Acquired Hemophilia in an Elderly Patient with Non-Small Cell Lung Cancer: a Case Report.

Acquired hemophilia A (AHA) is a rare autoimmune disease caused by autoantibodies against coagulation factor VIII and characterized by spontaneous hemorrhage in patients with no previous family or personal history of bleeding. We report here a case of AHA that occurred in the Department of Medicina D'Urgenza in Sant'Andrea Hospital in a patient with previous diagnosis of NSLC. The aim of this article is to allow a more comprehensive knowledge of AHA that both for the rarity and the poor literature is underdiagnosed; for all these reasons, it is important that different specialists, like emergency specialists, experts in internal medicine, hematologists, and oncologists, acquire a more complete knowledge of the clinical and laboratory features of this disease, allowing an early diagnosis crucial for the evolution of the coagulopathy.

Transferrin receptor mediates uptake and presentation of hepatitis B envelope antigen by T lymphocytes.

Human activated T lymphocytes expressing class II molecules are able to present only complex antigens that bind to their own surface receptors, and thus can be captured, internalized, and processed through the class II major histocompatibility complex processing pathway. We have used the antigen-presenting T cell system to identify the viral receptor used by hepatitis B virus (HBV) to enter cells, as well as the sequence of HB envelope antigen (HBenvAg) involved in this interaction. Results show that both CD4+ and CD8+ T clones can process and present HBenvAg to class II-restricted cytotoxic T lymphocytes and that the CD71 transferrin receptor (TfR) is involved in efficient HBenvAg uptake by T cells. Moreover, we provide evidence that the HBenvAg sequence interacting with the T cell surface is contained within the pre-S2 region. Since TfR is also expressed on hepatocytes, it might represent a portal of cellular entry for HBV infection. This system of antigen presentation by T cells may serve as a model to study both lymphocyte receptors used by lymphocytotropic viruses and viral proteins critical to bind them.

Enhanced production of interferon-gamma by T lymphocytes cloned from rejected kidney grafts.

Seventy-seven T cell clones were generated from cell blasts infiltrating rejected kidney allografts. All clones, either CD4 or CD8, displayed cytolytic activity evaluated by lectin-dependent cell-mediated cytotoxicity (LDCC) and natural killer activities. Furthermore, both types of clones were able to produce IFN-gamma following PHA stimulation. These data suggest that the graft infiltrate is characterized by T cell clones with cytolytic potential responsible for the killing of graft cells. The production of IFN-gamma, enhancing the class II MHC expression, may amplify the recipient immune response.

Tumor necrosis factor-alpha and interferon-gamma synthesis by cerebrospinal fluid-derived T cell clones in multiple sclerosis.

T cell clones derived from cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) were analysed for their capacity to produce interleukin 2 (IL-2), interleukin 4 (IL-4), interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). They were also compared with liver-infiltrating T cell clones from patients with chronic active hepatitis. All the CSF T clones (both CD4+ and CD8+) produced large amounts of IFN-gamma and particularly of TNF-alpha, that was synthesized in a significantly larger amount than compared clones. Moreover, they were capable of secreting IL-2, but not IL-4. From our results, we conclude that first, the CSF CD4+ T clones could constitute a subset with functional properties similar to the T helper 1 (Th1)/inflammatory cell subset of the mouse; and second, the large amounts of TNF produced by CSF T cell clones strongly suggests a significant role for this cytokine as well as of IFN-gamma in MS immunopathogenesis.

T cell recognition of hepatitis B envelope proteins.

We have studied the T-cell processing pathways of Hepatitis B antigens and the role of specific B lymphocytes. It could be shown that some form of processing by specific B cells is required for class I CTLs. This mechanism differs from class II endosomal processing. In addition, it could be shown that lysis of HBsAg-specific B cells may be partly responsible for chronic HBV carrier states.

Normalization of depressed natural killer activity after interferon-alpha therapy is associated with a low frequency of relapse in patients with chronic hepatitis C.

