Effect of clarithromycin on experimental rhinovirus-16 colds: a randomized, double-blind, controlled trial.

PURPOSE: Macrolide antibiotics are frequently prescribed to patients with symptoms of a common cold. Despite their lack of proven antiviral activity, macrolide antibiotics may have anti-inflammatory actions, such as inhibition of mucus secretion and production of interleukins 6 and 8 by epithelial cells. Because the symptoms of rhinovirus colds are attributed to the inflammatory response to infection, we studied the effects of treatment with clarithromycin on the symptomatic and inflammatory response to nasal inoculation with rhinovirus. SUBJECTS AND METHODS: We performed a prospective, double-blind, controlled trial in 24 healthy subjects who were seronegative for antibodies to rhinovirus-16. Subjects were randomly assigned to receive either clarithromycin (500 mg) or trimethoprim-sulfamethoxazole (800/160 mg, as a control antibiotic) twice a day for 8 days, beginning 24 hours before inoculation with rhinovirus-16. RESULTS: All 12 subjects in each group were infected and developed symptomatic colds. The groups did not differ in the intensity of cold symptoms (median [25th to 75th percentile] score in the clarithromycin group of 25 [5 to 33] versus 21 [11 to 26] in the trimethoprim-sulfamethoxazole group, P = 0.86), weight of nasal secretions (25 g [8 to 56 g] versus 12 g [5 to 28 g], P = 0.27), or decline in nasal peak flow during the 8 days following viral inoculation. In both groups, similar and significant increases from baseline were observed in the numbers of total cells and neutrophils, and in the concentrations of interleukins 6 and 8, in nasal lavage fluid during the cold. The changes that we observed did not differ from those in an untreated historical control group. CONCLUSIONS: We conclude that clarithromycin treatment has little or no effect on the severity of cold symptoms or the intensity of neutrophilic nasal inflammation in experimental rhinovirus-16 colds.

The cross-reactivity and immunology of beta-lactam antibiotics.

Allergic reactions to beta-lactam antibiotics are well described; however, only the immunochemistry of penicillin has been characterised. Although the major determinant of benzylpenicillin (penicillin G) is commercially licensed for diagnostic applications, minor determinants are only available at some centres to be used for identification of hypersensitive individuals. Cephalosporins share a common bicyclic nuclear structure with penicillin and most cross-reactivity is generated to the beta-lactam ring. It is not possible to determine the actual incidence of cross-reactivity between penicillins and cephalosporins, but evidence suggests the true rate is lower than usually appreciated. In vitro testing demonstrates extensive cross-reactivity between penicillin and the carbapenems. Although the rate of clinical cross-reactivity is not known, imipenem should not be given to patients with proven penicillin hypersensitivity. In contrast, aztreonam and the monobactams can be safely given to penicillin-allergic patients.

The SKW 6.4 line of human B lymphocytes specifically binds and responds to vasoactive intestinal peptide.

Vasoactive intestinal peptide (VIP1-28) is a neuromediator recognized by high-affinity receptors on human lymphocytes, which inhibits T-cell proliferation and cytokine secretion, and suppresses immunoglobulin production by mitogen-stimulated mixed mononuclear leucocytes. The direct interactions of VIP1-28 with B cells were studied in the SKW 6.4 line of EBV-transformed human B cells, that express a mean (+/- SD) of 6116 +/- 969 receptors for [125I]VIP1-28 with a mean Kd of 59 nM, that decreases to 12 nM after exposure to phorbol 12-myristate 13-acetate (PMA). The secretion of IgM by SKW 6.4 B cells stimulated optimally with 100 ng/ml of PMA, but not unstimulated secretion of IgM, was suppressed significantly by 10(-12) M to 10(-9) M VIP1-28 and up to a mean maximum (+/- SD) of 40 +/- 2% by 10(-10) M VIP1-28. VIP1-28 elicited concomitant increases in intracellular cyclic AMP up to a mean maximum of 163% at 10(-10) M VIP1-28. The requirement for specific signal transduction by the occupied VIP receptors to inhibit IgM secretion was demonstrated by the lack of effect of VIP4-28 on both cyclic AMP concentration and IgM secretion, despite the equal affinity of binding of VIP4-28 and VIP1-28. The effects of VIP on immunoglobulin secretion by stimulated mixed mononuclear leucocytes thus may be due in part to a direct action on B cells.

