Elevated baseline soluble FcεRI may be linked to early response to omalizumab treatment in chronic spontaneous urticaria

BACKGROUND

Omalizumab, an anti-IgE monoclonal antibody, is an effective treatment in chronic spontaneous urticaria (CSU). Predictors of fast and good response for omalizumab treatment have not yet been identified and characterized.

OBJECTIVE

To evaluate whether soluble FcεRI (sFcεRI), a marker of IgE-mediated mast cell activation, predicts the time of response to omalizumab in CSU.

METHODS

Sera of 67 CSU patients were obtained before omalizumab treatment and analysed for sFcεRI levels by ELISA (2 ng/mL was used as cut-off for elevated sFcɛRI). Treatment response during the first 4 weeks was assessed with the urticaria activity score (UAS7), urticaria control test (UCT) and the rolling UAS7 (rUAS7).

RESULTS

Elevated pre-treatment sFcɛRI levels were detected in more than 70% of patients with completely controlled disease (UCT = 16) and well-controlled disease (UCT = 12-15) and were significantly associated with disease control (χ2  = 4.94, p < 0.05). More than half of the patients (14/25) with low levels had poor disease control (UCT < 12). Of the patients who achieved complete and marked UAS7 response, respectively, 75% and 63% had elevated baseline sFcɛRI levels. Post-treatment UAS7 scores were lower in patients with elevated sFcɛRI levels reaching statistical significance at Week 3 (p < 0.05). Patients with elevated baseline sFcɛRI levels achieved rUAS7 ≤ 6 and = 0 earlier than those with lower levels (Days 9 vs. 13 and Days 12 vs. 14, respectively).

CONCLUSION

Elevated sFcεRI serum levels predict early and good response to treatment with omalizumab, which may help to better design treatment options for CSU patients.

Spleen tyrosine kinase inhibition blocks airway constriction and protects from Th2-induced airway inflammation and remodeling

BACKGROUND

Spleen tyrosine kinase (Syk) is an intracellular nonreceptor tyrosine kinase, which has been implicated as central immune modulator promoting allergic airway inflammation. Syk inhibition has been proposed as a new therapeutic approach in asthma. However, the direct effects of Syk inhibition on airway constriction independent of allergen sensitization remain elusive.

METHODS

Spectral confocal microscopy of human and murine lung tissue was performed to localize Syk expression. The effects of prophylactic or therapeutic Syk inhibition on allergic airway inflammation, hyperresponsiveness, and airway remodeling were analyzed in allergen-sensitized and airway-challenged mice. The effects of Syk inhibitors BAY 61-3606 or BI 1002494 on airway function were investigated in isolated lungs of wild-type, PKCα-deficient, mast cell-deficient, or eNOS-deficient mice.

RESULTS

Spleen tyrosine kinase expression was found in human and murine airway smooth muscle cells. Syk inhibition reduced allergic airway inflammation, airway hyperresponsiveness, and pulmonary collagen deposition. In naïve mice, Syk inhibition diminished airway responsiveness independently of mast cells, or PKCα or eNOS expression and rapidly reversed established bronchoconstriction independently of NO. Simultaneous inhibition of Syk and PKC revealed additive dilatory effects, whereas combined inhibition of Syk and rho kinase or Syk and p38 MAPK did not cause additive bronchodilation.

CONCLUSIONS

Spleen tyrosine kinase inhibition directly attenuates airway smooth muscle cell contraction independent of its protective immunomodulatory effects on allergic airway inflammation, hyperresponsiveness, and airway remodeling. Syk mediates bronchoconstriction in a NO-independent manner, presumably via rho kinase and p38 MAPK, and Syk inhibition might present a promising therapeutic approach in chronic asthma as well as acute asthma attacks.

Determination of sIgE to rPhl p 1 is sufficient to diagnose grass pollen allergy

BACKGROUND

New diagnostic tools such as the basophil activation test (BAT) and component-resolved diagnosis (CRD) are promising for Hymenoptera venom or food allergy. A clear benefit for inhalant allergens has not yet been shown. Our aim was to compare new and established tests for grass pollen allergy.