In the present study, we found that human recombinant interferon-alpha (rIFN-alpha) given at a dose of 3 x 10(6) units thrice weekly for three months, and 1.5 x 10(6) units thrice weekly for the next three months, was able to restore depressed natural-killer (NK) activity to normal values in 12 out of 21 chronic hepatitis C patients positive for anti-HCV antibodies. In all of these patients, NK normalization was still sustained after three months from suspension of therapy. Eighteen patients also showed a normalization of the alanine aminotransferase (ALT) level by the end of treatment (responder patients), independently of changes in NK activity. No significant improvement in either NK activity or aminotransferase levels was seen among 20 untreated patients. In 8 responder patients (1 with normalized and 7 with low NK activity), ALT levels returned to pre-therapy values within three months after suspension of rIFN-alpha administration (relapse). We found that patients who normalized NK activity had a lower frequency of relapse as compared to patients with low NK activity by the end of treatment (p > 0.01). Immunofluorescence analysis of biopsy-derived liver tissue revealed that rIFN-alpha was able to induce strong MHC class I antigen expression on hepatocytes of treated patients, but this was not related to the clinical course.

Tumour necrosis factor-alpha synthesis by cerebrospinal-fluid-derived T cell clones from patients with multiple sclerosis.

T cell clones derived from cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) were analysed for their ability to produce interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2) and interleukin-4 (IL-4). The CSF-T clones were compared for their ability to produce cytokines with autologous peripheral T clones and with liver-infiltrating T cell clones from patients with chronic active hepatitis. IL-4 production was also compared with that by peripheral T clones derived from atopic patients. All the CSF-T clones (both CD4+ and CD8+) produced large amounts of IFN-gamma and particularly of TNF-alpha. These cytokines were synthesized in significantly larger amounts by CSF T clones than by reference clones. Moreover, they were capable of secreting IL-2, but not IL-4. We conclude that the CSF-CD4+ T clones could constitute a subset with functional properties similar to those of T helper 1 (Th1)inflammatory cells of the mouse; and that the large amounts of TNF produced by CSF T cell clones strongly suggest a significant role for this cytokine in MS immunopathogenesis.

A calf thymus acid lysate improves clinical symptoms and T-cell defects in the early stages of HIV infection: second report.

Thymomodulin is a calf thymus acid lysate capable of inducing T lymphocyte maturation. Fifteen patients with HIV infection at different stages according to the Walter Reed classification were treated with 60 mg/day of thymomodulin syrup for more than 50 days. Two WR6B subjects had clinical and immunological parameters unchanged and died, while the patient suffering from Kaposi's sarcoma presented an evident clinical and laboratory improvement with remission of the neoplasia. The other 12 patients ranging from WR2 to WR5B showed an improvement of clinical symptoms after thymomodulin therapy accompanied by the normalization of CD4/CD8 ratio (P less than 0.001). This helpers/suppressors increase was due to a significant increase of CD4 cells (P less than 0.01) and also to a decrease of the CD8 lymphocytes (P less than 0.05). Thymomodulin administration did not cause an enhancement of the urinary levels of neopterin, a marker of T-cell activation.

Recognition of hepatitis B virus envelope proteins by liver-infiltrating T lymphocytes in chronic HBV infection.

The Ag specificity and cytotoxic function of human T cell clones, generated from lymphocytes infiltrating the liver of a chronic hepatitis B patient, were studied. Both class I- and class II-restricted T clones specifically proliferated to hepatitis B virus envelope proteins, but not to hepatitis B core Ag. The fine specificity of T cells was studied by using rAg having different composition in relation to HBV-envelope proteins or synthetic peptides of preS regions. The antigenic determinant recognized by T cell clones mapped to the preS2 region based on the response to r(preS1+preS2+S) and to r(preS2+S) and the failure to respond to S or preS1 alone. More precise epitope mapping was based on synthetic preS2 peptides 120-150 or 120-134, which stimulated both class I- and class II-restricted T clones, whereas preS2 153-171 or preS1 1-110 peptides did not; thus, the preS2 120-134 appears to contain both the residues binding to class I molecules and the residues binding to class II molecules. Moreover, strong and specific cytotoxic responses of these clones were observed only when HLA-matched EBV-lines, used as target cells, were previously sensitized with r(preS1+preS2+S) or preS2 peptides, which were shown to stimulate the clones. Thus, a preS2 epitope can represent a target Ag for liver-infiltrating T cells, which could kill the hepatocytes expressing the Ag plus the appropriate MHC molecule.

