Abstract OT2-07-06: Antibody-coupled T cell receptor (ACTR) engineered autologous T cells in combination with trastuzumab for the treatment of HER2-positive malignancies

Antibody-Coupled T cell Receptor (ACTR) is an autologous engineered T cell therapy developed to combine with tumor-targeting antibodies to exert potent anti-tumor immune responses and tumor cell killing. The ACTR construct is composed of the extracellular domain of CD16 fused to CD3ζ signaling and T cell co-stimulatory domains. ACTR-expressing T cells are universal in that they can be paired with a therapeutic antibody to target specific antigens on tumors. Unum has two ACTR constructs, ACTR087 and ACTR707, currently in clinical testing. ACTR087 and ACTR707 are being tested in combination with rituximab in subjects with CD20+ B cell lymphoma in two separate trials (NCT02776813 and NCT03189836, respectively). Preliminary data with ACTR087 + rituximab has demonstrated clinical proof-of-concept and a dose-response relationship in subjects with relapsed/refractory B cell lymphoma. ACTR087 is also being tested in combination with a novel BCMA-targeting antibody in subjects with multiple myeloma (NCT03266692).

While T cell therapies, such as chimeric antigen receptor (CAR) T cells, have demonstrated clinical activity in hematological cancers, the therapeutic potential of this approach has yet to be established in solid tumors. Challenges associated with targeting solid tumors with CAR-T cells include tumor antigen heterogeneity and antigen expression on normal tissues. HER2 is a well-established therapeutic target that is over-expressed in a number of cancer indications. HER2 is also expressed at low levels on normal epithelial cells, creating a risk for on-target/off-tumor toxicities of HER2-targeted CAR-T cells. Here we present nonclinical studies demonstrating that ACTR T cells in combination with trastuzumab have antigen density-dependent activity on HER2-expressing tumor cell lines, while trastuzumab-based CAR-T cells do not. We observed that ACTR + trastuzumab had robust activity against HER2-amplified tumor cells and more modest activity against non-amplified tumor cells, whereas HER2-targeting CAR-T cells had comparable activity against HER2-amplified and non-amplified tumor cells. On normal human primary cells, ACTR + trastuzumab had minimal activity in comparison to HER2 CAR-T cells, suggesting that ACTR + trastuzumab may exhibit a superior clinical therapeutic index. Furthermore, the activity of ACTR T cells against HER2-amplified tumor cells was titratable with antibody concentration, allowing for control of ACTR activity by modulation of trastuzumab concentration. Together, these data demonstrate the specificity of the ACTR T cell therapeutic approach to target HER2-amplified tumors and support clinical testing in combination with trastuzumab.

A phase 1, multicenter, single-arm, open-label dose escalation study, ATTCK-34-01, is proposed to evaluate ACTR T cells in combination with trastuzumab in subjects with advanced HER2-positive malignancies. The primary study objectives are to assess the safety and tolerability of the combination, and to define the recommended phase 2 dose combination for further study. Additional objectives include assessment of anti-tumor activity, ACTR T cell persistence and trastuzumab pharmacokinetics. Enrollment is expected to commence in early 2019.

Citation Format: O'Callaghan KM, Shin J, Cheung AS, Cheema T, Judge C, Ranger A, Huet HA, Ettenberg SA, Sachs J, Vasconcelles M, Motz G. Antibody-coupled T cell receptor (ACTR) engineered autologous T cells in combination with trastuzumab for the treatment of HER2-positive malignancies [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-07-06.

Preliminary investigations of magnetic modulated nanoparticles for microwave breast cancer detection

This paper investigates the potential of magnetic modulated iron oxide nanoparticles in terms of a contrast enhancement for Ultra-wideband (UWB) breast imaging. The work is motivated by the low dielectric contrast between tumor and normal glandular/fibroconnective tissue. The influence of an external polarizing magnetic field on pure and coated magnetite nanoparticles is investigated in this contribution. Measurements were conducted using M-sequence UWB technology and an oil-gelatin phantom. It is shown that a coating, which is necessary for clinical use, results in a lower signal response, and thus leads to a lower detectability of magnetic modulated nanoparticles.

