinese AITD is common in females and is strongly linked to the HLA haplotype A2B46DR9. We studied the HLA association, aberration p15, p16 and p73 promoter methylation and microsatellite instability in Chinese primary thyroid lymphoma patients to elucidate their relationship with AITD and the relationship between thyroid diffuse large cell lymphoma (DLCL) and marginal zone lymphomas (MZL). Despite a female preponderance (8:1) and the finding of cases with histological and immunological evidence of AITD, a significant HLA association was not found. MSI was absent, but aberrant promoter methylation was found in both thyroid MZL and DLCL and p73 methylation was unexpectedly common.

Strong association of HLA-DR3/DRw9 heterozygosity with early-onset insulin-dependent diabetes mellitus in Chinese.

Studies of Caucasian and Japanese patients with insulin-dependent diabetes mellitus (IDDM) have shown that heterozygosity for certain HLA-DR antigens confers a high risk of developing the disease. The HLA antigens of 75 Chinese patients and 100 Chinese controls in Hong Kong were studied to investigate the role of HLA-DR heterozygosity in Chinese individuals. Some of the patients and controls were also tested for allotypic variation in the complement components C2, C4, and BF. Three alleles, Aw33, B17, and DR3, had increased frequencies in patients compared with controls and frequently occurred together in the same phenotype, which suggested their existence as a haplotype. There were no statistically significant differences in complement allotype frequencies between patients and controls, although the C4B null allele seemed to be associated with Aw33, B17, and DR3. No other HLA-DR antigen appeared to be associated with IDDM. However, when the patients were separated on the basis of age at onset, the frequency of DR3/DRw9 heterozygosity was markedly increased in patients presenting in the first decade of life, but there was no increase in patients presenting at greater than 20 yr of age. DRw9 is strongly associated with autoimmune disease in Chinese, whereas DR3 is not. We suggest that the major IDDM susceptibility locus in Chinese is associated with HLA-DR3 and that patients with HLA-DR3 and HLA-DRw9 have an added predisposition to autoimmune disease and therefore develop IDDM earlier than patients without DRw9.

Susceptibility to IDDM in a Chinese population. Role of HLA class II alleles.

MHC associations with IDDM in a Chinese population were studied to investigate genetic susceptibility to the disorder. The frequency of HLA-DR3 was significantly higher in the diabetic patients (19/49 [38.7%] vs. control subjects, 11/105 [10.5%], Pc less than 1.3 x 10(-3), RR = 5.3 [CI 2.3-12.1]), whereas DR4 was not (11/49 [22.4%] vs. 28/105 [26.7%], NS). The frequency of DR3/4 heterozygosity was higher in the diabetic patients (6/49 [12.2%] vs. control subjects, 0/105 [0%], P = 1.7 x 10(-3), RR = 31.5 [CI 3.8-263.6]). The frequency of DR3/9 heterozygosity also was higher in the diabetic patients (6/49 [12.2%] vs. control subjects, 2/105 [1.9%], P = 0.03, RR = 6.2 [CI 3.0-12.7]). No significant associations were noted between DQB1 alleles and IDDM. Among DR4-positive subjects, the frequency of DQB1 allele DQB1*0302 was higher in the diabetic patients (10/11 [90.0%] vs. control subjects, 12/24 [50%], Pc less than 0.05, RR = 7.0 [CI 1.3-38.0]), and the frequency of DQB1*0401 was significantly lower in the diabetic patients (2/11 [18.2%] vs. control subjects, 16/24 [66.7%], Pc = 0.04, RR = 0.1 [CI 0.02-0.46]). No DR4 subtype was associated significantly with IDDM. The frequency of DQA1*0501, a DQA1 allele, was higher in diabetic patients (22/41 [53.7%] vs. control subjects, 20/95 [21.1%], Pc less than 3 x 10(-3), RR = 4.3 [CI 2.0-9.3]). The frequency of DQA1*0301, which has been associated consistently with IDDM in other ethnic groups, was not significantly higher in the diabetic patients in this study (27/41 [65.9%] vs. control subjects, 53/95 [55.8%], NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Autoimmune thyroid dysfunction after hematopoietic stem cell transplantation.

