Anti-HLA alloantibodies of the IgA isotype in re-transplant candidates part II: Correlation with graft survival

We reported previously on the widespread occurrence of anti-HLA alloantibodies of the IgA isotype (anti-HLA IgA) in the sera of solid-organ re-transplantation (re-tx) candidates (Arnold et al., ). Specifically focussing on kidney re-tx patients, we now extended our earlier findings by examining the impact of the presence and donor specificity of anti-HLA IgA on graft survival. We observed frequent concurrence of anti-HLA IgA and anti-HLA IgG in 27% of our multicenter collective of 694 kidney re-tx patients. This subgroup displayed significantly reduced graft survival as evidenced by the median time to first dialysis after transplantation (TTD 77 months) compared to patients carrying either anti-HLA IgG or IgA (TTD 102 and 94 months, respectively). In addition, donor specificity of anti-HLA IgA had a significant negative impact on graft survival (TTD 74 months) in our study. Taken together, our data strongly indicate that presence of anti-HLA IgA, in particular in conjunction with anti-HLA-IgG, in sera of kidney re-tx patients is associated with negative transplantation outcome.

HLA typing by next-generation sequencing - getting closer to reality

Next generation sequencing (NGS) denotes novel sequencing technologies that enable the generation of a large number of clonal sequences in a single sequencing run. NGS was initially introduced for whole genome sequencing and for quantitation of viral variants or genetic mutations in tumor tissues; more recently, the potential for high resolution HLA typing and high throughput analyses has been explored. It became clear that the complexity of the HLA system implicates new challenges, especially for bioinformatics. From an economical point of view, NGS is becoming increasingly attractive for HLA typing laboratories currently relying on Sanger based sequencing. Realizing the full potential of NGS will require the development of specifically adapted typing strategies and software algorithms. In the present review, three laboratories that were among the first to perform HLA-typing using different NGS platforms, the Roche 454, the Illumina Miseq and the Ion Torrent system, respectively, give an overview of these applications and point out advantages and limitations.

TNFA promoter alleles--frequencies and linkage with classical HLA genes in a South German Caucasian population

The tumor necrosis factor alpha (TNFA) promoter region exhibits several polymorphisms, which have been hypothesized to influence gene expression, thereby associating positively or negatively with inflammatory conditions. Many studies have focused on single nucleotide polymorphisms (SNPs) taking not into account additive or inverse effects between different SNPs. We typed 1,021 healthy Caucasian volunteer stem cell donors for their TNFA promoter as well as their HLA-A,-C,-B,-DRB1 loci. Using statistical methods, we reconstructed TNFA promoter alleles and analyzed their frequency and linkage with HLA genes. We show that the number of TNFA promoter alleles frequent enough to be analyzed in clinical studies is limited and that a strong linkage with classical HLA genes is present, especially for the extended HLA-haplotype HLA-A*01:01/HLA-C*07:01/HLA-B*08:01/TNFA promoter allele 3/HLA*DRB1*03:01. Taking into account SNP frequency information, it is possible to quite accurately deduce TNFA promoter alleles by generic Sanger sequencing, obviating the need for elaborating allele-specific sequencing. This information may enable investigators to consider the complete TNFA regulatory region in a phase-separated manner in contrast to previous approaches examining only one or few isolated SNPs.

16(th) IHIW: anti-HLA alloantibodies of the of IgA isotype in re-transplant candidates

In this multicentre study, sera from 803 retransplant candidates, including 775 kidney transplant recipients, were analysed with regard to the presence and specificity of anti-HLA alloantibodies of the IgA isotype using a modified microsphere-based platform. Of the kidney recipients, nearly one-third (n = 237, 31%) had IgA alloantibodies. Mostly, these antibodies were found in sera that also harboured IgG alloantibodies that could be found in a total of 572 (74%) of patients. Interestingly, IgA anti-HLA antibodies were preferentially targeting HLA class I antigens in contrast to those of the IgG isotype, which targeted mostly both HLA class I and II antigens. Donor specificity of the IgA alloantibodies could be established for over half of the 237 patients with IgA alloantibodies (n = 124, 52%). A further 58 patients had specificities against HLA-C or HLA-DP, for which no information regarding donor typing was available. In summary, these data showed in a large cohort of retransplant candidates that IgA alloantibodies occur in about one-third of patients, about half of these antibodies being donor specific.

