Histological examination of false positive tissue resection using 5-aminolevulinic acid-induced fluorescence guidance

Intraoperative 5-aminolevulinic acid (5-ALA)-induced fluorescence guidance for resection of malignant brain tumors was correlated with histological examination to investigate false positive findings in 42 patients with malignant glioma and six patients with metastatic brain tumor. Patients received a single 1 g oral dose of 5-ALA 2 hours before surgery. The tumor site was illuminated with a laser with a peak wavelength of 405 +/- 1 nm and output of 40 mW. Samples with strong fluorescence were obtained from the tumor bulk and samples with weak fluorescence from the tumor cavity. Fluorescence was observed in 36 of the 42 malignant gliomas and four of the six metastatic brain tumors. No tumor cells were found in fluorescent samples from six of the 36 malignant gliomas and all four metastatic brain tumors. Five of the six malignant gliomas were recurrent cases. Fluorescence was found in areas of peritumoral edema or inflammatory cell and reactive astrocyte infiltration. Intraoperative 5-ALA-induced fluorescence guidance is useful for the resection of initial malignant glioma since false positive results are rare, but only non-eloquent weak positive areas should be resected. In contrast, all weak positive areas of recurrent malignant gliomas must be resected. Weak positive areas of the peritumoral edema surrounding metastatic brain tumors should be removed carefully as false positive results are common.     

The effect of HLA-A, -B matching on cadaver renal allograft rejection comparing public and private specificities

Data collected prospectively on 3811 cadaver renal transplants performed between June 1977 and July 1982 by the 42 member institutions of the South-Eastern Organ Procurement Foundation (SEOPF) were analyzed to determine whether donor-recipient compatibility based on public rather than private HLA-A,-B specificities influenced the beneficial effect of HLA matching on outcome. HLA compatibility was calculated considering match and mismatch based on common private or various public (crossreactive group, [CREG]) specificities. Donor-recipient compatibility using certain CREG assignments provided an equivalent means of stratifying graft outcome by the degree of HLA-A,-B match or mismatch, and other CREGs assignments did not. Multivariate Cox regression analysis of donor-recipient compatibility based on certain public antigens showed as high an association (P less than 10(-5) between good matching and decreased graft rejection as did matching for private antigens alone. Patient stratification by HLA match provided a stronger association with graft outcome than by HLA mismatch, irrespective of whether private or public antigens were considered. The likelihood of finding a better match was significantly increased using CREG assignments, and patients with at least one matched private antigen had equivalent or better graft survival when additional public antigens were matched. These findings indicate that with conventional immunosuppressive therapy: (1) matching of private or public HLA-A,-B antigens plays a highly significant role in decreasing renal allograft rejection; (2) matching based on certain public antigens can provide the same or a better association with outcome as private antigens; and (3) the association (crossreactivity) of various HLA specificities can be defined on a functional basis in terms of graft survival.     

HLA Antigenic and Haplotype Frequencies Estimated in Hematopoietic Progenitor Cell Donors From Argentina

BackgroundHematopoietic progenitor cell transplantation is considered a standard-of-care treatment for defined hematological and non-hematological conditions affecting bone marrow–derived cells.MethodsPatients and potential donors are HLA typed for their HLA-A, -B, -C, -DRB1, and -DQB1 alleles. The best allogeneic donor is one for which each allele matches the patient at HLA-A, -B, -C, and -DRB1 (8/8). For patients with no related donor, the transplant physician will start a search for unrelated donors. The search is performed through a local registry and often includes the search for donors worldwide. The Argentinean HPC Donors Registry was established in 2003. Our National HPC Donor Registry has already typed more than 31,000 donors for HLA-A, -B, and -DR.ResultsWe present the analysis of HLA frequencies and haplotypes estimates for the subset of our donor database that is additionally typed for HLA-C. We analyzed HLA data from 2657 donors. Antigen and haplotype frequencies were estimated through the use of expectation maximization.ConclusionsOur analysis showed for the first time the antigenic HLA frequency distribution from HPC donors in Argentina. Knowing haplotype frequencies in our population will help us to select potential donors for high-resolution typing for the patients.     