Autoimmune thyroid disease (AITD) may occur in patients after hematopoietic stem cell transplantation (HSCT). In all, 10 cases of AITD (seven allogeneic and three autologous HSCT) were diagnosed among 721 HSCT recipients, including two patients with sequential hyper- and hypothyroidism. The 5-year actuarial rates for AITD after allogeneic and autologous HSCT were 2.9 and 4%, respectively. Significant risk factors included HSCT for chronic myeloid leukemia, the HLA B46 and DR9 loci and the A2B46DR9 haplotype, while female donors showed trend to significance. On multivariate analysis, only female donors and HLA DR9 remained significant. For autologous HSCT, the associations with HLA B46 and DR9 were also significant. Only three donors had a family history of AITD. A review of other reported cases confirmed the predominance of female donors, although the other associations including graft-versus-host disease, familial AITD and other autoimmune phenomena might be related to reporting bias. Since the actuarial incidence of AITD from female donors with predisposing HLA alleles may be over 30%, susceptible recipients should be carefully monitored. Owing to the small number of reported cases and different HLA associations with AITD in different populations, our observations await confirmatory data from other registries.

Metabolic and immunologic features of Chinese patients with atypical diabetes mellitus.

OBJECTIVE: To determine whether atypical diabetes mellitus (ADM) is present in the Chinese population in Hong Kong. RESEARCH DESIGN AND METHODS: The records of Chinese patients who attended the Diabetes Clinic at Queen Mary Hospital were reviewed. We identified 11 patients who initially presented with acute diabetic ketoacidosis but subsequently displayed clinical features more typical of type 2 diabetes. Metabolic studies and HLA typing were performed to characterize this group of Chinese patients with ADM. RESULTS: C-peptide response of the patients with ADM 1 h after a standard meal was intermediate between that of type 1 diabetic patients (matched for age and duration of diabetes) and that of nondiabetic control subjects (matched for age and BMI) (analysis of variance, P = 0.02). Insulin sensitivity measured by a short insulin tolerance test was not significantly different between patients with ADM and their matched nondiabetic control subjects. HLA typing showed that none of the patients with ADM had the DR3 allele and that the frequency of DR9 was not increased. Only one patient had significantly increased levels of antibodies to GAD and islet cell antigen 512. CONCLUSIONS: ADM, which was first described in African-Americans, is seen also in Chinese subjects. These patients have significant residual C-peptide secretory capacity and should not be misdiagnosed and treated as patients with type 1 diabetes with life-long insulin therapy.

Evans' syndrome complicating chronic graft versus host disease after cadaveric liver transplantation.

Acute graft versus host disease (GVHD) occurred in a patient after cadaveric liver transplantation from an HLA disparate donor. Immunosuppression resulted in a remission, but chronic GVHD with a scleroderma-like syndrome ensued. This was further complicated by immune hemolytic anemia and thrombocytopenia (Evan's syndrome). Semi-quantitative microsatellite analysis of circulating lymphoid cells showed that T cells were predominantly of donor origin, thereby explaining the chronic GVHD. The marrow hematopoietic cells remained recipient, so that the immune cytopenias were expected to be alloimmune in nature. However, the red cell antibodies were shown to have anti-C and anti-e specificity, with both the donor (R1R1) and recipient (R1r) possessing the C and e antigens. Therefore, the immune hemolysis might be considered both alloimmune and autoimmune. The patient finally died of sepsis. This case illustrates that chronic GVHD due to stable donor T cell engraftment may rarely occur in liver transplantation despite HLA disparity. Immunosuppression may result in dysregulation of T cell functions, leading to alloimmune and autoimmune problems.

HLA class I and class II frequencies of a Hong Kong Chinese population based on bone marrow donor registry data.