HLA-E polymorphisms in hematopoietic stem cell transplantation

Human leukocyte antigen (HLA)-E is an inhibitory ligand of natural killer cells and γ/δ T-cells. Differential expression of HLA-E alleles on the cell surface has been reported to influence outcome of hematopoietic stem cell transplantation (HSCT). We performed HLA-E genotyping in 116 HSCT patients and their HLA-matched unrelated donors. The impact of HLA-E genotypes on patient's overall survival (OS), disease free survival (DFS), cumulative incidences for relapse, transplant-related mortality (TRM) and acute graft vs host disease (aGvHD) was assessed. Neither univariate nor multivariate analysis showed any influence of HLA-E polymorphisms on the investigated endpoints of HSCT in our cohort. We could not confirm any of the previous observations in our cohort and consider it unlikely that HLA-E polymorphisms affect outcome of HSCT.

One amino acid change located in the conserved region of the alpha 1 domain specifies the novel HLA-C*07:147 allele

The novel HLA-C allele HLA-C*07:147 contains one nucleotide substitution in exon 2 leading to an amino acid change in the alpha 1 domain from phenylalanine to leucine.

HLA-Cw*0740, a new allele mistyped by generic sequencing and identified by allelic separation

Human leukocyte antigen (HLA)-Cw*0740 differs from HLA-Cw*070101 by one nucleotide substitution at codon 73 (GCT>ACT).

Distribution of 22 cytokine gene polymorphisms in the healthy Czech population

Cytokine gene polymorphisms (CGP) have been implicated in the pathogenesis of immune-mediated diseases including transplant complications via their effect on cytokine production and regulation. This study aimed to determine population frequencies of selected cytokine single nucleotide polymorphisms in the healthy Czech population and compare them with the data from other selected European populations. CGP were genotyped by polymerase chain reaction with sequence-specific primers (PCR-SSP) using the Heidelberg kit in 120 unrelated Czech healthy individuals. Chi-squared analysis was used to test for a deviation from Hardy-Weinberg equilibrium. Allelic and genotype frequencies and carriage rates were determined for 22 CGP located within 13 cytokine genes in total. The frequencies observed in this study were similar to those available from the other two geographically close Central European centres, but they differed for several CGP from the data reported in south European populations. The data on the distribution of 22 CGP in the healthy Czech population reported here may be utilized to investigate possible associations of CGP with diseases or transplantation outcome.

A new PCR-SSP typing method for six single-nucleotide polymorphisms impairing the blood-clotting cascade as well as T-cell stimulation

Single-nucleotide polymorphisms (SNPs) within the genes of factor V (FV) (G1691A; exon 10), prothrombin (FII) (G20210A; 3'untranslated - region) and methylenetetrahydrofolate reductase (MTHFR) (C677T; exon 4) are associated with hypercoagulability, and systematic screening of individuals being at higher risk of thrombosis has been suggested. SNPs in the 2q33 region within the genes of CD28 (+17T/C; intron 3) and CTLA4 (-318C/T; promoter and +49A/G; exon 1) are likely to affect T-cell proliferation and antigen presentation signaling, which may lead to altered sensitivity of allograft or self-tissue recognition and affect the incidence of autoimmune diseases. We developed primers that allow specific amplification of these six SNPs at test conditions identical with those used for HLA typing with the CTS PCR-SSP reagents. One hundred ninety-six healthy German Caucasian individuals were tested for the six SNPs. The genotype frequencies for all SNPs were in Hardy-Weinberg equilibrium. There was no significant difference in the distribution of genotypes when compared to other published studies in which these SNPs were tested. The described PCR-SSP method can be used to screen large numbers of patients for these SNPs.

Description and characterization of two new HLA alleles, B*4051 and DRB1*1364, identified by sequence-based typing*

Human leukocyte antigen (HLA)-B and HLA-DRB1 typing in two female individuals revealed reaction patterns that did not correspond to any known HLA-B specificity and appeared to identify a very rare HLA-DRB1 allele, respectively. Sequence-based analysis of these samples revealed two new HLA alleles, one similar to B*4023 and the other to DRB1*1308. The new HLA-B allele, which was assigned the name HLA-B*4051, could have been generated by a double crossing over recombination between B*4001 and B*1401 or 1402, whereas DRB1*1364, the new DRB1 allele, could have been generated either by a double crossing over recombination between DRB1*1308 and DRB1*1201, 1202, or 1203 or by two independent crossing over events between DRB1*1401, DRB1*1201, 1202, or 1203 and DRB1*1301.

Identification of two new HLA alleles: B*3546* and B*5611*. How reliable are the published HLA-B intron 2 sequences?

