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cITP Associated With Familial Autoimmune Dysregulation
Researchers shared retrospective data of patients with chronic immune thrombocytopenia (cITP) and associations with autoimmune dysregulation in parents and primary immunodeficiency disorders (PIDDs).
“ITP is the most common cause of thrombocytopenia during childhood. ITP can be a manifestation of immune dysregulation in patients with other autoimmune conditions, or PIDDs. We aimed to assess the characteristics of patients with cITP, including the presence of autoimmune or allergic disorders in the patients and family members,” explained Michell Chinga, MD, University of Utah/Primary Children’s Hospital, Salt Lake City, Utah, and co-investigators.
The study hypothesized that patients with cITP may have a higher incidence of immune dysregulation in family members in contrast to patients with acute ITP.
Data from 266 patients with ITP was collected from 2001 to 2021, with patient demographics, clinical presentation, and family history as factors to be reviewed. In all, 68.5 percent of patients had aITP, and 31.5 percent of patients had cITP, which was defined as platelet count <150 K/µl for more than 12 months.
Resolved ITP occurred in 33.3 percent of patients with cITP versus 66.7 percent who had ongoing thrombocytopenia. The mean duration of ITP in patients with resolved cITP was 2.9 years, and 4.6 years in patients with unresolved cITP at the time of last known platelet count. The mean age at diagnosis in the cITP group was 7.4 years, and 5.1 years in the aITP group.
“Concurrent allergic conditions were identified in 12 percent of patients with cITP, and 2.7 percent of patients with aITP. Autoimmune conditions were identified in 3.5 percent of patients with cITP, and 2.2 percent with aITP. First-degree family members of cITP patients were more likely to be reported with an autoimmune condition than first-degree family members of aITP patients,” elaborated Dr Chinga and co-authors.
In second- or third-degree relatives, this effect was not observed. Notably, the most common autoimmune condition reported in family members was autoimmune thyroid disease in both cohorts (2.7% in aITP, 9.5% in cITP).
Further, 14 patients were diagnosed with Evan syndrome (ES), all had cITP and were followed for over a year. Additionally, 4 patients with ES were previously diagnosed with 22q11.2 deletion and 1 with common variable immunodeficiency (CVID). In patients with ES, 28.6 percent and 35.7 percent had first- and second-degree family members with a reported autoimmune condition, respectively.
“There is increasing evidence that patients with chronic ITP may exhibit polyautoimmunity or other signs of immune dysregulation, suggesting that ITP may be the initial manifestation of another autoimmune process or PIDD. Patients with cITP have a history of autoimmunity in their family stronger than in patients with aITP. This association was even stronger in patients with ES,” concluded Dr Chinga, et al.—Alexa Stoia
Chinga M, Fluchel M, Meznarich J. Does Autoimmunity in Family Members of Children with Immune Thrombocytopenia Help Identify Patients at Higher Risk of Chronic Immune Thrombocytopenia? Presented at: the 2021 ASH Annual Meeting; Dec 11-14, 2021; Abstract 3168.
