Complement split products C3a and C4a are early markers of acute lyme disease in tick bite patients in the United States.

BACKGROUND: Current laboratory markers do not readily detect acute Lyme disease. We assessed the utility of complement and its split products as markers of Lyme disease in patients shortly after a tick bite. METHODS: Thirty-one consecutive acute Lyme disease patients, 14 with and 17 without erythema migrans (EM) skin rash, seen by a physician within 96 h of a tick bite were matched with 24 consecutive tick bite patients without Lyme disease symptoms and 46 healthy control subjects. Complement and split products measured included factor B, Bb, C4, C3c, C3a(des Arg), C4a(des Arg), C1q- and C3d-containing immune complexes, and C2. RESULTS: C2, C4, C3 and factor B levels were within normal ranges in all groups. C3a and C4a levels were significantly higher in acute Lyme disease patients than in tick bite and healthy control groups (both p < 0.001). All acute Lyme disease patients, regardless of EM, had elevated levels of C3a or C4a. Few tick bite controls had elevated levels of C3a (2/20) or C4a (5/24) and only 1 of the healthy control subjects had elevated C3a (0/46) or C4a (1/32). CONCLUSIONS: These findings suggest that C3a and C4a may be useful markers of Lyme disease in patients seen shortly after tick bite, even in those without EM.

Links between pollen, atopy and the asthma epidemic.

Pollen allergy has been found in 80-90% of childhood asthmatics and 40-50% of adult-onset asthmatics. Despite the high prevalence of atopy in asthmatics, a causal relationship between the allergic response and asthma has not been clearly established. Pollen grains are too large to penetrate the small airways where asthma occurs. Yet pollen cytoplasmic fragments are respirable and are likely correlated with the asthmatic response in allergic asthmatics. In this review, we outline the mechanism of pollen fragmentation and possible pathophysiology of pollen fragment-induced asthma. Pollen grains rupture within the male flowers and emit cytoplasmic debris when winds or other disturbances disperse the pollen. Peak levels of grass and birch pollen allergens in the atmosphere correlated with the occurrence of moist weather conditions during the flowering period. Thunderstorm asthma epidemics may be triggered by grass pollen rupture in the atmosphere and the entrainment of respirable-sized particles in the outflows of air masses at ground level. Pollen contains nicotinamide adenine dinucleotide phosphate (reduced) oxidases and bioactive lipid mediators which likely contribute to the inflammatory response. Several studies have examined synergistic effects and enhanced immune response from interaction in the atmosphere, or from co-deposition in the airways, of pollen allergens, endogenous pro-inflammatory agents, and the particulate and gaseous fraction of combustion products. Pollen and fungal fragments also contain compounds that can suppress reactive oxidants and quench free radicals. It is important to know more about how these substances interact to potentially enhance, or even ameliorate, allergic asthma.

Measuring allergen-specific IgE: where have we been and where are we going?

About 40 yr ago, two groups of investigators identified a new class of immunoglobulins, IgE. By exchanging their results and reagents, they proved that the immunoglobulin responsible for immediate hypersensitivity was IgE. From that day forward the science of allergy was greatly advanced. Within a few years of the IgE discovery, an assay for IgE was developed. This test was named the radio allergosorbent test. The specific IgE testing methodology has matured in the last four decades. Different means of detecting IgE bound to allergen is the subject of this review. We have included methods for measuring specific IgE using the ImmunoCAP 1000 instrument. The methodology for measuring basophile histamine release is also detailed in this chapter.

Identification and possible disease mechanisms of an under-recognized fungus, Aureobasidium pullulans.

BACKGROUND: Investigations into the occurrence and health effects of yeast-like fungi in the outdoor air in the US have been limited. We sought to identify a respirable-sized fungus common in the Pasadena air, locate a major source for the emissions and investigate its relevance to allergic disease. METHODS: Yeast-like fungi sampled from the environment were isolated, microscopically examined and sequenced. Pasadena allergy patients were skin tested with commercially available fungal extracts. Patient serum was immunoanalyzed for specific IgE reactivity. Nearby vegetation was analyzed in a controlled emission chamber to find a major source for the aerosols. RESULTS: Hyaline unicellular conidia comprised up to 90% (41,250 m(-3) of air) of total fungal counts and generally peaked at night and during periods of rainfall and ensuing winds throughout the fall and winter. Flowers were determined to be a major source of the emissions. The cellular and colonial morphology of isolates were consistent with Aureobasidium species. The sequence of the D1/D2 region of the 26S ribosomal subunit of isolates from flowers showed identity to two strains of Aureobasidium pullulans (black yeast). Seventeen percent (16/94) of atopic individuals had positive skin testing with A. pullulans extract. Patient sera IgE identified several high molecular weight allergens in Aureobasidium extracts. CONCLUSIONS: Respirable-sized conidia of A. pullulans are emitted from flowers and form high concentrations in the air. They are associated with immediate reactivity on skin tests, bind to patient sera IgE, and might be relevant in allergic upper and lower airway diseases.

