Hepatic calcification following dengue virus-induced fulminant hepatic failure.

Hepatic calcification can be seen with various infectious and neoplastic conditions. We report a 32-year- old man who developed massive calcification in the right lobe of liver following recovery from dengue virus-associated fulminant liver failure.

Identification of a new HLA-A null allele, A*2436 N.

We describe a new HLA-A null allele in a donor. This null allele resulted from the deletion of two nucleotides in exon 2, which effects a frameshift as well as a premature stop codon. This new null allele has been officially named HLA-A*2436 N.

Identification of a new HLA-B null allele, B*1817 N, in a family.

We describe a new HLA-B null allele found in a daughter and her mother. This null allele was due to a mutation at position 41 of exon 1 which resulted in a premature stop codon. This new null allele was officially named HLA-B*1817N*.

Microsatellite polymorphism of the MICA gene and susceptibility to rheumatoid arthritis.

We examined the role of MICA gene alleles in susceptibility to rheumatoid arthritis (RA). Ninety adult Caucasian patients with classical seropositive RA and 85 normal healthy Caucasian subjects from the same geographical area were typed for microsatellite repeat polymorphism in the transmembrane region of the MICA gene by the polymerase chain reaction. The results show that the MICA allele 6 may confer protection from the development of RA.

Prospective study of microchimerism in renal allograft recipients: association between HLA-DR matching, microchimerism and acute rejection.

The presence of donor-derived hematopoietic cells in blood and various tissues of the organ recipients, termed allogeneic microchimerism, has been considered to play an essential role in establishment of organ acceptance. In this study, we prospectively determined the presence of peripheral blood microchimerism (PBM) in 20 male-to-female renal allograft recipients up to 30 months post-transplantation. Recipients were categorized according to the pattern of microchimerism into microchimeric and nonmicrochimeric groups, and then state of human leukocyte antigens (HLA) Class II (DR/DQ) matching, episodes of acute rejection, age at transplantation, renal function, and history of blood transfusion were compared. DNA was extracted from donor, pre-transplant, and post-transplant (1 wk; 1, 3, 6, 12, 18, 24, and 30 months) peripheral blood samples. We analyzed PBM using nested polymerase chain reaction (PCR) amplification specific for the SRY region of the Y chromosome with a sensitivity up to 1:1 000 000. Microchimerism was detected in 13 (65%) of 20 recipients at various intervals. The highest frequency of microchimerism was at 1 wk (55%). Among microchimeric recipients, none were positive on all post-transplant analyses. Interestingly, nonmicrochimeric cases were negative throughout the study. The three recipients with an episode of acute rejection during the first week after transplantation were all in the nonmicrochimeric group with completely mismatched HLA-DR antigens. HLA-DR incompatibility was significantly lower (t-test, p<0.05) in microchimeric cases (1.0+/-0.58) than in nonmicrochimeric ones (1.9+/-0.38). But regarding HLA-DQ and other clinical parameters mentioned above, significant difference was not observed. We propose that there is an association between HLA-DR matching, microchimerism and acute graft rejection in our recipients. Our study demonstrates that, with routine immunosuppressive protocols, higher compatibility of HLA-DR antigens facilitates microchimerism induction. Then, development of new stronger immunosuppressive protocols (including conditioning) or augmentation of chimeric state (by donor-specific bone marrow infusion), especially in completely mismatched HLA-DR renal allograft recipients, may be useful for graft acceptance.

Polymorphism in the Y box controls level of cytokine-mediated expression of HLA-DRB1 genes.

The HLA class II molecules play an important role in immune response. The quality of immune response is dependent not only on the polymorphisms in the class II molecules, but also on the level of their cell-surface expression. In fact, it has been demonstrated that differences in the level of expression of DRB1 and DRB3 genes restricted and activated distinct CD4+ T lymphocytes. We and others have previously described allelic polymorphisms in the upstream regulatory regions of DRB genes, which affected DNA-protein interactions and resulted in significantly different promoter strengths. We showed that polymorphisms in both the X1 and Y box motifs affect level of constitutive expression of DRB1 genes in the DR1, DR51 and DR53 haplotype groups. In the present study, we examined the effect polymorphisms in the X1 box and the Y box on the cytokine (interferon-gamma (IFNgamma), tumor necrosis factor-alpha (TNFalpha) and granulocyte macrophage-colony-stimulating factor (GM-CSF))-mediated transcriptional activities of DRB1 promoters in these, i.e. DR1, DR51 and DR53, haplotype groups. The results demonstrate that the polymorphism in the X1 box does not affect cytokine-mediated strength of DRB1 gene promoters. In contrast, the polymorphism in the Y box, which affects the inverted CCAAT sequence, plays a dominant role on the cytokine-mediated transcriptional activity of DRB1 promoters.

HFE gene mutations in patients with rheumatoid arthritis.

