DR Antibodies Research Articles

106-P Clinical significance of dynamic monitoring of anti-HLA and anti-MICA antibodies after renal transplantation and specific immunoadsorption of anti-HLA DR antibodies

106-P Clinical significance of dynamic monitoring of anti-HLA and anti-MICA antibodies after renal transplantation and specific immunoadsorption of anti-HLA DR antibodies

DynaChip Anti-HLA Antibody Analysis In Sera of Patients Following Allo-HSCT From HLA-Mismatched Unrelated Donors.

AbstractAbstract 4575 Introduction:Anti-HLA antibodies constitute potentially important factor that may influence outcomes of HLA-mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT). The rationale of this study was to detect presence of anti-HLA antibodies in recipients of allo-HSCT from HLA-mismatched unrelated donors. Patients and Methods:Anti-HLA-A,B,C,DR,DQ,DP antibodies were identified in sera collected from 46 recipients of allo-HSCT from HLA-mismatched unrelated donors. Sera were collected between 1 month and 5.5 years after allo-HSCT, and additionally before allo-HSCT in 17 pts. We have used microchips spotted with purified HLA class I and HLA class II antigens to allow binding of anti-HLA antibodies present in tested sera to the surface of the microchip, pre-optimised reagents and DynaChip Processor (Dynal Invitrogen Corporation) for assay processing, data acquisition and analysis. Results:Antibodies against HLA class I, II or I and II were detected in 15%, 11% and 35% of pts whereas no antibodies were detected in 39% of patients. Antibodies were directed against HLA-A, B, C, DR and DQ in 37%, 46%, 35%, 48% and 35% of pts, respectively. Pre-transplant anti-HLA antibodies have been detected in 7 pts (41%) out of 17 tested before allo-HSCT. In this group percent of Panel Reactive Antibodies (% PRA) increased following allo-HSCT in 3 pts and decreased in 4. In 5 out of 10 remaining pts without pre-transplant antibodies, %PRA increased post-transplant. DynaChip software allowed to define specificities of HLA-A,B,C,DR and DQ antibodies on low and high resolution levels. The specificity of antigens that masked results of antibody identification has been also defined in 2 pts. At this stage we did not define exactly whether detected anti-HLA antibodies were donor-specific. Cross-reactive groups (CREG's) analysis has been also used to compare antibodies' reactivity. Anti-HLA-DP antibodies were not detected in the examined group of transplanted patients. Conclusions:Presented preliminary study results indicate, that anti-HLA antibodies can appear post-transplant in mismatched allo-HSCT recipients. Further analysis aiming to evaluate their influence on transplant outcomes is ongoing. We intend to extend the search for anti-HLA antibodies with use of Luminex LabScreen method. Disclosures:No relevant conflicts of interest to declare.

Usefulness of the CD63 basophil activation test in detecting Anisakis hypersensitivity in patients with chronic urticaria: diagnosis and follow-up

The basophil activation test (BAT) has been recently described as a useful in vitro tool for diagnosis of allergy to Anisakis species in patients with acute urticaria. To evaluate the relationship between sensitization to Anisakis simplex and chronic urticaria (CU), using flow cytometry analysis of in vitro BAT. Methods. A. simplex sensitization was evaluated in patients with CU (n = 57) and in atopic (n = 22) and healthy controls (n = 20) by means of skin prick test (SPT), specific IgE and Anisakis-induced BAT using a triple-labelled strategy with anti-CD123, anti-human leucocyte antigen DR and anti-CD63 antibodies. During a follow-up period of 6 months in 10 patients with CU who accepted a fish-free dietary regimen, the diagnostic performance of the in vivo and in vitro methods was calculated, and changes in specific IgE and BAT were evaluated with respect to clinical response. A significant association between CU and A. simplex sensitization was found, with an overall prevalence of 75.4% in patients with CU (43/57) compared with 18% (4/22) and 10% (2/20) of the atopic and healthy controls, respectively (P < 0.0001). BAT (cut-off > 13%) had the highest sensitivity and specificity, with significantly better ability than specific IgE testing for the identification of A. simplex sensitization in patients with CU. During the 6-month follow-up, clinical improvement was seen in all patients, and specific IgE and BAT results decreased to normal values in 6/10 (60%) and 10/10 (100%) patients, respectively. BAT can be considered a reliable new in vitro method to evaluate A. simplex hypersensitivity in patients with CU, supplementing standardized procedures in both diagnosis and follow-up.

