Fig 1.
Flow-chart for selection of the SSc/SRC and SSc/no SRC cases.
As described in the material and methods, screening of the military electronic medical records between 2005–2016 for Systemic Sclerosis was initially preformed. Following comprehensive review, 54 cases of SS/SRC were identified, of which only 16 had available serum samples. Thirty additional SSc/no SRC cases were then identified that were matched for age, gender and race with the SS/SRC group.
Table 1.
Clinical characteristics of SSc cohort.
Fig 2.
Serum autoantibody levels in the SSc/SRC and SSc/no SRC cohort.
Autoantibody measurements were made by LIPS against the 12 autoantigens in the 121 blinded serum samples corresponding to a total of 16 SRC and 30 SSc/no SRC cases. The Y axis reflects the antibody levels in LU determined by LIPS. The blue line is the cut-off value for each antigen. As shown by the numbers in blue, the most prevalent autoantibodies were against Ro52, while the least common were against the Jo-1 autoantigen.
Table 2.
Characteristics and specificity of luciferase-SSc autoantigen constructs.
Fig 3.
Heatmap analysis of autoantibodies in the SSc/SRC and SSc/no SRC cases.
Heatmap analysis of autoantibody responses are shown in the 12 seropositive SSc/SRC and 15 seropositive SSc/no SRC subjects. For each case, the time in years before (-) or after (+) initial systemic sclerosis diagnosis is denoted in the column on the left. Each group of rows represents the autoantibody profile in a single case, in which the blue colored codes represent SSc cases with autoantibodies detected after diagnosis. Color coding denotes relative antibody levels above the baseline cut-off value and the clear boxes represent seronegative responses with the autoantigens in a given subject. As shown by the key, seropositive autoantibody levels in the subjects ranged from low levels (yellow) to extremely high autoantibody levels (black). Based on the patterns that emerged, the SSc/no SRC and SSc/SRC subjects were then manually segregated into three autoantibody clusters for Ro6o/Ro52/La/Rnp-A, Topo1 and RNAP III.
Fig 4.
Representative autoantibody profiles seen in SSc/SRC cases before disease diagnosis.
Representative plots illustrating autoantibody levels in six SSc/SRC subjects before disease diagnosis. The X-axis denotes the time in years before diagnosis of SSc/SRC (time 0). The approximate time of SSc/no SRC diagnosis preceded SSc/SRC and is denoted by the black vertical arrow. The left Y axis represents the autoantibody levels in LU and the dotted line represent the approximate cut-off value for the autoantigens.
Fig 5.
Representative autoantibody profiles seen before diagnosis of SSc/no SRC.
Representative plots illustrating autoantibody levels in the six SSc/ no SRC subjects before diagnosis of the disease. The X-axis denotes the time in years before diagnosis. The left Y axis represents the scale of the autoantibody levels in LU and the dotted line represent the cut-off values for the antigens. All seropositive antibody responses against the autoantigen panel are shown.
Fig 6.
Higher autoantibody levels in SSc/SCR compared to SSc/no SRC cases.
The scatter plot graphs represent the total antibody response in individual seropositive SSc/SRC and SSc/no SRC cases. This analysis was accomplished by summing up the autoantibody values against the twelve autoantigens from the last time point of the seropositive subjects. The P values were calculated using the Mann-Whitney U test.