The effect of antinuclear antibody titre and its variation on outcomes in children with primary immune thrombocytopenia

Abstract

Antinuclear antibody (ANA) can be positive in children with primary immune thrombocytopenia (ITP), but the effect of ANA titre and its variation on outcomes of children with primary ITP remains unclear. Here, we conducted a single-centre retrospective cohort study of children with primary ITP at the Peking Union Medical College Hospital in China. A total of 324 children with primary ITP included in this study were followed for a median time of 25 months. In this cohort, 39.2% had an ANA titre of 1:160 or higher. Results from a generalized estimating equation model revealed that patients with higher ANA titres had lower platelet counts at onset but a higher recovery rate of subsequent platelet counts. Results from Cox regression models adjusted for potential confounders revealed that patients with ANA titres of 1:160 or more were more likely to develop to autoimmune disease (AID) than those without, and the risk of AID development increased with the rise of ANA titres (p value for trend less than 0.001). These data highlight the predictive value of ANA titre for platelet counts and the risk of AID development in children with primary ITP.

Clinical significance of antinuclear antibodies in primary immune thrombocytopenia

“…A selection of studies with large numbers of included patients is presented in Table 1. [11][12][13][14][15][16][17][18][19][20][21] Using the threshold of ≥1:160, recent studies conducted in children and adults estimated the prevalence up to 40%. 17,19,20 However, the prevalence estimates with lower titres ranged from 13% to 65%.…”

“…A selection of studies with large numbers of included patients is presented in Table 1 11–21 . Using the threshold of ≥1:160, recent studies conducted in children and adults estimated the prevalence up to 40% 17,19,20 . However, the prevalence estimates with lower titres ranged from 13% to 65%.…”

“…Conversely, 147 children with chronic ITP and the presence of ANAs at a titre ≥1:160 did not develop systemic lupus during the follow‐up 21 . However, clinical experience and ancient descriptions of cases favour the interest of regular assessment of signs of autoimmune systemic diseases during the follow‐up of patients with a high titre of ANAs and/or ANAs specifically directed towards DNA or ENA (SSA/La, SSB/Ro or Sm) 11,20,32 …”

“…The studies assessing the prevalence of ANAs in patients with primary ITP are mostly retrospective and highly heterogeneous as regards the population (children vs. adults, newly diagnosed ITP or not, across various continents), the threshold used to define ANA positivity, and the technique used. A selection of studies with large numbers of included patients is presented in Table 1 11–21 . Using the threshold of ≥1:160, recent studies conducted in children and adults estimated the prevalence up to 40% 17,19,20 .…”

“…The risk of developing another connective tissue disease in patients with ITP and ANAs is not well known. Of note, in a retrospective Chinese series of 324 children with primary ITP and a median follow‐up of 25 months, eight developed primary Sjögren syndrome: among them, six had ANAs at a titre ≥1:160 20 …”