Lack of HLA-molecules on human spermatozoa and in seminal plasma

Summary. The expression of human leukocyte antigens (HLA) on ejaculated spermatozoa and on lymphocytes was compared by flow cytometry using monoclonal antibodies towards HLA class I (pan-HLA-A, -B, -C) and class II (DR) antigens. Soluble antigens of HLA class I (s HLA-A, -B, -C) in seminal plasma and in blood plasma were monitored with an elisa technique. Lymphocytes showed specific fluorescence after incubation with the antibodies against HLA class I and class II (DR), whereas, on spermatozoa no positive immunofluorescence could be detected. No antibodies were bound to any significant extent either after modifications of sperm preparation (density gradient centrifugation, swim up-technique, addition of azide, foetal calf serum or benzamidine chloride) or after treatment of spermatozoa with detergens. Furthermore, different concentrations of soluble HLA-A, -B, -C in seminal plasma and in blood plasma were detected. The latter one showed soluble HLA about four-fold more concentrated than the seminal plasma (x ± SD: 262.5 ± 144.4 nmol 1-¹vs. 62.5 ± 27.1 nmol 1-¹). These results suggest, that the HLA-expression differs between human spermatozoa and somatic cells.     

HLA-A, -B, -C expression in colon carcinoma mimics that of the normal colonic mucosa and is prognostically relevant

Whether human leukocyte antigen (HLA)-A, -B, -C expression has any predictive value on the prognosis of human malignancies remains controversial. Herein, monoclonal antibodies with preferential reactivity for HLA-A, HLA-B, and HLA-C (HCA2, HC10, and L31) were used to stain an archival collection of 291 formalin-fixed/paraffin-embedded tissues, comprising neoplastic lesions from stages II and III colon carcinoma patients (n=165), and the uninvolved, morphologically normal mucosae from a subset (n=126) of these patients. Marked staining variability was detected not only in the tumors as in previous studies, but also in the normal paired mucosae. HLA-A, -B, -C expression was similar in approximately two thirds of the available 126 normal/neoplastic pairs, confirming in vivo our previous observation that most tumor cells mimic the HLA phenotypes of their normal counterparts. Both up and down-regulation occurred in the remaining third of the pairs, but did not coincide with high and low expression, respectively, conventionally evaluated on the tumor lesion only. Remarkably, a "paired" evaluation, but not high or low expression in the tumor, was predictive of the clinical outcome. Deviations from the expression in the normal paired mucosa (both increases and decreases) of HCA2-reactive class I molecules (possibly HLA-A), and down-regulation of L31-reactive class I molecules (possibly HLA-C), particularly in tumors from stage II patients, correlated with poor 5-year overall and disease-free survival, hazard risk ranging from 2 to 6, approximately. Thus, a paired immunohistochemical comparison reveals a novel immune evasion strategy that may impact on the prognosis of colon carcinoma.     

HLA class I and II antigens in South African Indians with NIDDM

The relationship between the HLA system and non-insulin-dependent diabetes mellitus (NIDDM) in South African Indians, a migrant Indian group, was evaluated by testing HLA-A, -B, and -C antigens in 184 patients and 1444 control subjects and HLA-DR antigens in 104 patients and 330 control subjects. There was a significant increase in the frequency of HLA-Bw61 in patients compared with control subjects (27.7 vs. 18%, P = .00155), although the degree of association was not very strong (relative risk 1.7). A similar association has been noted in Fiji Indians, another migrant Indian group. However, no relationship could be established at the DR locus. It is suggested that the relatively high frequency of the Bw61 allele in South African Indians could, in the presence of some environmental factor like obesity, confer increased susceptibility to NIDDM.     

