LAIR-1, a widely distributed human ITIM-bearing receptor on hematopoietic cells

C1QA is an invariant biomarker for tissue macrophages

Macrophages play a pivotal role in immune responses, particularly in the context of combating microbial threats within tissues. The identification of reliable biomarkers associated with macrophage function is essential for understanding their diverse roles in host defense. This study investigates the potential of C1QA as an invariant biomarker for tissue macrophages, focusing on its correlation with the anti-microbial pathway. C1QA, a component of the complement system, has been previously implicated in various immune functions. Our research delves into the specific association of C1QA with tissue-resident macrophages and its implications in the context of anti-microbial responses. Through comprehensive systems biology and Boolean analysis of gene expression, we aim to establish C1QA as a consistent and reliable marker for identifying tissue macrophages. Furthermore, we explore the functional significance of C1QA in the anti-microbial pathway. This research seeks to provide valuable insights into the molecular mechanisms underlying the anti-microbial functions of tissue macrophages, with C1QA emerging as a potential key player in this intricate regulatory network. Understanding the relationship between C1QA, tissue macrophages, and the anti-microbial pathway could pave the way for the development of targeted therapeutic strategies aimed at enhancing the host's ability to combat infections. Ultimately, our findings contribute to the expanding knowledge of macrophage biology and may have implications for the diagnosis and treatment of infectious diseases.

One Sentence Summary

C1QA is a fundamental biomarker of tissue macrophages.

Increased concentration of soluble leukocyte-associated immunoglobulin-like receptor in sera from patients with blistering diseases: possible pathophysiological implications?

BACKGROUND

Autoimmune blistering diseases (AIBD), are a heterogeneous group. Despite their pathogenesis is not completely understood, autoantibodies against directed adhesion molecules of the skin and adjacent mucous membranes could play a key role. The leukocyte-associated-Ig-like-receptor (LAIR) family is a small group of immunoreceptor-tyrosine-based-inhibition-motif-containing inhibitory receptors, recognizing collagens. LAIR-1 is a transmembrane glycoprotein expressed on human-peripheral-blood-leukocytes. LAIR-2 is a secreted receptor mainly produced by CD4⁺ T-lymphocytes, and is able to regulate the inhibitory potential of LAIR-1. Both LAIRs have been associated with several autoimmune diseases and inflammatory responses.

METHODS

We evaluated circulating LAIRs in patients with different blistering skin diseases by ELISA.

RESULTS

A significant increase of serum LAIR-2, and to a lesser extent of sLAIR-1 (with the exception of Pemphigus vulgaris), in the whole group of patients with bullous diseases, irrespective of the pathogenesis, compared to healthy controls was evident.

CONCLUSIONS

Although the pathophysiological meaning of LAIR is not completely elucidated, the presence of increased concentration of LAIR proteins can somehow modulate the cascade of inflammatory phenomenon occurring in bullous skin diseases, in different way depending upon specific skin disease considered.

Early signaling via inhibitory and activating NK receptors

This review focuses on recent findings on the structural features of inhibitory NK cell receptors containing immunoreceptor tyrosine-based inhibition motif (ITIM) and of NK cell activating receptors, both in human and mouse. First, the study of the inhibitory killer cell immunoglobulin-like receptors (KIR) unveiled the presence of intracytoplasmic ITIM and their capacity to recruit protein tyrosine phosphatases such as SHP-1 in vivo. A brief summary of the known SHP-1 targets may help us to understand the inhibition mediated by the KIR. The characterization of ITIM thus allowed the definition of a large group of inhibitory cell surface receptors. The second part of the review describes the known NK cell activating receptors. Most of them require association with ITAM-containing polypeptides in order to mediate cell activation.