Do neutrophil gelatinase-associated lipocalin and interleukin-18 predict renal dysfunction in patients with familial Mediterranean fever and amyloidosis?

Using urinary neutrophile gelatinase-associated lipocalin for prognosticate renal dysfunction in children with familial Mediterranean fever the study design: a pilot study

BACKGROUND

The most important finding that affects the prognosis in Familial Mediterranean Fever is renal amyloidosis. The aim of the present study was to analyze neutrophil gelatinase-associated lipocalin levels in the urine, and to investigate whether it may be used as an early marker for renal involvement.

METHODS

Forty attack-free children followed by diagnosis of Familial Mediterranean Fever with age range of 5 and 18 years, and 38 healthy children with similar ages and genders were enrolled into the study. Hemogram, sedimentation, C-reactive protein, urine analysis, creatinine in the spot urine, microalbumin and urinary neutrophil gelatinase-associated lipocalin levels were analyzed and evaluated statistically in the patients and controls.

RESULTS

There was not any statistically significant difference between the patient and control groups for age, gender, height and body weight. Although there was not any clinical sign of attack in the patient group, sedimentation, C-reactive protein and fibrinogen levels were significantly higher than the control group (p = 0.002, p = 0.023, and p = 0.006, respectively). Similarly, urinary neutrophil gelatinase-associated lipocalin level and urinary creatinine ratio were significantly higher in the patient group (p = 0.0001, p = 0.011, respectively). We found a positive correlation between uNGAL level and uNGAL/uCr ratio and number of attacks per year in FMF patients (r = 0.743, p = 0.001 and r = 0.516, p = 0.001; respectively).

CONCLUSIONS

Detection of significantly higher levels of urinary neutrophil gelatinase-associated lipocalin level and urinary neutrophil gelatinase-associated lipocalin level to creatinine ratio were suggested as urinary neutrophil gelatinase-associated lipocalin level as a non-invasive marker for renal involvement better than microalbumin.

Correlation of Secretory Activity of Neutrophils With Genotype in Patients With Familial Mediterranean Fever

OBJECTIVE

Familial Mediterranean fever (FMF) is an autoinflammatory disorder caused by pyrin-encoding MEFV mutations. Patients present with recurrent but self-limiting episodes of acute inflammation and often have persistent subclinical inflammation. The pathophysiology is only partially understood, but neutrophil overactivation is a hallmark of the disease. S100A12 is a neutrophil-derived proinflammatory danger signal that is strongly elevated in active FMF. This study was undertaken to characterize the secretory activity of neutrophils in vitro and investigate the association of S100A12 with disease activity and genotype in patients with FMF.

METHODS

Neutrophils from FMF patients carrying the p.M694V mutation (1 compound heterozygous and 5 homozygous) and neutrophils from 4 healthy control subjects were purified and stimulated in vitro. Neutrophil secretion of S100A12, interleukin-18 (IL-18), IL-1β, and caspase 1 was determined. Based on these in vitro analyses, serum concentrations of S100A12, IL-18, and IL-1β were also analyzed in 128 clinically and genetically characterized patients with FMF.

RESULTS

In vitro, unstimulated neutrophils from p.M694V-positive patients spontaneously secreted more S100A12, IL-18, and caspase 1 compared to neutrophils from healthy controls. Serum concentrations of S100A12 correlated with disease activity and genotype, with the levels being highest in homozygous patients and with compound heterozygotes displaying higher levels than heterozygotes. Compared to individuals negative for the p.M694V mutation, heterozygous, compound heterozygous, or homozygous p.M694V-positive patients had higher serum levels of S100A12 and IL-18 during inactive and subclinical disease.

CONCLUSION

The FMF phenotype is known to be more severe in patients carrying the p.M694V mutation. This report describes 2 molecules secreted by unconventional secretory pathways, S100A12 and IL-18, whose concentrations correlated with clinical disease activity and genotype in patients with FMF. In this clinically and genetically heterogeneous disease, management of these surrogate markers might help to improve patient care and outcomes.

The evaluation of renal hemodynamics changes in Familial Mediterranean fever with color Doppler sonography

BACKGROUND

Renal resistive index (RRI) scanned through renal Doppler is a practical marker employed in measuring blood flow in renal and intrarenal arteries and in noninvasive evaluation of renal vascular resistance. We aimed to investigate the renal hemodynamic variations in patients with Familial Mediterranean Fever (FMF).

