Clinical Significance of Lupus Anticoagulant and Anti-Beta₂ Glycoprotein I Antibodies in a Pediatric Cohort.

Antiphospholipid antibodies (APAs) (lupus anticoagulant (LA), anti-beta2 glycoprotein I (anti-B2GPI) and anti-cardiolipin) are seen in a variety of conditions, yet their clinical implication varies. In adults, some APAs cause thrombosis and/or recurrent pregnancy loss. LAs with specificity for anti-B2GPI appear to be more closely associated with thrombosis. In children, APAs are often transient after viral or bacterial illnesses and little is known about their pathologic potential. In this study, we sought to determine the clinical associations of positive LAs with and without anti-B2GPI activity. Patients and Methods: We tested remnant plasma from 115 pediatric patients with positive LA result (according to the International Society on Thrombosis and Haemostasis guidelines) for anti-B2GPI IgG, IgM, and IgA using an indirect EIA supplied by REAADS (Corgenix Inc, Broomfield, CO) and reviewed the patient's medical records to correlate with the results.

There were 61 females (53%) and 54 males (47%) with the average age of 10.6 years (range: 0.5 to 19.5 years). An underlying medical condition such as malignancy, autoimmune disorder, infection/sepsis, or concurrent thrombosis was observed in 97 patients (84%). Eighteen patients (16%) were healthy children and LA was detected incidentally during workup for a prolonged PTT. The mean age of the group with positive medical history (11.5 years; range: 0.5 to 13 years) was statistically different than that of the healthy children group which was 5.8 years (range: 0.5 to 3.75 years) (P<0.001). Of the 115 patients, 37 (32%) had thrombosis at the time of LA testing; only 6 patients had known inherited hypercoagulability. Thirty-four of the 37 thrombotic episodes (92%) were venous and 3 were arterial (8%). An autoimmune disorder was present in 46 patients (40%) and 10 developed a thrombosis. Forty-one patients (36%) had active infection/sepsis, and 15 had thrombosis. Of 12 patients with malignancies (10%), 4 had thrombosis. The average age of those with thrombosis, 13.3 years (range: 0.5 to 15 years) was higher than that of children without thrombosis, 10.3 years (range: 0.6 to 10.5 years) (P=0.018). Only 12 of 115 patients (10%) were positive for anti-B2GPI and 3 of them had venous thrombosis. Of the anti-B2GPI positive patients, 8 had underlying autoimmune conditions, 2 had no medical history but had current thrombosis, one had a malignancy with thrombosis, and another had an acute infection. Conclusions: In children, APAs occur in a variety of conditions, but may also be found incidentally. Perhaps surprising, LA was associated with thrombosis in 32% of patients. However, only 10% tested positive for anti-B2GPI, with an even smaller percentage having thrombosis (3%). These results suggest that anti-B2GPI is not necessary for the development of thrombosis in children with LA.

No relevant conflicts of interest to declare.