HLA-A, and -B antigen, gene and haplotype frequencies have been calculated from 18,774 southern Chinese donors on a Hong Kong-based bone marrow donor registry. Two hundred and fifty donors were also tested for HLA-DRB1, -DQA1, and -DQB1 alleles using the PCR-SSP technique. Forty-one HLA-A, -B combinations showed statistically significant positive linkage disequilibrium at the 0.05 level after adjustment for the number of haplotypes theoretically possible and 43 showed significant negative disequilibrium. Thirty-nine different DRB1-DQA1-DQB1 haplotypes were identified of which 20 occurred 5 or more times. The most prevalent was DRB1*0901-DQA1*0301-DQB1*0303 (haplotype frequency = 0.1620). This is the first paper to report the distribution of DQA1*0104, DQA1*05011 and DQA1*05012/13 alleles in Chinese. These data are important for phylogenetic, comparative and medico-legal studies and are of particular value in estimating the likelihood of obtaining appropriately matched donors for Chinese patients awaiting bone marrow transplantation.

Analysis of a Chinese population suggests that the TNFB gene is not a susceptibility gene for Graves' disease.

Graves' disease is associated with different HLA genes in different races. The TNFB gene lies between the class I and class II HLA genes and has two alleles, TNFB*1 and TNFB*2. Studies in Caucasians have suggested that the TNFB gene might be a susceptibility gene for Graves' disease. To investigate further the role of TNFB in predisposition to Graves' disease, we determined whether the TNFB disease associations in the Chinese were similar to those in Caucasians. A total of 57 patients with Graves' disease (32 male) were studied. A TNFB gene fragment was amplified from genomic DNA by using the polymerase chain reaction and digested with Nco I to distinguish the TNFB alleles (TNFB*1 and TNFB*2). Genotype frequencies were compared with those in a racially matched group of 92 controls. TNFB*1 homozygosity occurred in 15 (26%) Graves' and 22 (24%) control subjects. TNFB*1/TNFB*2 heterozygosity occurred in 29 (51%) and 48 (52%) and TNFB*2 homozygosity in 13 (23%) and 22 (24%), respectively (NS). There were gender differences in the frequencies of TNFB*1 homozygosity (13 male [41%], 2 female [8%]). TNFB*1/TNFB*2 heterozygosity (13 male [41%], 16 female [64%]) (chi 2 = 7.3, p = 0.02), and TNFB*2 frequency (19 male [59%], 23 female [92%]; pc = 0.04) in Graves' patients. We conclude that the TNFB associations with Graves' disease in the Hong Kong Chinese differ between the genders and from those described in Caucasians. The TNFB gene is not a susceptibility gene for Graves' disease.

Distribution and co-occurrence of MHC class I, II, and III markers in southern Chinese: implications for autoimmune disease.

A study of MHC class I, II, and III markers in a group of southern Chinese in Hong Kong is reported. HLA antigen frequencies and complement allele frequencies are given, together with statistically significant pair-wise co-occurrences. Over half of the statistically significant positive and negative linkage disequilibria relate to two extended haplotypes. These haplotypes, or components of them, are associated with a number of diseases in Chinese, particularly diseases of autoimmune origin. One haplotype, A2, Bw46, DRw9, appears to be an analogue of the haplotype A1, B8, DR3 which predisposes to similar diseases in Caucasians. The question is raised of why susceptibility to the same group of diseases in two different racial groups should be related to the haplotypes having the strongest linkage disequilibria within those racial groups.

Ten years of unrelated bone marrow transplantation in Hong Kong.

The Hong Kong Marrow Match Foundation was established as a charity in 1991 to set up and operate an unrelated bone marrow donor registry for the largely Chinese population of Hong Kong and to assist patients requiring bone marrow transplantation to locate donors in Hong Kong or elsewhere. In the 10 years that followed, the registry has recruited over 42000 predominantly Chinese donors and has provided donors for 150 patients in Hong Kong and overseas requiring transplantation. This report describes the current status of the Foundation.

Incidence of graft-versus-host disease in Hong Kong Chinese and its influence on survival after bone marrow transplantation from HLA-identical siblings.

