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J Mytilineos

Publications and source records attributed to J Mytilineos.

At least 19 recordsLinked to original sources
PubMed1997

Clinical relevance of HLA-DPB locus matching for cadaver kidney retransplants: a report of the Collaborative Transplant Study.

BACKGROUND: Matching for the HLA class I loci A and B and for the HLA class II locus DRB is known to influence the survival rate of kidney transplants. It is unknown whether matching for the HLA class II locus DPB also exerts an influence on graft outcome. METHODS: The influence of matching for the HLA-DPB locus was analyzed based on DNA typing results obtained in more than 3600 first and 1300 repeat cadaver kidney transplants. RESULTS: HLA-DPB mismatches had no deleterious influence on the outcome of first cadaver transplants. However, the influence was statistically significant for retransplants. One-year graft survival rates were 83+/-2% with no mismatch (n=345), as compared with 76+/-2% with one mismatch (n=702, P=0.02), and 73+/-3% with two mismatches (n=258, P=0.003). The deleterious influence of HLA-DPB mismatches was particularly strong in retransplant recipients with >50% reactivity of preformed lymphocytotoxic antibodies, for which the 1-year graft survival rate was 70+/-4% with no mismatch, as compared with 69+/-3% with one mismatch (P=0.05) and 61+/-5% with two mismatches (P=0.003). CONCLUSIONS: These results indicate that HLA-DPB is a clinically relevant histocompatibility locus in cadaver kidney retransplantation. It is proposed that prospective typing and matching for HLA-DPB should be implemented for cadaver kidney retransplants.

Cadaver↗
PubMed1997

Analysis of HLA-DR split-specificity matching in cadaver kidney transplantation: a report of the Collaborative Transplant Study.

The influence of mismatches for HLA-DR "split" specificities was investigated in more than 8000 cadaver kidney transplants. HLA-DR typing was performed using DNA methodology. Among first transplants, mismatches defined by HLA-DR split specificities did not have a deleterious influence. Among retransplants, however, graft survival was significantly decreased if a mismatch was defined, considering split specificities in patients with no mismatch according to the "broad" definition (P=0.04) and also in grafts with two split mismatches, which showed only one mismatch according to the broad definition (P=0.03). Moreover, consideration of further "subsplit" specificities resulted in clinically relevant mismatches only among retransplants. These data indicate that the recognition of HLA-DR split specificity mismatches is fundamentally different in primary and regraft recipients. The results imply that recipients and donors of kidney retransplants should be typed for HLA-DR split specificities and that these specificities should be considered for organ allocation.

Alleles↗
PubMed1997

HLA-DR7 predicts the response to alkylating agents in steroid-sensitive nephrotic syndrome.

There is a lack of reliable predictors of the response to alkylating agents in children with idiopathic nephrotic syndrome (NS). HLA-DR7 is strongly associated with the frequency of relapses in steroid-sensitive NS before cytostatic therapy. We therefore examined retrospectively the time to the first relapse and the incidence of subsequent relapses in 54 HLA-typed children with frequently relapsing NS, after treatment with cyclophosphamide (n = 49) or chlorambucil (n = 5) for 8 or 12 weeks; 38 patients were HLA-DR7 positive and 16 negative with 80% in both groups being steroid dependent. HLA typing was performed using serological or DNA typing methods. Renal biopsy showed minimal glomerular changes. A lower proportion of HLA-DR7 positive than negative patients remained in remission after 3 years (36% vs. 81%, P < 0.02) and 5 years (36% vs. 72%, P < 0.03). In the first 3 years after cytostatic therapy the mean number of prednisone-treated relapses was 1.3/patient per year in HLA-DR7-positive patients compared with 0.4 in negative patients (P < 0.025). There was no statistically significant difference in the proportion of relapse-free patients with and without steroid dependency. The HLA status predicts the response of NS patients to alkylating agents better than the rate of previous relapses.

Adolescent↗
PubMed1997

Oligotyping for HLA-DQA, -DQB, and -DPB in idiopathic nephrotic syndrome.

