Human platelet antigen polymorphisms (HPA-1, -2, -3, -4, -5 and -15) in major ethnic groups of Pakistan.
OBJECTIVE
Gene frequencies of human platelet antigens (HPA) determine the magnitude of platelet immunological disorders like neonatal alloimmune thrombocytopenia, platelet refractoriness and ease of availability of particular HPA-typed platelet donors in a given community.


BACKGROUND
However, the pattern of HPA in Pakistani population is not known.


OBJECTIVE
The aim of present study was to determine the gene frequencies of HPA (HPA-1 to -5 and -15) in individuals belonging to major ethnic groups and castes of Pakistani population.


METHODS
HPA genotyping was done in 593 individuals belonging to all ethnic groups of Pakistan, by polymerase chain reaction-sequence specific primers with detection on polyacrylamide electrophoresis.


RESULTS
The gene frequencies of the 'a' and 'b' alleles of HPA-1 to -5 and -15 in Pakistanis were as follows: HPA-1a/b, 0.885/0.115; HPA-2a/b, 0.92/0.08; HPA-3a/b, 0.69/0.31; HPA-4a/b, 1/0; HPA-5a/b, 0.9/0.1; HPA-15a/b, 0.59/0.41. Except for significant difference regarding gene frequency of HPA-3 between Pathans and Sindhis, there was no significant difference of HPA-1 to -5 and -15 between major ethnic groups of Pakistan. The estimated mismatch probability regarding platelet antigens 1-5 and 15 in Pakistanis, after transfusion of random donor platelets, is from 14 to 37%. The expected incidence of neonatal alloimmune thrombocytopenia due to anti-HPA-1a in Pakistani pregnant females is < 1 of 1000 pregnancies and 8-12 of 1000 in case of anti-HPA-5b. Homozygosity of HPA-1b, -2b and -5b genotypes ranged from 1 to 2% in the Pakistani population, whereas homozygosity of HPA-3b and -15b was 11 and 18%.


CONCLUSIONS
There is a need to establish donor registries typed for HPA in the transfusion centres of the country.
Bhatti
F A
FA
PNS Shifa Hospital, Karachi, Pakistan. farhatab@hotmail.com
Uddin
M
M
Ahmed
A
A
Bugert
P
P
D015703:Antigens, CD / Q000235:genetics*; D016824:Antigens, Human Platelet / Q000235:genetics*; D001771:Blood Banks; D001788:Blood Grouping and Crossmatching; D003430:Cross-Sectional Studies; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D058851:GPI-Linked Proteins; D005787:Gene Frequency; D005838:Genotype; D006301:Health Services Needs and Demand; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D009363:Neoplasm Proteins / Q000235:genetics*; D010154:Pakistan / Q000453:epidemiology; D010980:Platelet Membrane Glycoproteins / Q000235:genetics*; D011247:Pregnancy; D012042:Registries; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000208:ethnology / Q000235:genetics
D015703:Antigens, CD; D016824:Antigens, Human Platelet; C120523:CD109 protein, human; D058851:GPI-Linked Proteins; D009363:Neoplasm Proteins; D010980:Platelet Membrane Glycoproteins