Combining magnetic resonance imaging and ultrawideband radar: a new concept for multimodal biomedical imaging

Due to the recent advances in ultrawideband (UWB) radar technologies, there has been widespread interest in the medical applications of this technology. We propose the multimodal combination of magnetic resonance (MR) and UWB radar for improved functional diagnosis and imaging. A demonstrator was established to prove the feasibility of the simultaneous acquisition of physiological events by magnetic resonance imaging and UWB radar. Furthermore, first in vivo experiments have been carried out, utilizing this new approach. Correlating the reconstructed UWB signals with physiological signatures acquired by simultaneous MR measurements, representing respiratory and myocardial displacements, gave encouraging results which can be improved by optimization of the MR data acquisition technique or the use of UWB antenna arrays to localize the motion in a focused area.

The fusion of anatomic and physiologic imaging in the management of patients with cancer

Imaging is of major clinical importance in the noninvasive evaluation and management of patients with cancer. Computed tomography (CT) and other anatomic imaging modalities, such as magnetic resonance imaging (MRI) or ultrasound, have a high diagnostic ability by visualizing lesion morphology and by providing the exact localization of malignant sites. Nuclear medicine provides information on the function and metabolism of cancer. Over the last decade, there have been numerous attempts to combine data obtained from different imaging techniques. Fused images of nuclear medicine and CT (or to a lesser extent, MRI) overcome the inherent limitations of both modalities. Valuable physiologic information benefits from a precise topographic localization. Coregistered data have been shown to be useful in the evaluation of patients with cancer at diagnosis and staging, in monitoring the response to treatment, and during follow up, for early detection of recurrence. Time-consuming and difficult realignment and computation for fusion of independent studies have, until now, limited the use of registration techniques to pilot studies performed in a small number of patients. The development of the new technology of single photon emission computed tomography/CT and positron emission tomography/CT that allows for combined functional and anatomic data acquisition has the potential to make fusion an everyday clinical tool.

The new technology of combined transmission and emission tomography in evaluation of endocrine neoplasms

The clinical value of a novel technology of combined transmission and emission tomography (TET) was assessed in patients with endocrine tumors.

METHODS

TET technology, which combines simultaneous acquisition of SPECT and CT images, using the same imaging device, allows correct fusion of images of both modalities. TET was performed on 27 patients with known or suspected endocrine tumors. The radiopharmaceuticals used for the emission part of the study were chosen according to the tumor type: (111)In-octreotide for patients with neuroendocrine tumors (n = 10), (99m)Tc-sestamibi for patients with primary hyperparathyroidism (n = 8), (131)I for patients with thyroid cancer (n = 4), and (123)I-metaiodobenzylguanidine and (75)Se-cholesterol for patients with adrenal masses (n = 3 and n = 2, respectively). The additional information provided by TET compared with scintigraphy was assessed for both image interpretation and clinical utility.

RESULTS

TET did not provide any additional data in 16 patients (59%), including 5 patients with normal scintigraphy. In 11 patients (41%) with abnormal SPECT findings, TET improved image interpretation by providing a better anatomic localization of SPECT-detected lesions. It showed unsuspected bone involvement in 4 patients, it identified the organs involved and the relationship of the lesions to neighboring structures in 5 patients, and it differentiated physiologic uptake from tumor uptake in 2 patients. TET provided additional information of clinical value in 9 patients (33%). It assisted in better planning of surgery in 2 patients with neuroendocrine tumors and in 2 patients with ectopic parathyroid adenomas. It changed the treatment approach in 2 patients with neuroendocrine tumors and 1 patient with thyroid carcinoma, and it altered prognosis in 2 patients with thyroid malignancy.

CONCLUSION

TET enhances the already unique role of nuclear medicine procedures in the assessment and management of patients with endocrine neoplasms.

