[Diagnosis of drug hypersensitivity--state of the art].

Adverse drug reactions are ubiquitous in outpatient as well as inpatient clinical care. An allergic drug reaction is an immunologically mediated adverse drug reaction that exhibits specificity and recurrence on re-exposure to the offending drug. The diagnosis and treatment of drug allergies is limited by a number of factors. In most instances the exact epitope causing the reaction is unknown, the immunological mechanism is unclear, the presence of immunological recognition is not predictive of a clinical reaction and the gold standard for diagnosis, the drug challenge, a complicated and sometimes dangerous endeavor. Nevertheless, during the past few years a serious attempt at standardization and validation of in vitro and in vivo techniques for the diagnosis of drug allergies, has been in progress. New methods, like the basophil surface marker for activation, CD63 are replacing old ones like histamine release for immediate type hypersensitivity reactions. For instance, in the field of beta-lactam hypersensitivity, the specific epitopes are better defined and standardized protocols for both immediate and delayed type reactions are in the process of being introduced. A standardized European Network of Drug Allergies (ENDA) questioner, published in 1999, permits systematic data gathering of events surrounding the acute drug reaction, facilitating later immunological investigation and diagnosis. This review attempts to summarize the present and some of the future options in the diagnosis of this common iatrogenic complication.

In vitro effects of recombinant TNF-alpha binding protein (rTBP-1) on hematopoiesis of HIV-infected patients.

Tumor necrosis factor-alpha (TNF-alpha) is believed to contribute to the hematopoietic failure often observed in patients with AIDS. Soluble TNF receptors (sTNFR) compete for TNF-alpha with cell surface receptors and thus may block its activity. The effect of the p55 sTNFR (recombinant TNF-binding protein-1 [rTBP-1]) on the clonogenic growth of hematopoietic progenitor cells from 27 HIV-infected patients was evaluated in comparison with 11 normal study subjects. Peripheral blood-derived, myelopoietic (i.e., granulomonocytic colony-forming cells [GM-CFC]) and erythropoietic (i.e, burst-forming unit, erythroid [BFU-E]) colonies were grown in 10-day semisolid cultures with increasing concentrations of rTBP-1. Significantly, dose-dependent increases occurred in GM-CFC from 17 of 21 AIDS patients and 12 of 21 in BFU-E at rTBP-1 concentrations of 1microg/ml to 25 microg/ml. In contrast, rTBP-1 failed to induce any appreciably increased colony formation in normal cell cultures. In 6 patients treated with highly active antiretroviral treatment (HAART), TBP-1 alone did not demonstrate the in vitro hematopoiesis-enhancing effect. This study may provide an initial step in development of therapeutic use of TBP as a TNF-alpha antagonist in HIV-infected patients who do not benefit sufficiently from antiretroviral treatment, and in other conditions in which increased levels of TNF-alpha may contribute to hematopoietic deficiencies.

Effects of environmental pollutants on airways, allergic inflammation, and the immune response.

Particulate and gaseous air pollutants are capable of damaging the airway epithelial lining and of shifting the local immune balance, thereby facilitating the induction of persistent inflammation. Epidemiological studies are inconclusive regarding whether air pollution increases the incidence of asthma and chronic bronchitis in the population. Clearly, environmental pollution can, however, precipitate attacks and emergency-room admissions in those already suffering from such conditions. The catastrophic potential of airborne pollution was demonstrated in the 1960s and 1970s, when inverted atmospheric pressure conditions trapped smog over cities on the Eastern coast of the United States and over Europe. This smog resulted in thousands of hospital admissions and dozens of deaths. With the general rise in the incidence of atopy and asthma in the Western population, it is of major public health interest to reduce, as much as possible, the exposure of such populations to anthropogenic and natural sources of pollution.

Specific in vitro proliferative immune responses and lymphokine production in Ethiopian children with and without tuberculosis.

