Mansoura Programming

CAN EARLY MANAGEMENT PROGRAM OUR IMMUNE SYSTEM

HANY ALY, MD, FAAP Professor of Pediatrics, Obstetrics & Gynecology Director, Newborn Services

Incidence of Infectious Diseases (%)

Infections over Time 100

Rheumatic fever Mumps Measles Tuberculosis HepA

50

0 1950 1960 1970 1980 1990 2000

Bach JF. N Engl J Med. 2002;347:911-920.

Autoimmune Diseases over Time Incidence of Immune Disorders (%)

400

300 Crohn's disease (Th1) Multiple sclerosis (Th1) Type 1 diabetes (Th1) Asthma (Th2)

200

100 1950

1960

1970

1980

1990

2000

Acquisition of Indigenous Flora by the Newborn

• Fetus normally is in a sterile environment in the uterus

• Newborn acquires its indigenous

microflora during delivery  maternal flora provides the initial inoculum of colonizing organisms

Acquisition of Indigenous Flora by the Newborn

• Gestational age, mode of delivery, type of feeding  all can affect formation of the newborn’s indigenous flora

– VLBW infants: Intestinal colonization delayed, development of anaerobic flora diminished – Infants born by Cesarean Section delayed intestinal colonization with anaerobic bacteria, and gut colonization can be altered for as long as 6 months after birth Swanson D. Indigenous Flora. In Feigin RD et al., eds. Textbook of Pediatric Infectious Diseases. 5th ed. Philadelphia: WB Saunders;

Intestinal Flora and Mode of Feeding Formula feeding Log no. of Bacteria per gram feces

Log no. of Bacteria per gram feces

Breast feeding 11 10 9 8 7 6 5 4 3 2 1

2

3

4

5

6

11 10

30

9 8 7 6 5 4 3 2 1

Days after birth Bifidobacteria Enterococci

Formula feeding

2

3

4

5

6

30

Days after birth Bacteroides Lactobacilli

Enterobacteria Staphylococci From: Yoshioka, H. Pediatrics 1983;72:317-321.

Relative Numbers of Anaerobes

Microbiota Development Weaning

Bifidobacteria

Anaerobes Rapid accumulation of anaerobic growth

Day 1-3 Microbiota influenced by: Genetics Mode of delivery

Facultative anaerobes

(Anaerobic)

Bacteroides Clostridia Coliforms Staphylococcus Klesiella Salmonella Shigella Lactobacillus Streptococci Enterococcus

Age Day 4 – 10

Day 11 - 120

Microbiota influenced by: Feeding type

Adapted from: Rautava S. et al, JPGN

Determinants of Intestinal Microflora Ingested bacteria Original bacterial inoculum

Newborn

Environment

Breast milk (Including skin microbes)

Classification of Host Microbial Flora

 Normal resident flora: present routinely 

in a specified anatomic location; quickly re-established when disturbed Transient microbial flora: may colonize the host for periods ranging from hours to weeks, but does not permanently establish itself

Tramont EC and Hoover DL. Innate Host Defense Mechanisms. In Mandell GL et al., eds. Principles and Practice of Infectious Diseases. 5th ed. Philadelphia: Churchill Livingstone; 2000:31-

Acquisition of Indigenous Flora by the Newborn is Influenced by:

• Host Factors • Environmental Factors • Type of Feeding • Mode of Delivery • Gestational Age • Host Factors

Acquisition of Indigenous Flora by the Newborn

• “Exposure to organisms from other people and environmental sources contributes to the formation of the neonate’s eventual normal flora.”(Swanson D.

pg 107)

– Premature infants with prolonged hospitalization more frequently colonized with hospital flora than term newborns Swanson D. Indigenous Flora. In Feigin RD et al., eds. Textbook of Pediatric Infectious Diseases. 5th ed. Philadelphia: WB

Adult Microbiota: A Complex Ecosystem Esophagus No own microbiota Microbes from food and oral cavity

Duodenum 103-104 CFU/g Bacteroides Candida albicans Lactobacillus Streptococcus

Stomach 104 CFU/g Candida albicans Helicobacter pylori Lactobacillus Streptococcus

Jejunum Colon 1010-1011 CFU/g Bacteroides Bacillus Bifidobacterium Clostridium Enterococcus Eubacterium Fusobacterium Peptostreptococcus Ruminococcus Streptococcus