Stimulation of matrix metalloproteinase-dependent migration of T cells by eicosanoids.

Prostaglandin E2 (PGE2) and leukotriene B4 (LTB4), at nanomolar to micromolar concentrations, elicited migration of human blood T cells and cultured T lymphoblastoma cells of the Tsup-1 line through a layer of Matrigel basement membrane matrix. The density of Tsup-1 cell high-affinity receptors was low for PGE2 and high for LTB4, resulting in respectively predominant chemokinetic and chemotactic stimulation of migration. Migration-enhancing concentrations of PGE2 and LTB4 also increased Tsup-1 cell content and secretion of matrix metalloproteinases (MMPs) 2, 3, and 9, which were quantified by Western blots and zymography, and augmented Tsup-1 cell-surface expression of the MMPs, as shown by flow cytometry. That a specific MMP inhibitor suppressed migration of blood T cells and Tsup-1 cells through Matrigel, but did not affect PGE2- and LTB4-initiated T cell migration through micropore filters without Matrigel, suggests dual requirements for MMP expression and enhanced motility in T cell passage through basement membranes.

Clinical differences among women with and without self-reported perimenstrual asthma.

BACKGROUND: Studies suggesting that 30% to 40% of asthmatic women report significant perimenstrual (late luteal phase) exacerbations of asthma are primarily retrospective, rely on subjective findings and do not demonstrate a consistent association between asthma and the menstrual cycle. OBJECTIVE: In this exploratory analysis, women with and without self-reported perimenstrual exacerbations of asthma (PMA) were examined prospectively to determine the association between asthma and the menstrual cycle and to characterize associated clinical factors. METHODS: Thirty-two adult asthmatic women with regular menstrual periods recorded daily asthma symptoms, medication use, and peak expiratory flow rate (PEFR) over six consecutive menstrual cycles, and underwent spirometry and methacholine bronchoprovocation during the luteal and follicular phases of 2 cycles. RESULTS: Nine of 32 subjects (28.2%) reported PMA. Daily means of rescue medication use and AM peak flow computed for each perimenstrual day demonstrated significant non-parallelism of group profiles; subjects with PMA had increasing inhaled short acting beta 2-agonist use and decreasing AM peak flow rates during the perimenstrual interval. Luteal-follicular phase differences in FEV1 or methacholine bronchoprovocation between the groups were not detected. Subjects with PMA were older (P=.007), had longer duration of asthma (P=.039), and increased baseline asthma severity (P=.076) compared with subjects without PMA. CONCLUSION: The findings of this study suggest that women with self-reported perimenstrual asthma demonstrate perimenstrual differences in rescue bronchodilator use and AM peak flow and appear to constitute a distinct subset of women with asthma who are older, have longer duration of asthma, and increased severity of asthma compared with women without self-reported perimenstrual asthma. These factors identify women who require close monitoring of their asthma during their menstrual cycles.

Neuropeptide signaling of lymphocytes in immunological responses.

Peptidergic nerves in immune organs and lymphoid tissues of the lungs and gastrointestinal tract end on or in close proximity to lymphocytes, mast cells and macrophages. Vasoactive intestinal peptide, substance P and some other neuropeptides, that are recognized by distinct sets of cell surface receptors, regulate aspects of T cell differentiation in the thymus, such as negative selection, and contribute to mediating compartmental immune responses. The latter effects include stimulating expression of adhesive proteins by lymphocytes, enhancement of lymphocyte and macrophage migration in vascular and connective tissues, and modulation of proliferative and synthetic responses of lymphocytes to diverse antigens.