Enhanced Kidney Allocation to Highly Sensitized Patients by the Acceptable Mismatch Program

). Highly sensitized patientshave only a small chance to receive a crossmatch negativedonor kidney, because they have developed antibodiesagainstmanydifferentHLAantigensresultingfrompreviouscontacts with allogeneic cells by pregnancy, blood transfu-sions,orprevioustransplants.Ifnospecialmeasurementsaretaken, these patients will accumulate on the transplant wait-ing lists. More and more transplant centers are developingstrategiestoremovecirculatingHLAalloantibodiesinthesepa-tients to be able to transplant the patient with a donor kidneydespite a positive crossmatch (

Novel Mechanisms of Non-Apoptotic Cell Death Evoked by Type II Anti-CD20 (Tositumomab) and HLA-DR Monoclonal Antibodies

Monoclonal antibodies (mAb) directed to a range of cell surface antigens on malignant lymphoid cells are increasingly a key component of the treatment of a whole range of haematological malignancies and remain the focus of intense ongoing clinical investigation. The anti-CD20 mAb rituximab has over the last decade substantially increased clinical responses leading to a marked improvement in outcome for many patients with B cell malignancies. The pursuit of mAb to improve on the efficacy of rituximab is currently undergoing intensive research, with several new candidate mAb now undergoing clinical evaluation. These newer generation anti-CD20 mAb have largely focused on improvements in increasing the affinity of the Fc-FcgR interactions and the recruitment of immune effector cells as these are thought to underlie much of the mAb therapeutic effect. However the immune effector functions of mAb does not explain why certain mAb specificities are more potent than others in inducing tumour cell death. Previously, we have demonstrated that Type II anti-CD20 mAb (Tositumomab) were able to evoke direct cell death via a non-apoptotic mode of death that appeared to be linked with the induction of homotypic adhesion. In this study we have considerably extended these observations using both in vitro cell lines and primary CLL cells. Using time-lapse microscopy and the FRAP technique, we revealed that de novo F-actin synthesis within cell contact area is critical for both homotypic adhesion and cell death induced by both Type II anti-CD20 mAb (Tositumomab) and HLA DR Class II mAb (L243). We have demonstrated that the mode of cell death engaged is rapid, non-apoptotic and non-autophagic as detected by inability to inhibit this form of cell death with pan-caspase inhibitor QVD, overexpressed Bcl2 as well as with siRNA against key autophagy regulators Beclin 1 and ATG-12. Scanning and transmission electon microscopy studies revealed the cytoplasmic nature of cell death involving lysosomes which swell and then disperse their contents into the cytoplasm. The increase in the lysosomal compartment followed by lysosome membrane permeabilisation and subsequent cell death has also been confirmed by flow cytometry and fluorescence microscopy, using lysosome specific probe lysotracker. Furthermore, this cell death has been shown to be dependent on active V-type ATPase but not on chymotrypsinlike or trypsin-like serine proteases. Using time lapse microscopy, we show here for the first time that malignant B cells, undergoing homotypic adhesion, actively communicate via ~ 5 nm wide temporary inter-cytoplasmic bridges. The formation of these channels is accompanied by the exchange of plasma membrane components. Moreover, the extent of plasma membrane swapping correlates with the extent of cell death induced by both anti-CD20 and anti-HLA DR antibodies. This data provide new insights into the potential mechanisms underlying mAb-induced cell death and may guide the rational design of more effective mAb therapy in B cell malignancies.

