Genotyping of Eight Human Platelet Antigen Systems in Serbian Blood Donors: Foundation for Platelet Apheresis Registry.

INTRODUCTION: The aim of this study was to investigate the allele and genotype frequencies of 8 human platelet antigen (HPA) systems among blood donors from the Blood Transfusion Institute of Serbia and to compare them with published studies. These data would be useful to establish the basis for a platelet apheresis donor registry. MATERIAL AND METHODS: Seventy-two unrelated male platelet apheresis/blood donors from Serbia were typed for 8 HPA systems (HPA-1 to HPA-6, HPA-9, and HPA-15) via the FluoGene method, based on polymerase chain reaction-sequence-specific amplification (PCR-SSP; PCR using sequence-specific primers) with fluorometric signal detection. Allele and genotype frequencies were estimated by direct counting and compared to the expected genotype frequencies according to the Hardy-Weinberg principle. The transfusion mismatch probability was calculated for every HPA specificity. RESULTS: The allele frequencies were: HPA-1a, 0.868; HPA-1b, 0.132; HPA-2a, 0.917; HPA-2b, 0.083; HPA-3a, 0.611; HPA-3b, 0.389; HPA-5a, 0.903; HPA-5b, 0.097; HPA-9a, 0.993; HPA-9b, 0.007; HPA-15a, 0.472; and HPA-15b, 0.528. For HPA-4 and HPA-6 only allele a was detected. DISCUSSION: The HPA allele frequencies of European populations showed no significant differences in comparison with our results. Statistically significant differences were revealed in comparison with some populations of non-European origin. In the tested donors no HPA-2 bb genotype was detected, but we found 1 donor with the rare HPA-9b allele. The biggest transfusion mismatch probability in the Serbian population is for systems HPA-15 (37.4%) and HPA-3 (36.2%), which means that more than a third of random transfusions could cause mismatch in these systems. This study was enabled by the introduction of molecular HPA typing, and it provides initial results of the HPA allele and genotype frequencies in the population of blood donors in Serbia. They will be used to provide a compatible blood supply on demand for treating patients with alloimmune thrombocytopenic disorders. The successful implementation of PCR-SSP with fluorometric signal detection could be further complemented in the future by the introduction of high-throughput methods, which will largely depend on the available financial resources.

Giving blood donors something to drink before donation can prevent fainting symptoms: is there a physiological or psychological reason?

The vasovagal reaction has been widely studied but its anatomic and physiological nature remains uncertain. The mechanisms underlying vasovagal reaction related to blood donation are not completely understood either. Does its occurrence depend on the blood donors' physical characteristics and health variables or psychological factors? On the basis that a psychological approach considerably prevents donor reactions, the effect of fruit juice ingestion was studied in a group of 1849 first-time high-school students as a simple strategy to avoid systemic reactions at blood donation. The reasons for the psychological effect of this hydration protocol are stressed also in light of previous physiological studies on the hemodynamic effects of water or carbohydrate drinks.

Emotional support to apheresis donors: effect and implication.

It is widely accepted that well-being and satisfaction are unavoidably interlinked requirements that predispose donors to become regular. Detecting in advance even the mildest symptoms of discomfort during first donation, that may simply be the result of an unknown experience, is useful in preventing more disturbing symptoms (mens sana in corpore sano). Being able to recognize any form of uneasiness, even when not immediately apparent, creates in donors the awareness that staff is professionally skilled and really interested in their safety and comfort. This reinforces the staff/donor relationship and gives donors the chance to keep their calm and to learn how to manage disturbing emotions. Emotional support given to first-time platelet familiar donors during donation prevented or mitigated the onset of vaso-vagal symptoms and also freed positive emotions that reinforced the desire to donate. As a result, 62% of these donors, informed about the shortage of voluntary platelet donors, spontaneously gave their address contact to be called also for non-familiar recipients. The application of the psychological approach in Italy increased the rate of donor return to 97% and its partial application in Serbia was useful in converting familiar donors into voluntary ones.

Blood donor satisfaction and the weak link in the chain of donation process.

Recruiting and retaining enough donors is a problem. Six hundred and thirty nine blood donors were interviewed to identify the elements that can influence their satisfaction and the decision to become regulars. The majority of them were satisfied with staff skill and communication, they declared they were calm before donating and felt well after donation. First-time donors (FTDs) were more frightened, showed anticipatory anxiety, were less sure they would donate again (p<0.01) and the youngest were also less satisfied with the staff's behavior after donation. Identifying the more scared FTDs and diminishing their anxiety before donating could positively influence their decision to become regulars.

[Treatment of 36 cases of thrombotic thrombocytopenic purpura]. / Rezultati lecenja trombozne trombocitopenijske purpure na 36 bolesnika.

Thirty-six patients (pts.) with thrombotic thrombocytopenic purpura (TTP) were treated between May 1990 and May 2003. There were 31 women and 5 men; the average age was 37 years. Twenty-five cases were idiopathic and 11 secondary (3 infection--related, 5 occurred during pregnancy and 3 were drug--associated). The mean lag period between the first symptoms and the diagnosis was 8.5 days (in 14 pts. < or = 5; in 22 > 5). On diagnosis neurological symptoms were present in 31, bleeding in 33, fever in 21 and renal impairment in 27 patients. The mean hemoglobin was 67.5 g/L, the mean platelet count was 10 x 10(9)/L, and the mean reticulocytosis was 17%. The mean serum LDH was 1457 IU. Treatment included plasma exchange (PE) in 24 pts. and only plasma infusions in 12 pts. There were 24 complete responders (20 on PE) and 12 deaths (4 on PE); PE significantly improved survival (p < 0.01). There were 5 treatment-related complications due to the infection and bleeding, 17 exacerbations and 4 relapses. The mean time delay before the onset of symptoms and the treatment initiation lasted for 9 days suggesting the poor disease recognition; the mean time delay from diagnosis to PE institution was 6 days, indicating postponed PE. The mean treatment duration in all patients was 18 days; the mean number of PE cycles needed for the platelet count stabilization was 9. Good prognostic indicators of survival were: the longer prodromal period (> 5 days), the secondary form of TTP and the absence of coma at presentation. The use of PE significantly improved survival. TTP is a severe disorder requiring early recognition and diagnosis in general medical care facilities, which should lead to the timely treatment with PE.