Complement determinations in human disease.

OBJECTIVE: To define techniques used for complement measurements and examine the clinical relevance of alterations of complement determinations in disease. DATA SOURCES: Data have been assembled from the authors' research, original articles, and reviews, as well as chapters and complete books on complement. STUDY SELECTION: Studies were chosen for inclusion by the opinions of the authors, relevant complement reviews, publications, and books. RESULTS: Complement has been shown to possess approximately 31 proteins, some of which are enzymes (C1r, C1s, C2, factor B, factor D), some cofactors, some inhibitors or inactivators, and others composed of membrane-integrated proteins. All of the complement proteins have been purified, and many of the respective genes have been identified. The complement cascade is a dual-edged sword, causing protection against bacterial and viral invasion by promoting phagocytosis and inflammation. Pathologically, complement can cause substantial damage to blood vessels (vasculitis), kidney basement membrane and attached endothelial and epithelial cells (nephritis), joint synovium (arthritis), and erythrocytes (hemolysis) if it is not adequately controlled. CONCLUSIONS: Definitive evidence is available that complement-mediated tissue destruction occurs after immune complex injury in the kidney and lung and may be important in lupus erythematosus and adult respiratory distress syndrome. Future studies on complement receptor structure and function may provide clues to treat effectively lupus, hemolytic anemias, and nephritis. In addition, gene therapy and antibody therapy need further refinement to treat immunodeficiency diseases.

Birch pollen rupture and the release of aerosols of respirable allergens.

BACKGROUND: Birch pollen allergens have been implicated as asthma triggers; however, pollen grains are too large to reach the lower airways where asthmatic reactions occur. Respirable-sized particles containing birch pollen allergens have been detected in air filters, especially after rainfall but the source of these particles has remained speculative. OBJECTIVE: To determine the processes by which birch pollen allergens become airborne particles of respirable size with the potential to contribute to airways inflammation. METHODS: Branches with attached male catkins were harvested and placed in a controlled emission chamber. Filtered dry air was passed through the chamber until the anthers opened, then they were humidified for 5 h and air-dried again. Flowers were disturbed by wind generated from a small electric fan. Released particles were counted, measured and collected for immuno-labelling and high-resolution microscopy. RESULTS: Birch pollen remains on the dehisced anther and can rupture in high humidity and moisture. Fresh pollen takes as long as 3 h to rupture in water. Drying winds released an aerosol of particles from catkins. These were fragments of pollen cytoplasm that ranged in size from 30 nm to 4 microm and contained Bet v 1 allergens. CONCLUSION: When highly allergenic birch trees are flowering and exposed to moisture followed by drying winds they can produce particulate aerosols containing pollen allergens. These particles are small enough to deposit in the peripheral airways and have the potential to induce an inflammatory response.

Release of allergens as respirable aerosols: A link between grass pollen and asthma.

BACKGROUND: Asthma incidence has long been linked to pollen, even though pollen grains are too large to penetrate into the airways where asthmatic responses originate. Pollen allergens found in small, respirable particles have been implicated in a number of asthma epidemics, particularly ones following rainfall or thunderstorms. OBJECTIVE: The aim of this study was to determine how pollen allergens form the respirable aerosols necessary for triggering asthma. METHODS: Flowering grasses were humidified and then dried in a controlled-environment chamber connected to a cascade impactor and an aerosol particle counter. Particles shed from the flowers were analyzed with high-resolution microscopy and immunolabeled with rabbit anti-Phl p 1 antibody, which is specific for group 1 pollen allergens. RESULTS: Contrary to what has been reported in other published accounts, most of the pollen in this investigation remained on the open anthers of wind pollinated plants unless disturbed-eg, by wind. Increasing humidity caused anthers to close. After a cycle of wetting and drying followed by wind disturbance, grasses flowering within a chamber produced an aerosol of particles that were collected in a cascade impactor. These particles consisted of fragmented pollen cytoplasm in the size range 0.12 to 4.67 microm; they were loaded with group 1 allergens. CONCLUSION: Here we provide the first direct observations of the release of grass pollen allergens as respirable aerosols. They can emanate directly from the flower after a moisture-drying cycle. This could explain asthmatic responses associated with grass pollination, particularly after moist weather conditions.