Polymerase chain reaction-sequence-specific primer (PCR-SSP) typing for human leukocyte antigen (HLA)-B in a male 25-year-old Caucasian individual of Iranian origin and in a 42-year-old German Caucasian bone marrow donor revealed reaction patterns that did not agree with any known HLA specificity, thus suggesting in both cases the existence of a novel allele. Sequence-based typing (SBT) after allelic separation revealed the sequences of the new alleles HLA-B*5611 and B*3546. The sequence patterns of both new alleles might have been generated as the results of double crossing over, possibly over several generations. During the analysis of the HLA-B*3546 intron 2 sequence for possible crossing over points, a base insert, an additional G after position 700, was found. This insert was analyzed using SBT and PCR-SSP and was found to be present not only in all samples carrying B*35, but also in all HLA-B specificities tested. It appears that all known HLA-B alleles may contain a G insert at position 700 of intron 2, and that the published intron 2 sequence alignments of the HLA-B locus may contain errors at this position.

Characterization of a new HLA-A allele, A*0256, identified in a Caucasian individual

HLA-A typing by the PCR-SSP method in a male 21-year-old Caucasian individual revealed a very rare allele combination corresponding to a unique reaction pattern. Therefore, the result was examined using sequence-based typing. Sequencing of exons 2 and 3 of the HLA-A locus after allelic separation with specific primers revealed the sequence of a new allele, similar to A*0245. Sequencing of exons 1 and 4 resulted in no additional inconclusive positions. The sequence pattern of the new allele HLA-A*0256 might have been generated as a result of a double crossing over recombination of an A*0201 and either an A*03 or an A*11.

Human leukocyte antigens and prognosis in patients with head and neck cancer: results of a prospective follow-up study

BACKGROUND

Prognostic information is essential for optimal treatment of patients with head and neck cancer. We studied the relationship of class I and class II human leukocyte antigens (HLA) on prognosis in patients with head and neck cancer.

METHODS

HLA-A, -B, -C and -DR antigens were determined in 209 patients with squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx. The patients were subjected to follow-up investigations for a period of 5 years.

RESULTS

Five-year survival rates in relation to tumor stage varied between 86% for stage I tumors and 28% for stage IV tumors (P <.0001, log-rank trend test). The EBA-A11 antigen showed a significant negative correlation with survival. While the 5-year survival of 124 HELA-A11-negative patients was 58%, none of the 17 HLA-A11-positive patients survived 5 years (P = .0002). A significant negative correlation with survival was also observed for HLA-DR6. While the 5-year survival rate of 106 HLA-DR6-negative patients was 60%, it was only 40% in 35 HLA-DR6-positive patients (P = .0313).

CONCLUSIONS

If the findings of our study can be confirmed, HLA-A11 and HLA-DR6 might become clinically important supplemental prognostic markers in head and neck cancer.

Human papillomavirus 16 E6 polymorphisms in cervical lesions from different European populations and their correlation with human leukocyte antigen class II haplotypes

Infection with high-risk human papillomavirus (HPV) is necessary for the development of a cervical lesion, but only a fraction of precursor lesions progress to cancer. Additional factors, other than HPV type per se, are likely to increase the probability for progression. Intratype genome variations have been reported to be associated with viral persistence and the development of a major cervical disease. We have recently shown that the prevalence of specific HPV16-E6 variants in invasive cervical cancer (ICC) varies between Italian and Swedish women. To extend our initial study we have analyzed E6 variants in cervical lesions from Czech women, ranging from low-grade cervical intraepithelial neoplasia (LCIN) to ICC and scaled up the sample size of our initial study of Swedish and Italian women. In addition, we have correlated the cases of cancers with human leukocyte antigen (HLA) class II haplotypes. In line with our earlier observation, the distribution of specific HPV16-E6 genotypes in CIN and ICC varied in the 3 cohorts. For instance, the HPV16-E6 L83V variant, which has been found to be positively associated with ICC in Swedish women (p = 0.002), was more prevalent in LCIN than in ICC in Italian and Czech women (p = 0.01 and = 0.03, respectively). These data indicate that host genetic factors, such as HLA polymorphism, may determine the potential oncogenicity of the HPV16-E6 L83V variant. Indeed, the DR04-DQ03 haplotype, which is approximately 3-fold more abundant in the normal Swedish population than in those in Italy and the Czech Republic, was found to be positively associated with HPV16-E6 L83V in the 3 cohorts investigated (p = 0.01). This observation may explain why L83V is a risk factor more in Sweden than in the other 2 countries.

