Frequency of Fc gamma receptor IIIa-158V polymorphisms in Egyptian children with immune thrombocytopenic purpura

Immune thrombocytopenic purpura [ITP] is a bleeding disorder of infants, children and adults. The majority of affected children have the acute form of ITP, defined by duration of thrombocytopenia [<150 x 10[9]/L] of <6 months. Previous studies have shown that Fc gamma receptor [FcyRs] play crucial roles in platelet phagocytosis; antibodies bound to platelets have their Fc portion exposed which allows binding to monocytes/macrophages that express Fc receptors for lgG [FcgammaRs]. The Fc gammaRIIla Valine [V] has increased affinity for three separate lgG subclasses when compared with the FcgammaRIlIa Phenylalanine [F]. The aim of the present study was to assess the frequency of occurrence of the high affinity allelic variant FcgammaRllIa-158V in Egyptian children with ITP in comparison to normal individuals. Determination of FcgammaRlIIa genotype was performed for 30 ITP patients and 10 healthy control subjects by nested PCR followed by RFLP analysis. In our study, the allelic frequency of FcgammaRIlIa-158V was [76.6%] among ITP patient group in contrast to [20%] among the control group. These results suggest that FcgammaRllIa-158 V/F polymorphism contributes to the pathogenesis of childhood ITP by increased clearance of antibodysensitized platelets by the high affinity FcgammaRlIIa-158V allelic variant. Besides the epidemiologic and pathophysiologic interest, this knowl edge may be of use in the future designing of novel therapeutic interventions

On-pump versus off-pump CABG: Study of platelet activation

Coronary revascularization on a beating heart avoids many of the side effects of cardiopulmonary bypass. Off-pump coronary bypass surgery offers an excellent chance to examine the impact of the surgery and the relatively high dose of heparin on platelet functions without using cardiopulmonary bypass. Sixty patients with coronary artery disease were prospectively randomized to [1] on-pump CABG with conventional cardiopulmonary bypass and worm cardioplegic arrest and [2] off-pump CABG on the beating heart. Platelet studies including bleeding time, platelet count, mean platelet volume, platelet aggregation using ADP and surface expression of P-selectin and Annexin-V using flow cytometry as markers of platelet activation. Platelet studies revealed definite platelet dysfunction in the on-pump group, however there was still statistically significant elevation of markers of platelet activation in the off-pump group. Platelet activation occurs in coronary bypass surgery even when CPB is no: used. This may correlate with previous reports of thrombotic complications of OPCAB surgery