Interactions between malignant cells and neighboring stromal and immune cells profoundly shape cancer progression. New forms of therapies targeting these cells have revolutionized the treatment of cancer. However, in order to specifically address each population, it was essential to identify and understand their individual roles in interaction between malignant cells, and the formation of the tumor microenvironment (TME). In this review, we focus on the myeloid cell compartment, a prominent, and heterogeneous group populating TME, which can initially exert an anti-tumoral effect, but with time actively participate in disease progression. Macrophages, dendritic cells, neutrophils, myeloid-derived suppressor cells, mast cells, eosinophils, and basophils act alone or in concert to shape tumor cells resistance through cellular interaction and/or release of soluble factors favoring survival, proliferation, and migration of tumor cells, but also immune-escape and therapy resistance.

Mast cells (MCs) are multifaceted innate immune cells often present in the tumor microenvironment (TME). However, MCs have been only barely characterized in studies focusing on global immune infiltrate phenotyping. Consequently, their role in cancer is still poorly understood. Furthermore, their prognosis value is confusing since MCs have been associated with good and bad (or both) prognosis depending on the cancer type. In this pilot study performed on a surgical cohort of 48 patients with Non-Small Cell Lung Cancer (NSCLC), we characterized MC population within the TME and in matching non-lesional lung areas, by multicolor flow cytometry and confocal microscopy. Our results showed that tumor-associated MCs (TAMCs) harbor a distinct phenotype as compared with MCs present in non-lesional counterpart of the lung. Moreover, we found two TAMCs subsets based on the expression of CD103 (also named alphaE integrin). CD103⁺ TAMCs appeared more mature, more prone to interact with CD4⁺ T cells, and located closer to cancer cells than their CD103⁻ counterpart. In spite of these characteristics, we did not observe a prognosis advantage of a high frequency of CD103⁺ TAMCs, while a high frequency of total TAMC correlated with better overall survival and progression free survival. Together, this study reveals that TAMCs constitute a heterogeneous population and indicates that MC subsets should be considered for patients’ stratification and management in future research.

Immunoglobulin E (IgE) antibodies play a key role in allergy and its most dangerous and life-threatening manifestation, anaphylaxis. Anti-IgE monoclonal antibodies (mAbs) have been developed to treat IgE-dependent diseases such as allergic asthma, food allergy, and chronic spontaneous urticaria. However, their use is still restricted to a minority of patients suffering from the most severe symptoms because treatment is costly and requires repeated administration. Therefore, we developed a conjugate vaccine against human IgE as a potential alternative therapy for long-term protection from IgE-dependent diseases. The IgE conjugate vaccine was generated by coupling a mutated fragment containing the Cε3-4 domains of human IgE with the carrier protein diphtheria cross-reactive material 197 (CRM ₁₉₇ ) using kinoid technology to raise autoantibodies against a self-antigen by engrafting it onto the highly immunogenic CRM ₁₉₇ carrier. To assess the efficacy of IgE-kinoid (IgE-K) vaccination, we generated a mouse model humanized for IgE and its high-affinity receptor FcεRI. IgE-K vaccination induced long-term production of anti–human IgE neutralizing antibodies without any detectable adverse effect. Anti-IgE antibodies were detected in the sera of IgE-K–immunized mice for up to 12 months postvaccination with a similar avidity as the approved anti-IgE mAb omalizumab. Furthermore, IgE-K vaccination protected against both IgE-mediated cutaneous and severe systemic anaphylaxis in IgE/FcεRI-humanized mice. Our results demonstrate that long-term reduction in IgE activity can be achieved through vaccination with human kinoids and can protect against anaphylaxis in humanized mice. This may represent a cost-effective, long-term therapeutic strategy for the treatment of IgE-mediated diseases.

Background: Diagnosis of allergies is mostly based on the patient's clinical history and allergen provocation tests. Determination of specific IgE (sIgE) profiles can be performed to support allergy diagnosis. This is commonly done in vivo by the skin prick test or in vitro with automated systems. Several platforms exist to quantify sIgE levels, but all these methods require access to specific instruments, often delaying the test's results. The IgE luciferase‐linked immunosorbent assay (LuLISA) allows bioluminescent quantification of IgE against peanut in microliter samples, but this method awaits extension to other allergens. This study aimed to validate a new method, named LuLIPLEX, for multiplexed bioluminescent detection of sIgE against 20 major molecular allergens. Methods: Quantification of sIgE against 12 recombinant or purified food allergens and eight aeroallergens was performed by LuLIPLEX versus standard IgE detection methods (ImmunoCAP, ISAC, ALEX, or NOVEOS). Multiplexed detection of IgE against these 20 allergens was performed within 45 min using 50 μL of serum, plasma, or whole blood samples. Results: A head‐to‐head comparison between LuLIPLEX and standard IgE detection methods showed a high correlation among all allergens tested. sIgE profiles in polysensitized subjects could be determined within 45 min in serum and plasma samples, as well as using a single drop of capillary blood. Conclusions: LuLIPLEX is a rapid and sensitive method to quantify sIgE levels against multiple allergens. Given that the test is very fast and can be performed on small and inexpensive luminometers, the IgE LuLIPLEX could allow point‐of‐care testing of sIgE profiles in allergic subjects.