UNLABELLED: We investigated the profile of some in vitro parameters of cellular immune responses in non-HIV-infected Ethiopian children and young adults with and without tuberculosis (TB) as compared to healthy Ethiopian and non-Ethiopian controls. The in vitro proliferative responses of peripheral blood mononuclear cells (PBMC) to purified protein derivative (PPD) were determined in 15 Ethiopian children and young adults with TB, 12 healthy Ethiopian children who were contacts of TB patients, 20 Ethiopian children without contact with TB and ten non-Ethiopian controls. All TB patients and contacts had a positive Mantoux skin test. The PBMC proliferative response to PPD of the Ethiopian children with TB was significantly higher than that of the Ethiopian children without TB, while all Ethiopian children demonstrated stronger proliferative response as compared to non-Ethiopian healthy controls. Interleukin 2 (IL-2), interferon gamma (IFN-gamma), interleukin 4 (IL-4) and interleukin 6 (IL-6) were measured by ELISA assays performed on the supernatant of PPD-stimulated and non-stimulated PBMC cultures of seven Ethiopian children with TB, ten Ethiopian children without TB and eight non-Ethiopian controls. IFN-gamma and IL-4 were undetectable and IL-2 levels in unstimulated supernatants were low in all groups. PPD stimulation induced a significant rise in IL-2 levels in Ethiopians with TB as compared to all other groups. There was no increase above baseline in IL-6 levels in any group studied. CONCLUSIONS: Ethiopian children with TB exhibit a strong cellular immune response as expressed by Mantoux tests and lack of stimulation of IL-4 and IL-6 production. This pattern suggests a Th1 type effective cellular immune response to mycobacteria in a cohort of young Ethiopians with TB.

Eosinophils bind rhinovirus and activate virus-specific T cells.

Episodes of virus-induced exacerbations of asthma are accompanied by increased eosinophils (EOS) in respiratory secretions and evidence of EOS degranulation. Although rhinoviruses (RV) are the viruses most often implicated in exacerbations of asthma in both children and adults, little is known about the immune response to this group of viruses and, in particular, EOS-RV interactions. To define such interactions, we incubated human rhinovirus type 16 (RV16), a serotype using ICAM-1 as a receptor, with EOS purified from PBMC, and measured EOS-RV binding, EOS-mediated Ag presentation and T cell activation, and EOS cell surface marker expression and superoxide production. Significant RV16 binding occurred to EOS that were pretreated with granulocyte-macrophage CSF, and this binding was inhibited by anti-ICAM-1 mAb. EOS also presented viral Ags to RV16-specific T cells, causing T cell proliferation and secretion of IFN-gamma. RV16 induced a significant shift from CD18dim to CD18bright, but did not affect EOS expression of CD54, CD69, or HLA-DR. Finally, RV16 did not induce superoxide production from peripheral blood EOS. These findings suggest that RV16 also binds to airway EOS, which resemble granulocyte-macrophage CSF-treated blood EOS in terms of high expression of ICAM-1. Furthermore, our findings suggest that EOS could participate in RV-induced immune responses through Ag presentation and T cell activation. By activating RV-specific T cells, EOS may play an important role in the initiation of antiviral T cell responses, and these effects could also contribute to enhanced airway inflammation and increased asthma symptoms in susceptible individuals.

Side effect profile of azathioprine in the treatment of chronic schizophrenic patients.

Various findings suggest auto-immune changes in schizophrenia. We have recently demonstrated that platelets from schizophrenic patients bear autoantibodies (PAA) which cross-react with brain antigens. Accordingly, treatment of schizophrenia with an immunosuppressant might be of potential benefit. In a recent case study, a chronic schizophrenic patient treated with azathioprine has demonstrated a clear psychiatric improvement preceded by a decrease in PAA level. A phase I study designed for assessing side-effects of short-term azathioprine treatment in a group of schizophrenic patients is described here. From a group of 40 chronic non-responsive patients, 14 patients demonstrating high PAA level have entered the study and 11 have complied all along. Two groups were tested in parallel. In the first (6 patients) 150 mg/day was given for 7 weeks while in the second (5 patients) the same regimen was given for two periods of 7 weeks with an interval of 6 weeks. Blood biochemistry and cell count, as well as determination of PAA were carried out weekly, starting 3 weeks before the trial and continuing up to 7 weeks after the treatment. Two out of 11 patients developed leucopenia in week 4. No other side-effects were recorded in any of the patients. A substantial reduction in PAA was observed in 3 out of 6 patients in group I and 4 out of 5 in group II. Two patients showed improvement of psychiatric symptomatology. Our results demonstrate that short-term azathioprine treatment induces transient leucopenia in 18% of the patients receiving the drug, much alike the percentage reported for other patient populations.