Increased number of CD4 cells able to bind to natural killer cell targets in the peripheral blood of AIDS related complex patients.

CD4 cells forming conjugates with natural killer target cells (K562 cells) were measured in the peripheral blood of anti-HIV antibody positive AIDS related complex (ARC) patients and in three control groups (asymptomatic individuals at risk, normal healthy people and patients with acute hepatitis B). These CD4 cells, which are unable to kill K562 cells, were significantly increased in ARC patients as compared to the control groups. Our data indicate that classical CD4 cells are partially replaced, in ARC patients, by a population of natural killer-target binding granular CD4 lymphocytes, and suggest that the functional abnormalities of helper T cells in these patients may be in part a consequence of the relative predominance of these non IL-2 and BCGF producing cells within the circulating CD4 population.

Liver-derived T cell clones in autoimmune chronic active hepatitis: accessory cell function of hepatocytes expressing class II major histocompatibility complex molecules.

Thirty T cell clones were generated from T cell blasts, infiltrating the liver of autoimmune chronic active hepatitis (CAH) patients, stimulated with autologous hepatocytes expressing class II major histocompatibility complex (MHC) molecules and interleukin 2 (IL2). Sixteen clones were CD4+ and 14 were CD8+; all were CD25+ and WT31+, revealing that all cell lines expressed the alpha/beta chains of T cell receptor. Five CD4+ and 4 CD8+ T clones proliferated in response to hepatocytes expressing both class I and class II antigens. The hepatocyte recognition was MHC restricted because only class II MHC-matched hepatocytes were able to stimulate the CD4+ T clones, while only class I-matched hepatocytes stimulated CD8+ T clones, and because MoAbs to monomorphic determinants of class II antigens or to class I antigens appeared to block the response of the CD4+ and CD8+ T clones, respectively. These findings, together with the observation that autologous irradiated peripheral blood mononuclear cells (iPBMC) were unable to stimulate the clones, indicate that the response of these clones was directed to a liver membrane antigen in association with class II or class I MHC molecules on the surface of the hepatocytes. All the CD8+ T clones and 5 CD4+ T clones expressed high cytotoxic activity in a lectin-dependent cell-mediated cytotoxicity assay; 10 CD8+ and 3 CD4+ T clones also showed natural killer (NK)-like function. The cytolytic machinery was also present in those clones (both CD8 and CD4) recognizing the HLA-matched hepatocytes. All liver-derived T clones were able to produce high amounts of interferon (IFN)-gamma, as well as being capable of secreting IL2, following PHA stimulation.

[Phenotypic and functional characterization of cloned T-lymphocytes from cerebrospinal fluid of patients with multiple sclerosis]. / Caratterizzazione fenotipica e funzionale di cloni T linfocitari di derivazione liquorale in pazienti affetti da sclerosi multipla.

T cell clones derived from the cerebrospinal fluid of patients with multiple sclerosis were investigated for their ability to produce IL2, IL4, IFN gamma and TNF alpha. As controls, liver infiltrating T lymphocyte clones from patients with chronic active hepatitis were used. All CSF clones (both CD4+ and CD8+) produced high amounts of IFN gamma and particularly of TNF alpha. TNF was synthesized in a significantly higher amount than control clones. Moreover, they were capable of secreting IL2 but not IL4. From our results we conclude that CSF-CD4+ T clones could constitute a subset with functional properties similar to those of the Th1/inflammatory cells of the mouse. The unusually high amount of TNF produced by CSF derived T cell clones strongly suggests a significant role for this cytokine in MS immunopathogenesis.

Selective killing of hepatitis B envelope antigen-specific B cells by class I-restricted, exogenous antigen-specific T lymphocytes.