Effects of allergic inflammation of the nasal mucosa on the severity of rhinovirus 16 cold.

BACKGROUND: Despite the strong association of asthma exacerbations with rhinovirus (RV) infection, inoculation of asthmatic subjects with RV only causes small changes in lower airway function, suggesting that RV infection is not itself sufficient to provoke asthma exacerbations. OBJECTIVE: Our purpose was to test whether allergic inflammation increases the airway response to RV infection. METHODS: We compared the severity of RV type 16-induced colds in 2 groups of 10 subjects with allergic rhinitis. One group received 3 nasal challenges with allergen and the other received challenges with placebo over the week before nasal inoculation with RV type 16 (4000 tissue culture infective dose 50% per subject). Subjects kept symptom diaries and were assessed with spirometry, methacholine challenge, nasal lavage, and sputum induction on days 2, 4, 7, 10, 15, and 30 after inoculation. RESULTS: The 2 groups developed equal rates of infection (90%), similar cold symptoms (Jackson score median [interquartile range], 11 [6-33] vs 20.5 [6-42] for allergen and placebo groups respectively, P =.54), and similar changes in cellular profile and in IL-6 and IL-8 concentrations in nasal lavage fluid and induced sputum after RV inoculation. The incubation period was significantly longer in the allergen group (2.5 [1-5.5] vs 1 [1-1] day, P =.03) and the duration of cold symptoms was shorter (5 [4-7] vs 8.5 [6-10] days, P =.008). We also found an inverse correlation between the percent of eosinophils in nasal lavage fluid before inoculation and the severity of cold symptoms (r = -0.58, P =. 008). CONCLUSION: In subjects with allergic rhinitis, augmented nasal allergic inflammation before inoculation with RV type 16 does not worsen the severity of cold symptoms but delays their onset and shortens their duration.

Specific recognition of the human neuroendocrine receptor for vasoactive intestinal peptide by anti-peptide antibodies.

Rabbit polyclonal IgG antibodies were generated to three distinct synthetic peptide substituents of the human neuroendocrine-type 7 transmembrane-domain receptor for vasoactive intestinal peptide (VIP), including a portion of the amino-terminus, first extracellular loop, and carboxyl-terminus. Immunofluorescent staining of both human K293 cell transfectants, expressing recombinant VIP receptors, and HT-29 human intestinal epithelial cells, bearing native VIP receptors, was observed with each of the antibodies and was eliminated specifically after absorption of antibodies with the respective peptide immunogen. Each of the antibodies recognized the same approximately 70-kDa membrane proteins, extracted from both K293 cell transfectants and HT-29 cells, in sodium dodecyl sulfate-polyacrylamide gel electrophoresis blots. Neither IgG nor Fab preparations of the antibodies inhibited VIP binding to cellular receptors at a concentration of 1 microgram/ml, that yielded optimal immunofluorescence, or at 5-300 micrograms/ml. In contrast, 5-200 micrograms/ml of anti-peptide antibodies as IgG, but not Fab, significantly inhibited the increase in concentration of cyclic AMP in HT-29 cells elicited by 1 nM VIP, without affecting the greater increase evoked by 100 nM VIP or alone altering the level of cyclic AMP. Antibodies to several peptide substituents thus bind specifically to VIP receptors in immunoblots and permeabilized cells, and may affect the cellular functions of VIP receptors with sufficient selectivity to reduce transduction of signals, without altering the binding of VIP.

Upregulation of neuropeptides and neuropeptide receptors in a murine model of immune inflammation in lung parenchyma.