Adsorption of cytotoxic anti-HLA antibodies with HLA class I immunosorbant beads

In an effort to generate HLA immunosorbants to specifically remove anti-HLA antibodies from sera of highly sensitized patients, we purified HLA proteins, covalently coupled them onto Sepharose, and adsorbed antisera from five patients with narrowly reactive cytotoxic anti-HLA antibodies and from one patient with broadly reactive antibodies. We found that an HLA-A2 immunosorbant depleted anti-HLA-A2 cytotoxic antibodies, but did not deplete anti-HLA-B7 or anti-HLA-B44 cytotoxic antibodies from the narrowly reactive patient sera. Patient S.C. developed high PRA (81%) with strong cytotoxicity against HLA-A1 and -A2 following rejection of an HLA-A1, -B57 mismatched kidney. We adsorbed his sera with five HLA immunosorbants including HLA-A2 and HLA-A1,28. We found that the HLA-A2 immunosorbant depleted antibodies to HLA-A2+ and HLA-B57+ cells but not to HLA-A1+ cells, while the HLA-A1,A28 immunosorbant depleted antibodies to both HLA-A1+ cells and to the HLA-A28 cross-reactive HLA-A2+ cells. Adsorption was specific for HLA-A alleles to which the patient was sensitized, since neither HLA-B-C immunosorbants (containing HLA-B7, -B8, -B13, -B27, or -B37 plus HLA-C gene products) nor the control immunosorbants (bovine serum albumin or diphtheria toxoid) depleted serum S.C. of cytotoxic anti-HLA antibodies. Our results indicate that HLA immunosorbants are stable to sequential cycles of adsorption and elution, and thus may be of future therapeutic value in treatment of sensitized patients.     

Is there MHC Class II restriction of the response to MHC Class I in transplant patients?

BACKGROUND: In this study, we evaluated distinct HLA-DRB1 alleles to determine class II restriction of the production of HLA-A2-specific antibodies in renal transplant patients. METHODS: Data from 217 renal transplant patients who received an HLA-A2-mismatched renal graft were analyzed with regard to HLA-A2 humoral responsiveness. High-resolution DNA typing of class II HLA-DR alleles was performed by polymerase chain reaction-sequence-specific primer. Patients who had one of the following eight HLA-DRB1 alleles were included in the study: -*0101, -*0301, -*0401, -*0701, -*1101, -*1301, -*1401, and -*1501. Serum samples were screened posttransplantation with the standard complement-dependent cytotoxicity procedure. In addition, recombinant HLA-A2 monomers (the "MonoLISA" assay) were used as a target for the detection of HLA-A2 group-specific antibodies. The following HLA-A2 amino acid positions (termed "epitopes") that are responsible for the induction of an antibody response were defined: 74H, 65-66GK, 62G, 114H, 142-145TTKH, and 107W-127K. The definition of the "HLA-DR permittors" of anti-HLA-A2 response was based on a "class II restriction table" designed for this purpose. Prediction of immunogenic and/or nonimmunogenic HLA-A2 peptides was based on an MHC database. RESULTS: The HLA-DRB1-*0101 and -*1401 alleles had a trend toward a positive correlation with the production of HLA class I-specific antibodies against the HLA-A2 shared (public) epitopes 65-66GK and -62G, respectively. Only the DRB1-*1501 allele had higher trend toward a positive correlation with the production of antibodies against the HLA-A2 private (74H) epitope. In 42 patients with the HLA-DRB1-*1501 allele, 11 (26%) patients produced HLA-specific antibodies against the HLA-A2 group of epitope(s). Moreover, in these patients, spreading of the alloreactivity against "other" HLA antigens was detected. Many of these other HLA antigens did not belong to HLA-A2 group but had newly defined shared epitopes with this group. Furthermore, the epitope prediction, based on an MHC database, revealed differences in the ligation strength (score) to the HLA allele (class I and II) for a specific HLA-A2 peptide in the 42 patients (responders and nonresponders). CONCLUSIONS: The data presented in this paper suggest that the HLA class II allele and the type of the bound allopeptide may influence the humoral and cellular response. The immunogenicity of these allopeptides could be predicted with an MHC database (high-scored peptide=activating peptide and low-scored peptide=suppressor peptide). In the future, production of synthetic peptide analogues, on the basis of these predictions, could be used for induction of T-cell anergy and/or tolerance. In the short term, algorithms, on the basis of our approach, could be tested for influence on graft survival and allosensitization in current high-quality data sets.     

