Thomas Wendland

HAART in HIV-infected patients: restoration of antigen-specific CD4 T-cell responses in vitro is correlated with CD4 memory T-cell reconstitution, whereas improvement in delayed type hypersensitivity is related to a decrease in viraemia.

OBJECTIVE To analyse prospectively the effect of highly active antiretroviral treatment (HAART) on CD4 T-cell responses in vitro and in vivo in HIV-infected patients. DESIGN Prospective study with 49 protease inhibitor-naive adult patients. Data were collected at baseline and after 3 and 6 months of HAART. METHODS In vitro CD4 T-cell reactivity was analysed by stimulation of peripheral blood mononuclear cells with several antigens. In vivo CD4 T-cell reactivity (delayed type hypersensitivity) was assessed by Multitest Merieux. Both measurements were correlated to CD4 (memory) T-cell count and HIV-1 viraemia. RESULTS Restoration of specific CD4 T-cell proliferation was observed in most patients. The in vitro T-cell response was restored more frequently against antigens to which the immune system is constantly exposed (Candida albicans, Mycobacterium tuberculosis, M. avium) as compared with a low-exposure antigen (tetanus toxoid). Overall, delayed type hypersensitivity detection rate increased under HAART. Multivariate analysis showed improvement of antigen-specific T-cell proliferation to be significantly associated with an increase in memory CD4 T-cells, whereas improvement of the delayed type hypersensitivity response was associated with a decrease in plasma HIV-1 RNA. CONCLUSIONS HAART for 6 months restored antigen-specific CD4 T-cell response to several antigens. In vitro immune reconstitution was closely correlated with an increase in memory CD4 cells. Restoration of delayed type hypersensitivity was associated with suppression of viraemia. It appears that in addition to expansion of memory CD4 cells, suppression of viraemia following HAART may allow an improved inflammatory reaction, thus providing even stronger immune reconstitution.

High IL-5 production by human drug-specific T cell clones

To analyze whether and how T cells are involved in drug allergies, we analyzed the drug-induced activation of T cell subsets, T cell receptor V-beta usage and cytokine secretion of T cells from the peripheral blood of drug-allergic individuals. The specificity of the T cells was demonstrated by specific restimulation of drug specific clones. We found that drugs which do not need to be metabolized to become immunogenic (haptens like penicillin G) can stimulate CD4+ and CD8+ T cells in vitro. The T cell response to penicillin can be oligoclonal (use of a certain T cell receptor Vbeta only) or polyclonal. Only polyclonal T cell lines were cross-reactive with other beta-lactam antibiotics. Sulfamethoxazole and lidocaine are thought to gain their ability to bind to proteins by intracellular drug metabolism. They were found to stimulate CD4+ and CD8+ T cells in vitro, and some reactive T cell lines were oligoclonal. The majority of lidocaine-specific clones secreted rather high amounts of IL-5 and IL-4 after PMA/ionomycin stimulations (Th2-like), but some CD4+ and all CD8+ clones had a Th1-like phenotype (high INF-gamma and TNF-alpha). The data clearly demonstrate the existence of drug-specific alphabeta+ T cells in the circulation of drug-allergic individuals and reveal a great heterogeneity of T-cell-mediated responses. Further studies are needed to correlate the type of T cell response to the clinical picture, which can be quite heterogeneous.

Distinct serum cytokine levels in drug- and measles-induced exanthema.