Second German consensus on immunogenetic donor search for allotransplantation of hematopoietic stem cells

The present paper summarizes the results of the second German consensus meeting on immunogenetic donor search for allotransplantation of hematopoietic stem cells held in Essen in November 1999 under the auspices of the German Society for Immunogenetics (DGI) and the German Working Party for Blood and Marrow Transplantation (DAG-KBT). Immunogeneticists and transplant physicians from all over the country agreed to update the national standards for: (1) search strategy including the role of unrelated and extended family donor search after unsuccessful core family donor search, (2) histocompatibility loci to be typed, (3) histocompatibility typing techniques to be used (HLA serology vs DNA-based HLA typing, cellular tests, serum cross-match), and (4) acceptable HLA mismatches in the context of a defined underlying disease, donor type, and conditioning regimen.

Human leukocyte antigen class II allele frequencies and haplotype association in Iranian normal population

The polymorphism of the HLA class II genes DRB1, DQA1, and DQB1 was investigated in 100 unrelated Iranian individuals from Fars province in Southern Iran, using the restriction fragment length polymorphism (RFLP) method. Subtyping of DRB1*04, *15, and *16 alleles was performed using PCR amplification with sequence specific primes (PCR-SSP). The allele and the haplotype frequencies were calculated. The most common DRB1 alleles were DRB1*11, DRB1*15, and DRB1*04 with a frequency of 25.0%, 14.5%, and 10.5%, respectively. In contrast, the allelic frequency of DRB1*12 and DRB1*08 was very low (1.5% for each). In the DR15 group DRB1*1501 was the most prevalent variant (6.0%). Concerning DR4, the most common alleles were DRB1*0405 and DRB1*0402 (3.5% for each). Interestingly, DRB1*0402 was associated with DQB1*0302 and DRB1*0405 was associated with DQB1*0302 and DQB1*02, the latter being a rare DRB1/DQB1 haplotype in Caucasian individuals. The most frequent DQB1 alleles were DQB1*0301 (31.0%), and DQB1*05 (22.0%). The most frequent DQA1 variants were DQA1*0501 (39.0%) and DQA1*0102 (14.5%). The most common haplotype was DRB1*11-DQB1*0301-DQA1*0501 (25.0%) followed by DRB1*0301-DQB1*02-DQA1*0501 (10%) and DRB1*0701- DQB1*02-DQA1*0201 (6.5%). Data presented in this study suggest that the Iranian population shares some HLA components with populations resident in eastern and southern European countries.

HLA compatibility and organ transplant survival. Collaborative Transplant Study

The influence of HLA compatibility on organ transplant survival was analyzed in more than 150,000 recipients transplanted from 1987 to 1997 at transplant centers participating in the Collaborative Transplant Study. A statistically highly significant effect of HLA matching on graft and patient survival rates was found in the analysis of kidney transplants (P < 0.0001). Ten years after transplantation, the graft survival rate of first cadaver kidney transplants with a complete mismatch (6 HLA-A+B+DR mismatches) was 17% lower than that of grafts with no mismatch. During the first post-transplant year, the class II HLA-DR locus had a stronger impact than the class I HLA-A and HLA-B loci. During subsequent years, however, the influence on graft survival of the three loci was found to be equivalent and additive. For optimal graft outcome, compatibility at all three HLA loci is, therefore, desirable. The excellent correlation of HLA matching observed in recipients of cadaver kidneys with very short ischemic preservation (0-6 hours) or recipients of kidneys from living unrelated donors contradicts reports that short ischemia can eliminate the influence of matching. Although HLA has a significant effect on graft outcome regardless of the state of presensitization, the matching effect is potentiated in patients with highly reactive preformed lymphocytotoxic antibodies. Among first cadaver transplant recipients with an antibody reactivity against > 50% of the test panel, the difference in graft survival at 5 years between patients with 0 or 6 mismatches reached 30%. A collaborative project, in which molecular DNA typing methods were employed, showed that the correction of serological HLA typing errors by more accurate DNA typing results in a significantly improved HLA matching effect. Moreover, matching for the class II locus HLA-DP, a locus that can be typed reliably only by DNA methods, showed a significant effect in cadaver kidney retransplants, especially in the presence of preformed lymphocytotoxic antibodies. The analysis of heart transplants showed a highly significant impact of HLA compatibility on graft outcome (P < 0.0001). This result is of particular interest because donor hearts are not allocated according to the HLA match. A biasing influence of donor organ allocation (i.e. a preferential allocation of good matches to good risk recipients) can, therefore, be excluded. In liver transplantation, neither matching for HLA class I nor HLA class II could be shown to influence transplant outcome.