METHODS

Forty-nine patients with grass pollen allergy and 47 controls were prospectively enrolled in the study. A symptom score was calculated for each patient. Conjunctival provocation tests (CPT), skin prick tests (SPT), BAT, and sIgE determination including CRD were performed. Sensitivity and specificity were compared and results were correlated with the symptom score.

RESULTS

Single determination of sIgE to rPhl p 1 showed the best balance between sensitivity (98%) and specificity (92%). Use of additional components, such as rPhl p 2 and 5, did not increase sensitivity. Generally, sensitivity of tests was high: SPT 100%, ISAC-112 100%, sIgE to timothy grass 98%, BAT 98%, ISAC-103 84%, and CPT 83%. Specificity ranged from 79% (SPT) to 96% (CPT). All test results and calculated values (e.g. ratio sIgE/tIgE) did not correlate with symptom severity. Asymptomatic sensitization to timothy grass in controls was rare in the CAP (11%) and predominantly due to Phl p 1 sensitization.

CONCLUSION

rPhl p 1 was sufficient to diagnose grass pollen allergy, and sIgE patterns were the same in symptomatically and asymptomatically sensitized subjects. The testing of multiple components was of minor importance, and no test correlated with symptom severity.

Confinement scaling laws for the conventional reversed-field pinch

A series of high resolution, 3D, resistive MHD numerical simulations of the reversed-field pinch are performed to obtain scaling laws for poloidal beta and energy confinement at Lundquist numbers approaching 10(6). Optimum plasma conditions are attained by taking the transport coefficients to be classical, and ignoring radiation losses and resistive wall effects. We find that poloidal beta scales as beta(straight theta) approximately I-0.40 and that the energy confinement time scales as tau(E) approximately I0.34 for fixed I/N, with aspect ratio R/a = 1.25.

Persistence of hepatitis C virus in a human megakaryoblastic leukaemia cell line

Thrombocytopenia is a frequent clinical finding in patients with hepatitis C virus (HCV) infection. Platelets from patients with HCV infection have been identified as carriers of HCV RNA in our previous studies. The present study was designed to further investigate the possibility of HCV replication in megakaryoblasts from which platelets are eventually released. A megakaryoblastic cell line (MEG-01), established from a chronic myelogenous leukaemia patient 13 years ago, was used for this study. The MEG-01 cells were inoculated with fresh serum from a patient with HCV infection and renamed MEG-01-I cells. Surprisingly, both MEG-01 and MEG-01-I were positive by HCV reverse transcription-polymerase chain reaction (RT-PCR) for the existence of HCV RNA and minus-strand HCV RNA, regardless of inoculation. This was further confirmed by in situ RT-PCR. The HCV antigens, such as core, envelope, and non-structural (NS)3 and NS4, were also present in both cell lines, as identified by Western blotting and indirect immunofluorescence staining. In addition, virus-like particles were observed by electron microscopy in the MEG-01 cell line as well as in the MEG-01-I cell line. These findings indicate that the megakaryoblasts are vulnerable to HCV infection and that replication of HCV can occur in these cells. This may help us to better understand the pathogenesis of thrombocytopenia in patients with HCV infection. The MEG-01 cell line, which may have been continuously shedding HCV for years, should be a useful model for experimental research into HCV.

Hepatitis C virus antibodies in systemic lupus erythematosus

To determine the prevalence and significance of serum antibody to hepatitis C virus (HCV) in patients with systemic lupus erythematosus (SLE), we measured serum antibodies to HCV by enzyme-linked immunosorbent (ELISA) and by Abbott MATRIX Immunoblot assays in 42 patients with SLE, a condition associated with hypergammaglobulinemia. We used the polymerase chain reaction (PCR) to identify patients with HCV viremia. Five of 42 (11.9%) patients were seropositive for anti-HCV by ELISA; of these only two were positive by PCR; only one of three patients seropositive by Immunoblot assay was also positive by PCR. Both ELISA and the Immunoblot assays may be falsely positive for ongoing HCV infection in patients with SLE. Suspected HCV infection should be confirmed with PCR for serum HCV RNA in these patients.