The lung is richly supplied with peptidergic nerves that store and secrete substance P (SP), vasoactive intestinal peptide (VIP), and other neuropeptides known to potently modulate leukocyte function in vitro and airway inflammation in vivo. To investigate and characterize neuromodulation of immune responses compartmentalized in lung parenchyma, neuropeptide release and expression of neuropeptide receptors were studied in lungs of antigen-primed C57BL/6 mice after intratracheal challenge with sheep erythrocytes. The concentrations of cytokines in bronchoalveolar lavage (BAL) fluid rose early and peaked on day 1 for interleukin (IL)-2, interferon gamma, and IL-10; days 1 to 2 for IL-6; and day 3 for IL-4, whereas the total number and different types of leukocytes in BAL fluid peaked subsequently on days 4 to 6 after i.t. antigen challenge. Immunoreactive SP and VIP in BAL fluid increased maximally to nanomolar concentrations on days 1 to 3 and 2 to 7, respectively in lungs undergoing immune responses. The high-affinity SP receptor (NK-1 R), and VIP types I (VIPR1) and II (VIPR2) receptors were localized by immunohistochemistry to surface membranes of mononuclear leukocytes and granulocytes in perivascular, peribronchiolar, and alveolar inflammatory infiltrates during immune responses. As quantified by reverse transcription-polymerase chain reaction, significant increases were observed in levels of BAL lymphocyte mRNA encoding NK-1 R (days 2 to 4), VIPR1 (days 2 to 4), and VIPR2 (days 4 to 6), and in alveolar macrophage mRNA encoding NK-1 R (days 2 to 6) and VIPR1 (days 2 to 4), but not VIPR2. Systemic treatment of mice with a selective, nonpeptide NK-1 R antagonist reduced significantly the total numbers of leukocytes, lymphocytes, and granulocytes retrieved by BAL on day 5 of the pulmonary immune response. The results indicate that SP and VIP are secreted locally during pulmonary immune responses, and are recognized by leukocytes infiltrating lung tissue, and thus their interaction may regulate the recruitment and functions of immune cells in lung parenchyma.

A multicenter, randomized, double-blind, placebo-controlled trial of high-dose intravenous immunoglobulin for oral corticosteroid-dependent asthma.

To determine the efficacy of high doses of intravenous gammaglobulin (IVIG) for the treatment of severe, steroid-dependent asthma in patients between 6 and 68 years of age, a randomized, double-blind, placebo-controlled multicenter clinical trial was conducted in private and university hospitals in the United States. Patients were randomized to one of three treatment arms: 2 g IVIG/kg/month (16 patients); 1 g IVIG/kg/month (9 patients); or 2 g iv albumin (placebo)/kg/month (15 patients). The treatment consisted of seven monthly infusions followed by a posttreatment observation period. The primary outcome measurement was mean daily prednisone-equivalent dose requirements, determined during the observation month preceding initiation of treatment and compared to the month preceding the seventh infusion. Secondary clinical endpoints measured were pulmonary function, frequency of emergency room visits or hospitalizations, and number of days absent from school or work. When adjusted for body weight, the mean dose requirements fell by 33, 39, and 33% in the placebo, IVIG (1 g/kg), and IVIG (2 g/kg) treatment arms, respectively. The differences between therapies were not statistically different (P = 0.9728). The mean percentage-of-predicted FEV1 fell in all three treatment groups during the treatment period but there was no significant difference between treatment groups (P = 0.8291). There was also no significant difference in the percentage of subjects requiring emergency room visits or hospitalizations or missing days of work/school, among the three treatment groups. The trial was terminated prematurely after interim analysis determined the adverse experience rate was different between the three groups. Three patients, all randomized to the 2-g/kg IVIG dose group, were hospitalized with symptoms consistent with aseptic meningitis. In summary, in this randomized, double-blind, placebo-controlled multicenter study, high doses of IVIG did not demonstrate a clinically or statistically significant advantage over placebo (albumin) infusions for the treatment of corticosteroid-dependent asthma. Subgroup analysis failed to identify markers predicting responsiveness. High-dose IVIG can also be associated with a significant incidence of serious adverse events.