Platelet Aggregometry - Dose-related Responses to Arachidonic Acid in Childhood Nephrotic Syndrome.
A recent unexpected finding of inhibited platelet aggregation in response to a single (1.64 mmol/l) dose of arachidonic acid (AA), during the relapse of childhood nephrosis, prompted us to assess aggregation in response to multiple doses of AA: 1.64,0.82,0.41,0.20 mmol/l, in two groups of children, in the relapse (n = 34) or remission (n=41) phase of nephrotic syndrome. During relapse: the highest dose of AA (1.64 mmol/l) evoked reversible and inhibited aggregation in 91% of patients. However, at the lower doses there were enhanced responses as measured by both maximum aggregation (%) and slopes of the aggregation curves. In contrast, during remission, irreversible aggregation was obtained at the highest AA dose, while at the lowest two doses (0.41 and 0.20 mmol/l), no aggregation responses were obtained in 4 (9%) and 7 (17%) patients respectively; in those who responded there was a long lag phase. Healthy controls (n = 21) exhibited their highest responses to 1.64 and 0.82 mmol/l AA and at the lowest AA doses (0.41 and 0.20 mmol/l), a total absence of responses was noted in 40% and 71% of samples respectively. We conclude that during relapse platelet sensitivity, as shown by irreversible aggregation in response to multiple AA doses, shifts towards the lower doses, when compared with healthy controls; while during remission responses fall in-between the relapse and control groups, indicating the maintenance of platelet sensitivity during this phase of nephrosis.
Department of Paediatrics, College of Medicine and the King Khalid University Hospital, Riyadh, 11461, Saudi Arabia.
M M
MM
Al-Mugeiren
A M
AM
Gader
S A
SA
Al-Rasheed
H M
HM
Bahakim
A K
AK
Al-Momen
A
A
Al-Salloum