Acute sporadic non-A, non-B, non-C, non-D, non-D, non-E hepatitis

Patients presenting with clinical and laboratory features consistent with a diagnosis of acute non-A, non-B hepatitis were evaluated for evidence of hepatitis C or hepatitis E infection and for evidence of severe or prolonged disease. Antibody to hepatitis C virus (anti-HCV) was detected in 75 of 108 (69%) patients, antibody to hepatitis E virus (anti-HEV) in three patients (3%), and neither antibody in 31 (29%) patients. One patient had both anti-HCV and anti-HEV. HCV RNA was not detected in sera from any of 20 patients with seronegative (non-ABCDE) hepatitis, but in all 10 patients with anti-HCV who were tested by polymerase chain reaction (PCR). Compared with patients with acute hepatitis C, those with non-ABCDE hepatitis had a lower incidence of parenteral risk factors (6% vs. 70%; P < .001), higher peak serum bilirubin levels (45% vs. 5% with peak levels > 15 mg/dL; P < .001), more prolonged jaundice (25% vs. 0% with peak bilirubin >5 weeks after onset; P < .01), more severe prothrombin time abnormalities (26% vs. 0% with >3 second prolongation; P < .001), more severe hypoalbuminemia (39% vs. 9% with albumin <3 g/dL; P < .01), and more frequent major clinical complications (13% vs. 0% with encephalopathy; P < .01; 10% vs. 0% with death or transplant; P = .024). Patients with acute non-ABCDE hepatitis were less likely to develop chronic hepatitis than those with acute hepatitis C (23% vs. 68%; P < .05). Thus, patients with acute non-ABCDE hepatitis are epidemiologically distinct from those with acute hepatitis C and have a significantly more severe acute illness.

Identification of hepatitis C virus by immunoelectron microscopy

Sequencing of the hepatitis C virus (HCV) has provided a better understanding of the natural history, immunology, and epidemiology of this virus. However, the morphology of HCV has not been definitively characterized. In this study, through a sequence of concentration processes, virus-like particles were isolated from human serum and liver tissue, visualized by transmission electron microscopy and identified as hepatitis C virion by immunoelectron microscopy. Spherical flavi-like virus particles, approximately 70 nm in diameter, were observed in the fraction with 1.04-1.12 g ml-1 sucrose density and bound to immunogold particles with monoclonal antibodies (mAb) against hepatitis C. The nucleocapsid of the particles, which were 50 nm in diameter, appeared to be icosahedral in structure and surrounded by an envelope covered with surface projections. A 'tadpole' form of particles was also observed. The findings indicate that the low buoyant density in sucrose and the morphological features of the hepatitis C virion are consistent with the characteristics of flaviviruses and pestiviruses.

Antibody to hepatitis C virus second envelope (HCV-E2) glycoprotein: a new marker of HCV infection closely associated with viremia

The second envelope protein (E2) of the hepatitis C virus (HCV) was cloned and expressed in Chinese hamster ovary (CHO) cells. This E2 glycoprotein was purified using ion exchange and lectin chromatography and used to construct an enzyme immunoassay for HCV E2 antibodies. The assay was shown to have good specificity, and detection of E2 antibodies was positively correlated (97.3%) to the presence of HCV RNA in serum and plasma. A high concordance between HCV 2.0 and E2 EIA reactivities was also observed. E2 antibody was the first serological marker to appear in 3/5 HCV seroconversion panels. This work demonstrated that 42.4% of core and 15.4% of NS3 indeterminate specimens also contained antibodies to E2, suggesting that HCV infection had occurred in these individuals. The E2 antibody assay was used to evaluate HCV 2.0 EIA-positive, HCV 3.0 EIA-negative plasma donors with indeterminate reactivity on RIBA HCV 2.0 or MATRIX HCV 1.0. Several HCV 3.0-negative specimens were shown to contain E2 antibodies in addition to an original indeterminate serological marker, primarily core. It is concluded that anti-E2 is a useful marker for determining HCV infection, and that the presence of antibodies to two nonoverlapping viral gene products suggests true HCV exposure. New HCV 3.0 blood screening tests should detect HCV 2.0-positive donors who present with an indeterminate pattern by RIBA or MATRIX and who also carry E2 antibodies.

