IgG In Nasal Secretions Research Articles

Comparison of SARS-CoV-2 spike-specific IgA and IgG in nasal secretions, saliva and serum.

Several novel vaccine platforms aim at mucosal immunity in the respiratory tract to block SARS-CoV-2 transmission. Standardized methods for mucosal sample collection and quantification of mucosal antibodies are therefore urgently needed for harmonized comparisons and interpretations across mucosal vaccine trials and real-world data. Using commercial electrochemiluminescence antibody panels, we compared SARS-CoV-2 spike-specific IgA and IgG in paired saliva, nasal secretions, and serum from 1048 healthcare workers with and without prior infection. Spike-specific IgA correlated well in nasal secretions and saliva (r>0.65, p<0.0001), but the levels were more than three-fold higher in nasal secretions as compared to in saliva (p<0.01). Correlations between the total population of spike-specific IgA and spike-specific secretory IgA (SIgA) were significantly stronger (p<0.0001) in nasal secretions (r=0.96, p<0.0001) as opposed to in saliva (r=0.77, p<0.0001), and spike-specific IgA correlated stronger (p<0.0001) between serum and saliva (r=0.73, p<0.001) as opposed to between serum and nasal secretions (r=0.54, p<0.001), suggesting transudation of monomeric spike specific IgA from the circulation to saliva. Notably, spike-specific SIgA had a markedly higher SARS-CoV-2 variant cross-binding capacity as compared to the total population of spike specific IgA and IgG in both nasal secretions, saliva and serum, (all p<0.0001), which emphasizes the importance of taking potential serum derived monomeric IgA into consideration when investigating mucosal immune responses. Taken together, although spike-specific IgA can be reliably measured in both nasal secretions and saliva, our findings imply an advantage of higher levels and likely also a larger proportion of SIgA in nasal secretions as compared to in saliva. We further corroborate the superior variant cross-binding capacity of SIgA in mucosal secretions, highlighting the potential protective benefits of a vaccine targeting the upper respiratory tract.

Importance of allergic etiology in nasal polyposis.

Sensitization to environmental allergens in nasal polyposis was evaluated in an in vitro study conducted on 90 patients undergoing polypectomy by measuring total and specific IgE for a panel of common allergens and levels of IgG, IgA and albumin in serum, and nasal secretions (NSe). Fifty healthy individuals were chosen as a control group. Total IgE concentrations were higher in patients with nasal polyps than in controls. RAST was positive in serum in 34 (38%), in NSe in 29 (32%), and exclusively in NSe in 10 patients (11%). Allergens most frequently involved were mites and cat dander. No differences were found between the study and control groups for serum and NSe IgA, albumin, and serum IgG, whereas IgG in NSe were significantly higher in patients with nasal polyps. Subjects with positive RAST only in NSe had significantly lower secretory IgA than did controls. Our data indicate that in nasal polyposis: 1) sensitization to aeroallergens is relatively common; 2) a local production of specific IgE may occur, especially for perennial allergens; 3) prolonged exposure to these allergens gives rise to chronic nasal inflammation, with altered local production of immunoglobulins.

A double‐blind study of hyposensitization with an alginate‐ conjugated extract of Dermatophagoides pteronyssinus (Conjuvac®) in patients with perennial rhinitis

In a 2-year double-blind placebo controlled study an immunological evaluation was carried out on 33 patients (15 males, 18 females, mean age 29.2 years) with mite-induced perennial rhinitis who were submitted to specific immunotherapy (IT) with an alginate-conjugated extract of D. pteronyssinus. The behaviour of IgE, IgG, IgG1 and IgG4 antibodies specific to D. pteronyssinus and its major allergen Der p1 was characterized by assessment of their changes in serum, and changes in IgG in nasal secretions during the treatment. The placebo-treated patients did not show any significant variation in the levels of specific antibodies, while in the actively treated patients we found: a statistically significant decrease (P less than 0.005) of specific IgE, a statistically significant increase of specific IgG (P less than 0.005), IgG1 (P less than 0.005) and IgG4 (P less than 0.005) in serum and a statistically significant increase (P less than 0.001) of specific IgG in nasal secretions. The IgG response showed an early relative predominance of the IgG1 subclass and a late absolute predominance of IgG4 subclass, that confirmed the model of IgG4 restriction in prolonged allergen stimulation. No correlation was found between immunological and clinical data.

The pathophysiology of rhinitis: III. The control of IgG secretion

To examine the sources of IgG in nasal secretions, nasal provocation tests with histamine (H) and methacholine (MC) were performed on 22 subjects. Nasal lavages were assayed for IgG, total protein, albumin (Alb), nonsecretory IgA (nonsIgA), and secretory IgA (sIgA). H stimulation dramatically increased the secretion of IgG, nonsIgA, and Alb and also increased the proportion of these proteins compared to total protein. H-induced protein secretion was significantly inhibited by nasal pretreatment with chlorpheniramine maleate but was unaffected by atropine sulfate. sIgA was also stimulated by H challenge, but unlike IgG and other vascular proteins, the proportion of sIgA to total protein (sIgA percent) decreased after H challenges. MC stimulation also increased secretion of IgG, Alb, nonsIgA, and sIgA but did not alter their proportions, compared to total protein. Topical atropine significantly inhibited secretion of all proteins, suggesting a mode of transportation mediated by glandular muscarinic receptor stimulation. Thus, MC can increase the amount of IgG secretion, whereas H increases both the amount and relative proportion of IgG in nasal secretions. These data suggest that pharmacologic stimulation of IgG into nasal secretions may be used as a tool to modulate mucosal immunity.

Changes in IgA and IgG Concentrations in Nasal Secretions Prior to the Appearance of Antibody during Viral Respiratory Infection in Man

Abstract To investigate the mechanisms of appearance of locally synthesized and plasmaderived proteins at the nasal membrane surface during upper respiratory viral infection, nasal secretions and sera from six volunteers experimentally infected with coxsackievirus A type 21 or rhinovirus type 15 were analyzed for their content of viral neutralizing antibodies, immunoglobulin and albumin. Nasal IgA increased significantly 24 hr after viral inoculation and before transudation started. In coxsackievirus infection, nasal secretion IgA concentrations continued to rise for 2 weeks to nearly twice baseline levels, whereas in rhinovirus infection a sustained rise in IgA began only after illness had subsided. Significant amounts of specific antibody did not appear in the nasal secretions during the same period. Marked transudation of albumin and IgG from plasma occurred during respiratory illness. Before illness half of the IgG in nasal secretions was synthesized locally; the remainder came from plasma as indicated by the quantity of isotopically labeled IgG which entered nasal secretions from the circulation. Viral infection inhibited local IgG synthesis; therefore, after illness subsided, nearly all IgG in nasal secretions came from the plasma. These results are consistent with the hypothesis that immunoglobulins are delivered to the nasal membrane surfaces by three different mechanisms: release of pre-formed secretory IgA during the incubation period of viral infection, transudation from the plasma before and after illness but particularly during the rhinorrhea phase of illness, and local synthesis of IgA and IgG. After illness subsides, local IgG synthesis is inhibited, but there is a marked stimulation of IgA synthesis, which, after a further period, develops specificity for the infecting virus.