Defining and refining international donor support for combating the AIDS pandemic

The international aid effort against AIDS is greatly incommensurate with the severity of the epidemic. Drawing on the data that international aid donors self-reported to the Organization for Economic Cooperation and Development (OECD), we find that, between 1996 and 1998, finance from all rich countries to sub-Saharan Africa for projects designated as AIDS control averaged US $69 million annually, and, assuming a safe margin for under-reporting and misreporting, we estimate that total donor spending on HIV/AIDS control was perhaps twice that at most. Since the late 1980s, aid levels have dropped relative to the prevalence of HIV infection, and stood recently at about $3 per HIV-infected person. Lack of finance is now the primary constraint on progress against AIDS, notwithstanding the widespread belief that a lack of interest from the goveements of poor countries is limiting. We argue that to produce a meaningful response to the pandemic, international assistance must be based on grants, not loans, for the poorest countries; be increased within the next 3 years to a minimum of $7.5 billion or more; be directed toward funding projects which are proposed and desired by the affected countries themselves, and which are judged as having epidemiological merit against the pandemic by a panel of independent scientific experts; and fund concurrent needs, including prevention, drug treatment (such as highly active antiretroviral therapy), and blocking mother-to-child HIV transmission. An effort of this scope and scale will both radically alter the prospects for intervention against AIDS in poor countries, and together with comparable efforts to control other infectious diseases, is easily afforded by the OECD donor economies, whose aggregate national income recently surpassed $21 trillion annually.

Dipole lattice membrane model for protein calculations

A dipole lattice model for lipid membranes and their interactions with peptides is presented. It uses the Langevin dipole method to calculate electrostatic interactions in the heterogeneous membrane environment. A series of test cases are presented, including spherical charges, dipoles, side chain analogs, and helical peptides. The model consistently produces qualitatively correct results.

Item-level and subscale-level factoring of Biggs' Learning Process Questionnaire (LPQ) in a mainland Chinese sample

BACKGROUND

The learning process questionnaire (LPQ) has been the source of intensive cross-cultural study. However, an item-level factor analysis of all the LPQ items simultaneously has never been reported. Rather, items within each subscale have been factor analysed to establish subscale unidimensionality and justify the use of composite subscale scores.

AIMS

It was of major interest to see if the six logically constructed items groups of the LPQ would be supported by empirical evidence. Additionally, it was of interest to compare the consistency of the reliability and correlational structure of the LPQ subscales in our study with those of previous cross-cultural studies.

METHODS

Confirmatory factor analysis was used to fit the six-factor item level model and to fit five representative subscale level factor models.

SAMPLE

A total of 1070 students between the ages of 15 to 18 years was drawn from a representative selection of 29 classes from within 15 secondary schools in Guangzhou, China. Males and females were almost equally represented.

RESULTS

The six-factor item level model of the LPQ seemed to fit reasonably well, thus supporting the six dimensional structure of the LPQ and justifying the use of composite subscale scores for each LPQ dimension. However, the reliability of many of these subscales was low. Furthermore, only two subscale-level factor models showed marginally acceptable fit. Substantive considerations supported an oblique three-factor model.

CONCLUSIONS

Because the LPQ subscales often show low internal consistency reliability, experimental and correlational studies that have used these subscales as dependent measures have been disappointing. It is suggested that some LPQ items should be revised and other items added to improve the inventory's overall psychometric properties.

Motivational Beliefs, Study Strategies, and Mathematics Attainment in High- and Low-Achieving Chinese Secondary School Students

In order to examine the relationship between cognitive and motivational variables and their relationship to mathematics attainment, Hong Kong-Chinese students enrolled in schools for high-, average-, and low-achievers completed questionnaires in Year 10 and in Year 11. Low-achievers perceived academic learning as being less useful over time and reported spending less time studying in Year 10 than in Year 11 but high- and low-achievers did not differ on their use of self-regulated learning strategies. Performance on the public examination in mathematics was predicted by prior achievement and Self-Concept of Mathematics Ability. Results underscore the importance of considering cultural beliefs systems and educational systems in models of academic motivation. Copyright 2000 Academic Press.