Human leukocyte antigen and its role in transplantation biology

Human leukocyte antigens (HLA), the human version of the major histocompatibility complex (MHC), an integral part of maintenance of immune surveillance, have been widely studied for their roles in transplantation biology. A donor with an identical HLA system can donate tissue more successfully than the one who is not matched. The MHC is divided into class I, II, and III antigens; class I and II play important roles in transplantation immunology. HLA is codominantly expressed on chromosome 6 in every individual; HLA-A, -B, and -DR is known as the "haplo-type." There are two sets of HLA antigens in each individual. Thus a child can inherit four different haplo-type combinations from parents. There is a 25% chance of totally matched or mismatched siblings and a 50% chance of half-matched siblings among a family with parents being a 50% match. The main purpose of HLA typing and lymphocyte crossmatching (LCM) in transplantation is to assess donor-recipient immune compatibility and identify the presence of preformed donor-specific cytotoxic alloantibodies in the recipient. It can be tested by serology or molecular techniques. We studied 8462 individuals for HLA typing by serology supplemented with molecular techniques (sequence-specific primers with low resolution). The common alleles were HLA-A19 (9.4%), -A1 (7.7%), -A2 (7.2%), -B5 (10.2%), -B35 (6.6%), -B40 (5.3%), -DR2 (10.2%), -DR5 (7.5%), and -DR7 (5.1%). HLA typing and LCM testing support successful transplantation.     

Close association between Fc receptor and HLA-D-associated (Ia-like) determinants on human lymphoid cells.

The inhibitory effect of HLA antisera on Fc receptors of human lymphoid FcRFC and K cells was investigated. Antisera recognizing determinants of the HLA-A, -B, and -C series had no effect on FcRFC, while specific inhibition was observed with an antiserum reacting with determinants closely associated to HLA-DW2. This inhibitory effect was also demonstrated by the Fab' fragments. Specific inhibition of K cells was observed with all HLA antisera, but this effect was lost in the Fab' fragments. We concluded that the Fc receptor of FcRFC may be closely associated with products of the HLA-D region. This is analogous to the association between the Fc receptor and the Ia antigens on murine splenic B lymphocytes.     

The role of HLA-DR antigens in transplantation--survival of skin allografts in HLA-haploidentical donor-recipient combinations.

The results of 79 skin grafts performed in haploidentical donor-recipient pairs are correlated with HLA-A, -B, -C, and -DR compatibility. A strong detrimental effect of DR incompatibilities has been demonstrated. This effect is independent from that exerted by products of the HLA-A, -B, and -C loci. An additive effect of HLA-A, -B, and -DR incompatibilities on allograft survival time has been observed.     

IS20I,a specific alphavbeta3 integrin inhibitor,reduces glioma growth in vivo

OBJECTIVE: The biological features of malignant gliomas include high cell proliferation, extensive local infiltration of tumor cells into normal brain, and marked neovascularization. alphavbeta3 integrin is highly expressed in malignant gliomas and plays a role in glioma growth. This article investigates the in vitro and in vivo effects of a synthetic alphavbeta3 integrin inhibitor called IS20I on human malignant gliomas. METHODS: The in vitro effects of IS20I were studied by performing adhesion assays, competition studies, semi-in vivo angiogenic assays, and migration and proliferation assays. For the in vivo experiments, IS20I was administered systemically in nude mouse intracranial and subcutaneous malignant glioma models. RESULTS: IS20I reacted selectively to alphavbeta3 integrin in glioma cells and tissues. In vitro, IS20I strongly inhibited angiogenesis and simultaneously exhibited potent antimitotic and antimigratory effects on numerous tumor and endothelial cell lines. In addition, at high concentrations, IS20I induced endothelial and tumor cell apoptosis. In vivo, when IS20I was administered intraperitoneally in subcutaneous and intracranial nude mouse glioma models, it potently reduced malignant glioma growth. Inhibition levels of 76 and 82% were observed at concentrations of 1 and 5 mg/kg, respectively, in the U87 intracranial model. The suppression of tumor growth is associated with a decrease in tumor vascularity, an increase in apoptosis, and a decrease in tumor cell proliferation. CONCLUSION: This work expands the understanding of the effects of anti-alphavbeta3 integrin inhibitors on malignant gliomas. In addition to direct proapoptotic and antiangiogenic effects, IS20I inhibits tumor and endothelial cell proliferation and migration, resulting in a potent inhibition of glioma growth in vivo.     

