AIM/CD5L ameliorates autoimmune arthritis by promoting removal of inflammatory DAMPs at the lesions

Release of apoptosis inhibitor of macrophage (AIM) from pentameric IgM in serum predicts prognosis after hemodialysis initiation

BACKGROUND

The optimal timing for initiating dialysis and prognostic markers in chronic kidney disease (CKD) patients are under debate, with mortality and cardiovascular risks varying among patients. This study investigates whether the apoptosis inhibitor of macrophage (AIM), which is mostly bound to pentameric IgM, could serve as an effective indicator.

METHODS

We prospectively followed 423 patients at dialysis initiation and 563 at various CKD stages. AIM dissociation from IgM and other serum components were measured in their serum samples. In vitro treatment of IgM-AIM complexes with their serum was conducted to assess AIM release from IgM. Survival analysis determined the associations of each variable with mortality and cardiovascular risk, and a cutoff value was calculated and validated using cross-validation.

RESULTS

AIM dissociation from IgM increases with CKD progression and correlates with the serum uremic state, as shown by enhanced AIM release from IgM in vitro with sera from patients starting dialysis, but not those at earlier CKD stages. Patients at dialysis initiation with high proportion of serum IgM-free AIM (fAIM%) show elevated uremic toxins and other toxic metabolites, higher mortality, and increased cardiovascular risk compared to those with low fAIM%. This prognostic association is not seen with other CKD biomarkers, such as eGFR, creatinine, or inositol-phosphate. We determined the fAIM% cutoff of 46.27%, which predicts mortality two years post-dialysis initiation.

CONCLUSIONS

These findings suggest that the serum fAIM% could function as a prognostic marker at dialysis initiation and may have potential as a criterion for determining dialysis timing.

The Role of Alarmins in the Pathogenesis of Rheumatoid Arthritis, Osteoarthritis, and Psoriasis

Alarmins are immune-activating factors released after cellular injury or death. By secreting alarmins, cells can interact with immune cells and induce a variety of inflammatory responses. The broad family of alarmins involves several members, such as high-mobility group box 1, S100 proteins, interleukin-33, and heat shock proteins, among others. Studies have found that the concentrations and expression profiles of alarmins are altered in immune-mediated diseases. Furthermore, they are involved in the pathogenesis of inflammatory conditions. The aim of this narrative review is to present the current evidence on the role of alarmins in rheumatoid arthritis, osteoarthritis, and psoriasis. We discuss their potential involvement in mechanisms underlying the progression of these diseases and whether they could become therapeutic targets. Moreover, we summarize the impact of pharmacological agents used in the treatment of these diseases on the expression of alarmins.