HLA class II DNA-RFLP typing in 102 individuals from Northern Greece

The serological identification of HLA class II alleles is often doubtful. Since accurate HLA typing is essential for the matching of donor-recipient pairs in allogeneic transplantation, an effort was made to establish DNA restriction fragment length polymorphism (RFLP) typing and to assess the correlation between the serological and RFLP techniques in the population of Northern Greece. One hundred and two healthy individuals (204 HLA-DR alleles) from Northern Greece were HLA-DR, DQ typed with both the microcytotoxicity and the Taq I RFLP method, using three exon-specific probes. DNA-RFLP typing revealed (1) concordant results with serology in 69.9% (142/204) of the alleles and (2) at least one HLA-DR allele discrepant to serology in 30.4% (62/204) of the alleles. Incorrect serological DR types (weak reactions or inability to distinguish between two alleles with a common epitope) were identified in 54 alleles (26.5%), while 3.9% (8/204) of serological "blank" alleles turned out to be definable alleles by RFPL. Of the individuals tested, 10.8% (11/102) were DR-homozygous by RFLP. This comparison of results obtained by serology and RFLP demonstrated the necessity of the clinical application of DNA typing, especially for organ transplantation where accurate HLA typing has an important influence on graft survival.

Comparison of serological and DNA HLA-DR typing results for transplantation in Western Europe, Eastern Europe, North America and South America

In a previous study, DNA typing revealed that 25% of serological HLA-DR typings of kidney transplants were incorrect. In the current study, we analyzed whether this error rate had improved in recent years, and whether there were differences according to geographical region. From 1988 to 1991 the error rate of serological typing improved slightly in Western Europe from 19% to 16%, and in North America, from 21% to 16%. In Eastern Europe, the error rate decreased from 49% to 33% in 1991, whereas the rate remained high in South America at 60% in 1988 and 72% in 1991. The high error rates in South America and Eastern Europe reflected a lack of good quality serological typing reagents. The 16% typing errors in Western Europe and North America demonstrated the current limit of serological techniques for cadaver donor typing and underlined the need for prospective DNA typing.

A method for HLA-DQA typing by the PCR-SSP technique

There is preliminary evidence that matching for HLA-DQ is important for kidney graft survival. We developed a method for HLA-DQA typing based on the PCR-SSP principle. The procedure consisted of three steps: DNA isolation, PCR amplification and visualization of the PCR product under UV light. For the identification of all currently known DQA1 alleles, we designed 18 different primers that allowed typing for the specificities DQA1*0101, *1012, *0103, *0104, *0201, *03, *0401, *0501 and DQA1*0601. For the typing of a single individual, 12 PCR mixes were needed, each containing a primer pair specific for a certain allele group, and a pair of control primers that amplified a non-polymorphic region. The time required for this procedure was approximately 3 h from the time of blood collection. Comparison of this method with DQA typing by the RFLP method in 151 individuals revealed only a single discrepancy. The method can be easily applied for prospective cadaver donor typing.

Prominent T cell response to a selectively in vivo expressed Borrelia burgdorferi outer surface protein (pG) in patients with Lyme disease

Diagnosis of Lyme disease by analysis of T cell immune responses in vitro is curtailed by poor correlation between test results and status of infection. This is probably due to the inherent nonspecific activation potential of the causative agent, the spirochete Borrelia burgdorferi, for bystander lymphocytes, in particular via their outer surface lipoproteins. We have now applied a novel protocol to determine specific T cell responses in Lyme disease patients and exclude unrelated cellular responses in vitro. Non-lipidated spirochetal antigens (OspA, OspC and P39) including those selectively expressed in the mammalian host (pG and BapA) were used for antigenic stimulation and autologous dendritic cells served as antigen-presenting cells. The majority of patients with well-defined early and late manifestations of Lyme disease exhibited specific T cell proliferative responses to one or more of the indicated antigens, however at distinct levels. Most notably, among the five antigens tested, pG was specifically recognized by the majority of T cell populations (>70%) - mainly Th1 cells - from patients but not control individuals. These data indicate a causal relationship between B. burgdorferi infection and T cell reactivity to pG, thus making this protein a promising additional diagnostic marker for Lyme disease.

Association of elevated blood levels of pentachlorophenol (PCP) with cellular and humoral immunodeficiencies