Risk of intracranial hemorrhage in glioma patients receiving anticoagulant therapy for venous thromboembolism

To determine the risk of intracranial hemorrhage in patients with malignant gliomas who are treated with anticoagulant drugs for late postoperative venous thromboembolism, the authors retrospectively reviewed the computerized data base of all patients with primary brain tumors seen at the University of California, San Francisco, over a 9-year period. Of 915 patients 18 years of age or older who had a pathological diagnosis of malignant glioma and an initial Karnofsky performance scale score of 60% or higher, 36 (4%) developed venous thromboembolism 6 to 246 weeks postoperatively and 22 were treated with anticoagulant drugs. Anticoagulant therapy usually consisted of intravenous heparin for 7 to 10 days, followed for at least 3 to 6 months by either subcutaneous heparin (5000 to 8000 U twice daily) or oral warfarin. All patients were closely monitored to ensure control of hypertension, compliance with therapy, maintenance of prothrombin time within the therapeutic range, and early recognition of adverse side effects. No patient had an intracranial hemorrhage. Thus, anticoagulant agents can be safely administered after intracranial operations for malignant gliomas without increased risk of morbidity or mortality if the patients are carefully monitored according to established guidelines.     

Determination of acceptable HLA mismatches in highly sensitized patients by soluble HLA class I ELISA inhibition

BACKGROUND: Acceptable HLA mismatches for highly sensitized patients are determined so as to increase their chances of receiving transplants. The disadvantage of the current procedures is that the antibody reactivity of the patients' sera is tested against HLA antigens expressed on cells or HLA antigens isolated from cell lysates. Therefore, two (homozygous for HLA-A and -B) to four (heterozygous for HLA-A and -B) different HLA class I antigens are present in the test. This might cause reactivity toward nonacceptable mismatches to mask the determination of acceptable mismatches. METHODS: Recently we observed that the detection of soluble HLA class I antigens is inhibited by HLA-specific antibodies. In the present study, inhibition of soluble HLA-specific ELISAs (anti-soluble HLA-A2, -B7, -B12) was evaluated as a tool used to determine acceptable mismatches. The results were compared with current determination of acceptable mismatches (which is by complement-dependent cytotoxicity and/or fluorescence-activated cell sorter analysis). RESULTS: In the case of acceptable mismatches determined by conventional methods, sera from the patients were not interfering in these ELISAs, whereas in the case of nonacceptable mismatches (thus specific antibodies), significant inhibition was observed in most instances. Among the nonacceptable mismatches, the test showed significant inhibition in 20 of 24 cases, whereas among acceptable mismatches, no inhibition was observed (in eight of eight), indicating the lack of specific antibodies. CONCLUSIONS: In highly sensitized patients, the introduction of soluble HLA-specific ELISAs is of additional and confirmatory value for the determination of acceptable mismatches. The major advantage of this approach is that antibody reactivity is tested against single antigens only.     

