Hemolytic disease of newborn

Dr. Tariq M.Roshan

Dept. of Hematology

PPSP

Objectives

Definition & characteristics ABO vs Rh hemolytic disease of the

newborn Pathogenesis Incidence Blood types of mother and baby Severity of disease Laboratory data Prevention Rh immune globulin Tests for feto-maternal hemorrhage Exchange transfusion protocol

Hemolytic disease of newborn

Hemolytic disease of the new born and fetus (HDN) is a destruction of the red blood

cells (RBCs) of the fetus and neonate by antibodies produced by the mother

It is a condition in which the life span of the fetal/neonatal red cells is shortened due to

maternal allo-antibodies against red cell antigens acquired from the father

Antibodies

Five classes of antibodies IgM IgG IgA IgD IgE

Blood groups specific antibodies are IgG IgM and rarely IgA

Biochemistry of antibodies

Made from four polypeptide chains

Two light (L) chains Two identical heavy (H)

chains

Each class has immunologically distinct heavy chain

Biochemistry of antibodies

IgG1 IgG2 IgG3 IgA IgM IgE

Compliment fixation

++ + +++ - +++ -

Placental transfer

++ + + - - -

Lymphocyte / macrophage FcR binding

+ - + - - -

Blood group antibodies

Blood group antibodies can be classified as Naturally occurring and immune antibodies

Depending on presensitization

Cold and warm antibodies Thermal range of antibodies Most natural Abs are cold & some e.g wide thermal range like

Anti A and Anti B Most immune Abs are warm and can destroy red cell in-vivo

Complete and incomplete antibodies Depends on agglutination of saline suspended red cells IgM is complete antibody; most naturally occurring antibodies

are complete and of IgM class IgG is incomplete antibody

Antibodies of ABO system

Anti- A Naturally occurring Immune

Anti- B Naturally occurring Immune

Anti- A1

Anti- H

Antibodies of Rh system

Naturally occurring Anti- E Occasionally anti-D and anti Cw

Immune antibodies D antibodies are more immunogenic Other are anti c, E, e, C. Most common is anti- E After anti- D, anti- c is the common cause of HDN

(The vast majority of Rh antibodies are IgG and do not fix complement)

Antibodies from other blood group systems

Anti- K Kell blood group system Usually is immune antibody Warm Ab

Anti- Jka

Kidd blood group system Usually is immune antibody Warm Ab

Complement

Complements are series of proteins, present in plasma as an inactive precursors

When activated and react sequentially with each other they mediate destruction of cells and bacteria

Complement activation involves two stages Opsonization Lytic stage

Complement

Antibodies can fix complement and cause rapid destruction of red cells

Destruction depends on the amount of antibody and complement

In ABO- incompatible transfusion no surviving A or B red cells can be seen after 1 hour of transfusion

Why? Remember naturally occurring Abs. are IgM and fix

complement mediating the hemolysis

Disease mechanism - HDN

There is destruction of the RBCs of the fetus by antibodies produced by mother

If the fetal red cells contains the corresponding antigen, then binding of antibody will occur to red cells

Coated RBCs are removed by mononuclear phagocytic system

Conjugatedbilirubin

Unconjugatedbilirubin

Neonatalliver is immature and

unable to handle bilirubin

Coated red blood cellare hemolysed in

spleen

Pathogenesis; beforebirth

Pathogenesis; afterdelivery

Clinical features Less severe form

Mild anemia

Severe forms Icterus gravis neonatorum (Kernicterus)

Intrauterine death Hydrops fetalis

Oedematous, ascites, bulky swollen & friable placenta

Pathophysiology Extravascular hemolysis with extramedullary

erythropoiesis Hepatic and cardiac failure

Hemolytic disease of newborn HDNBOFORE BIRTH Anemia (destruction of red cells) Heart failure Fetal death

AFTER BIRTH Anemia (destruction of red cells) Heart failure Build up of bilirubin Kernicterus Severe growth retardation

Blood film of a fetus affected by HDN showing polychromasiaand increased number of normaoblasts