Rosette formation by macrophages with adhered T lymphocytes is precluded by inhibitors of antigen processing and presentation

We had previously found in autologous human leukocyte cultures, in which dead neutrophils phagocytosis by macrophages occur, macrophages and T CD4 lymphocytes perform a selective cell-cell interaction showing many figures of either one, two or several T- lymphocytes adhering to a central macrophage were seen. Considering that antigen presentation would be necessary for the formation of these immune synapses, we attempted to block rosette formation (i.e., the formation of macrophage associations with at least three lymphocytes) by interfering with both antigen processing and presentation. Culture samples of autologous leukocytes from 7 healthy donors were subjected to either brefeldin A, chloroquine or to an anti-HLA DR antibody. Rosette formation was significantly inhibited in the treated samples (either with brefeldin A, chloroquine or the anti- HLA DR; ANOVA, p<0.001, as compared with the untreated controls). It is concluded that interference with antigen processing and presentation precludes the formation of these cell-cell interactions.

Interference with TRALI‐causing anti‐HLA DR alloantibody induction of human pulmonary microvascular endothelial cell injury by purified soluble HLA DR

Antibodies to human leucocyte antigens (HLA) and human polymorphonuclear neutrophil (PMN) antigens are considered etiologic agents of transfusion-related acute lung injury (TRALI). The aim of this study was to clarify the role of anti-HLA DR antibodies in the pathophysiology of TRALI and the ability of purified soluble HLA DR (psHLA DR) to inhibit the release of cytokines in an in vitro model. A coculture of human pulmonary microvascular endothelial cells (HMVEC) and monocytes in the presence of serum containing anti-HLA DR alloantibodies previously associated with cases of TRALI was used as an in vitro TRALI model. The release of leukotriene B(4) (LTB(4)) and tumour necrosis factor-alpha (TNF-alpha), the apoptosis of HMVECs were measured. The release of LTB(4) and TNF-alpha and apoptosis of HMVECs were observed in the model. The addition of psHLA DR markedly reduced the release of LTB(4) and TNF-alpha and inhibited apoptosis of HMVECs. These results support the critical role of anti-HLA DR alloantibodies in the pathogenesis of TRALI and suggest that the soluble HLA DR could inhibit TRALI development caused by anti-HLA DR alloantibodies.

46-P: Majority of non-donor specific DR antibodies shares epitopes with mismatched donor antigens in renal transplant recipients

46-P: Majority of non-donor specific DR antibodies shares epitopes with mismatched donor antigens in renal transplant recipients

Impaired Maturation of Monocyte Derived Dendritic Cells from Birch Allergic Individuals

RATIONALE: To study whether monocytes differentiated dendritic cells (DCs) from healthy and birch allergic asthmatic individuals differs in their phenotypic receptor expression and cytokine secretion. METHODS: Monocytes were isolated from separated mononuclear cell from allergic (n= 14) and healthy (n=14) individuals. Differentiated DCs were further pulsed by adding birch and cat allergens and LPS, and non- stimulated DCs were included as controls. DCs stained with anti-CD83, -CD80, - CD1a; -CD86, -CD11c and - HLA DR antibodies were analysed by four-colour flow cytometry. Cytokines and chemokines were measure in DCs supernatant in a Bio-Plex Human 7-plex assay, including IL-6, IL-8, IL-10, IL-12p70, MCP-1/MCAF, TNF- and MIP-1. RESULTS: The percentages of DCs expressing HLA-DR, CD80, CD86, CD83, CD1a and CD11c were similar in cells from allergic and healthy individuals. However, while cells from healthy donators showed similar activation of the CD80 and double CD80/CD86 receptors after stimulation as compared to non-stimulated cells, birch allergen was unable to increase CD80 and double CD80/CD86 expression on cells from allergics. Levels of IL-12p70 and TNF-α were higher in supernatant from non-stimulated cells from healthy and further increased after birch and LPS stimulation. After cat stimulation, increased levels of IL-8, IL-10, MIP-1 and MCP-1 were detected in samples from allergic while the levels after birch stimulation. CONCLUSIONS: Our results suggest an impaired specific maturation of DCs from birch allergic individuals in association to birch specific immune responses. Lower secretion of IL-12p70 indicated that the specific Th1 function seems to be affected in allergics.