Using a small sample Q sort to identify item groups

A small sample of 40 second-year university students in Hong Kong were asked to perform a Q sort on the 36 items of a questionnaire used to assess six dimensions of student approaches to learning, the Learning Process Questionnaire. Participants were instructed to sort the items into as many groups as they liked with the only conditions being that all items within a group be as similar as possible in perceived meaning and that no item be placed into more than one group. By treating participants' responses as a form of multiple-choice data and by applying optimal scaling, three solutions were obtained. A two-dimensional plot of the optimal item scores for the first two solutions yielded 10 clearly defined item clusters suggesting a possible ten-factor model as opposed to the six-factor model found in studies of this questionnaire. The implications of using this approach to identify potential competing factor models, especially within a cross-cultural context, are discussed.

Lymphohematopoietic graft-vs.-host reactions can be induced without graft-vs.-host disease in murine mixed chimeras established with a cyclophosphamide-based nonmyeloablative conditioning regimen

Mixed hematopoietic chimerism can be induced in mice receiving allogeneic bone marrow transplantation (BMT) after nonmyeloablative host conditioning with depletion T cells with of anti-T cell monoclonal antibodies (mAbs), low-dose (3 Gy) total-body irradiation (TBI), and local thymic irradiation (7 Gy). These mice are specifically tolerant to donor and host antigens. When nontolerant donor T cells are given to chimeras several months after BMT, full donor-type chimerism develops, but graft-vs.-host disease (GVHD) does not occur. The induction of such lymphohematopoietic GVH reactions without GVHD could provide an approach to separating graft-vs.-leukemia (GVL) from GVHD in patients with hematologic malignancies. To make the nonmyeloablative conditioning regimen described above more cytoreductive for such malignancies, we have now modified it by replacing TBI with cyclophosphamide (CP). Treatment with anti-CD4 and anti-CD8 mAbs on day -5, 200 mg/kg CP on day -1, and 7 Gy thymic irradiation on day 0 was only slightly myelosuppressive and allowed fully major histocompatibility complex (MHC)-mismatched (with or without multiple minor antigen disparities) allogeneic bone marrow to engraft and establish long-term mixed chimerism in 40 to 82% of recipients in three different strain combinations. The administration of nontolerant donor spleen cells at 5 weeks or at 5, 8, and 11 weeks posttransplant was capable of eliminating host hematopoietic cells, leading to full or nearly full donor chimerism in six of six and two of four chimeric animals in two different strain combinations. No clinical evidence of GVHD was observed in any recipients of these donor leukocyte infusions (DLI). These studies demonstrate that induction of mixed chimerism with nonmyeloablative conditioning followed at appropriate times by DLI might allow lymphohematopoietic GVH reactions, and hence GVL effects, to eliminate chronic hematologic malignancies without causing clinically significant GVHD.

Efficient transfer of a tumor antigen-reactive TCR to human peripheral blood lymphocytes confers anti-tumor reactivity

The tumor-associated-Ag MART-1 is expressed by most human melanomas. The genes encoding an alphabeta TCR from a MART-1-specific, HLA-A2-restricted, human T cell clone have been efficiently transferred and expressed in human PBL. These retrovirally transduced PBL cultures were MART-1 peptide reactive, and most cultures recognized HLA-A2+ melanoma lines. Limiting dilution clones were generated from three bulk transduced PBL cultures to investigate the function of individual clones within the transduced cultures. Twenty-nine of 29 CD8+ clones specifically secreted IFN-gamma in response to T2 cells pulsed with MART-1(27-35) peptide, and 23 of 29 specifically secreted IFN-gamma in response to HLA-A2+ melanoma lines. Additionally, 23 of 29 CD8+ clones lysed T2 cells pulsed with the MART-1(27-35) peptide and 15 of 29 lysed the HLA-A2+ melanoma line 888. CD4+ clones specifically secreted IFN-gamma in response to T2 cells pulsed with the MART-1(27-35) peptide. TCR gene transfer to patient PBL can produce CTL with anti-tumor reactivity in vitro and could potentially offer a treatment for patients with metastatic melanoma. This approach could also be applied to the treatment of other tumors and viral infections. Additionally, TCR gene transfer offers unique opportunities to study the fate of adoptively transferred T cells in vivo.

