RESUMO
BACKGROUND: The current transfusion policy recommended for individuals with serologic weak-D phenotype is based on data derived from European-descent populations. Data referring to the distribution of RH alleles underlying weak-D phenotype among people of mixed origin are yet incomplete, and the applicability of European-based transfusion guidelines to this specific population is questionable. GOAL: To evaluate the distribution of RHD variant genotype among individuals with serologic weak-D phenotype of both African and European descent. METHODS: Donors and patients of mixed origin and with serologic weak-D phenotype were selected for the study. They were investigated using conventional RHD-PCR assays and RHD whole-coding region direct sequencing. RESULTS: One hundred and six donors and 58 patients were included. There were 47 donors and 29 patients with partial-D genotype (47/106, 44.3%, and 29/58, 50%, respectively). RHD*DAR and RHD*weak D type 38 represented the most common altered RHD alleles among donors (joint frequency of 39.6%), while weak D types 1-3 accounted for 10.4% of the total D variant samples. RHD*DAR was the most common allele identified in the patient group (frequency of 31%), and weak D types 1-3 represented 29.3% of the total. CONCLUSION: The frequency of partial D among mixed individuals with serologic weak-D phenotype is high. They should be managed as D-negative patients until molecular tests are complete.
Assuntos
Doadores de Sangue , Polimorfismo de Nucleotídeo Único/genética , Sistema do Grupo Sanguíneo Rh-Hr/genética , Imunoglobulina rho(D)/genética , Alelos , Transfusão de Sangue , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Fenótipo , Estudos Retrospectivos , Imunoglobulina rho(D)/sangue , População BrancaRESUMO
Hemolytic disease of the newborn develops mainly when an Rh negative (D-) mother becomes sensitized and produces anti-Rh possitve (anti-D) antibodies capable of hemolysing D+ fetal erythrocytes. Maternal alloimmunization can be prevented by the administration of anti-D gamma-globulin immediately after the birth of each Rh positive child. In order to identify the frequency of prevention of alloimmunization at the Instituto Mexicano del Seguro Social(IMSS), the amount of mothers at risk of sensitization from 1985 to 1995 was estimated from Rh and ABO blood group frequencies and with the number of deliveries and abortions at the Medical Institutions. Also, information in regard to the dose of gamma-globulin units purchased by the Institute of Social Security from 1985 to 1993 was obtained. The number of mothers at risk stedily increased from 16,616 in 1985 to 21,071 in 1995, amounting to a total of 203,203 in the 10-year period, while only 120,800 gamma-globulin units were purchased in that same period. The findings in this study suggest the need to define reasonable policies for the acquisition of gamma-globulin lots to prevent alloisoimmunization of mothers at risk