Peripheral-blood mononuclear cell responses to recombinant hepatitis C virus antigens in patients with chronic hepatitis C

Peripheral blood mononuclear cell proliferative responses in vitro to recombinant yeast or Escherichia coli hepatitis C virus fusion proteins were evaluated in 20 patients with chronic hepatitis C who were reactive for antibody to hepatitis C virus (on enzyme immunoassay, version 2.0, and a four-antigen recombinant immunoblot assay). Twenty age-matched, healthy individuals negative for antibody to hepatitis C virus were used as a control group. Peripheral-blood mononuclear cells from all chronic hepatitis C patients with antibodies to hepatitis C virus antigens c22 and c100-3 proliferated in vitro in response to the corresponding recombinant hepatitis C virus fusion protein. Peripheral-blood mononuclear cells from 75% of patients infected with hepatitis C virus proliferated in response to cytidine monophosphate-keto-3-deoxyoctulosonic acid-core recombinant antigen but there was no proliferative response to cytidine monophosphate-keto-3-deoxyoctulosonic acid-EF (derived from the NS5 region). All hepatitis C virus-infected patients had 33c antibody, but peripheral-blood mononuclear cells from only 9 of 14 (64%) proliferated in vitro in response to 33c. Ninety-five percent of all hepatitis C virus-infected patients had peripheral-blood mononuclear cells that proliferated in response to at least one recombinant hepatitis C virus fusion protein. The numbers and percentages of CD3 T cells, CD19 B cells and natural killer cells from patients with chronic hepatitis C virus infection did not differ from those in the healthy control group. However, the number of non-major histocompatibility complex-restricted cytotoxic T cells (CD3-positive, CD56-positive, CD16-positive) was increased in patients with chronic hepatitis C virus infection (p < 0.05).

Frequency and severity of HCV infection following orthotopic liver transplantation. Effect of donor and recipient serology for HCV using a second generation ELISA test

HCV is the principal etiologic agent of post-transfusion (PTH) hepatitis. The incidence and course of HCV hepatitis in liver transplant recipients is not well established. To resolve this information deficit, all records of recipients of single liver transplant (OLTx) between March 1986 and March 1990 at the University of Pittsburgh in whom both the donor and recipients' pre-OLTx sera were available (n = 516) were reviewed. All sera were assayed for HCV antibody using a second generation ELISA method developed by Abbott Laboratories. On the basis of the anti-HCV status of the donor and recipient pre-OLTx sera, four groups could be classified: group I (donor-, recipient-) n = 375; group II (donor-, recipient+) n = 111; group III (donor+, recipient-) n = 25; and group IV (donor+, recipient+) n = 5. Post OLTx liver biopsies were obtained for a clinical indication in 473 of these 516 patients. The prevalence of anti-HCV among recipients pre-OLTx was 22.5% (116/516) which is three times greater than the 5.8% (30/516) prevalence in the donors. Histologic hepatitis not ascribable to any cause other than HCV occurred in 76/516 (15%) recipients: 42 in group I; 28 in group II; 6 in group III and none in group IV. The overall risk of HCV hepatitis at 6 months, 1 year and 2 years post-OLTx was 4.8% (25/516), 7.6% (39/516) and 10.1% (52/516), respectively. At each of these time intervals, no significant difference between groups for the prevalence of HCV hepatitis was evident.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-RNA polymerase I antibodies in the urine of patients with systemic lupus erythematosus

Urine samples from patients with systemic lupus erythematosus (SLE) (n = 80), patients with rheumatoid arthritis (RA) (n = 21), and healthy controls (n = 36) were analyzed by radio-immunoassay (RIA) for anti-RNA polymerase I (RPI) antibodies. Significant levels of anti-RPI antibodies were detected in the urine of 46% of the patients with SLE but in only 19% of the patients with RA and in no sample from healthy individuals. The presence of anti-RPI antibodies in the urine was confirmed by demonstrating that IgG purified from the urine of patients with SLE was capable of inhibiting the transcriptional activity of RPI in vitro. If the quantity of anti-RPI antibodies excreted is related to disease activity, analysis of urine for these antibodies may be a useful alternative for the purpose of monitoring the progression of disease in individuals with SLE because of the ease by which the sample can be collected.