[Digital storage phosphor mammography in a magnification technic: experimental studies for spatial resolution and for detection of microcalcifications]

PURPOSE

Since the routine use of storage phosphor systems for mammography has been limited by its inadequate spatial resolution of 5 linepairs/mm, a combination of a magnification mammography technique with storage phosphor plates was investigated to detect microcalcifications.

MATERIAL AND METHODS

A new mammography system with a microfocus tube using an anode of 0.05-0.12 mm allowed to obtain survey views of the breast with 1.7x magnification (m), and spot views with 4x magnification. The digital image receptor comprised a high resolution storage phosphor plate. To determine spatial resolution, contrast transfer curves were obtained, and the detection of microcalcifications was investigated by ROC (receiver operating characteristic) analysis.

RESULTS

Spatial resolution for digital survey views (m = 1.7) was 8 linepairs/mm and for spot views (m = 4) was 18 linepairs/mm. ROC analysis demonstrated a significantly higher performance of the digital magnification technique compared to the conventional screen-film mammography technique.

CONCLUSIONS

The limitations of digital mammography with respect to spatial resolution can be overcome by using a high magnification technique.

Substance P as an immune modulator of anxiety

Peripheral blood concentrations of the proinflammatory peptide substance P (SP) have been shown to increase in response to psychological anxiety in human subjects. In this study, we examined changes in SP levels in peripheral blood in response to the anxiety of a diagnostic medical procedure. The levels of SP were found to he higher in subjects with high initial anxiety as compared to subjects with low initial anxiety as measured on the Multiple Affect Adjective Checklist. Changes in the percentages of CD-8-expressing T lymphocytes were found to correlate with alterations in measures of anxiety as well as SP. These changes persisted for 3 days following the diagnostic procedure. The results of the study seem to indicate that SP may serve as a mediator in stress-induced immune reactions.

The pharmacological effect of sodium phosphate after absorption from the peritoneal cavity

Hyperosmolar solutions are frequently used in clinical practice for enemas. In a review of the literature we found 43 published cases of severe complications connected with the use of hyperosmolar enemas. The absorption of sodium phosphate led to a raise of the temperature up to 41.1 degrees C, massive acidosis and electrolyte disturbances with hypocalcemia and hypernatremia. The clinical picture was dominated in most of the cases by somnolence or coma. In our experiment the absorption of sodium phosphate from the peritoneal cavity of rats led to similar clinical symptoms and--depending on the amount of sodium phosphate absorbed--to the death of the animals. Hypovolemia, hypernatremia, hypocalcemia and a direct toxic effect of phosphate on the kidneys is responsible for the complex mode of intoxication. Sodium phosphate solutions should not be used in patients with inflammatory bowel disease with a high risk of laceration of the mucosa or perforation of the bowel.

Autoimmunity--towards the year 2001

The interactive roles of T cells, major histocompatibility complex (MHC) class I and II molecules and antigen-presenting cells in the generation of autoimmunity is the subject of much discussion. A recent symposium contributed to the debate by inviting experts in several fields of immunology to answer specific questions relating to the mechanisms that trigger autoimmunity.

A ligand-epitope in vitro analysis of major histocompatibility determinants expressed on B and T lymphocytes

Human histocompatibility leucocyte antigen (HLA)-specific monoclonal antibody probes were used to determine the affinity constant, and cell-surface density of HLA class I and class II determinants. The measurements were estimated for single-cell units of B-lymphoblastoid cell line (B-LCL) and cloned activated T cells in different functional states. Each HLA subset showed unimodal affinity constant values for the interaction with the corresponding HLA-specific antibodies. Such values ranged between 2.2 x 10(7) M-1 (class I) and 4.0 x 10(7) M-1 (class II) for different histocompatibility epitopes. In both B and T cells there was a rank order of epitope expression, class I being highly expressed (5 x 10(6) epitopes/cell) followed by DR, DQ and DP, (1.1-3.0 x 10(6) epitopes/cell). Suppressive clones carrying functionally defined stimulating determinants previously designated 'DY' carried similar numbers of DR, DQ and DP binding sites to DY- non-suppressive clones, but showed selective increases of class II determinants reactive with broad class II-specific antibodies. The results are discussed in the context of the functional consequences of different patterns of HLA epitope expression in immune responses.

