Flow cytometric measurement of platelet‐associated immunoglobulin in children with newly diagnosed Immune Thrombocytopenia

Abstract

Approximately one-quarter of children are PAIG-negative, and these children have milder bleeding tendency at diagnosis and lower morbidity during follow-up. Raised PAIG possibly may cause some degree of platelet dysfunction.

Anti‐platelet antibody immunoassays in childhood immune thrombocytopenia: a systematic review

“…Moreover, sensitivity was the same for newly diagnosed, as well as chronic ITP, and for glycoprotein‐specific assays . The results were unchanged when only the largest studies were considered .…”

“…Moreover, when measuring antibodies at diagnosis, Fu et al found that patients with a prognosis of chronic ITP showed enrichment of anti‐GP Ib/IX antibodies, compared to those with transient disease courses (N = 18 vs. N = 113) . Findings of these two studies are contrasted by Biglino et al who observed equal rates of anti‐GPIIb/IIIa or anti‐GPIb/IX antibodies in patients with transient or chronic disease courses (N = 49 vs. N = 25) and Nielsen et al who showed a similar rate of anti‐platelet antibodies by PA‐IgG/IgM amongst patients with transient and chronic diseases courses (N = 46 vs. N = 12). Taken together, some studies indicate a role of anti‐platelet antibody testing to determine prognosis, but in the presence of conflicting evidence further data are required.…”

“…Eight of the 40 included studies were judged to be of low risk of bias regarding the inclusion of ITP patients, but none of them explicitly reported control data (Fig. ; lower panel) . We subsequently focused our analysis on the nine studies which allowed assessment of diagnostic accuracy data and describe data of the eight studies with low risk of bias and the remaining studies, as applicable.…”

“…Three of the eight studies with low risk of bias assessed immunoassays for evaluation of anti‐platelet IgM antibodies, two in newly diagnosed ITP and one in chronic ITP (Table ; full results, Table ). The sensitivity for detection of IgM autoantibodies was 0·62–0·69, indicating that IgM class autoantibodies could potentially be as prevalent as anti‐platelet IgG antibodies . Due to a lack of control data, the specificity could not be determined.…”

Anti‐platelet antibodies in childhood immune thrombocytopenia: Prevalence and prognostic implications

“…It is now known that multiple platelet glycoproteins can be involved, including GP V and the GP Ib/IX complex . In childhood ITP, IgM anti‐platelet antibodies have been suggested to be at least as prevalent as anti‐platelet IgG antibodies . Apart from affecting platelet clearance, anti‐glycoprotein antibodies can functionally impair platelet aggregation by blocking the fibrinogen receptor interactions, or may potentially inhibit effective thrombopoiesis through GPIbα‐mediated hepatocyte thrombopoietin production …”