OBJECTIVE: To investigate the role of C282Y and H63D mutations in HFE gene in susceptibility to rheumatoid arthritis (RA). METHODS: The distribution of C282Y and H63D mutations in patients with RA and in healthy subjects was examined by restriction endonuclease digestion of polymerase chain reaction amplified genomic DNA. RESULTS: The prevalence of C282Y mutation in patients with RA was the same as in healthy controls. In contrast, the distribution of H63D mutation was significantly higher in the total RA patient population and in DRB1 QKRAA/QRRAA epitope positive patients compared to respective groups of controls. Analysis of data showed that (1) both H63D mutation and QKRAA/QRRAA DRB1 epitope are individually associated with RA susceptibility; (2) there is interaction between these 2 factors in development of RA; and (3) both these factors combined have stronger association with RA susceptibility than with these factors individually. CONCLUSION: H63D mutation appears to play a role in pathogenesis of RA. This study is small and must be regarded as preliminary. These data therefore need confirmation from independent studies.

HLA class III region and susceptibility to rheumatoid arthritis.

OBJECTIVE: We examined the contribution of the HLA class III region in susceptibility to rheumatoid arthritis (RA). METHODS: Patients with RA, healthy subjects and homozygous typing cell (HTC) lines were typed for HLA class I (A, B, C), class II (DR, DQ) and class III (D6S273, Bat 2, and TNFa microsatellites, and HSP70 promoter region) alleles by molecular techniques. RESULTS: Based on the distribution of microsatellites D6S273, Bat2 and TNFa, and HSP70 promoter region alleles in HTCs and homozygous unrelated individuals, a class III region haplotype, D6S273 138-HSP70c-Bat2 138-TNFa2 was identified. This haplotype showed a significant primary association with susceptibility to RA in DRB 1 QKRAA/QRRAA epitope-negative patients. CONCLUSION: Since the QKRAA/QRRAA epitope does not provide any risk for disease susceptibility in RA-susceptibility DRB1 epitope-negative patients, the present data suggest that the class III region haplotype D6S273 138-HSP70c-Bat2 138-TNFa2 provides an additional risk for the development of RA. These results show that two regions in MHC, class II (DRB1) and class III (D6S273 138-HSP70c-Bat 2 138-TNFa2), contribute to susceptibility to RA and more completely define the risk for development of the disease.

NRAMP1 gene polymorphisms in patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease associated with HLA-DR genes that share amino acid sequence motif QKRAA/QRRAA from position 70 to 74 in the third hypervariable region of DR1 molecule. The contribution of HLA in RA is however about 37%, suggesting a role for other genes. One such candidate is the gene that encodes natural resistance-associated macrophage protein (NRAMP1), which plays a crucial role in inflammation and tissue destruction. In the present study, we examined the role of NRAMP1 gene polymorphisms in susceptibility to RA. The results show that variation at position 543 in exon 15, which involves substitution of negatively charged aspartic acid (D) by uncharged asparagine (N), and the deletion of TGTG in the 3' UTR may confer protection from development of RA.

Polymorphism in heat-shock protein 70-1 (HSP70-1) gene promoter region and susceptibility to tuberculoid leprosy and pulmonary tuberculosis in Asian Indians.

Heat shock proteins (HSP) act as immunological target structures either by themselves because of an unusual expression pattern, or they are carrier proteins for immunogenic peptides. A three-allele polymorphism of HSP70-1 promoter region was analysed in random patients with pulmonary tuberculosis (PTB), or with tuberculoid (TT) leprosy and healthy controls from North India. HSP70-1A and HSP70-1C occurred more frequently (> 60%) while HSP70-1B occurred infrequently in this population. Only HSP70-1A allele was significantly increased in TT leprosy as compared to healthy controls (91.8% Vs 71.1%, Pc < 0.03, RR = 4.58). Although a strong association of HLA-DR15 was observed with both of these patient groups in earlier studies, no correlation was found between HSP70-1 promoter alleles with any of the HLA allotypes. Amongst six possible genotype combinations of HSP70-1 promoter allele, only four (A/A, A/B, A/C, C/C) were encountered in Asian Indians. A significant increase of HSP70-1 A/C genotype was observed among DR15 negative PTB patients as compared to DR15 negative controls (87.5% Vs 35.7%, X2 = 8.6, Pc < 0.02) giving highest relative risk of 12.6. These findings suggest that HSP70-1 genes may play a secondary role to HLA-DR in governing susceptibility to mycobacterial infectious diseases.

Genetic basis for rheumatoid arthritis.

