Predictors of renal histopathology in antineutrophil cytoplasmic antibody associated glomerulonephritis

Urinary angiotensinogen: an indicator of active antineutrophil cytoplasmic antibody-associated glomerulonephritis

BACKGROUND

One of the major challenges in improving the management of antineutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN) is the lack of a disease-specific indicator for histological lesions and disease activity. Here we tested the utility of urinary angiotensinogen (UAGT) as a biomarker of renal disease activity in ANCA-GN.

METHODS

A prospective, two-stage cohort study was performed in ANCA-GN patients. In Stage I, UAGT was measured at the time of renal biopsy in 69 patients from two centers (test set) and 25 patients from two other centers (validation set). In Stage II, UAGT was monitored in 50 subjects in the test set for 24 months.

RESULTS

In Stage I, UAGT significantly increased in ANCA-GN patients, correlating well with cellular crescents formation and active interstitial inflammation. Patients with crescentic ANCA-GN exhibited the highest UAGT compared with other histopathological classes of ANCA-GN. After multivariable adjustment, the highest quartile of UAGT, compared with the lowest quartile, associated with a 6-fold increased risk of crescentic ANCA-GN. For predicting crescentic ANCA-GN, UAGT [area under the receiver operating characteristics curve (AUC) = 0.88] outperformed albuminuria (AUC = 0.73) and estimated glomerular filtration rate (AUC = 0.69). UAGT improved the performance of those clinical markers in diagnosing crescentic ANCA-GN (P < 0.034), suggesting a role of UAGT in identifying active crescentic ANCA-GN. In Stage II, UAGT decreased after immunotherapy and increased at the time of renal relapse during the 2-year follow-up, suggesting the usefulness of UAGT to monitor disease activity over time.

CONCLUSIONS

These results suggest the potential use of UAGT for assessing disease activity and renal relapse in ANCA-GN.

Autoimmunity in 2016

The number of peer-reviewed articles published during the 2016 solar year and retrieved using the "autoimmunity" key word remained stable while gaining a minimal edge among the immunology articles. Nonetheless, the quality of the publications has been rising significantly and, importantly, acquisitions have become available through scientific journals dedicated to immunology or autoimmunity. Major discoveries have been made in the fields of systemic lupus erythematosus, rheumatoid arthritis, autoimmunity of the central nervous system, vasculitis, and seronegative spondyloarthrithritides. Selected examples include the role of IL17-related genes and long noncoding RNAs in systemic lupus erythematosus or the effects of anti-pentraxin 3 (PTX3) in the treatment of this paradigmatic autoimmune condition. In the case of rheumatoid arthritis, there have been reports of the role of induced regulatory T cells (iTregs) or fibrocytes and T cell interactions with exciting implications. The large number of studies dealing with neuroimmunology pointed to Th17 cells, CD56(bright) NK cells, and low-level TLR2 ligands as involved in multiple sclerosis, along with a high salt intake or the micriobiome-derived Lipid 654. Lastly, we focused on the rare vasculitides to which numerous studies were devoted and suggested that unsuspected cell populations, including monocytes, mucosal-associated invariant T cells, and innate lymphoid cells, may be crucial to ANCA-associated manifestations. This brief and arbitrary discussion of the findings published in 2016 is representative of a promising background for developments that will enormously impact the work of laboratory scientists and physicians at an exponential rate.

Stress and Disease Onset in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

To explore the potential contribution of stress as a trigger for disease onset in patients with antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV).

METHODS

53 AAV and 85 rheumatoid arthritis (RA) patients as well as 53 healthy controls (HC) were thoroughly asked for the number and impact of stressful life events, coping strategies, and available social support 12 months prior to disease onset. Anxiety, depression, personality dimensions, insomnia, and fatigue were also determined.

RESULTS

AAV patients reported higher scoring of the impact of stressful life events compared to the RA and HC group prior to disease onset (2.8 ± 3.1 vs 1.8 ± 2.1 vs 1.7 ± 2.3, p-values: 0.047 and 0.053, respectively). While the number of reported stressful events was found to be significantly higher in AAV vs RA patients but not HC, certain coping strategies and social support features were more commonly implemented by AAV patients compared to HC, but not RA patients. As far as personality and other psychosocial characteristics, AAV patients displayed significantly higher psychoticism traits compared to RA, with no other differences being detected between AAV patients and both RA and HC. After adjusting for potential cofounders, scoring of the impact of stressful life events >3 was independently associated with AAV development compared to both RA and HC [ORs (95% CI): 4.6 (1.6-13.4) and 4.4 (1.0-19.0), respectively].

CONCLUSION

The perceived impact of stressful life events prior to disease onset emerged as a contributing factor for AAV development.