Relevance of a positive crossmatch in liver transplantation

We studied 27 liver transplants in 24 patients performed between November 1984 and January 1988. We investigated retrospectively the importance of donor reactive HLA class I and class II and of non-HLA antibodies for graft survival in these patients. In order to determine the specificity and class of the antibodies, we used monoclonal antibodies to HLA-A,-B,-C and DR and DQ antigens to block cytotoxicity of sera and the reagent dithiothreitol to characterize the immunoglobulin class. We found that humoral immunity to HLA antigens in liver-grafted patients, demonstrable as the presence of cytotoxic antibodies reactive with donor splenic T and/or B cells in the pretransplantation period, is associated with significantly lower graft survival as compared with patients without demonstrable preformed HLA antibodies (P=0.01). In addition we found that a substantial proportion of patients had donor-reactive cytotoxic antibodies which were not HLA specific. Thus, our study shows that HLA immunity can influence liver allograft survival, and that it is useful to have patient cytotoxic antibodies characterized with regard to HLA reactivity prior to transplantation.     

Newly Diagnosed High-Grade Gliomas

High-grade or malignant gliomas are aggressive cancers. The World Health Organization (WHO) grading system recognizes grade III and grade IV primary brain tumors of astrocytic, oligodendroglial, or mixed lineage. Identification of these tumors is prompted by symptoms such as insidious headaches, seizures, or focal weakness or numbness, with imaging findings of an enhancing mass lesion. Following surgery, radiation therapy has been known since the late 1970s to improve survival in malignant gliomas. More recently, the concurrent use of temozolomide (TMZ) and radiation therapy and the incorporation of bevacizumab have offered hope for patients with glioblastoma (WHO grade IV glioma). Although radiation is regularly used for up-front treatment of grade III gliomas, the role of chemotherapy is still being refined. In the past, patients with high-grade gliomas were often referred to a dedicated neuro-oncology center, but with improved outcomes and increased survival, these patients now are often treated by community oncologists. We believe substantial changes will develop with pending investigations that refine the dose and length of TMZ treatment, define specialized treatment for the elderly, and assess efficacy of bevacizumab in up-front therapy. The field is also conducting the required studies to define the role of chemotherapy for grade III malignant gliomas. These promising advances are needed as most patients with high-grade gliomas still succumb to their disease.     

Stem cells as vehicles for the treatment of brain cancer

Stem cell therapy represents a promising new therapeutic modality for infiltrative gliomas. The promise of this emerging technology centers on the potent migratory tropism exhibited by stem cells for disseminated foci of intracranial pathologic findings. This important characteristic, which has been validated in a wide set of preclinical studies, forms a foundation for the use of transplanted stem cell populations as vehicles for the delivery of tumor-toxic molecules to sites of intracranial tumor. Nevertheless, although experimental models using this technique to target brain tumors have shown encouraging results, many concerns and questions remain to be addressed before realistic clinical implementation of this strategy can begin. Key among these are an inadequate understanding of the specific tropic mechanisms that govern stem cell migration toward invasive tumors and the need to identify appropriate tissue sources and culture processes for the generation of adequate therapeutic stem cell populations. Despite these limitations, the use of stem cells as vectors for the treatment of brain tumors holds significant promise and may prove to be an important therapeutic modality for patients with malignant glioma.     

Expression of cALLa/NEP on gliomas: A possible marker of malignancy

Summary First described on pre-B leukemia cells, the common acute lymphoblastic leukemia antigen (cALLa) is also expressed on glioma cellsin vitro. Its identity to neutral endopeptidase (NEP) (E.C.3.24.11) was corroborated by our finding that cALLa positive glioma cells had NEP activity. To study cALLa/NEP distribution on glial tumours in vivo, we examined 76 brain tumour biopsies by immunostaining techniques on frozen tissue sections using anticALLa (FAH99) and anti-NEP (135 A 3) monoclonal antibodies. We found that 96% of grade 4 gliomas (25/26) expressed NEP. Whereas only 45% (4/9) of grade 3 or anaplastic astrocytomas did. In low grade gliomas, we found 2 positive tumours out of 21 tested (10%). Double immunostaining procedures revealed that NEP was co-expressed with GFAP. However no NEP could be detected on non-glial brain tumours nor on reactive astrocytes. These results suggest that cALLa/NEP expression could be linked to malignant progression of gliomas.