Immunohematology-complete-notes

INTRODUCTION

  • Sources: Harmening 7th ed.

  • Definitions:

    • Allele: A gene at a particular locus that differs in their nucleotide sequence.

    • Polymorphic: Having two or more possible alleles at a locus.

    • Allelic: One of two or more different genes that may occupy a specific locus on a chromosome.

    • Antithetical: Opposite form of a gene, different allele, or opposite antigens encoded at the same locus.

    • Genotype vs Phenotype:

    • Genotype: Total genetic composition of an individual, detectable using molecular methods.

    • Phenotype: Detectable or expressed characteristics of a gene, detectable using serotyping.

MENDELIAN INHERITANCE PRINCIPLES

  • Gregor Mendel: Father of genetics.

  • Mendelian Genetics: Genes occur in pairs, one gene is passed from parent to offspring.

  • Two Laws of Mendelian Inheritance:

    • Law of Independent Segregation (First Law):

    • States that parental genes must separate randomly and equally into gametes, allowing equal chance of allele inheritance.

    • Law of Independent Assortment (Second Law):

    • States that genes for different traits are inherited separately, allowing for all possible combinations of genes in offspring.

  • Inheritance Patterns:

    • Blood group antigen inheritance can be predicted using Punnett squares.

    • Definitions:

    • Homozygous: Individual inherits identical alleles at a gene locus from both parents.

    • Heterozygous: Individual inherits different alleles at a gene locus from each parent.

DOSAGE EFFECT

  • Agglutination reactions are generally stronger for homozygous than heterozygous cells, due to a higher number of antigens in homozygous cells.

HISTORICAL DISCOVERIES IN BLOOD TRANSFUSION

Year

Scientist

Works/Discovery

1492

Pope Innocent VII

1st recorded blood transfusion

1869

Braxton, Hicks

Use of sodium phosphate/phosphate soda as blood preservative

1914

Albert Hustin

Use of sodium citrate as blood preservative

1915

Richard Lewison

Determined the minimum citrate concentration as anticoagulant

1943

Loutit & Mollison

Acid citrate dextrose as preservative

1957

Gibson

Citrate phosphate dextrose as blood preservative

1901

Karl Landsteiner

Discovered ABO blood group

1914

Dr. Charles Drew

Father of modern blood banking

1985

Yves Lapierre

Gel technology

BASIC GENETICS

  • Genetics: Study of transmission of inherited characteristics.

  • Chromosomes in Humans: 46 total (1 pair from each parent, 23 pairs).

  • Gene: Segment of DNA arranged at a specific position (locus) on a chromosome, basic unit of heredity.

  • Inheritance Patterns of Genes:

    • Dominant Genes: Only one allele must be inherited for expression.

    • Recessive Genes: Need identical allele from both parents to be expressed; not expressed if dominant gene is present.

    • Codominant: Neither allele is dominant; both expressed equally.

    • Autosomal Dominant Genes: Expressed equally