Saliva antibody profiles are associated with reaction threshold and severity of peanut allergic reactions.

BACKGROUND: Reaction threshold and severity in food allergy are difficult to predict, and noninvasive predictors are lacking. OBJECTIVE: We sought to determine the relationships between pre-challenge levels of peanut (PN)-specific antibodies in saliva and reaction threshold, severity, and organ-specific symptoms during PN allergic reactions. METHODS: We measured PN-specific antibody levels in saliva collected from 127 children with suspected PN allergy before double-blind, placebo-controlled PN challenges in which reaction threshold, severity, and symptoms were rigorously characterized. Low threshold (LT) PN allergy was defined as reaction to <300 mg of PN protein cumulatively consumed. A consensus severity grading system was used to grade severity. We analyzed associations between antibody levels and reaction threshold, severity, and organ-specific symptoms. RESULTS: Among the 127 children, those with high pre-challenge saliva PN IgE had higher odds of LT PN allergy (odds ratio [OR] 3.9, 95% CI 1.6-9.5), while those with high saliva PN IgA:PN IgE ratio or PN IgG4:PN IgE ratio had lower odds of LT PN allergy (OR 0.3, 95% CI 0.1-0.8; OR 0.4, 95% CI 0.2-0.9). Children with high pre-challenge saliva PN IgG4 had lower odds of severe PN reactions (OR 0.4, 95% CI 0.2-0.9). Children with high saliva PN IgE had higher odds of respiratory symptoms (OR 8.0, 95% CI 2.2-26.8). Saliva PN IgE modestly correlated with serum PN IgE levels (Pearson r = 0.31, P = .0004). High and low saliva PN IgE levels further distinguished reaction threshold and severity in participants stratified by serum PN IgE, suggesting endotypes. CONCLUSIONS: Saliva PN antibodies could aid in noninvasive risk stratification of PN allergy threshold, severity, and organ-specific symptoms.

ICOS agonist vopratelimab modulates follicular helper T cells and improves B cell function in common variable immunodeficiency.

Common variable immunodeficiency (CVID) is an immune defect characterized by hypogammaglobulinemia and impaired development of B cells into plasma cells. As follicular helper T cells (TFH) play a central role in humoral immunity, we examined TFH cells in CVID, and investigated whether an inducible T cell co-stimulator (ICOS) agonist, vopratelimab, could modulate TFH, B cell interactions and enhance immunoglobulin production. CVID subjects had decreased TFH17 and increased TFH1 subsets; this was associated with increased transitional B cells and decreased IgG+ B and IgD-IgM-CD27+ memory B cells. ICOS expression on CVID CD4+ T cells was also decreased. However, ICOS activation of CD4+ T cells by vopratelimab significantly increased total CVID TFH, TFH2, cell numbers, as well as IL-4, IL-10 and IL-21 secretion in vitro. Vopratelimab treatment also increased plasma cells, IgG+ B cells, reduced naïve & transitional B cells and significantly increased IgG1 secretion by CVID B cells. Interestingly, vopratelimab treatment also restored IgA secretion in PBMCs from several CVID patients who had a complete lack of endogenous serum IgA. Our data demonstrate the potential of TFH modulation in restoring TFH and enhancing B cell maturation in CVID. The effects of an ICOS agonist in antibody defects warrants further investigation. This biologic may also be of therapeutic interest in other clinical settings of antibody deficiency.

IL4Rα and IL17A Blockade Rescue Autoinflammation in SOCS1 Haploinsufficiency.

By inhibition of JAK-STAT signaling, SOCS1 acts as a master regulator of the cytokine response across numerous tissue types and cytokine pathways. Haploinsufficiency of SOCS1 has recently emerged as a monogenic immunodysregulatory disease with marked clinical variability. Here, we describe a patient with severe dermatitis, recurrent skin infections, and psoriatic arthritis that harbors a novel heterozygous mutation in SOCS1. The variant, c.202_203delAC, generates a frameshift in SOCS1, p.Thr68fsAla*49, which leads to complete loss of protein expression. Unlike WT SOCS1, Thr68fs SOCS1 fails to inhibit JAK-STAT signaling when expressed in vitro. The peripheral immune signature from this patient was marked by a redistribution of monocyte sub-populations and hyper-responsiveness to multiple cytokines. Despite this broad hyper-response across multiple cytokine pathways in SOCS1 haploinsufficiency, the patient's clinical disease was markedly responsive to targeted IL4Rα- and IL17-blocking therapy. In accordance, the mutant allele was unable to regulate IL4Rα signaling. Further, patient cells were unresponsive to IL4/IL13 while on monoclonal antibody therapy. Together, this study reports a novel SOCS1 mutation and suggests that IL4Rα blockade may serve as an unexpected, but fruitful therapeutic target for some patients with SOCS1 haploinsufficiency.