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Suppression of basophil FcɛRI activation by serum from active chronic idiopathic/spontaneous urticaria (CIU/CSU) subjects.

Sterba PM, Hamilton RG, Saini SS - J. Invest. Dermatol. (2015)

View Article: PubMed Central - PubMed

Affiliation: Division of Allergy and Clinical Immunology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.

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Active CIU/CSU patients uniquely display suppressed basophil FcεRI-mediated histamine release (BHR)... In this study, we examined the ability of active CIU/CSU patients’ serum to transfer FcεRI-mediated BHR suppression to healthy basophils and further test the contributions of IgE, IgG, and complement in the observed basophil mediator suppression... In select experiments, CIU/CSU serum were tested as follows: 1) paired sera from patients before and after remission, 2) serum depleted of IgE by overnight incubation with omalizumab covalently coupled to Sepharose-CL-4B as previously validated to achieve a 98% IgE depletion rate, 3) serum heat inactivated at 56°C for 30 minutes to denature IgE and inactivate complement, 4) serum IgG-depleted by adsorption with Staphylococcal Protein G Sepharose 4B-CL (>93% depletion)... In remission, CIU/CSU patients show an increase in their basophil HR profile... Therefore, we compared the effect of serum culture from CIU/CSU patients during active disease and in remission... IgE depletion by immunoadsorption failed to change the degree of BHR suppression obtained with intact serum (Figure 2a)... Similarly, the use of heat-inactivated serum, inactivating IgE and complement, also did not alter BHR suppression after culture (Figure 2b)... Serum from patients with CIU/CSU disease before and after clinical improvement on omalizumab therapy (Figure 2c) did not differ in their capacity to transfer BHR suppression... We consistently observed marked suppression of FcεRI-mediated BHR in cultures using active CIU/CSU patients’ serum, but found the serum from patients in remission had less capacity to suppress basophil HR... These observations suggest that the suppressive factor in the serum of CIU/CSU patients acts through the IgE receptor pathway, but is not IgE... Furthermore, IgG depletion of active CIU/CSU serum also failed to alter the transfer of mediator suppression, indicating that IgG antibodies are not directly involved in the phenomenon... While the nature of the serum factor responsible for suppressing BHR in CIU/CSU remains unknown, its significance as a potential disease biomarker for CIU/CSU is apparent, but more work is needed... The suppression factor is present in active disease, reduced as the patient experiences natural disease remission and is independent of IgE and IgG antibodies.

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The source of the suppressive factor is not complement, IgE, or IgG autoantibodyFcεRI mediated BHR suppression does not appear to be affected by a) serum IgE depletion by immunoadsorption (n=4), or b) heat inactivation of IgE and complement (n=3). The 3 sera used in figure 2a contained 33, 212, and 355 ng/ml of IgE and after immunoadsorption, levels were reduced levels to 2% of original values. c) Serum from patients pre and post omalizumab therapy (n=6) showed no differences in the degree of histamine suppression observed. d) IgG was depleted from active CIU/CSU serum using protein G Sepharose, and evaluated in comparison to untreated serum for BHR suppression (n=3). No statistical differences were seen among the active, IgG depleted, or sham depleted sera.
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Figure 2: The source of the suppressive factor is not complement, IgE, or IgG autoantibodyFcεRI mediated BHR suppression does not appear to be affected by a) serum IgE depletion by immunoadsorption (n=4), or b) heat inactivation of IgE and complement (n=3). The 3 sera used in figure 2a contained 33, 212, and 355 ng/ml of IgE and after immunoadsorption, levels were reduced levels to 2% of original values. c) Serum from patients pre and post omalizumab therapy (n=6) showed no differences in the degree of histamine suppression observed. d) IgG was depleted from active CIU/CSU serum using protein G Sepharose, and evaluated in comparison to untreated serum for BHR suppression (n=3). No statistical differences were seen among the active, IgG depleted, or sham depleted sera.

Mentions: Given that omalizumab therapy rapidly reduces symptoms in CIU/CSU patients (Gober et al., 2008; Maurer et al., 2013; Saini et al., 2011), we explored the role of IgE in conveying BHR suppression. IgE depletion by immunoadsorption failed to change the degree of BHR suppression obtained with intact serum (Figure 2a). Similarly, the use of heat-inactivated serum, inactivating IgE and complement, also did not alter BHR suppression after culture (Figure 2b). Serum from patients with CIU/CSU disease before and after clinical improvement on omalizumab therapy (Figure 2c) did not differ in their capacity to transfer BHR suppression. Likewise, basophils cultured in IgG depleted CIU/CSU serum showed similar suppression of HR to sham-depleted serum (Figure 2d).