Graft-versus-host disease (GVHD) is an important complication of allogeneic bone marrow transplantation (BMT). To assess its influence on transplant outcome, we studied 90 Chinese patients with hematologic disorders with BMT from HLA-identical siblings. GVHD prophylaxis consisted of a combination of methotrexate (MTX) and cyclosporine A (CsA). The incidence of grade II-IV acute GVHD was 29% (95% CI 19-38%). The incidence of limited and extensive chronic GVHD was 30% (95% CI 20-40%). For patients transplanted for early hematologic malignancy (n = 40), those with GVHD (acute and/or chronic) had lower relapse rate (17% (95% CI 0-36%) vs. 54% (95% CI 26-82%), P = 0.043). They had higher transplant-related mortality (12% (95% CI 0-28%) vs. 6% (95% CI 0-18%), P = 0.715) and event-free survival (EFS) (73% (95% CI 53-93%) vs. 43% (95% CI 17-69%), P = 0.104) that had not reached statistical significance. For patients transplanted for advanced hematologic malignancy (n = 37), those with GVHD also had lower relapse rate (5% (95% CI 0-15%) vs. 72% (95% CI 50-94%), P = 0.002) and higher transplant-related mortality (50% (95% CI 27-73%) vs. 8% (95% CI 0-24%), P = 0.006) than those without any GVHD. They had higher EFS (47% (95% CI 24-70%) vs. 26% (95% CI 5-47%), P = 0.609) that had not reached statistical significance. Therefore, the incidence of acute and chronic GVHD in Chinese was similar to that of their Caucasian counterparts using MTX and CsA for GVHD prophylaxis.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterisation of immunofluorescent heterophile antibodies which may be confused with autoantibodies.

Approximately 6% of sera submitted for routine immunofluorescent autoantibody screeening produced characteristic reaction patterns against a variety of animal and human tissues. It is suggested that these non-tissue-specific patterns represent a complex family of heterophile antibodies which could be confused with certain autoantibodies. It is further suggested that these heterophile antibodies bear a relationship to IgG isohaemagglutinins.

Post-transplantation lymphoproliferative disease in Chinese: the Queen Mary Hospital experience in Hong Kong.

Post-transplantation lymphoproliferative disease (PTLD) is an unique iatrogenic complication after bone marrow transplantation (BMT) and solid organ transplantation (SOTx). The pattern of EBV related lymphoma in Chinese is different from Caucasians. We surveyed the incidence, clinical and pathological spectrum of PTLD among 541 cases of allogeneic BMT, 145 cases of renal transplant, 35 cases of heart/lung transplantation and 146 cases of orthotopic liver transplantation (OLT). From 1994 to 2001, 13 consecutive cases of PTLD were diagnosed, ranging from disseminated NK cell lymphoma to localized plasmacytoma. Both donor and recipient derived PTLD was documented. Disease was often heralded by cytomegaloviral disease and antithymocyte globulin (ATG) usage. Two cases were diagnosed post-mortem, and six patients died of PTLD at a median of 3 months. Complete and partial remission was only achieved in 3 and 2 cases, respectively, despite a range of treatment (reduced immunosuppression, explantation, radiotherapy, combination chemotherapy, donor lymphocytes, autologous marrow infusion and rituximab). Most responding patients died subsequently of rejection, infection and graft versus host disease (GVHD). The incidence of PTLD is not increased in Chinese patients. However, some patients may be at increased risk, especially mismatched allogeneic BMT, parental OLT (especially involving young infants) and heavy ATG exposure.

The new HLA.

The application of molecular genetics and biochemical techniques to the study of the HLA system over the past few years has resulted in tremendous advances in our knowledge of this area of the human genome. In this article, we describe the "new HLA" that has been pieced together recently through the combined efforts of molecular geneticists, biochemists, and HLA serologists, as well as developments in attempts to elucidate the associations of HLA antigens and disease.

Fourteen-year experience of human leucocyte antigen typing in cases of disputed parentage in Hong Kong.

Seventy-seven cases of disputed parentage were studied using the human leucocyte antigen system over a 14-year period in Hong Kong. Of these, 30 (39.0%) related to the amendment or verification of birth registration details, 20 (26.0%) were for divorce or affiliation proceedings, and 19 (24.7%) were related to overseas resident visa applications. An exclusion of parentage of at least one of the alleged parents was shown in 23 (29.9%) cases; none of the cases related to overseas resident visa applications showed an exclusion. The study illustrates that human leucocyte antigen testing is a very powerful tool in the elucidation of disputed parentage in Hong Kong.