Rhinovirus enters but does not replicate inside monocytes and airway macrophages.

Potential interactions between rhinovirus (RV) and both the airway macrophage and its precursor cell, the blood monocyte, were investigated in terms of direct binding, intracellular replication, cell survival, and cytokine production. When HeLa cell suspensions are inoculated with RV as a positive control, virus titer increases by 100-fold in the first 24 h, confirming intracellular replication. In contrast, RV titer in monocyte and macrophage suspensions steadily decreased. Despite a lack of productive RV replication, cell-associated RV RNA was detectable using a biotin-labeled cDNA probe as early as 6 h after inoculation. Direct binding of RV16 to macrophages was confirmed using radiolabeled virus, although preincubation with anti-ICAM-1 mAb did not block this interaction. Synthesis of RV RNA, as indicated by [3H]uridine incorporation in actinomycin D-treated cells, was detected in HeLa cells but not macrophages, suggesting that the viral RNA detected inside macrophages was from input virus and was not newly synthesized. RV inoculation did not adversely affect monocyte or macrophage viability. Finally, RV caused macrophage activation, as indicated by the induction of TNF-alpha secretion. These in vitro findings suggest that macrophages interact with major group RV in vivo, and raise the possibility that there is a second cellular receptor for these viruses. Furthermore, macrophages do not serve as permissive host cells during in vivo RV infection, but instead may be active participants in anti-RV immunity and RV-induced airway inflammation.

Histamine enhances granulocyte-macrophage colony-stimulating factor and interleukin-6 production by human peripheral blood mononuclear cells.

The effect of histamine on the production of cytokines by subpopulations of mononuclear cells was studied. A 3.5-fold increase in the number of myeloid colony-forming units (CFU-C) was observed when bone marrow cells were cultured in the presence of conditioned medium prepared from nonadherent mononuclear cells cultured with 10(-4) M histamine (CM-histamine) compared with phosphate-buffered saline (CM-PBS). Using ELISA and radioimmunoassay kits, histamine was found to enhance the production of GM-CSF (9.6-fold) and IL-6 (8.2-fold) by mononuclear cells but not by nonadherent cells or large granular lymphocytes. Anti-GM-CSF and anti-IL-6 antibodies markedly blocked cytokine activity in CM-PBS, whereas the blocking effect in CM-histamine was moderate, indicating enhanced GM-CSF and IL-6 activity in CM-histamine. No GM-CSF or IL-6 levels could be detected in CM-histamine or CM-PBS prepared from CD3+, CD4+, or CD8+ lymphocytes. Preincubation of CM-histamine with H1 and H2 receptor antagonists resulted in complete blocking of the histamine-enhanced colony-stimulating activity. We conclude that histamine is able to activate human mononuclear cells to generate cytokines such as GM-CSF and IL-6 via H1 and H2 receptors.

Autoantibodies in male homosexuals and HIV infection.

We have used ELISA to study the frequency of autoantibodies to several antigens in the serum of 17 male homosexuals (MHS) negative for HIV (HIV-), 11 asymptomatic HIV seropositive MHS (HIV+) and patients with ARC (N = 15) or AIDS (N = 13), and compared them to 20 matched healthy heterosexual controls. Serum antibody binding to histones, cardiolipin, ss-A, ss-B and Sm was found to be significantly higher in each of the MHS groups studied as compared to controls (P less than 0.001), and was also increased in the HIV+ patients vs. the HIV- group (P less than 0.05). In contrast, no increase in autoantibodies to ss-DNA, ds-DNA, poly(I), poly(G) or RNP were found in any of the groups tested. These results enlarge the spectrum of autoimmunity previously reported in HIV infection and identify a similar pattern to a lesser degree, already present in HIV- MHS, suggesting a role for HIV or concomitant virus infections in its pathogenesis.