Background: Macular or maculopapular skin reactions are frequent events in drug allergy as well as in viral infections. Clinically, the differentiation may be difficult in the absence of a clear relationship to drug intake or failure to detect virus–specific antibodies of the IgM class. Studies on drug–specific T cell lines and T cell clones isolated from drug–allergic patients have suggested that these cells may represent a significant source of IL–5. On the other hand, viral infections are frequently associated with elevated IFN–γ levels. Objective: Determination of serum–cytokine levels to differentiate between drug– and virally induced skin eruptions. Patients: 18 patients suffering from acute drug allergy and 19 patients with acute measles, rubella or parvovirus infection. Measurements: Cytokine–ELISA (IL–5, IL–4 and IFN–γ) of sera collected during acute drug allergy or during acute measles, rubella or parvovirus infection. Results: In 12/18 patients with drug allergy, IL–5 and/or IL–4 were elevated. A significant correlation (rSpearman = 0.84) between IL–5 serum levels and eosinophil counts in the blood was found. No correlation was detected between IL–4 and blood eosinophilia or between IL–4 and IL–5 levels. After remission, IL–5 and IL–4 decreased to undetectable levels. IFN–γ on the other hand was not measurable in patients with drug allergy while elevated IFN–γ serum levels were detected in 17/19 patients with measles, rubella or parvovirus infection; 2 patients with acute virus infection had elevated IL–5, and/or IL–4 and IFN–γ levels. Conclusion: These data underline the distinct pathogenesis of these morphologically similar exanthemas and suggest that the combined analysis of eosinophilia in the blood, IL–4 and IFN–γ might help in differentiating skin eruptions.

Multiple drug hypersensitivity: normal Treg cell function but enhanced in vivo activation of drug-specific T cells.

To cite this article: Daubner B, Groux‐Keller M, Hausmann OV, Kawabata T, Naisbitt DJ, Park BK, Wendland T, Lerch M, Pichler WJ. Multiple drug hypersensitivity: normal Treg cell function but enhanced in vivo activation of drug‐specific T cells. Allergy 2012; 67: 58–66.

CD80 AND CD86 COSTIMULATORY MOLECULES ON CIRCULATING T CELLS OF HIV INFECTED INDIVIDUALS

The expression of CD80 and CD86 costimulatory molecules, typical for antigen presenting cells (APC), was measured on circulating T cells of 20 HIV-infected individuals and of 11 HIV-negative healthy controls. The CD80 and CD86 molecules were present on both circulating T subsets of HIV-infected individuals (mean of CD80 expression within CD4+ T cells [CD80/CD4]: 5.0%; and CD86/CD4: 2.6%; CD80/CD8 4.1% and CD86/CD8: 2.7%) and were associated with HLA-DR expression. Some CD80 and CD86 expression was also found in normal controls, and only the expression of CD86 was significantly (P < 0.05) increased on CD4 + and CD8 + T cells of HIV-infected individuals. The expression of CD28 was decreased on T cells of HIV-infected individuals and was negatively correlated to the expression of HLA-DR and CD86 (mean CD28 within CD3+T cells: HIV+ 29.5%, HIV - 67.6%; correlation coefficient, - 0.75 and - 0.71, respectively). The more the disease proceeds, the less CD28 and the more DR and CD86 are found on circulating T cells. This suggests that during HIV infection T cells themselves develop an antigen presenting phenotype by upregulating expression of HLA-DR, CD86 and CD80 molecules.

Strong αβ and γδ TCR response in a patient with disseminated Mycobacterium avium infection and lack of NK cells and monocytopenia

Abstract Infection with atypical mycobacteria occurs mainly in patients with a compromised cellular immune system, in particular in those with a defective T cell or monocyte function. Here we analyzed the specific immune response of an adolescent HIV-negative patient with disseminated mycobacterium avium infection and fatal varizella zoster virus infection. The patient presented with dysplastic hematopoesis of all cell lineage’s and a bicytopenia of erythrocytes and leukocytes, but a hematological malignancy could not be found. We found a peripheral lymphopenia and monocytopenia, as well as a lack of NK-cells and B-cells. Lymphocytes consisted of 95% T cells, which contained up to 40% of TCR γδ+CD4-CD8-T-cells (mainly TCR γ9δ2), few monocytes and B-cells. Approximately 50% of CD3+ T-cells showed a CD57+ NK-like phenotype. Functional analysis of PBMC revealed a good antigen-specific T cell function if antigen-presenting cells were supplemented from a HLA-matched donor. Moreover, a strong M. avium specific cytotoxicity mediated by TCR αβ+T-cells could be found in vitro and even ex vivo. In contrast, NK-killing was absent. No evidence for a defect in IL-12 or IFN-γ production and signaling were found. The data indicate that a strong αβ and γδ T cell immunity tries to compensate for a deficient monocyte and NK cell function in this patient.