Associations of human leukocyte antigens (HLA) with the idiopathic nephrotic syndrome (NS) have mainly been described for alleles of the HLA-DR locus. In the present study the polymorphism of HLA-DQ and -DP at the molecular level was investigated in 167 children with NS (129 steroid-sensitive) using the polymerase chain reaction and sequence-specific oligonucleotides in a French and a German cohort. HLA-DR typing was also performed by classical serology. In steroid-sensitive patients we observed an increased frequency of the alleles HLA-DQA1*0201 and -DQB1*0201 in both populations with relative risks ranging from 3.8 to 8.5 (Pb < 0.01 to Pb < 0.00001 after Bonferoni's correction). In contrast, the frequency of HLA-DQA1*0102 and DQB1*0602 was significantly decreased. In children with frequent relapses the HLA associations were generally more pronounced than in those with infrequent or no relapses. Applying logistic regression analysis, a nephrotic child bearing DQA1*0201 or DR7 was five times more likely to be in the steroid-sensitive group of patients than in the steroid-resistant group compared with nephrotic children not bearing one of these alleles. These HLA alleles therefore seem to be useful indicators of a steroid-sensitive frequently relapsing course of NS. No associations with DPB alleles were observed, which narrows the region genetically involved in the disease susceptibility to the DR-DQ region. Steroid-resistant NS was not associated with HLA.

Adolescent↗
PubMed1996

Endogenous retroviral long terminal repeats of the HLA-DQ region are associated with susceptibility to insulin-dependent diabetes mellitus.

HLA-DQ genes are the main inherited factors predisposing to IDDM. This gene region harbors long terminal repeat (DQ LTR) elements of the human endogenous retrovirus HER V-K, which we analyzed for a possible association with disease. We first investigated whether LTR segregate with DQ alleles in families. Members (n = 110) of 29 families with at least one diabetic child, unrelated patients with IDDM (n = 159), and healthy controls (n = 173) were analyzed. Genomic DNA was amplified for DQ LTR3 by a nested primer approach as well as for DQA1 and DQB1 second exons, to assign DQA1 and DQB1 alleles. DQ LTR segregated in 24 families along with DQ alleles. Of the 29 families, 20 index patients were positive for DQ LTR. The DQ LTR was in all patients on the haplotype carrying the DQA1 *0301 and DQB1 *0302 alleles. A majority of patients had DQ LTR (62%) compared with controls (38%) (p < 1.3 x 10(-5)), even after matching for the high-risk alleles DQA1 *0501, DQB1 *0201-DQA1 *0301, and DQB1 *0302 (79% of patients and 48% of controls; p < 0.02). Subtyping for DRB1 *04 alleles in all DQB1 *0302+ individuals showed 56% DRB1 *0401, DQB1 *0302 [LTR' patients vs. 29% controls with the same haplotype (p < 0.002)]. In conclusion, these data demonstrate the segregation of DQ LTR with DQA1, DQB1 alleles on HLA haplotypes. Furthermore their presence on DRB1 *0401-, DQA1 *0301-, and DQB1 *0302-positive haplotypes suggest that they contribute to DQ-related susceptibility for IDDM.

Diabetes Mellitus, Type 1↗
PubMed1995

Clinical implications from studies of HLA antigens in idiopathic nephrotic syndrome in children.

HLA class I and II antigen frequencies were determined in two large cohorts of children with idiopathic nephrotic syndrome (NS) from Southwest France (n = 199) and Southwest Germany (n = 152) and compared with unrelated healthy individuals from the same geographical areas. Strength of HLA association was expressed by the relative risk (RR) estimated by Odd's ratio. We examined 105 steroid-resistant and 242 steroid-sensitive NS patients who were subdivided in non-relapsers, infrequent relapsers and frequent relapsers or steroid-dependent patients. In steroid-sensitive patients significant associations were found with HLA-DR7 (RR 5.1 in French, 3.2 in Germans), -DQ2 (RR 4.7/2.3) and with the phenotypic combination HLA-DR3/DR7 (RR 5.6/7.7). Significant negative associations were encountered with HLA-DR2, -DR6 and -DQ1. The associations were stronger in frequent relapsers/steroid-dependent patients than in infrequent relapsers and were not significant in non-relapsers. In steroid-resistant patients the only significant association found was with the combined occurrence of HLA-DR3/DR7. We propose that in childhood NS tissue typing for selected HLA class II antigens is helpful in prediciting the clinical course.

Adolescent↗
PubMed1994

HLA class I alleles and responsiveness of melanoma to immunotherapy with interferon-alpha (IFN-alpha) and interleukin-2 (IL-2).