Ocular defense mechanisms with special reference to the demonstration and functional morphology of the conjunctiva-associated lymphoid tissue in Japanese monkeys

In order to define the histological components of ocular defense, the conjunctiva in Japanese monkeys was studied using a whole mount method, light microscopy, and electron microscopy. We investigated the distribution of the conjunctiva-associated lymphoid tissue (CALT) using stereoscopic observations of the conjunctiva immunostained with human leukocyte antigen (HLA)-DR antibody and /or stained with alcian-blue. The outer surface of the conjunctival fornix was lined by sheets of mucus secreting goblet cells, with small epithelial patches without goblet cells, scattered among them. The patches, termed CALT, consisted of flattened epithelial cells, intraepithelial lymphocytes and dendritic cells, and lymphoid follicles with a germinal center. The CALT in Japanese monkeys was fundamentally similar in structure to those found in other animal species. CALT patches ranged in size ranging from 200 microm to 300 microm in diameter. The number of patches varied from 20 to 40 in the superior eyelid and 10 to 20 in the inferior eyelid. Latex microspheres administrated as eye drops were selectively taken up first by flattened associated epithelial cells covering the surfaces of CALT patches and then by intraepithelial dendritic cells of the CALT. These morphological findings show that CALT patches in the eyelids of primates are focal sites for particulate uptake and contact with lymphoid constituents, indicating that they are inductive sites for the common mucosal immune system as well as important components in ocular defense.

Characterization of anti-islet cytotoxic human T-cell clones from patients with type 1 diabetes mellitus

To identify important anti-islet T-cells and their target antigen(s), we have isolated and characterized seventeen human T-cell clones which are reactive to an extract of rat insulinoma (RIN) cells from three children with new onset type 1 diabetes mellitus (T1D). Of these 17 clones, 15 were found tissue specific. Six of eight tested tissue specific clones did not recognize known islet antigens such as GAD, 52 kDa islet protein, insulin, ICA512, and heat shock protein 60 (hsp60), suggesting that these clones recognize an autoantigen not previously identified. All tested clones were phenotypically CD4 and functionally Th0 or Th0/Th1 cells. One RIN extract reactive clone (2E9) recognized hsp60 and was CD4 and TCR α/β positive. This clone also proliferated in response to human and rat islets suggesting that the antigen is conserved between species. This clone and 75% of all the tested RIN reactive clones exhibited anti-islet cytotoxicity by lysing target cells coated with RIN extract. HLA DR determinants may play a role in this cytotoxic activity since preincubation with HLA DR antibody decreased the anti-islet cytoxicity of the two tested clones. In conclusion, we have isolated RIN reactive CD4+T-cell clones from diabetic subjects, six of which appears tissue specific and non-reactive to putative important islet antigens, and in turn may be recognizing yet undiscovered islet antigens. The high frequency anti-islet cytotoxic properties of the islet reactive clones provides evidence for a role of CD4+ cytotoxic T-lymphocytes in the diabetic process. Further, the isolation of hsp60 reactive clone with anti-islet cytotoxic properties suggests that cell mediated immunity against hsp60 may be important in the pathogenesis of diabetes.

Possible mechanisms underlying development of transfusion‐related acute lung injury: roles of anti‐major histocompatibility complex class II DR antibody

Anti-major histocompatibility complex (anti-MHC) antibodies (Abs) and antipolymorphonuclear neutrophil (anti-PMN) Abs are generally considered as the main causes of the development of transfusion-related acute lung injury (TRALI), which is one of the most severe and sometimes lethal side effects of transfusion. These Abs are postulated to activate recipient's leucocytes, resulting in the release of soluble factors such as reactive oxygen species and detrimental cytokines and chemokines. The harmful effects on the lung tissues and resident leucocytes of these malignant factors are suspected to be profoundly involved in TRALI reactions. Several reports have indicated the principle effect of biologically active lipids on the pathogenesis of TRALI. However, the precise mechanisms of TRALI development remain unclear. To resolve this issue, we have been investigating cytokines that induce continuous inflammation of the lungs, specifically focusing on the cytokines derived from activated PMNs. We observed that the granulocyte-macrophage colony-stimulating factor (GM-CSF) markedly enhances the expression of MHC class II DR in PMNs. Moreover, MHC class II DR-expressing PMNs were also proved to express a high-affinity receptor for immunoglobulin E (IgE) (FcepsilonRI) and to produce tumour necrosis factor-alpha, interferon-gamma and interleukin-18 following a challenge with an anti-MHC class II DR monoclonal Ab (MoAb) or anti-DR antiserum. It is strongly suggested that amongst various inflammatory mediators, at least these three cytokines may contribute to the duration of inflammatory reactions in the lungs. Furthermore, FcepsilonRI expression, in GM-CSF-treated PMNs, suggests the involvement of PMNs in IgE-mediated immune reactions.

