[Trampolining-induced gross hematuria : Unmasking the nutcracker syndrome]. / Trampolinspringen-induzierte Makrohämaturie : Das demaskierte Nussknackersyndrom.

The case of a 12-year-old boy with sports-induced recurrent macrohematuria and left-sided flank pain is reported. After extensive laboratory and imaging diagnostics, the diagnosis of nutcracker syndrome is made based on the characteristic clinical manifestation. Under a conservative approach and abstention from the triggering sport, a clinical as well as image-morphologically confirmed maturation occurred.

M-DC8+ leukocytes--a novel human dendritic cell population.

Dendritic cells (DC) constitute a heterogeneous leukocyte population having in common a unique capacity to induce primary T cell responses and are therefore most attractive candidates for immunomodulatory strategies. Two populations of blood DC (CD11c+ CD123(dim) and CD11c- CD123(high)) have been defined so far. However, their direct isolation for experimental purposes is hampered by their low frequency and by the lack of selective markers allowing large scale purification from blood. Here we describe the monoclonal antibody (mAb) M-DC8, which was generated by immunizing mice with highly enriched blood DC. This mAb specifically reacts with 0.2-1% of blood leukocytes and enables their direct isolation by a one-step immunomagnetic procedure from fresh mononuclear cells. These cells can be differentiated from T cells, B cells, NK cells and monocytes using lineage-specific antibodies. M-DC8+ cells express HLA class II molecules, CD33 and low levels of the costimulatory molecules CD86 and CD40. Upon in vitro culture M-DC8+ cells spontaneously mature into cells with the phenotype of highly stimulatory cells as documented by the upregulation of HLA-DR, CD86 and CD40; in parallel CD80 expression is induced. M-DC8+ cells display an outstanding capacity to present antigen. In particular, they proved to be excellent stimulators of autologous mixed leukocyte reaction and to activate T cells against primary antigens such as keyhole limpet hemocyanin. Furthermore, they induce differentiation of purified allogeneic cytotoxic T cells into alloantigen-specific cytotoxic effector cells. While the phenotypical analysis reveals similarities with the two known blood DC populations, the characteristic expression of FcgammaRIII (CD16) and the M-DC8 antigen clearly defines them as a novel population of blood DC. The mAb M-DC8 might thus be a valuable tool to determine circulating DC for diagnostic purposes and to isolate these cells for studies of antigen-specific T cell priming.

A novel dendritic cell population in human blood: one-step immunomagnetic isolation by a specific mAb (M-DC8) and in vitro priming of cytotoxic T lymphocytes.

Originating from a common progenitor cell, dendritic cells (DC) appear to develop along early branched pathways into various yet ill-defined subpopulations residing at various sites throughout the body where they capture and present antigen in the most professional fashion. Here we give evidence for a unique subpopulation of human DC circulating in blood that account for 0.5-1% of blood leukocytes only, their most specific characteristic being the expression of a cell surface protein recognized by a novel monoclonal antibody (M-DC8) which enables their isolation by a one-step immunomagnetic procedure. The isolated cells (> 97% pure) present morphologically as typical dendritic cells. They express the Fc(gamma)RIII (CD16), so far not found on DC, and avidly phagocytose latex beads as well as opsonized erythrocytes. These cells not only present antigens efficiently to naive T cells but also induce purified CD8+ T cells to become alloantigen-specific cytotoxic cells. Furthermore, when loaded with a tyrosinase-derived peptide they stimulate T cells from normal donors and melanoma patients to exhibit MHC-restricted specific cytotoxicity against melanoma cells.

Structural diversity of monoclonal CD4 antibodies and their capacity to block the HIV gp120/CD4 interaction.

A number of monoclonal antibodies have been raised against CD4, the receptor on T cells for the HIV envelope glycoprotein gp120. In the present paper we describe biological activities and sequence analysis of seven CD4 MAb. Five of these MAb preparations compete with HIV/gp120 for CD4 binding. The sequences of the variable regions for these MAb were determined in order to ascertain any correlation with selective V gene usage. A relationship was found between the expressed variable region genes and the CD4 recognition pattern. The VH genes that are used can be subdivided into two major groups expressing either a VH gene belonging to the J558 family or to the VGam family. The usage of the VL genes varies, indicating that the epitope specificity is predominantly determined by the rearranged VH genes. The distinct cross-reactivity pattern of these MAb also correlates with their capacity to block binding of recombinant gp120 to CD4 in vitro. Although five of these MAb were able to block gp120 binding none of the CDR sequences shows a relevant homology to the gp120 sequence. This indicates a steric hinderence mechanism for blocking gp120 binding and not a direct interaction with the receptor binding site on CD4. The data also confirm the failure of these MAb as a potential target for receptor mimicry.

Recombinant CD4-IgE, a novel hybrid molecule, inducing basophils to respond to human immunodeficiency virus (HIV) and HIV-infected target cells.