MHC-restricted recognition of melanoma cells by cytotoxic T lymphocytes is an important mechanism in vitro. Several HLA alleles can function as restriction elements for melanoma cell recognition. In this study we investigated whether there is a correlation between responsiveness of patients with metastatic melanoma (MM) to immunotherapy and the HLA type of the patient. Seventy-two patients received immunotherapy with IFN-alpha and IL-2 according to two different schedules with an overall response rate of 24%. In 54 patients, including 16 responders and 16 patients with stable disease, in whom peripheral blood lymphocytes were available, we determined HLA haplotypes. As a control group we prospectively determined HLA types in 67 melanoma patients of all stages who underwent surgery or received chemotherapy and of 126 healthy donors from our blood bank. Two HLA alleles that have been shown to function as restriction elements in vitro were observed more frequently in responding patients, namely Cw7 (p = 0.014) and A1 (p = 0.19). No association was found for A2 and B44. These observations provide evidence that the responsiveness of MM to immunotherapy with IL-2 is associated with certain HLA types, suggesting an important role of HLA-restricted T lymphocytes for IL-2-induced tumour regression.

Alleles↗
PubMed1994

HLA class II associations with idiopathic nephrotic syndrome in children.

The occasional familial occurrence of idiopathic nephrotic syndrome (NS) points to a genetic predisposition. Reports on associations with certain HLA class II antigens support this hypothesis. In order to define the immunogenetic background of NS more precisely, HLA class II allele frequencies in 161 children with NS were studied by restriction fragment length polymorphism (RFLP) typing. The patient cohorts consisted of 87 children from Southwest-France and 74 from Southwest-Germany. The control group consisted of 118 French and 101 German unrelated individuals from the same geographical areas. HLA alleles were defined in patients with steroid-sensitive (SS) and steroid-resistant (SR) NS and in controls. RFLP typing revealed that the previously reported association between SSNS and HLA-DR7 is confined to the RFLP split 7.1 (DRB1*07) with a combined relative risk (RRcomb) of 6.2. HLA-DQB typing showed an increased frequency of the allele DQB2b (DQB1*0201) (RRcomb = 7.8). HLA-DQA typing showed an association of SSNS with DQA3 (DQA1*0201,0301,0302) (RRcomb = 4.1). The highest RR (16.5) for SSNS was found in German patients who carried the two DRB1 specificities 17.1 (DRB1*0301) and 7.1 (DRB1*07). All associations were stronger in SS patients with frequent relapses or steroid dependency than in non- or infrequent relapsers. SR patients exhibited no significant associations with HLA class II alleles.

Alleles↗
PubMed1994

[Effect of HLA compatibility on kidney transplantation].

The influence of the HLA system on the success rate of kidney transplantations was evaluated in a worldwide collaborative study. The results confirm the influence of the HLA chromosome on transplants from related donors. Moreover, a highly significant effect of compatibility for the HLA-A, -B, -DR antigens was observed in cadaver transplants (p < 0.0001). The great importance of a good quality of tissue typing was emphasized by a) the observation that a significant influence of compatibility for the HLA-A, -B antigens was evident only if donors and recipients were typed for 'split' specificities and not when they were typed for 'broad' antigens, and b) an improved effect of HLA-DR compatibility when serological typing errors were corrected by molecular (DNA) typing. Computations show that kidney allocation according to the best possible HLA compatibility results in a gain of 800 transplant function years per 1,000 transplantations over a 10-year period.

Cadaver↗
PubMed1993

DNA HLA-DR typing results of 4000 kidney transplants.

Recipients (4076) and donors (3325) of kidney transplants performed at 110 transplant centers were typed for HLA-DRB by the DNA RFLP method. The discrepancy rate of replicate samples distributed among 8 participating laboratories was a low 2.6%. The discrepancy rate between RFLP-DRB and serological HLA-DR typings was 25.0% for organ donors and 27.6% for kidney recipients. Discrepancy rates at the different transplant centers ranged from 9.7% to 86.7%. The discrepancies consisted of antigens being incorrectly interpreted by serology (16.8%), and of serological "blanks" turning out to be definable alleles by the DNA method (10.8%). The alleles that were mainly affected by discrepancies were DR1, DR8, DR10, DR12, DR13, DR14, DR16, DR17.2, and DR18.

Alleles↗
PubMed1993

Analysis of HLA-DR matching in DNA-typed cadaver kidney transplants.

The effect of matching for HLA-DR antigens was analyzed retrospectively in 3455 cadaver kidney transplants that were typed by the DNA-RFLP method. HLA-DR matching improved the one-year graft survival rate significantly (P < 0.01). Importantly, in 718 first transplants in which the number of mismatches assigned by serological typing was different from that assigned by DNA typing, only the DNA results showed a significant impact of matching on graft outcome (P = 0.03). These results demonstrate that DNA typing is clinically relevant. We were unable to confirm that the HLA-DR6 specificity or the DR6-split DRB1*1302 are associated with poor graft survival.

Cadaver↗