Multicentric inflammation in epicardial coronary arteries of patients dying of acute myocardial infarction

ObjectivesWe sought to test the hypothesis of whether inflammatory cell infiltration in patients dying of an acute myocardial infarction (MI) is a multifocal event involving multiple coronary branches. BackgroundCoronary instability is thought to reflect local disruption of a single vulnerable plaque. However, previous postmortem studies have not addressed the question of whether activation of inflammatory cells, particularly T lymphocytes, is limited to the culprit lesion only or rather diffuse in the coronary circulation. MethodsWe performed a systematic flow cytometric study in three groups of autopsied patients (group 1 = acute MI; group 2 = old MI; group 3 = no ischemic heart disease). Cell suspensions of enzymatically digested coronary arteries were stained for flow cytometry with CD3, CD68, alpha-smooth muscle actin, and human leukocyte antigen (HLA)-DR antibodies. ResultsThe coronary plaques showed: 1) a higher proportion of inflammatory cells in groups 1 and 2 than in group 3; 2) a higher percentage of T lymphocytes in group 1 than in group 2 (11.67 ± 0.70% vs. 5.67 ± 0.74%, p = 0.001) and in group 2 than in group 3 (p = 0.008); and 3) diffuse cell activation in the whole coronary tree of group 1, but not of group 2 subjects. ConclusionsOur study suggests that lymphocytes may play a key role in coronary instability by determining activation of various cellular types throughout the coronary circulation. Activated T lymphocytes and their products may well represent a new target in both the treatment and prevention of acute coronary syndromes.

Enhanced killing of B lymphoma cells by granulocyte colony-stimulating factor-primed effector cells and Hu1D10--a humanized human leucocyte antigen DR antibody.

Antibody-based approaches have become a novel treatment modality for lymphoma patients. Humanized 1D10 (Hu1D10; Remitogen) is among the antibodies that are currently under evaluation in phase II clinical trials in lymphoma patients. The 1D10 antibody is directed against a polymorphic epitope on the beta-chain of human leucocyte antigen (HLA) class II. We found expression of the 1D10 epitope on B cells and monocytes from approximately 50% of healthy donors. Analyses of 1D10 expression on malignant cells revealed that approximately half of the HLA class II-positive haematological malignancies expressed the 1D10 epitope. In whole blood antibody-dependent cellular cytotoxicity (ADCC) assays, Hu1D10 was more effective than rituxan in killing malignant ARH-77 B cells. Interestingly, Hu1D10-mediated lymphoma cell lysis was significantly enhanced when blood from granulocyte colony-stimulating factor (G-CSF)-treated patients was compared with blood from healthy controls. Analyses of the relevant effector cell populations revealed that FcgammaRI (CD64)-positive polymorphonuclear cells were critical for enhanced Hu1D10-mediated lymphoma killing during G-CSF therapy, while the same effector cell population induced only marginal lysis with rituxan. Furthermore, Hu1D10 was highly effective in inducing apoptosis in primary lymphoma cells from B chronic lymphocytic leukaemia patients. These preclinical results form the basis for a phase I/II clinical trial of Hu1D10 in combination with G-CSF.

Unusual expression of human lymphocyte antigen class II in normal renal microvascular endothelium