Specific B lymphocytes can act as very efficient antigen-presenting cells. They bind antigen with high affinity via their immunoglobulin receptors, process it through the class II major histocompatibility complex (MHC) pathway, and present its fragments to class II-restricted T lymphocytes. In general, exogenous antigens and noninfectious viral particles enter the class II pathway and are selectively associated with class II MHC molecules. The presentation of an exogenous antigen in association with class I molecules has been reported for only a few antigens, including the hepatitis B envelope antigen (HBenvAg). Here we demonstrate that antigen-specific B cells can efficiently deliver HBenvAg to the class I pathway, presenting its fragments to class I-restricted cytotoxic T lymphocytes (CTLs) which kill the specific B cells. This could represent a mechanism of suppression of neutralizing anti-hepatitis B virus (HBV) antibody response, a phenomenon that accompanies the development of the chronic HBV-carrier state.

Soluble transferrin mediates targeting of hepatitis B envelope antigen to transferrin receptor and its presentation by activated T cells.

In a previous study, we identified that transferrin receptor (TfR) is the receptor utilized by hepatitis B virus (HBV) to enter T cells. We demonstrated that hepatitis B envelope antigen (HBenvAg) is taken up by activated T cells via TfR, processed in endosomal compartments, and presented on class II molecules to specific CD4+ T cell clones. Herein, we report that binding to soluble ferric Tf by HBenvAg is needed in TfR-mediated endocytosis. Accordingly, presentation of HBenvAg by activated T cells is not observed in serum-free medium and is restored by addition of soluble Tf. Moreover, we provide evidence that pre-S2 and S regions of HBenvAg contain the critical residues for the interaction with soluble Tf. Our data not only explain HBV entry into a variety of host activated cells, but may also help in developing strategies to alter the course of chronic HBV infection.

Selective expansion of cytotoxic T lymphocytes with a CD4+CD56+ surface phenotype and a T helper type 1 profile of cytokine secretion in the liver of patients chronically infected with Hepatitis B virus.

Highly purified CD4+ T cells isolated from liver biopsies of patients with hepatitis B virus-induced CAH had a strong cytotoxic activity and were comprised of a substantial number of cells (25%-40%) expressing CD56 surface marker. These cells were absent in CD4+ T cells from the peripheral blood of CAH patients or normal controls and these suspensions did not have cytotoxic activity. CD4+CD56+ T cells were further characterized by studies at the clonal level. A total of 71 hepatitis B envelope antigen-specific CD4+ T cell clones was investigated (23 from liver biopsies, 48 from peripheral blood of patients or normal vaccinated individuals). A total of 16 out of 23 (69.5%) of the clones from liver biopsies, but only 4.1% (2 out of 48) of those from PBLs, expressed CD56. A clone was defined as CD56+ when 40% or more of the cells expressed the marker. Production of TNF-alpha, IL-4, IL-5, IL-2, and IFN-gamma was investigated in 15 CD4+CD56+ and in 18 CD4+CD56- T cell clones, which shared the same HLA restriction element (DR2w15) and the same fine specificity (peptide 193-207 of the S region). All of the clones from the two groups released TNF-alpha and IL-2. However, all of the CD4+CD56+ T cell clones produced IFN-gamma but not IL-4 and IL-5 (Th1-like cell clones). Fourteen of the CD4+CD56- clones released IFN-gamma, IL-4, and IL-5 (Th0-like cell clones); three produced IL-4 and IL-5 but not IFN-gamma (Th2-like cell clones); and only one had a Th1 cytokine secretion profile. Cell fractionating studies within single CD4+CD56+ T cell clones showed that cells expressing high density CD56 had a stronger cytotoxic activity and produced higher levels of IFN-gamma than cells with low density CD56, thus further supporting a correlation between CD56 expression and cell functions. The results indicate that: 1) in CAH patients, cytotoxic CD4+ T cells with a Th1 cytokine secretion profile are compartmentalized in the liver, 2) these cells may be identified by the expression of CD56, 3) the expansion of these cells may be facilitated by antigenic stimulation within the inflammatory environment of the liver, and 4) CD4+CD56+ cells may play a pathogenetic role in hepatitis B virus infection.