Does parasitic infection affect platelet factor 4 concentration?

Blood platelets actively participate in defense mechanisms of the organism, e.g. in antiparasitic immunity. Platelet stimulation may be a result of direct contact with parasite, increased IgG and/or IgE concentrations, the presence of complement, CRP or lymphokins. The aim of the study was to find out whether parasitic infection induces platelet activation. The study involved 35 patients (30 patients were infected with Giardia intestinalis and 5 patients were infected with Echinococcus granulosus). Blood for analysis was collected twice, before treatment (A1) and after it (A2). The concentrations of platelet factor 4 were assayed using a set of ASSERACHROM according to the immunoenzymatic method with labelled antibodies. The mean concentration of platelet factor 4 (PF4) was 20.3 +/- 9.4 IU/ml in the patients prior to the antiparasitic therapy and being reduced to 6.0 +/- 3.0 IU/ml after treatment. In the control group the mean PF4 concentration was 2.27 +/- 0.08 IU/ml. The differences between the values in control group and the two groups tested were statistically significant. Although platelets do not get into a direct contact with the parasite, an increase is observed in the concentration of platelet factor 4, which may indicate the involvement of platelets in the parasitic disease.