N

P

Rh HEMOLYTIC DISEASE OF NEWBORN

Antibodies against Anti-D and less commonly anti-c, anti-E

Mother is the case of anti-D is Rh -ve (negative) Firstborn infant is usually unaffected Sensitization of mother occurs

During gestation At the time of birth

All subsequent offspring inheriting D-antigen will be affected in case of anti-D HDN

Pathogenesis

Fetomaternal Hemorrhage

Maternal Antibodies formed against Paternally derived antigens

During subsequent pregnancy, placental passage of maternal IgG antibodies

Maternal antibody attaches to fetal red blood cells

Fetal red blood cell hemolysis

Factors affecting immunization and severity

Antigenic exposure

Host factors

Antibody specificity

Influence of ABO group ABO-incompatible Rh- positive cells will be hemolysed

before Rh antigen can be recognized by the mother’s immune system

Diagnosis and Management Cooperation between

Pregnant patient

Obstetrician

Her spouse

Clinical laboratory

Recommended obstetric practice

History; including H/O previous pregnancies or and disease needing blood transfusion

ABO and Rh testing Antibody detection;

To detect clinically significant IgG Ab which reacts at 370C

Repeat testing required at 24 or 28 weeks if first test negative

Antibody specificity Parental phenotype Amniocyte testing

Antibody titres Difference of 2 dilutions or score more

than 10 is significant

Amniocentesis and cordocentesis

Concentration of bilirubin Spectrophotometric scan

Indirect method Increasing or un-change OD as

pregnancy advance shows worsening of the fetal hemolytic disease

Fetal blood sample can be taken and tested for

Hb, HCT, blood type and DCT (Direct Coombs test)

PercutaneousUmbilical bloodsampling

Liley graph

Diagnosis and Management contd.

Intrauterine transfusion Zone II or III Cordocentesis blood sample Hb less than 10g/dl Ultrasound evidence of hydrops

Early delivery Phototherapy Newborn transfusion

Exchange transfusion Effects of transfusion

Removal of bilirubin Removal of sensitized RBCs, and antibodies Suppression of incompatible erythropoiesis

Diagnosis and Management contd.

Selection of blood

Group O RBCsRh-negativve units for Rh-negative caseWhole blood group OBlood less than 7 days old

Diagnosis and Management contd.

Prevention of Rh- HDN

Prevention of active immunization Administration of corresponding RBC antibody

(e.g anti-D) Use of high-titered Rh-Ig (Rhogam)

Calculation of the dose Kleihauer test for fetal Hb

Mechanism of action Administered antibodies will

bind the fetal Rh- positive cells

Spleen captured these cells by Fc-receptors

Suppressor T cell response is stimulated

Spleen remove anti-D coated red cells prior to contact with antigen presenting cells “antigen deviation”

ABO HEMOLYTIC DISEASE OF NEW BORN

For practical purpose, only group O individuals make high titres IgG

Anti-A and anti-B are predominantly IgM

ABO antibodies are present in the sera of all individuals whose RBCs lack the corresponding antigens

ABO HDN contd. Signs and symptoms

Two mechanism protects the fetus against anti-A and anti-B Relative weak A and B antigens o fetal red cells Widespread distribution of A & B antigen in fetal tissue diverting

antibodies away from fetal RBCs Anemia is most of the time mild ABO- HDN may be seen in the first pregnancy

Laboratory findings Differ from Rh- HDN; microspherocytes are characteristic of ABO-

HDN Bilirubin peak is later; 1- 3 days after birth Collection of cord blood and testing eluates form red cells will

reveal anti-A or anti-B

Treatment Group O donor blood for exchange transfusion which is rarely

required

HDN- due to other antibodies Anti-c

Usually less severe than that cause by Anti-D

Anti-K May cause severe fetal anemia

Blood transfusion for the treatment should lack the appropriate antigen

Summary.

Hemolytic disease of newborn occurs when IgG antibodies produced by the mother against the corresponding antigen which is absent in her, crosses the placenta and destroy the red blood cells of the fetus.

Proper early management of Rh- HDN saves lives of a child and future pregnancies

ABO- HDN is usually mild

Other blood group antigens can also cause HDN