Different patterns of longitudinal changes in antinuclear antibodies titers in children with systemic lupus erythematosus and Sjögren's syndrome

Abstract

Objective: to investigate the trend of autoantibody titers during a 2-year follow-up in pediatric systemic lupus erythematosus (pSLE) and pediatric Sjögren's syndrome (pSS).

Methods: Autoantibodies testing was performed every 3-4 months during 2 years from disease onset in a cohort of children with pSLE and pSS.

Results: We enrolled 21 children with pSLE and 22 children with pSS. All pSLE patients at 2 years showed ANA titers significantly lower compared to disease onset. Eleven patients (73%) were still ANA positive at 2 years, while 4 (26%) became ANA negative. At diagnosis, 12 (80%) patients showed a homogeneous pattern, while 3 (20%) patients showed a speckled pattern. The latter remained ANA positive with the same pattern; only 2 patients with a homogenous pattern converted to speckled, 4 patients with a homogeneous pattern became ANA negative. ANA negative pSLE patients showed lower levels of interferon score compared to ANA positive patients. Anti-dsDNA titers declined equally in the two groups. All patients with pSS, at disease onset, were ANA and anti-Ro positive and 14 (66%) were anti-La positive. After 2 years of follow-up, 100% remained ANA positive but showed significant lower titers. During follow-up anti-Ro and anti-La titers remained stable.

Conclusion: different patterns in changes of ANA and ENA titers in pSLE and pSS were shown. At 2 years of follow-up, all pSLE patients had a lower ANA titer and 26% became negative; however, all pSS patients remained both ANA and ENA positive. This evidence may be due to different pathogenetic pathways in SLE and pSS.

Keywords: Antinuclear antibodies (ANA); extractable nuclear antigen (ENA); interferon (IFN) signature; sjögren’s syndrome (SS); systemic lupus erythematosus (SLE).

Figure 1.

Autoantibody profile in patients with pSLE. Titers of ANA at diagnosis and at 2-years follow-up; connected dots indicate individual patients; red dots indicate patients that become ANA negative at 2 years follow-up (a). Circos plot showing the frequency of ANA pattern at diagnosis and at 2-years follow-up (b). Plot showing the ANA titers at diagnosis and over a 2-years follow-up; lines indicate average trend with shaded 95% confidence intervals for the two groups Two groups defined according to ANA status at 2-years follow-up: Group 0. ANA neg and Group 1: ANA pos) (c). Plot showing the anti-dsDNA titers at diagnosis and over a 2-years follow-up time; lines indicate average trend with shaded confidence intervals for the two groups. Two groups defined as in (c) (d). Plot showing SLEDAI score at diagnosis and over a 2-years follow-up time; lines indicate average trend with shaded confidence intervals for the two groups, defined as in panel (c) (e). Interferon score at 2 years after diagnosis for the two groups, defined as in panel (c) (f). A, Wilcoxon test; F, Mann–Whitney U test. H = homogenous pattern, S = speckled pattern, Neg = negative ANA test.

Figure 2.

Autoantibody profile in patients with pSS. Titers of ANA at diagnosis and at 2-years follow-up; connected dots indicate individual patients (a). Circos plot showing the frequency of ANA pattern at diagnosis and at 2-years follow-up (b). Plot showing ESSDAI score at diagnosis and after 2 years; connected dots indicate individual patients (c). Plot showing the ANA titers at diagnosis and over a 2-years follow-up time; line indicate average trend with shaded confidence intervals (d). Plot showing the anti-Ro autoantibody titers at diagnosis and over a 2-years follow-up time; line indicate average trend with shaded confidence intervals (e). Plot showing the anti-La autoantibody titers at diagnosis and over a 2-years follow-up time; line indicate average trend with shaded confidence intervals (f). Plot showing serum levels of total IgG at diagnosis and over a 2-years follow-up time; line indicate average trend with shaded confidence intervals (g). A and C, Wilcoxon test. H = homogenous pattern, S = speckled pattern.