GDA-J/F3 monoclonal antibody as a novel probe for the human sperm tail fibrous sheath and its anomalies

GDA-J/F3 monoclonal antibody (MoAb) recognized an antigen in the fibrous sheath (FS) of human spermatozoa. This was based on: (i) intracellular localization of the antigen which was limited to the principal piece of the sperm tail; (ii) its absence from the cilia of trachea and nasal mucosa which lack FS; (iii) immunogold electron microscopy (IEM) which confirmed its ultrastructural localization to the FS. The antibody was used for the detection of abnormal germ cells in human semen. Nucleated cells other than spermatozoa (NCOS) obtained from oligozoospermic donors were screened with GDA-J/F3 MoAb using the indirect immunofluorescence test. The antibody which stains only the tails in normal cells, produced diffuse cytoplasmic immunofluorescence inside some spermatids. Using phase contrast microscopy, the tails in these spermatids were either present or undetectable. Electron microscopy studies of the NCOS showed the lack of the FS in those which had the tails (afibrous tail), or the presence of disorganized tails (tail dysgenesis) in the others. This antibody therefore provides a useful analytical tool for probing the FS as well as for the easy identification of certain abnormal germ cells in human semen.

Host defense during pregnancy: monocyte adherence and killing

Pregnant women are more susceptible to candida infections than nonpregnant women. Since monocytes play a major role in host defense against candida, their association with radiolabeled candida and their capacity for killing candida were compared in sera of pregnant and nonpregnant women. While the basal rate of these monocyte functions was similar in both groups of women, candida opsonized with serum from pregnant women was less effective in enhancing these monocyte activities. Serum from nonpregnant women increased the association about twofold, whereas serum from pregnant women increased it only by about one and a half times in the two groups of women. Pretreatment of candida with serum from pregnant women increased the killing to 28%, whereas the serum from nonpregnant women was more effective, increasing the killing to 40%. The difference between the effect of the sera could not be attributed to the level of serum complement or IgG.

Major histocompatibility complex (MHC) protein analysis by optimised two-dimensional electrophoretic methods

Human histocompatibility molecules HLA-Class I and Class II (DR, DQ, DP) were analysed using three two-dimensional protocols: nonequilibrium pH gradient electrophoresis (NEPHGE), isoelectric focusing-acidic gradient (IEF-AG) and isoelectric focusing-basic gradient (IEF-BG). The three methods differ in their carrier ampholyte combinations and electrophoretic conditions. They provide different pH gradients and therefore different electrofocusing profiles. The NEPHGE protocol was adequate for separating proteins across a broad range of pI mobilities, i.e. 4.4 pH units between the acidic and the basic end. In contrast, the IEF-AG and the IEF-BG protocols gave a separation power across a narrow pH range, 1.9 and 1.7 pH units respectively. Thus, whereas the NEPHGE protocol provides a tool for a global major histocompatibility complex (MHC) antigen profile analysis, the IEF-AG and -BG allows one to investigate subcomponents of the individual MHC chains. For example, NEPHGE analysis of the HLA Class I heavy chain revealed a single spot. However, IEF-BG revealed the presence of six equidistantly spaced spots spanning a short pH gradient with identical molecular weight. Similar improved resolution was seen for the HLA-DR, DQ, and DP molecules. The IEF acidic gradient was adequate for separating the alpha chain; the IEF basic gradient gave better resolution of the beta chains. This data provides a baseline set of conditions for both analytical and preparative MHC protein studies prior to amino acid sequencing.