Complement-dependent immune complex-induced bronchial inflammation and hyperreactivity.

Bronchoconstriction responses in the airway are caused by multiple insults and are the hallmark symptom in asthma. In an acute lung injury model in mice, IgG immune complex deposition elicited severe airway hyperreactivity that peaked by 1 h, was maintained at 4 h, and was resolved by 24 h. The depletion of complement with cobra venom factor (CVF) markedly reduced the hyperreactive airway responses, suggesting that complement played an important role in the response. Blockade of C5a with specific antisera also significantly reduced airway hyperreactivity in this acute lung model. Complement depletion by CVF treatment significantly reduced tumor necrosis factor and histamine levels in bronchoalveolar lavage fluids, correlating with reductions in airway hyperreactivity. To further examine the role of specific complement requirement, we initiated the immune complex response in C5-sufficient and C5-deficient congenic animals. The airway hyperreactivity response was partially reduced in the C5-deficient mice. Complement depletion with CVF attenuated airway hyperreactivity in the C5-sufficient mice but had a lesser effect on the airway hyperreactive response and histamine release in bronchoalveolar lavage fluids in C5-deficient mice. These data indicate that acute lung injury in mice after deposition of IgG immune complexes induced airway hyperreactivity that is C5 and C5a dependent.

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.

Upper airways involvement in bronchial asthma.

The upper airways--the nose, pharynx, and mouth--lead through the larynx and into the tracheobronchial tree of the lung (the lower airways). This cavernous void in the upper airways transports external air to the alveolar sacs, in the distal segments of the tracheobronchial tree. Oxygen is absorbed from the alveolar sacs and carbon dioxide is released. Yet, under adverse physiologic conditions such as allergic or nonallergic rhinitis, sinusitis, and bronchitis, obstruction of the upper and lower airways occurs and leads to sneezing, rhinitis, and bronchospasm. The simultaneous occurrence of upper airways disease and asthma is addressed in this review.

Particulate air pollution: possible relevance in asthma.

The relative importance of air pollution in the pathogenesis of bronchial asthma has been of interest for several decades. Numerous studies on the role of gaseous air pollution containing ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide have been published. Very little attention has been focused on the role of respirable particles in the causation of asthma. In this article we summarize some of our ongoing investigations into the sources and composition of airborne particles in the Los Angeles and Pasadena atmosphere, including the search for biologically active particles that may induce asthma attacks. If is found that the urban atmosphere contains not only combustion-derived particles from diesel engine exhaust and gasoline-powered motor vehicle exhaust, but also particles formed from biological starting materials including plant debris, cigarette smoke, wood smoke, and meat smoke as well as tire debris containing some natural rubber and paved road dust. Paved road dust is a very complex mixture of particles including garden soil, tire dust, plant fragments, redeposited atmospheric particles of all types, and pollen fragments presumably ground up by passing traffic. We have shown previously that latex allergen can be extracted from tire dust, from roadside dust, and from respirable air samples taken at Los Angeles and Long Beach. At present, work is underway to identify the larger range of allergens that may be contributed by the entrainment of paved road dust into the atmosphere. The possible importance of pollen fragments present in paved road dust in very small particle sizes is discussed as well as their potential relevance in asthma.

Latex allergens in tire dust and airborne particles.