It has long been suspected that pentachlorophenol (PCP) exerts a damaging influence on the immune system. In this study, the possible relationship between blood levels of PCP and immune function was studied in 190 patients who had been exposed for more than 6 mo to PCP-containing pesticides. The patients suffered from frequent respiratory infections and general fatigue. Lymphocyte subpopulations, in-vitro responses to mitogens, allogeneic stimulator cells, plasma neopterin, cytokines, soluble cytokine receptors, soluble adhesion molecules, and immunoglobulin autoantibodies were determined. A dose-response relationship between blood levels of PCP and cellular and humoral immune parameters was established. Blood levels of PCP were associated negatively with (a) total lymphocyte counts (p = .0002), CD4/CD8 ratios (p = .0015), and absolute counts of CD3+ (p < .0001), CD4+ (p < .0001), CD16+ (p < .0001), CD25+ (p = .0003), DR+ (p < .0001), CD8+/56+ (p = .020), and CD19+ cells (p = .092); (b) plasma levels of interleukin-2 (IL-2) (p < .0001), soluble IL-2R (p < .0001), IL-6 (p < .0001), IL-10 (p = .0039), interferon-gamma (IFN-gamma) (p < .0001), tumor necrosis factor-alpha (TNF-alpha) (p < .0001), transforming-growth factor-beta2 (p = .023), soluble IL-1 receptor antagonist (sIL-1 RA) (p < .0001), soluble intercellular adhesion molecule-1 (p = .0003); and (c) immunoglobulin (Ig) M-anti-Fab type autoantibodies (p = .0353). PCP levels were associated positively with (a) number of impaired stimulation assays per patient (p = .041); (b) number of circulating CD11b+ monocytes (p = .0015); and (c) plasma levels of neopterin (p < .0001), IL-4 (p = .020), and sIL-6R (p = .020). Compared with patients who had PCP plasma levels that were less than or equal to 10 microg/l, patients with blood levels of PCP that exceeded 10 microg/l experienced the following more often: low numbers of total blood lymphocytes (p = .054), CD3+ (p = .0014), CD4+ (p = .0001), DR+ (p = .0003), CD16+ (p = .0033), and CD25+ cells (p = .0033). In addition, the same aforementioned patients experienced the following more frequently: undetectable plasma levels of IL-2 (p = .0057), IL-6 (p = .042), IL-8 (p = .038), IL-10 (p = .0001), TNF-alpha (p = .0062), and IFN-gamma (p = .016); and impaired in-vitro responses of lymphocytes (p = .071). The authors concluded that increased blood levels of PCP were associated significantly with cellular and humoral immunodeficiencies. Recurrent respiratory infections and general fatigue could originate from PCP-associated immunosuppression.

Microchimerism in bone marrow-derived CD34(+) cells of patients after liver transplantation

Lymphoid and dendritic cells of donor origin can be detected in the recipient several years after a solid organ transplantation. This phenomenon is termed microchimerism and could play a role in the induction of tolerance. The fate of other hematopoietic cells transferred by liver transplantation, in particular of stem and progenitor cells, is unknown. For this reason, we studied peripheral blood and bone marrow samples of 12 patients who had received a liver transplant from an HLA-DR mismatched donor. Eight patients were long-term survivors between 2.8 and 10.1 years after allografting. CD34(+) cells from bone marrow were highly enriched with the use of a 2-step method, and a nested polymerase chain reaction was applied to detect donor cells on the basis of allelic differences of the HLA-DRB1 gene. Rigorous controls with DRB1 specificities equal to the donor and host were included. In 5 of 8 long-term liver recipients, donor-specific CD34(+) cells could be detected in bone marrow. Microchimerism in the CD34(+) cell fraction did not correlate to the chimeric status in peripheral blood. In conclusion, our results demonstrate a frequent microchimerism among bone marrow-derived CD34(+) cells after liver transplantation. The functional role of this phenomenon still needs to be defined. (Blood. 2000;96:763-767)

Passenger lymphocyte syndrome with severe hemolytic anemia due to an anti-Jk(a) after allogeneic PBPC transplantation

BACKGROUND

After allogeneic peripheral blood progenitor cell (PBPC) transplantation, a patient developed a severe hemolytic transfusion reaction due to passenger lymphocyte syndrome.

CASE REPORT

A 50-year-old woman with secondary acute myeloid leukemia transforming from a myelodysplastic syndrome received an ABO-compatible PBPC graft from her HLA-identical sister. For prophylaxis of GVHD, the patient was treated with cyclosporine and methotrexate. Eighteen days after the transplant, the patient experienced a severe hemolytic transfusion reaction due to an alloantibody (anti-Jk(a)) produced by donor lymphocytes.

RESULTS

The patient was typed as group A, Jk(a+) before transplantation; the donor was typed as group A, Jk(a-). On Day 18 after transplantation, the immunohematologic screening revealed a positive DAT (C3d 3+) and an alloanti-Jk(a). Hemolysis in the patient at that time was indicated by a drop in the Hb and an increase in the LDH level (maximum, 592 IU/L on Day 23).