Association of DR4 related RFLP bands and RA in Greeks

Using the Taq1 restriction enzyme and DR beta, DQ alpha probes, the DNAs of Greek RA patients and controls were characterised for RFLP's associated with DR4. Three DR beta bands, 14.8kb, 6.1kb and 5.4kb were observed at significantly higher frequency in the patients compared with controls. By using a DQ alpha probe, the 2.6kb band (associated with DR1, DRw10, DRBR and DRw14 (Dw9)) was at a significantly raised frequency in the patients. The DQ alpha 5.3kb band associated with DR4, DR7 and DR9 was also raised in the RA patients although this increase did not reach statistical significance. In view of the previously documented lack of association between DR4 (and other DR antigens) and RA in Greeks, the results suggest that some degree of HLA class II association exists with RA in this population at the DNA level which may not be overtly reflected serologically.

Detecting Chlamydia trachomatis in men with urethritis: serology v isolation in cell culture

The accuracy of single serovar (L2) inclusion immunoperoxidase assay (IPA) to show serum IgG and IgA antibodies specific to chlamydiae was compared with culture for Chlamydia trachomatis to diagnose chlamydial infection in 73 men with acute urethritis. C trachomatis only was isolated from 18 (25%), Neisseria gonorrhoeae only from 17 (23%), and both organisms from six (8%). Thus 24 (33%) yielded chlamydiae. Assays based on IgG antibodies to chlamydiae at a titre of 1/64 or more showed high sensitivity (96%) and a good negative predictive value (80%), but low specificity (13%) and agreement (48%) compared with culture. IgG antibodies to chlamydiae at a titre of 1/128 or more showed lower sensitivity (75%) but higher specificity (72%), negative predictive value (79%), and agreement (73%). IgA antibodies to chlamydiae at a titre of 1/8 or more showed a sensitivity of 88%, specificity of 72%, negative predictive value of 88%, and agreement of 79%. An appreciable (fourfold or more) decrease in IgA and IgG titres was observed in most (10) of the 15 men from whom second blood samples were obtained one to two years after treatment. Measuring specific IgA and IgG antibodies to chlamydiae by IPA may serve as a useful complementary test for diagnosing and following up patients with urethritis.

Characterization of two monoclonal antibodies raised against human testicular cells

Human testicular cells isolated from biopsy tissue were used for generation of monoclonal antibodies. Two hybridoma supernatants C3 and D4 were selected according to their reaction with sperm-precursor cells (immature sperms) in an enzyme-linked immunosorbent assay (ELISA). C3 reacted with testicular but no other tissue. D4 did not reveal any pattern of testicular staining in spite of its similarity to C3 in binding to sperm-precursor cells in ELISA and microcytotoxicity test.

HLA associations with multiple sclerosis in Sicily and Malta

The islands of Sicily and Malta have very different prevalence rates for multiple sclerosis (MS): at least 44 per 100,000 in Sicily and only 4 per 100,000 in Malta. In Northern Europe, MS is associated with HLA-DR2/Dw2. The other components of the commonest DR2-containing haplotype of this region, HLA-A3-B7-DR2-Dw2, also tend to be present at higher frequency in MS patients. HLA Class I and II antigen frequencies and associations in controls and MS patients from Sicily and Malta were studied to discover whether they might account for the difference in MS prevalence. In Sicilian MS patients, DR2 is increased in frequency compared with controls and four out of five DR2-positive patients also type as Dw2. In the Maltese population, DR2 is present at high frequency but approximately half of the DR2 positive individuals do not type as Dw2 so that DR2 is probably most commonly present as part of Class II haplotypes other than those commonly associated with MS. Additional differences in HLA profile of the Sicilian and Maltese populations were found when HLA-A, -B, and B-DR antigen associations were examined. Therefore, some of the difference in MS prevalence might be explained by genetic factors.

A DR3-related DX alpha gene polymorphism strongly associates with insulin-dependent diabetes mellitus

HLA-DQ alpha and HLA-DX alpha gene polymorphisms were analyzed by Southern blot techniques in 78 Caucasoid insulin-dependent diabetes mellitus (IDDM) subjects and 55 control subjects. Five restriction fragment length polymorphisms of the HLA-DQ alpha gene correlated with HLA-DR typing. Two allelic DX alpha-related gene fragments, of 2.1 kb (U) and 1.9 kb (L) in size were identified. Genotype frequencies in the IDDM group for UU, UL, and LL were 54%, 38.5%, and 7.5%, respectively, whereas the corresponding frequencies in the control group were 24%, 40%, and 36% (P less than 0.00005 for differences in genotype frequencies). The U allele was associated particularly with IDDM patients who were DR3, with healthy controls who were DR3, as well as with IDDM patients who were not DR3. Thus, if this DX alpha U allele is not the DR3-associated IDDM susceptibility gene, it is the closest marker hitherto studied.