MATERIAL AND METHODS

Seventy-nine FMF patients and 51 healthy subjects suitable for age and sex were included. Patients were divided into two groups according to their urinary albumin excretion. Fifty-two patients with 0-29 mg/day albuminuria were included in the normoalbuminuric group while 27 patients with 30-299 mg/day albuminuria were included in the microalbuminuric group.

RESULTS

RRI values were higher in patients with FMF compared to the healthy subjects (p < 0.0001). Additionally, RRI values were found to be higher in the microalbuminuric patients group compared to the normoalbuminuric patients group, and RRI values were also higher in normoalbuminuric patients group compared to the control group (p = 0.002, p < 0.0001). The ROC curve analysis suggested that the optimum RRI cutoff value for microalbuminuria in patients was 0.63, sensitivity of 66%, specificity of 60%, and p = 0.013.

CONCLUSION

RRI may be a marker that may be used in assessing resistance to renal blood flow, early renal damage, and progression of renal damage in FMF patients.

Red cell distribution width is associated with albuminuria in adults with familial Mediterranean fever

Systematic inflammation, enhanced oxidative stress, and endothelial dysfunction are important for evolution and progression of renal damage, and they cause an increase in red cell distribution width (RDW). Familial Mediterranean fever (FMF) patients who are in the attack-free period and its relation with albuminuria and performance on assessment of microalbuminuria. One hundred and seventy-seven patients who had been diagnosed in accordance with Tel-hoshmer criteria and were in the attack-free period, and 143 age- and sex-matched healthy individuals were enrolled in our study. RDW values of FMF patients were higher compared with those of the controls (13.85 ± 1.07 and 13.15 ± 0.91, respectively; p < 0.0001). RDW values of FMF patients with microalbuminuria were higher compared with those of FMF patients with normoalbuminuria and the control group (p = 0.002 and p < 0.0001, respectively). RDW values of FMF patients with normoalbuminuria were higher compared with those of the control group (p < 0.0001). We have showed RDW levels are positively correlated with albuminuria (r = 0.185, p = 0.014). When assessing microalbuminuria with RDW in the patients, a cutoff value of 13.85 with sensitivity of 60%, specificity of 62%, and p = 0.002 (area under curve: 0.651, 95% confidence interval 0.563-0.738), was observed according to receiver-operating characteristic curve analysis. Among the various variables associated with albuminuria in multivariate logistic regression analyses, RDW remained an independent predictor of albuminuria (95% confidence interval 0.479-0.942, p = 0.021). RDW may be associated with albuminuria in FMF patients and it can be a predictor of microalbuminuria.

The Relationship Among the Level of Serum Amyloid A, High-Density Lipoprotein and Microalbuminuria in Patients With Familial Mediterranean Fever

BACKGROUND

Serum amyloid A (SAA), which is produced in the liver, acts as an apoprotein of high-density lipoprotein (HDL) accumulation in extracellular matrix of tissues and organs. SAA elevations play a significant role in the development of amyloidosis. Microalbuminuria (MAU) is the early period of amyloidosis in patients with familial Mediterranean fever (FMF). We assessed the association between SAA as an important factor for the development of amyloidosis in patients with FMF and cytokines, HDL, and MAU.

METHODS

A total of 40 FMF patients diagnosed with Tel-Hashomer criteria and making regular follow-up visits at the tertiary referral center from 2012 to 2013 were included in this study, besides 40 age- and sex-matched individuals as controls.

RESULTS

Compared with controls, FMF patients had higher SAA (25.20 ± 45.78 vs. 1.68 ± 0.63 ng/ml; P = 0.002). Also, FMF patients had higher MAU than controls (23.20 ± 39.86 vs. 9.40 ± 5.32 mg/day; P = 0.036). HDL was significantly lower in the patient group than in controls (39.35 ± 10.45 vs. 47.82 ± 15.31 mg/dl; P = 0.023). Interleukin-1 beta (IL-1), IL-6, and tumor necrosis factor alpha (TNF-α) levels were higher in the FMF group than in controls (P < 0.0001, P = 0.009, P = 0.003, respectively).

CONCLUSIONS

Our results suggest that IL-1, IL-6, TNF-α, SAA, and HDL may serve as markers of subclinical inflammation in FMF patients. Due to increased plasma HDL levels, antiinflammatory and antioxidant effects may elevate in FMF patients.