CONCLUSION

The course of hemolysis and the time of appearance of an alloantibody in this patient meet the criteria for passenger lymphocyte syndrome. In most cases, this syndrome is triggered by ABO system antibodies. This is the first reported case of passenger lymphocyte syndrome after PBPC transplantation that was due to an alloantibody that did not belong to the ABO system.

High-resolution typing for HLA-DRB1*15 amd -DRB1*16 by fluorescence-marked sequence-specific priming (TaqMan assay)

Sequence-specific primed polymerase chain reaction (PCR-SSP) is widely used in HLA laboratories. The TaqMan method, which is described here for high-resolution typing of HLA-DRB1*15 and -DRB1*16, does not require elaborate and time-consuming post-PCR detection steps. In this one-tube assay, conventional PCR-SSP and fluorescence detection of the amplicon with a doubly labeled fluorescent probe are combined: a fluorogenic hybridization probe (FHP) labeled with a spectral resolvable fluorescent reporter dye (FAM or TET) at its 5' terminus and a common quencher dye (TAMRA) at its 3' terminus is cleaved by the 5' nuclease activity of Taq DNA polymerase only if the target sequence is amplified. An increase of fluorescence intensity indicates a successful amplification. For high-resolution typing of HLA-DRB1*15 and -DRB1*16 alleles we designed two FHPs and 14 specific primer mixes (7 for DR15 and 7 for DR16). Amplification of the specific sequence was detected by a FAM-labeled FHP, whereas amplification of the internal control was detected by a TET-labeled FHP. We were able to type all heterozygous DRB1*15/DRB1*16 subtype combinations. For evaluation, 60 HLA-DRB1*15-positive and 40 HLA-DRB1*16-positive individuals were typed and the results were compared with conventional PCR-SSP DR15/16 subtyping. There were no discrepancies between the two methods. The TaqMan method is an alternative to conventional PCR-SSP typing which is suitable for routine use in HLA laboratories.

Association of cervical artery dissection with recent infection

BACKGROUND

Cervical artery dissection (CAD) is an important cause of ischemic stroke in younger patients. However, its cause is insufficiently understood.

OBJECTIVE

To test the hypothesis that CAD is frequently associated with recent infection.

SUBJECTS AND METHODS

We compared the prevalence of infection during the preceding week in 43 consecutive patients with acute CAD and 58 consecutive patients younger than 50 years with acute cerebral ischemia from other causes (control patients). In subgroups of patients, we correlated infectious status with electron microscopic studies of skin biopsy specimens and investigated pathways potentially linking infection and CAD.

RESULTS

Recent infection was more common in patients with CAD (25/43 [58.1%]) than in control patients (19/58 [32.8%]; P=.01). Respiratory tract infection was preponderant in both groups. Recent infection, but not the mechanical factors cough, sneezing, or vomiting, was independently associated with CAD in multivariate analysis. Investigation of serum antibodies against Chlamydia pneumoniae, smooth muscle cells, endothelial cells, collagen types I through IV, and heat shock protein 65 and assessment of serum alpha1-antitrypsin and HLA did not contribute to the understanding of the pathogenesis of CAD. More patients with pathologic findings in skin biopsy specimens tended to have had a recent infection (13/21 [62%]) than patients without pathologic findings (2/9 [22%]; P=.11).

CONCLUSION

Our results suggest a significant association between recent infection and CAD that is not explained by mechanical factors occurring during infection.

Comparison of serological and DNA PCR-SSP typing results for HLA-A and HLA-B in 421 Black individuals: a Collaborative Transplant Study report

In a recent study, we observed a discrepancy rate of 8.5% between the results of molecular and serological HLA class I typing in Caucasian kidney donors and recipients. In the present study we addressed the question how often black individuals are mistyped using the serological technique. 421 Blacks whose HLA typing results were reported to the Collaborative Transplant Study (CTS) were typed retrospectively for HLA-A and -B using a PCR-SSP method. 78 of the 421 individuals (18.5%) showed a discrepancy for HLA-A and 107 individuals (25.4%) for HLA-B. 36.3% of all individuals tested showed either an HLA-A or an HLA-B discrepancy. 13.1% of the discrepancies at the HLA-A locus were due to antigen misassignments and 4.8% were due to missed antigens. HLA-B discrepancies were caused in 15.7% by antigen misassignments and in 10.5% by missed antigens. These results demonstrate an impressive advantage of the PCR-SSP method for HLA-A and HLA-B locus typing over serological typing in black individuals. The high typing discrepancy rate observed in Blacks provides a strong argument for replacing serological typing by the DNA method. It is likely that this will improve the HLA matching correlation in clinical transplantation in Blacks.

