Serum 14-3-3h was detected at levels above the 0.2 ng/mL cutoff among all JIA subtypes (23%, 34/151), including the OJIA group. As demonstrated in Table 1 and Figure 1, PJIA RF+ group had the highest rate of positive 14-3-3h at (49%; 19/39). The PJIA RF- group had the lowest rate of positive 14-3-3h (8%, 3/39). Remarkably, the OJIA group had the second highest rate of positive 14-3-3h. There were 4 patients with extended OJIA within OJIA group and only 1 patient had positive 14-3-3h. Nevertheless, the odds of a positive 14-3-3h tests in PJIA RF+ subjects was 3.3 times that of OJIA subjects (OR 3.27, p-value 0.029). Similarly, the odds of a positive 14-3-3h tests was nearly 8 fold greater in PJIA RF+ subjects than in PsA subjects (OR 7.8, p-value 0.008).
Gender comparison of serum 14-3-3η results:
Among the 5 subtypes of JIA subjects included in this cohort, 78% (118/151) were female. Fifty-seven of patients within this cohort were within the PJIA RF+ and PJIA RF- groups, which also had the highest female to male ratios (87% female in both groups). Positive 14-3-3h results were more common among female patients (31/118; 26%) than male patients (3/33; 9%). The highest rate of 14-3-3h positivity among female group was in the PJIA RF+ female group (17/34; 50%). The second highest prevalence of positive 14-3-3h among female subjects was among OJIA (8/28; 29%) compared to other groups: PsA (2/11; 18%), ERA (1/11; 9%) and PJIA RF- (3/34; 9%). None of the male patients in the PJIA RF-, OJIA, or PsA groups had a positive 14-3-3h titer (PJIA RF+ 2/5; 40% and ERA 1/7; 14%).
Comparison of 14-3-3η , RF, and CCP antibodies within each group:
OJIA subjects had the highest rate of positive 14-3-3h (19%) in the absence of other biomarkers: RF or CCP antibody (Table 2). Of note, 8 out of 36 (22%) of the OJIA patients had detectable 14-3-3h, most of whom (88%) were positive for only 14-3-3h (negative for RF and CCP antibodies; Table 2). Also, 4 out of 36 OJIA patients had extended OJIA, while only one out of 4 of these patients had positive14-3-3h. The OJIA, PsA, and ERA groups were the least likely to be positive for 14-3-3h, in addition to RF or CCP antibody or both. Overall, the PJIA RF+ group had a higher proportion of triple positive patients with 14-3-3h, CCP antibody, and RF (41%) than any other group.
Comparison of RF and CCP antibodies with 14-3-3η :
There was a linear trend in 14-3-3η positivity with cumulative RF/CCP antibody positivity. Of the 30 subjects positive for both RF and CCP antibody, 16 (53% [34%, 72%, respectively]) were positive for 14-3-3η. Among the 15 subjects positive for either RF or CCP antibody, 6 (40% [16%, 68%]) were positive for 14-3-3η. Lastly, among the 106 subjects negative for both RF and CCP antibody, only 12 (11% [6%, 19%]) were positive for 14-3-3η (p-value for trend in proportions = 3.5x10-7). RF positivity was strongly associated with CCP antibody positivity (p < 2.2x10-16). In PJIA RF+ patients 77% (30/39) had a positive CCP antibody (Table 2), while 41% (16/39) were positive for RF, CCP antibody and 14-3-3η.
Positive CCP antibody levels were more commonly observed in PJIA groups. However, OJIA, PsA, and ERA groups were more likely to have a positive 14-3-3h compared to CCP antibody. Twenty two percent of OJIA subjects had a detectable 14-3-3h level, while only 6% had a positive CCP antibody. However, PJIA RF+ group had a higher prevalence of CCP antibody (77%) vs. 14-3-3η (49%).
Comparison of Serum 14-3-3η at different cut off levels of >0.4ng/ml and >0.8ng/ml:
Overall, a similar proportion of patients with elevated 14-3-3h titer >0.2ng/ml had 14-3-3η level equal to or greater than 0.4 ng/ml and 0.8 ng/ml. There was a wide range of 14-3-3h titer, from 0.2ng/ml to >20ng/ml, among all groups. As mentioned previously, 23% of all patients had a positive 14-3-3h result at >0.2 ng/ml. Eighty eight percent (30/34) of those patients had 14-3-3h titers of >0.4 ng/ml, and 71% (24/34) had titers >0.8 ng/ml. Among OJIA, PJIA RF-, and PsA groups, all subjects with positive 14-3-3h had 14-3-3h titers at 0.4 ng/ml or greater. However, large numbers (84%, 16/19) of PJIA RF+ patients also had 14-3-3h levels >0.4 ng/ml. Additionally, 58% of PJIA RF+ (11/19) and 67% of PJIA RF- (2/3) patients with positive14-3-3h had titers 10 times (>2 ng/ml) greater than the cutoff value. Only 3 (38%) OJIA, 1 (50%) PsA, and none of ERA patients had elevated 14-3-3h titers 10 times higher than the baseline.
Comparison of 14-3-3η vs. ANA and HLA-B27:
Positive ANA was found among all groups; the highest prevalence was among OJIA subjects (64%) and the lowest prevalence was among PJIA RF- (38%). Thirty-one percent of PJIA RF+ population had a positive ANA and 14-3-3h compared to OJIA 19%, PsA 11%, ERA 6%, and PJIA RF- 0% (Table 2). Overall, 60% of PJIA RF+ patients with positive ANA had serum 14-3-3h levels above baseline. There was no association between positive ANA and 14-3-3h among all groups (p-value = 0.119, OR 1.96).
As expected, positive HLA-B27 was found at a higher rate among ERA patients 33%, vs. PsA 11%, OJIA 6%, PJIA RF+ 5%, and PJIA RF- 5%. There was no correlation between positive 14-3-3h and elevated CRP (p-value=1, OR 1.1).
Comparison of 14-3-3η and disease activity:
There was no association between disease activity based on JADAS-71 and positive 14-3-3h results, in any of the JIA types (Table 3). There was no association between age of onset, age at the time of blood draw, and having a positive 14-3-3h titer. Furthermore, no correlations between detectable 14-3-3h level and treatments (NSAIDs, DMARD, or biologics) were observed (Table 4). Methotrexate and anti-TNFa were the most common therapies used. Interestingly, a large proportion of OJIA patients required DMARD (81%) and/or anti-TNFa (42%) therapy. OJIA patients required biologics less commonly compared to the other groups. All of the OJIA subjects with positive 14-3-3h titer required DMARDs, 38% of whom also required biologics. However, all of PJIA RF- subjects with elevated 14-3-3h level required biologics, which was different than PJIA RF+ (84%), PsA (50%), and ERA (50%).
Comorbidities among OJIA and serum 14-3-3η level:
Overall, uveitis was more common among OJIA patients than in other groups. Chronic uveitis was found in 12 (33%) of 36 OJIA patients, more frequently than in PJIA RF+ (0/39), PJIA RF- (6/39; 15%); PsA (3/19; 16%), and ERA (5/18; 28%). Among OJIA patients with positive 14-3-3h titer, only 3 (38%) had a diagnosis of uveitis. Although the numbers were too small for statistical analysis, uveitis was as common in OJIA patients with 14-3-3h (9/28; 33%) as in those without 14-3-3h (3/8; 38%). In other JIA groups, 14-3-3h was not detected in patients with uveitis.