Rheumatoid arthritis (RA) is a common disabling disorder of unknown etiology. In the past 2 decades, a number of studies have examined the genetic basis for RA. One major focus of these studies has been to identify genes within the MHC class II (HLA-DR) chromosomal region, which confer susceptibility/resistance to RA. A strong association between HLA-DR4 and adult seropositive RA has been observed in majority of populations. In addition, there is evidence of a positive association between HLA-DR1 and RA. On the basis of prevalence of DR1 (B1*0101) and of subtypes of DR4 (B1*0401, B1*0404 and B1*0405), it has been suggested that a five amino acid sequence motif (QKRAA/QRRAA) from position 70 to 74 in the third hypervariable region of DRbeta1 molecules is associated with susceptibility to RA. These associations between RA and HLA-DR genes are however incomplete in that about 1/4 of patients do not carry RA-susceptibility DRB1 epitope. Since MHC class III region contains genes that are involved in immune response, we have recently examined the role of a number of microsatellites (D6S273, Bat2, TNFa) and HSP70 promoter region alleles in susceptibility to RA. The results demonstrate that two regions in MHC, class II (DRbeta1) and class III (D6S273, HSP70, Bat2, TNFa) more completely define the risk for development of RA.

Genetics of rheumatoid arthritis (RA): two separate regions in the major histocompatibility complex contribute to susceptibility to RA.

We analyzed HLA-DR antigens and microsatellite Bat2 alleles in 97 adult caucasian patients with classical seropositive rheumatoid arthritis (RA) and 95 normal healthy controls. The results demonstrate that the prevalence of microsatellite Bat2 138 allele was significantly higher in RA-susceptibility DRB1 QKRAA/QRRAA epitope-negative patients as compared with normal controls. Analysis of the data suggested that Bat2 138 allele has primary association with RA-susceptibility in QKRAA/QRRAA epitope-negative patients. The Bat2 138 allele thus provides an additional risk in RA-susceptibility. In addition, microsatellite Bat2 138 allele showed a highly significant positive association with microsatellite D6S273 138 allele, which has similar (identical) association with RA development in DRB1 QKRAA/QRRAA epitope-negative patients. The present data demonstrate that DRB1 QKRAA/QRRAA epitope and microsatellite Bat2 138/D6S273 138 alleles more completely define the risk for development of RA. The results in the present study therefore suggest that two regions in MHC, class II (DRB1) and class III (Bat2 and D6S273 in HSP70-Bat2 region), contribute to susceptibility to RA.

D6S273 microsatellite polymorphism and susceptibility to rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic articular inflammatory disease associated with HLA-DR genes that share a five amino acid sequence motif, QKRAA or QRRAA, from position 70 to 74 in the third hypervariable region of the DRB1 molecule. Since these associations between DRB1 genes and susceptibility to RA are incomplete, we examined the role of a CA repeat polymorphic microsatellite marker, D6S273, located between HSP70 and Bat2 genes in the class III region of MHC, in susceptibility to RA. Ninety-seven adult patients with seropositive RA and 100 normal healthy subjects were studied. Two D6S273 alleles (132 and 138) showed significant differences in their prevalence in RA patients as compared to normal controls; allele 132 was significantly higher in total patients and in DRB1 QKRAA/QRRAA epitope-positive patients, and allele 138 was significantly higher in QKRAA/QRRAA-negative patients. Analysis of data suggested that the association of D6S273 132 allele with RA was secondary to that of DRB1 genes. On the other hand, D6S273 138 allele showed primary association with RA susceptibility in QKRAA/QRRAA epitope-negative patients. The D6S273 138 allele thus provides an additional risk in RA susceptibility. The results in the present study therefore suggest that two regions in MHC, DRB1 and D6S273, contribute to susceptibility to RA.

DQCAR microsatellite polymorphism and susceptibility to rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease associated with HLA-DR genes that share a five amino acid sequence motif, QKRAA or QRRAA, from position 70 to 74 in the third hypervariable region of the DRbeta1 molecule. Since the associations between DRB1 genes and susceptibility to RA are incomplete, in this study we examined the CA repeat polymorphic marker DQCAR, located between DQA1 and DQB1 genes, alleles in 98 adult patients with seropositive RA and 100 normal healthy controls. The prevalence of the DQCAR 117 allele was significantly higher in RA patients as compared to normal controls. On the other hand, the frequency of DQCAR 99 was lower in patients than in normal subjects. Analysis of the data suggested that DRB1 genes sharing the QKRAA/QRRAA epitope have the primary association with disease susceptibility and DQCAR alleles do not provide an additional risk for the development of RA.

HLA-DM polymorphisms in patients with rheumatoid arthritis.

OBJECTIVE: To investigate the contribution of HLA-DMA and DMB genes, which play a crucial role in the HLA class II restricted antigen presentation pathway, in susceptibility to rheumatoid arthritis (RA). METHODS: The distribution of DMA and DMB alleles was examined in patients with RA and in healthy subjects by oligotyping of PCR amplified genomic DNA with sequence specific oligonucleotide probes. RESULTS: There were no significant differences in the prevalence of DMA and DMB alleles in patients with RA as compared to healthy controls. In addition, no significant differences in frequencies of DMA and DMB alleles were observed in RA susceptibility epitope positive RA patients and controls. CONCLUSION: DMA and DMB genes do not appear to play a role in susceptibility to RA.