Basophils and mast cells, as the main effector cells in IgE-mediated type I hypersensitivity, are involved in the elimination of parasites and, according to recent findings, may also play an important role in the defense against bacterial and viral infections. Using a genetic engineering approach we wanted to redirect this potent IgE-mediated defense system against intruding human immune deficiency virus. We constructed a recombinant CD4-IgE molecule, consisting of the two N-terminal domains of CD4 and the CH2-4 domains of the IgE heavy chain, thus providing the IgE with specificity for the gp120 of human immunodeficiency virus (HIV). The binding properties of hybrid CD4-IgE to the high-affinity receptor for IgE (Fc epsilon RI) on basophils as well as to the low-affinity receptor (Fc epsilon RII or CD23) for IgE on lymphoid cells were found to be similar to those of native IgE. At the same time, the CD4 domains of the recombinant molecule retained the gp120 binding specificity with an affinity similar to that of the native CD4. By functional tests, we demonstrated that CD4-IgE armed basophils can be triggered by free HIV and by HIV-infected cells to release their mediators. We further show that HIV-triggered basophils lead to a decreased replication of HIV in susceptible T cells. We, therefore, conclude that the type I hypersensitivity effector cells can be engaged in the elimination of HIV-infected cells, at least in vitro. Because of the strong binding of the CD4-IgE construct to the Fc epsilon RI, we assume that CD4-IgE has a short t1/2 in serum, but may similarly to IgE exhibit prolonged resident time on basophils and mast cells, which are located close to mucosal surfaces or in the connective tissue. Thus CD4-IgE could play an important role in the elimination of HIV also in vivo.

[Involvement of the lungs in neurofibromatosis]. / Lungenbeteiligung bei Neurofibromatose.

Two patients, a 66-year-old man (case 1) and a 55-year-old woman (case 2), had been known (for 40 and 35 years, respectively) to have type 1 neurofibromatosis. Dyspnoea, recently even at rest, had developed in both over the past few years. Both were emaciated (weight 62 kg, height 180 cm; 42 kg, 166 cm, respectively). In both the chest radiography had net-like increased interstitial markings. Computed tomography in case 1 showed largely subpleural small-blister-like changes bilaterally (honeycomb lung), while there were large apical cysts bilaterally in case 2. Lung function tests demonstrated restrictive changes in case 1 (vital capacity 48% of norm, relative one-second capacity 88%) and severe ventilation abnormality in case 2 (vital capacity 42% of norm, relative one-second capacity 47%). Both had marked hypoxaemia even at rest and the walking limit was 200 m in case 1, 40 m in case 2. The pulmonary changes were most likely manifestations of the neurofibromatosis. Symptomatic treatment consisted of long-term oxygen therapy with a portable liquid oxygen system (flow rate: 1-2 l/min at rest and 3-5 l/min on exercise; duration: 24 h/d). This achieved a walking distance without hypoxaemia of 500 and 200 m, respectively, with marked improvement in the patients' condition.

The monoclonal CD4 antibody M-T413 inhibits cellular infection with human immunodeficiency virus after viral attachment to the cell membrane: an approach to postexposure prophylaxis.

Infectious cellular uptake of human immunodeficiency virus (HIV) is initiated by a complex sequence of interactions between the viral envelope gp120/gp41 complex and the cellular CD4 receptor resulting in the exposure of a hydrophobic region of gp41 that mediates the irreversible fusion of the virus with the cell membrane. Here we show that viral penetration into a susceptible cell can be inhibited by the high-affinity monoclonal CD4 antibody (CD4 mAb) M-T413 even when it is added as late as 30-120 min after the initial contact of virus with the cell membrane. Inhibition of infection was assessed by monitoring cultures for 34 days after exposure to virus using four different methods simultaneously, including detection of viral DNA by PCR. The interval during which HIV remains sensitive to postbinding neutralization by CD4 mAb depends on strain of virus and type of target cell. Preparations of recombinant soluble CD4 (and the immunoadhesin CD4-IgG1) were much less efficient when compared with mAb M-T413, particularly in blocking infection by fresh HIV-1 isolates. Also cellular transmission of HIV, as determined by syncytia formation within 24 hr, was prevented by mAb M-T413 when added within 45 min of contact of infected H9 cells with uninfected C8166 cells. Together with the favorable clinical experience obtained with CD4 mAbs as immunomodulatory drugs, these data suggest that infusion of CD4 mAb M-T413 may be a therapeutic modus for immediate prophylactic intervention after occupational exposure to HIV and for prevention of intrapartum mother-to-infant HIV transmission.

Pharmacokinetic and pharmacodynamic studies in man simulating acute and chronic treatment with oral pirenzepine.

Nine healthy, male subjects received controlled-rate i.v. infusions of a new formulation of pirenzepine to produce constant plasma levels of 40 ng/ml and 105 ng/ml. They also received stepped infusions resulting in plasma levels of 20, 40, 80 and 40 ng/ml for defined periods. Peptone-stimulated gastric acid and volume secretion and near point vision decreased dose dependently, whereas gastric acidity was unchanged. There was a significant correlation between inhibition of gastric acid secretion and the pirenzepine concentration in plasma and in gastric juice. During the stepped i.v. infusion, changes in near point vision were closely related to the plasma drug concentration. Antimuscarinic side-effects occurred more frequently when the plasma drug level was high. Overall, there was a close relationship between the plasma concentrations and the effects and side-effects of pirenzepine. Its gastric inhibitory action was characterized only by a reduction in gastric volume secretion. Increasing plasma concentrations during the first days of treatment may be essential for its efficacy as an antiulcer drug.