Increased proteasome activator 28 gamma (PA28γ) levels are unspecific but correlate with disease activity in rheumatoid arthritis

Table 2 Mean PA28 γ level (ng/ml), standard deviations (SD), minimum (min.) and maximum (max.) values from patients with different diseases

Disease	n	mean	SD	min.	max.	PA28γpositive	P value
Healthy	20	17.5	7.4	1.4	29.6	0.0% (0/20)
Cancer	28	39.6	72.7	11.9	407.8	10.7% (3/28)	**0.003
RA	104	37.6	33.5	0.0	205.8	26.9% (28/104)	**0.0002
SS	34	37.1	36.1	0.0	195.2	29.4% (10/34)	**0.008
AOSD	15	23.8	11.9	12.4	52.9	13.3% (2/15)	0.142
CTD:
Polymyositis	18	31.1	21.2	6.7	85.4	22.2% (4/18)	*0.033
SLE	37	60.0	127.7	0.0	636.6	24.3% (9/37)	0.432
UCTD	11	35.9	15.4	18.4	61.7	36.4% (4/11)	**0.001
total CTD	66	48.1	96.8	0.0	636.6	25.8% (17/66)	*0.040

Data over the calculated cutoff are defined as PA28γ positive. P values represent significance (*, P & 0.05 and **, P & 0.01) compared with healthy control group. AOSD; adult-onset Still’s disease, CTD; different connective-tissue diseases, RA; rheumatoid arthritis SLE; systemic lupus erythematosus, SS; Sjögren’s syndrome, UCTD; undifferentiated connective-tissue disease.