Sources of variance in the double normalized value: an evaluation of its reproducibility as a measure on HLA-D locus identity

Two different sets of mixed lymphocyte culture (MLC) experiments were performed using HLA-D homozygous typing cells (HTC). In all stimulator-responder combinations the median cpm's of four replicate cultures were reduced into double normalized values (DNV). In the first experimental set the responder panel was unselected, whereas the responders for the second set were chosen on the basis of either sharing an HLA-D determinant with the stimulator (ID) or not (non-ID). The experiments were designed: Set 1: To estimate the technical variability in the DNV's and to observe the distribution of this variability. The standard deviation of an observation on a stimulator-responder combination was approximately 24 DNV units. Thus, by running 6 experiments on each responder we would have a mean DNV with a standard error of 10 DNV units. Set 2: To determine whether stimulators typing for the same Dw specificity had the same distribution of DNV's and to investigate the variability between responders, between experiments and within experiments. Although the mean DNV is the same for all HTC's, the variability in observations was greater for some HTC's than for others. The variability may be completely technical for some HTC's, whereas for other HTC's there is evidence of responder variability and between experiment variability. Important implications of these results are: (1) that in using a single cut-off value of 60 for all HTC to define typing responses one will have a very high misclassification rate for a large percentage of ID responders; (2) for some HTC this error rate can be reduced through repeating the experiment 4 times and raising the cut-off point; (3) this error, together with the technical and/or experimental variance can be further reduced by using 2 or more HTC's of the same specificity in each experiment and by combing their data; (4) misclassification can be reduced in every situation by doing 4 experiments, using 2 HTC per responder and computing a cut-off which gives a misclassification rate for each Dw type of 10% in ID's and in non-ID's. Thus the best approach to achieving Dw locus typing with a desirable low rate of misclassification would be to do similar control studies of every HTC, to estimate technical experimental and responder variance and then use this information to determine a cut-of value and the number of HTC's and experiments per responder required to keep the error rate at a satisfactory level.

HLA antigens in chronic relapsing idiopathic inflammatory polyneuropathy

Observations are reported on 14 patients with a clinical diagnosis of recurrent or chronic relapsing idiopathic inflammatory polyneuropathy of Guillain-Barré type. The results suggest the possibility of a disease susceptibility gene for this disorder associated with the HLA-A1, -B8, -DRw3, and -Dw3 haplotype.

HLA antigens in Guillain-Barré syndrome

Sixty patients with suspected lumbar herniated disk and/or canal stenosis were studied prospectively with surface coil MRI, CT, and/or myelography, and the results were compared with the surgically confirmed abnormality. Forty-eight patients had lumbar surgery at 62 levels. There were no negative explorations. Thirty-nine patients had a myelogram and CT. Thirty of the CTs were performed following the injection of metrizamide for myelography. Nine patients had a CT without intrathecal contrast material 1 to several days before the myelogram. Six patients had myelography only, and three patients had CT only. All studies were evaluated for the location and type of disease in a forced choice fashion. Independent of the surgically correlated levels, there was 86.8% agreement between the MR and CT studies in all patients at 151 levels and 87.2% agreement between MR and myelography at 218 levels. At the operative levels, there was 82.6% agreement between MR and surgical findings for both type and location of disease; 83% agreement between CT and surgical findings; and 71.8% agreement between myelography and surgical findings. There was 92.5% agreement when MR and CT were used jointly, and 89.4% agreement when CT and myelography were used jointly. The results of this study indicate that a technically adequate MR examination was equivalent to CT and myelography in the diagnosis of lumbar canal stenosis and herniated disk disease. CT and MR can be complementary studies, and surface coil MR can be viewed as an alternative to myelography.