HLA class II (DRB1, DQA1 and DQB1) associated genetic susceptibility in Iranian multiple sclerosis (MS) patients

The association of HLA class II alleles with multiple sclerosis (MS) has been amply documented. In the present study, the role of HLA class II (DRB1, DQA1 and DQB1) alleles and haplotypes was investigated in 43 unrelated Iranian chronic progressive multiple sclerosis (CP-MS) patients compared with 100 healthy individuals. HLA typing for DRB1, DQA1 and DQB1 was performed by restriction fragment length polymorphism (RFLP). Subtypes of DR4, DR15 and DR16 were defined using polymerase chain reaction (PCR) amplification with sequence-specific primers (PCR-SSP). The results show that, among DR2-positive MS patients and the control group, a positive association with the DRB1*1503, DQA1*0102, DQB1*0602 haplotype (21% vs. 2.7%, P = 0.057, RR = 9.8) and a negative association with the most frequent DR15 haplotype in the control group, DRB1*15021, DQA1*0103, DQB1*0601 (7% vs. 24.3%, P = 0.001), were observed. No significant association was found with the analysed HLA-DRB1, DQA1 and DQB1 alleles.

Distribution of human platelet antigens in a Chinese population

We report the distribution of the human platelet antigens HPA-1, -2, -3, -4 and -5 as determined using the polymerase chain reaction with sequence-specific primers in 100 random, healthy Chinese in Hong Kong. The HPA-1a, -2a, -4a and -5a genes were present in every sample tested, HPA-1b, -2b and -5b were rare, and the sample was monomorphic for HPA-4a. HPA-3a and -3b genes showed frequencies of 0.525 and 0.475 respectively. There was no departure from Hardy-Weinberg equilibrium in any of the five HPA systems studied.

HLA class I DNA typing of 215 "HLA-A, -B, -DR zero mismatched" kidney transplants

DNA typing for HLA class II improves the typing quality and this was shown previously to be relevant for kidney graft survival. In this project we addressed the question whether molecular typing for HLA class I also increases the efficacy of HLA matching in kidney transplantation. 215 HLA-A,-B,-DR zero-mismatched donor/recipient pairs as defined by serological typing were selected. Retrospective HLA-A and HLA-B typing was performed both by the PCR-SSP and the PCR-SSOP method. DNA typing for HLA-A revealed discrepant results to serology in 5.7% of the donors and 2.8% of the recipients. HLA-B typing discrepancies were found in 6.6% of the donors and 5.6% of the recipients. 10.4% of the donors and 6.5% of the recipients showed either an HLA-A or an HLA-B discrepancy Nearly one-third of the HLA-A discrepancies affected A19 splits. The most common reason for HLA-A discrepancies was the erroneous assignment of serological blanks, whereas HLA-B errors were caused mainly by the assignment of incorrect specificities. DNA typing allowed the definition of HLA-A and -B split specificities in all 118 "splitable" cases for which only broad specificities were reported based on serological typing. A total of 183 DNA class I compatible transplants had a 15% higher one-year graft survival rate than 32 transplants for which DNA typing revealed a class I incompatibility

Comparison of typing results by serology and polymerase chain reaction with sequence-specific primers for HLA-Cw in 650 individuals

HLA-Cw typing by standard serological techniques is associated with a high frequency of blanks, and reliable typing reagents for several of the Cw specificities are scarce. We evaluated the PCR-SSP technique for Cw typing in 370 kidney transplant patients and 280 healthy blood donors. Serological typing of all individuals was performed in our laboratory from 1995 to 1997 using commercially available tissue-typing trays. Comparison between serological and PCR-SSP typing revealed a discrepancy rate of 33.6% (n= 94) in blood donors and 32.4%) (n=120) in kidney recipients. Incorrect antigen assignments occurred only rarely (3.6% of the blood donors and 3.2% of the kidney recipients). The vast majority of discrepancies were due to antigens that were not detected serologically. In 26 individuals no Cw antigen was detected by serological typing, whereas PCR-SSP showed 1 allele in 13 and 2 alleles in the other 13 cases. Another 269 individuals were typed serologically with one blank (presumably homozygous). Of these, only 108 were confirmed to be homozygous, whereas an additional Cw allele was found in the remaining 161 cases using the SSP technique. Most of the "missed" specificities (86.5%) were those for which serological reagents were not available (HLA-Cw*12-*17). The most commonly "missed" specificity was HLA-Cw*1203, which occurred in 13.9% of the healthy blood donors. These results indicate that serological HLA-Cw typing is insufficient for examining the clinical importance of HLA-Cw matching in transplantation. Future studies based on molecular typing should allow the proper investigation of HLA-Cw matching in kidney and bone marrow transplantation.

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.

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.

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.