The human lymphocyte antigen (HLA) class II proteins (DR, DQ, and DP) and DM, a protein involved in loading antigenic peptide onto the class II molecules, have a coordinate regulation that facilitates antigen presentation to CD4+ T cells. CIITA is a specific transcription factor responsible for the coordinate regulation of these genes. DR expression in the kidney was described to be constitutive on renal microvascular endothelium in the early 1980s, but expression of other genes involved in class II antigen presentation (DQ, DP, DM, and CIITA) has not been characterized. Expression of the HLA class II proteins, DM, and CIITA in normal human kidney cortex was evaluated by immunofluorescence microscopy, Northern blots, and reverse transcriptase-polymerase chain reaction (RT-PCR). The endothelium of glomerular and peritubular capillaries constitutively express DR, as indicated by colocalization of DR and CD31 antibodies. However, the endothelium of larger renal blood vessels is devoid of class II proteins. Capillaries that express DR do not have detectable DQ, DP, or DM by immunofluorescence. Northern blots identified DR, DP, and DM mRNAs but not DQ mRNA. CIITA was amplified by RT-PCR at a level that could account for the class II expressed by the microvascular endothelium. The renal microvascular endothelium constitutively expresses DR without the other class II proteins or DM. This discoordinate expression of HLA class II genes is unusual and may contribute to the kidney's ability to control CD4+ T-cell responses.

High incidence of maternal HLA A, B and C antibodies associated with a mild course of haemolytic disease of the newborn

Mild courses of haemolytic disease of the foetus or newborn (HDN) due to Rh (D) blood group antibodies are associated with and may therefore be ameliorated by maternal antibodies reacting with human leucocyte antigens (HLA) of the child, an observation drawn from our own earlier data (Neppert J, Kissel K. Lancet 1992;339:1481). This study (i) corroborates this association; (ii) reveals shortcomings in the published data; and (iii) examines the characteristics of HDN cases when these shortcomings have been rectified. Samples from 51 women with antibodies against their child's blood group antigens of the Rh system were analysed for HLA A, B, C and DR antibodies during parturition. The mothers were divided into two groups, either severe or mild, dependent upon the clinical course of the HDN, and the incidence of HLA antibody production was determined for each group. HLA A, B, C and/or DR antibodies were detected in 85.2% of those women whose children had a mild course of HDN prenatally or perinatally (n=27). This is statistically greater than the incidence of 50.0% (Fisher's exact test: p=0.014) found in the group of women whose children had a severe HDN either pre- or perinatally (n=24) and is greater than the 35% (n=20; p=0.0001) found in women without Rh or other irregular antibodies. HLA DR antibodies were detected in three cases. The findings support our hypothesis that maternal anti HLA A, B and C antibodies may protect against a potential severe HDN. We therefore assume that those women will benefit who have already had a child with a severe HDN and in whom HLA antibodies were not previously detected, if HLA antibody production is provoked by subcutaneously inoculating with the father's leucocytes before or at the beginning of the new pregnancy.

Allele-unrestricted presentation of lidocaine by HLA-DR molecules to specific alphabeta+ T cell clones.

T cells recognize peptide and non-peptide antigens. Drugs represent typical examples of non-peptide antigens. The majority of drug-specific T cells are alphabeta+ TCR T cells and are MHC class I or II restricted. Here we show the existence of drug (lidocaine)-specific T cell clones which proliferate in the presence of antigen-presenting cells (APC) with different HLA alleles. Two clones (SFT24 and E20) were analyzed in detail. They show a narrow dose-dependent proliferation to lidocaine, but not to procaine. With the use of a panel of HLA-typed allogeneic APC, we observed that certain allogeneic APC plus lidocaine lead to a similar, others to partial and some to no proliferation of the lidocaine-specific T cell clones. An APC-independent proliferation could be excluded since both clones proliferated only marginally without APC and increasing the number of APC resulted in a higher proliferation. Blocking experiments with anti-DP, -DQ and -DR antibodies showed that lidocaine is presented in a HLA-DR-restricted way both with autologous or allogeneic APC. Mouse fibroblasts transfected with an allogeneic HLA-DRB1*01 but not HLA-DR-negative mouse fibroblasts could serve as presenting cells. Fixation of APC did not hamper drug presentation, but pulsing of APC with the drug was not possible, indicating that processing is not required and that lidocaine binds in an unstable way to the MHC-peptide complex. This degenerate drug recognition has certain features of superantigen recognition, such as the ability of drugs to bind from the outside to multiple HLA-DR alleles. Such features of drug recognition may open new therapeutic possibilities to intervene with TCR-MHC interactions in a selective way.

