The document discusses the ABO and Rh blood group systems. It notes that Rh factor is determined by the presence of the D antigen, and that Rh negativity can lead to complications in pregnancy and blood transfusions if the mother is exposed to Rh-positive blood. Specifically, it explains that during a first pregnancy, a Rh-negative mother will not produce anti-Rh antibodies if carrying a Rh-positive baby. However, in subsequent pregnancies, she may produce antibodies that can cross the placenta and destroy Rh-positive fetal blood cells, leading to hemolytic disease of the newborn. Proper testing of blood types is crucial to avoid transfusion reactions from Rh mismatches.

1. Prabeen Kumar Mahato
4th semester
J. K. College, Purulia

2. ABO Blood Group System
 But in case of Rh system there is no anti-Rh antibody in the plasma of Rh negative person unless this person get blood
transfusion from a Rh positive person.

3. What is Rh-factor ?
• Type → Nonglycosylated, Hydrophobic cell
surface proteins.
• Location → Cell membrane of RBC
• Discovered → by Landsteiner and Wiener in
1940 in the blood of Rhesus monkey.
• Types of antigens in Rh factor → approximately
49 types of antigens

4. Which antigen determines
Positivity of Blood Group ?
Primary antigens → C(or c) D(or d) E(or e)
antigens, although it actually contains many more.
D antigen plays significant role in determining
the positivity of the Rh system.
Antigenicity order of Rh antigens:
D > c > E > C > e

5. Brief account on the Genetics of Rh factor
Fig. (A) Genes for Rh antigens at p arm of Chromosome 1; (B) Rh antigens on RBC

6. Percentage of Rh(+)
Blood among People
• 85% of Caucasians are Rh(+).
• 95% of American blacks are Rh(+).
• 99% of Asians are Rh(+).
• 100% of Africans are Rh(+).

7.  Rh-positive(D-positive) or Rh-negative(D-negative) determinant
 The Rh antigens are thought to play a role in maintaining the integrity
of the RBC membrane—RBCs which lack Rh antigens have an abnormal
shape.
 Anti-Rh antibody production in Rh-negative blood
 Rh factor is very much significant in blood transfusion process.
Significance of Rh-factor

8. Significance in Blood Transfusion
 D-negative individuals who have received a transfusion of D-positive
blood (even years previously) can have appreciable anti-D antibodies
and thus may develop transfusion reactions when transfused again
with D-positive blood. And this can lead to death of the recipient.
 So it is very important to cross check the Rh group of the donor and
recipient to avoid transfusion reaction.

9. Significance of Rh in
Blood Transfusion
 Transfusion reaction
 Need to be cross checked

10. ABO Mismatch Rh Mismatch
Immediate transfusion reaction  No transfusion reaction in 1st transfusion
 Immediate transfusion reaction in 2nd transfusion
Anti-A/Anti-B already present in blood 2-4 weeks → significant amount of Anti-Rh antibody
Antibody type IgM(unable to cross placenta) IgG(able yo cross placenta)
Transfusion Reaction

11. Rh incompatibility in Pregnancy
 There is a great complication due to Rh incompatibility arises when an Rh-negative
mother carries an Rh-positive fetus. Small amounts of fetal blood leak into the
maternal circulation at the time of delivery, and mothers develop significant titers
of anti-Rh antibodies during postpartum period.
 If the mothers carry Rh positive fetus for the second time, the anti-Rh agglutinins
will cross the placenta(as these are IgG) and cause hemolysis and various forms of
hemolytic disease of the newborn (erythroblastosis fetalis)(HDN).
 For this the infant may die in uterus or may develop severe anemia, severe jaundice,
and edema (hydrops fetalis).

12. Rh incompatibility in Pregnancy
Rh-positive is dominant
over Rh-negative

13. Severe Jaundice

14. Hydrops fetalis

16. Summary
 Rh antigens, present on the surface of RBC cell membrane are very
significant factor for blood grouping.
 Out of about 49 types of Rh antigens D antigen is most important factor
for antigenicity of Rh factor.
 It is very important to cross check the Rh group of donor and recipient
before blood transfusion.
 We have to be aware of Rh incompatibility in pregnancy.

17.  Ganong’s Review of Medical Physiology,
24th edition, Tata McGraw Hill
 Principles of Physiology,
Debasis Pramanik, 5th edition, Jaypee
 Human Physiology,
Lauralee Sherwood, 9th edition, Cengage
Learning
 Textbook of Medical Physiology,
Guyton & Hall 13th edition, ELSEVIER
 Internet resources

18. THANK
YOU