Suppression of basophil FcɛRI activation by serum from active chronic idiopathic/spontaneous urticaria (CIU/CSU) subjects.

Sterba PM, Hamilton RG, Saini SS - J. Invest. Dermatol. (2015)

The source of the suppressive factor is not complement, IgE, or IgG autoantibodyFcεRI mediated BHR suppression does not appear to be affected by a) serum IgE depletion by immunoadsorption (n=4), or b) heat inactivation of IgE and complement (n=3). The 3 sera used in figure 2a contained 33, 212, and 355 ng/ml of IgE and after immunoadsorption, levels were reduced levels to 2% of original values. c) Serum from patients pre and post omalizumab therapy (n=6) showed no differences in the degree of histamine suppression observed. d) IgG was depleted from active CIU/CSU serum using protein G Sepharose, and evaluated in comparison to untreated serum for BHR suppression (n=3). No statistical differences were seen among the active, IgG depleted, or sham depleted sera.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4402712&req=5

Figure 2: The source of the suppressive factor is not complement, IgE, or IgG autoantibodyFcεRI mediated BHR suppression does not appear to be affected by a) serum IgE depletion by immunoadsorption (n=4), or b) heat inactivation of IgE and complement (n=3). The 3 sera used in figure 2a contained 33, 212, and 355 ng/ml of IgE and after immunoadsorption, levels were reduced levels to 2% of original values. c) Serum from patients pre and post omalizumab therapy (n=6) showed no differences in the degree of histamine suppression observed. d) IgG was depleted from active CIU/CSU serum using protein G Sepharose, and evaluated in comparison to untreated serum for BHR suppression (n=3). No statistical differences were seen among the active, IgG depleted, or sham depleted sera.
Mentions: Given that omalizumab therapy rapidly reduces symptoms in CIU/CSU patients (Gober et al., 2008; Maurer et al., 2013; Saini et al., 2011), we explored the role of IgE in conveying BHR suppression. IgE depletion by immunoadsorption failed to change the degree of BHR suppression obtained with intact serum (Figure 2a). Similarly, the use of heat-inactivated serum, inactivating IgE and complement, also did not alter BHR suppression after culture (Figure 2b). Serum from patients with CIU/CSU disease before and after clinical improvement on omalizumab therapy (Figure 2c) did not differ in their capacity to transfer BHR suppression. Likewise, basophils cultured in IgG depleted CIU/CSU serum showed similar suppression of HR to sham-depleted serum (Figure 2d).

View Article: PubMed Central - PubMed

Affiliation: Division of Allergy and Clinical Immunology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Active CIU/CSU patients uniquely display suppressed basophil FcεRI-mediated histamine release (BHR)... In this study, we examined the ability of active CIU/CSU patients’ serum to transfer FcεRI-mediated BHR suppression to healthy basophils and further test the contributions of IgE, IgG, and complement in the observed basophil mediator suppression... In select experiments, CIU/CSU serum were tested as follows: 1) paired sera from patients before and after remission, 2) serum depleted of IgE by overnight incubation with omalizumab covalently coupled to Sepharose-CL-4B as previously validated to achieve a 98% IgE depletion rate, 3) serum heat inactivated at 56°C for 30 minutes to denature IgE and inactivate complement, 4) serum IgG-depleted by adsorption with Staphylococcal Protein G Sepharose 4B-CL (>93% depletion)... In remission, CIU/CSU patients show an increase in their basophil HR profile... Therefore, we compared the effect of serum culture from CIU/CSU patients during active disease and in remission... IgE depletion by immunoadsorption failed to change the degree of BHR suppression obtained with intact serum (Figure 2a)... Similarly, the use of heat-inactivated serum, inactivating IgE and complement, also did not alter BHR suppression after culture (Figure 2b)... Serum from patients with CIU/CSU disease before and after clinical improvement on omalizumab therapy (Figure 2c) did not differ in their capacity to transfer BHR suppression... We consistently observed marked suppression of FcεRI-mediated BHR in cultures using active CIU/CSU patients’ serum, but found the serum from patients in remission had less capacity to suppress basophil HR... These observations suggest that the suppressive factor in the serum of CIU/CSU patients acts through the IgE receptor pathway, but is not IgE... Furthermore, IgG depletion of active CIU/CSU serum also failed to alter the transfer of mediator suppression, indicating that IgG antibodies are not directly involved in the phenomenon... While the nature of the serum factor responsible for suppressing BHR in CIU/CSU remains unknown, its significance as a potential disease biomarker for CIU/CSU is apparent, but more work is needed... The suppression factor is present in active disease, reduced as the patient experiences natural disease remission and is independent of IgE and IgG antibodies.

Show MeSH
Related in: MedlinePlus