Characterization of a Human T Cell Line Reactive to a 52 kDa Islet Protein

A 52 kDa islet protein has recently been identified as the target of autoantibodies in the NOD mouse model of IDDM and humans with IDDM. However, the presence of T cell immunity against the 52 kDa islet protein in IDDM has not been reported. We report the establishment and characterization of a T cell line (19KW) that reacts to purified 52 kDa islet protein (purified p52) from a subject with IDDM. The purified p52 induced a proliferative response as measured by thymidine incorporation in the 19KW T cell line with a stimulating index of up to 48. The proliferative responses were greater with increasing doses of purified p52 (0.1, 0.5, 2.0, and 6.0 μg/well). No reactivity was found to a liver fraction purified in the same manner as 52 kDa protein, BSA, ovalbumin, extracts of rat muscle, fibroblast, adrenal, or pituitary tissue and to a rat exocrine cell tumor. Irradiated PBMC were required as antigen presenting cells (APC) for 19KW reactivity to the purified p52. The addition of anti-HLA DR or anti-HLA DQ antibodies significantly decreased the islet antigen-induced proliferative response. The addition of antibodies to HLA DP and class I MHC had no effect. Flow cytometric analysis revealed that the majority of T cells expressed CD4 and CD45RO molecules. T cell receptors Vβ6 and Vβ5.1 were found on 30 and 14% of the CD3+(T cells) 19KW cells, respectively. In conclusion, a purified p52-reactive human T cell line predominantly consisting of TCR Vβ6+and Vβ5.1+cells has been established from a subject with IDDM. Reactivity to the purified p52 is antigen dose-dependent, tissue specific, requires irradiated PBMC as antigen presenting cells, and is HLA DR- and HLA DQ-restricted. T cell lines specifically reactive to p52 may be useful for investigating further the role of this antigen in the pathogenesis of IDDM.

Chronic inflammatory demyelinating polyradiculoneuropathy. Study of 18 cases

This is a prospective study that describes 18 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), idiopathic type. The patients have been followed for a period of 4 to 127 months. We evaluated the clinical characteristics, the evolution, and therapeutic response. Male patients outnumbered female patients in a proportion of 1.25:1. Symptoms first appeared at an age ranging from 6 to 85. Most of the patients denied the occurrence of preceding events and a progressive evolution prevailed over relapsing evolution. All patients had both motor and sensory dysfunction associated with loss of tendon reflexes, and only three patients (16.7%) had cranial nerve involvement. The cerebrospinal fluid protein levels were increased in 88.9% of the patients and mean level was 203.4 mg/dl. Electrophysiological studies revealed demyelination in all patients and axonal damage in 94.4%. Preponderant characteristics in the sural nerve biopsy of seven patients showed demyelination and remyelination, and changes indicative of axonal damage were often present. The anti-HLA Dr antibodies were found in the sural nerve of one patient and anti-CD3 antibodies in the sural nerve of two. All patients were first treated with prednisone. The drug was maintained in reduced doses and given in alternate days to 72.2% of the patients with success. Two patients (11.1%) are asymptomatic even after the withdrawal of all medication. We administered azathioprine, associated or not with corticoid, to the four patients who had not had a satisfactory response to the prednisone treatment. By the time of the last evaluation 16 patients (88.9%) had functional improvement.

Reactivity of antibodies directed against human antigens with surface markers on canine leukocytes.

A panel of anti-human antibodies was used in order to investigate their cross-reactivity with canine leukocytes. The labeling was carried out at the microscopic level by immunocytochemical staining. Of 50 antibodies 22 cross-reacted with canine leukocytes from afferent lymph and peripheral blood. All leukocytes reacted with MHM23 (CD18). Two anti-HLA DR antibodies, DK22 and L243, reacted mostly with veiled cells and with PHA-stimulated lymphocytes, whereas TAL1B5 was cross-reactive with all canine lymphocytes. The activation markers CD25, Ki-67, PCNA were identified on PHA-stimulated lymphocytes with ACT1, Ki-67 and PC10 clone produced antibodies. Canine eosinophils reacted with MHM6 (CD23) antibody. A large number of antibodies reacted with canine lymph veiled cells. Canine granulocytes and a subset of lymphocytes were stained with the anti-CD15 antibody only after treatment of cytospins with neuraminidase.