The prevalence and severity of latex allergy has increased dramatically in the last 15 years due to exposure to natural rubber products. Although historically this health risk has been elevated in hospital personnel and patients, a recent survey has indicated a significant potential risk for the general population. To obtain a wide-spread source for latex exposure, we have considered tire debris. We have searched for the presence of latex allergens in passenger car and truck tire tread, in debris deposited from the atmosphere near a freeway, and in airborne particulate matter samples representative of the entire year 1993 at two sites in the Los Angeles basin (California). After extraction of the samples with phosphate buffered saline, a modified-ELISA inhibition assay was used to measure relative allergen potency and Western blot analyses were used to identify latex allergens. The inhibition studies with the human IgE latex assay revealed inhibition by the tire tread source samples and ambient freeway dust, as well as by control latex sap and latex glove extracts. Levels of extractable latex allergen per unit of protein extracted were about two orders of magnitude lower for tire tread as compared to latex gloves. Western blot analyses using binding of human IgE from latex-sensitive patients showed a band at 34-36 kDa in all tire and ambient samples. Long Beach and Los Angeles, California, air samples showed four additional bands between 50 and 135 kDa. Alternative Western blot analyses using rabbit IgG raised against latex proteins showed a broad band at 30-50 kDa in all samples, with additional bands in the urban air samples similar to the IgE results. A latex cross-reactive material was identified in mountain cedar. In conclusion, the latex allergens or latex cross-reactive material present in sedimented and airborne particulate material, derived from tire debris, and generated by heavy urban vehicle traffic could be important factors in producing latex allergy and asthma symptoms associated with air pollution particles.

Comparative effect of C3a and C5a on adhesion molecule expression on neutrophils and endothelial cells.

Complement activation is known to enhance neutrophil binding to human umbilical vein endothelial cells (HUVECs). Recently, we have shown that recombinant human C5a upregulates P-selectin in HUVECs. Unstimulated human neutrophil binding is also increased on C5a stimulated HUVECs. We demonstrate in this report that C5a upregulates CD11b/CD18 in human neutrophils. Also shown is that synthetic C3a57-77 and an analog 15 amino acid C3a peptide (C3a15) neither upregulate CD11b/CD18 nor do the C3a peptides increase P-selectin, ICAM-1 or E-selectin in HUVECs. Thus C5a and not C3a is responsible for early (approximately 30 minutes) neutrophil adhesion to endothelial cells after complement activation.

Cetirizine in patients with seasonal rhinitis and concomitant asthma: prospective, randomized, placebo-controlled trial.

OBJECTIVE: This study explored the safety and efficacy of cetirizine for treatment of allergic rhinitis and asthma. METHODS: Daily treatment for 6 weeks with cetirizine 10 mg (93 patients) was compared with placebo treatment (93 patients) in a randomized, double-blind parallel study of patients with allergic rhinitis and asthma. This multicenter study was started just before onset of the fall pollen season. Rhinitis and asthma symptoms were assessed twice daily; spirometry was performed weekly. RESULTS: Placebo-treated patients experienced a worsening of rhinitis symptoms from baseline throughout the study, whereas cetirizine-treated patients had a significant improvement in rhinitis symptoms at week 1, which was maintained after onset of the pollen season. Asthma symptoms in the cetirizine group improved from baseline at week 1; symptoms were significantly better than in the placebo group for 5 of 6 weeks of the study. Pulmonary function did not worsen in patients taking cetirizine or placebo; there were no differences between treatments as determined by spirometry. Albuterol use was less frequent in the cetirizine-treated patients for every week of the study, but differences did not reach significance. Pseudoephedrine use was similar in both groups. More cetirizine-treated patients (90%) completed the trial than did placebo-treated patients (74%). Both treatments were well tolerated. CONCLUSION: Cetirizine 10 mg daily is safe and effective in relieving both upper and lower respiratory tract symptoms in patients with seasonal allergic rhinitis and concomitant asthma.

C5a-induced expression of P-selectin in endothelial cells.

Human umbilical vein endothelial cells have recently been shown to respond to C5a with increases in intracellular Ca2+, production of D-myo-inositol 1,4,5-triphosphate and superoxide anion generation. In the current studies, C5a had been found to cause in a time- and dose-dependent manner rapid expression of endothelial P-selectin, secretion of von Willebrand factor, and adhesiveness for human neutrophils. The effects of C5a in P-selectin expression and adhesiveness of neutrophils were similar to the effects of histamine and thrombin on endothelial cells. The adhesiveness of C5a-stimulated endothelium for neutrophils was blocked by anti-P-selectin, but not by antibodies to intercellular adhesion molecule 1, E-selectin, or CD18. A cell-based ELISA technique has confirmed upregulation of P-selectin in endothelial cells exposed to C5a. Binding of C5a to endothelial cells has been demonstrated, with molecules bound being approximately 10% of those binding to neutrophils. By a reverse transcriptase-PCR technique, endothelial cells have been shown to contain mRNA for the C5a receptor. These data suggest that C5a may be an important inflammatory mediator for the early adhesive interactions between neutrophils and endothelial cells in the acute inflammatory response.