Cytotoxic HIV-1 p55gag-Specific CD4+ T Cells Produce HIV-Inhibitory Cytokines and Chemokines

CD4+ T-helper cells appear to be essential in sustaining immune responses in chronic viral infections, as the maintenance of CD8+ cytotoxic T-lymphocyte responses and the control of viremia were demonstrated to depend on CD4+ T cell help. In order to investigate the function of HIV-specific CD4+ T cells in chronic HIV-1-infection, 49 chronically HIV-infected patients were analyzed before and 3 and 6 months after initiation of antiviral treatment. Ten patients showed a substantial, although weak, proliferative response to HIV-1-p55gag protein for which no improvement was observed upon initiation of HAART. From one individual, HIV-1-p55gag-specific CD4-positive T-cell clones were generated that were heterogeneous in their TCR Vβ gene usage and HLA-DRB1*13 and DRB1*03 restricted, respectively. In addition, some CD4+ TCC produced substantial amounts of IFN-γ and MIP-1α/β, were perforin-positive, and showed cytotoxic activity. These diverse functional features of HIV-specific CD4+ T cells suggest that they may exert direct antiviral activity.

Ceftobiprole associated agranulocytosis after drug rash with eosinophilia and systemic symptoms induced by vancomycin and rifampicin

Drug rash with eosinophilia and systemic symptoms (DRESS) is a severe drug hypersensitivity reaction [1]. Sulfonamides, antiepileptics, allopurinol, minocyclin, diltiazem, vancomycin and β-lactam antibiotics are the most common elicitors. Symptoms include fever, skin rash, facial oedema, organ involvement such as hepatitis or interstitial nephritis, pneumonitis and myocarditis. Lymphadenopathy and splenomegaly may occur. DRESS syndrome is characterized by the presence of eosinophilia and atypical lymyphocytes in blood. The syndrome occurs within 1–12 weeks after initiating drug treatment [2]. Mortality is around 10%, most often due to liver failure. Drug-specific circulating T-cells seem to play a central role in its pathogenesis [3].

Necrotizing herpes-simplex virus tonsillitis mimicking peritonsillar abscess.

cell volume harboring enlarged nuclei (Fig. 1b). Some cells were multinucleated. In part of the cells intranuclear ground-glass inclusions were present. Immunohistological staining demonstrated positivity for Herpes simplex virus (HSV) (Fig. 1c), PCR confirmed it to be HSV-1. The patient was treated with high-dose intravenous Aciclovir with a delay of 7 days after tonsillectomy. She developed PCR proven HSV viremia, pneumonia, esophagitis and colitis in the course. Only a few cases of necrotizing HSV-1 tonsillitis have been reported so far, mostly in immunocompromised patients [1–3]. The clinical and radiological manifestation can be indistinguishable from bacterial tonsillar infections, which are by far more common. The clue to the diagnosis of necrotizing HSV tonsillitis is the cytopathogenic effect demonstrated by conventional histopathological examination. This finding should trigger further immunohistological staining to confirm the diagnosis. A 63-year-old neutropenic woman under treatment with cytarabin and idarubicin for acute myeloid leukemia complained of left-sided throat pain and increasing difficulties in swallowing. She was already receiving cefepime and metronidazole for neutropenic fever. Physical examination revealed a febrile patient with an enlarged fibrinous coated medially displaced left tonsil in the absence of oral blisters. A computed tomography demonstrated a peritonsillar abscess formation (Fig. 1a). Needle aspiration of the peritonsillar collection was unsuccessful making a tonsillectomy mandatory. The tonsil appeared brittle and disaggregated in several pieces while performing tonsillectomy. No purulent discharge was seen during the procedure. There was no growth of microorganisms in the retrieved tissue samples. Histopathological examination of hematoxylin and eosin stained tonsillar tissue showed necrotic areas containing numerous squamoid cells with increased