105-107 CFU/g Bacteroides Candida albicans Lactobacillus Streptococcus

Ileum 107-108 CFU/g Bacteroides Clostridium Enterobacteriaceae Enterococcus Lactobacillus Veillonella

500 - 1000 species

Surface Areas of Exposure to the Environment • Skin • Respiratory mucosa • Intestinal mucosa

1-2 sq m 100 sq m 300 sq m – Gut epithelium 0.03 mm – Bacterial gut content up to 1012 / ml Tightly regulated mucosal immunity is needed to maintain health

GALT Gut associate lymphoid tissue (GALT) comprises 80% of immunologic cells in the body GALT is the largest immune organ

Two Arms of Defense to any Foreign Substance (antigen) Entering the Body: • Gut barrier (mechanical) function • Immune function • The innate immune response • The adaptive immune response

Atopic Sensitization and Allergy Symptoms Among Children Living on Farms and Children in Same Rural Community from Non-farming Families

% Children

40 30

*

Farm Non-farm

*

20 10

*

*

0

Wheeze

Hay fever

*P<0.05; bivariate analysis.

Positive RAST to Outdoor Allergens

Positive RAST to Indoor Allergens

Braun-Fahrlander CH. Clin Exp Allergy 1999;29:28-34.

Adjusted Odds Ratio

Influence of Cesarean Delivery on Relative Risk of Childhood Food Allergy 8 7 6 5

*

CI = 1.9-32.0

4 3 2 1 0

CI = 1.0-7.0

No Maternal Hx Vaginal Delivery

Maternal Hx Vaginal Delivery

Maternal Hx Cesarean Section

*P<0.01; adjusted for covariates. Food Allergy to egg confirmed by testing at age 1 – 2. Eggesbo M et al. J Allergy Clin Immunol 2003;112:420-426.

Childhood Antibiotics and Risk of Allergy • Oral broad spectrum antibiotics in the first 2

years of life: increased risks of eczema, allergic rhinitis and asthma (OR: 2.07, p < 0.0001)

• Increased courses of antibiotics correlated with atopic risk

• Peripartum antibiotics are associated with increased risk for asthma and hay fever

McKeever TM, Am J Crit Care Med 2002,166:827

Farooqi IS and Hopkin JM. Thorax 1998;53:927-932. Wicken K., et al. Clin Exp Allergy 1999;29:766-771. von Mutius E. Eur Respir J 1999;14:4-11.

Intestinal Microflora is Altered in Allergic Infants •

Reduced ratio of Bifidobacteria to clostridia in early gut microflora precedes allergic disease Kalliomaki M., et al. J Allergy Clin Immunol 2001;107:129-134.

•

Allergic infants are less colonized with lactobacilli and Bifidobacteria Bjorksten B., et al. Clin Exp Allergy 1999;29:342-346.

•

Allergic infants harbor adult like Bifidobacteria; healthy infants have typical infant Bifidobacteria Ouwehand AC., et al. J Allergy Clin Immunol 2001;108:144-145.

Intestinal Flora of Individuals with IBD Differs from Normal Controls • Increases in E. coli and bacteroides species have been noted in patients with Crohn’s disease compared to controls

Giaffer MH., et al. J Med Microbiol 1991;238243.

• Colonic biopsies from patients with active UC have decreased anaerobic bacteria and lactobacilli compared to controls Fabia R., et al. Digestion 1993;54:248-255.

Intestinal Flora of Individuals with IBD Differs from Normal Controls (cont.)

• Stool of patients with Crohn’s disease has

less Bifidobacteria compared to healthy controls Favier C., et al. Dig Dis Sci 1997;42:817-822.

• Stool of patients with active pouchitis has less Bifidobacteria and lactobacilli and more clostridia than controls Ruseler-van Embden JGH., et al. Gut 1994;35:658-664.

“Modern” Lifestyle Has Decreased Exposure to Bacteria

• • • • •

More sterile processed food Decreased intake in foods produced by natural fermentation Increased hygiene measures Urban life Antibiotics

Less exposure to bacteria

“Give us this day, our daily germs.”

Rook GA. Immunol Today 1998;19:113-11

Microflora

Antigens

Intestinal Lumen Epithelium

Antigen Presentation

Activated T cell

Intestinal Mucosa

Th0

Th1 TNF-α IFN-γ IL-2 Over Expression

IBD

TReg

TGF-β

Tolerance

Th2 IL-4 IL-5 IL-10 Over Expression

Allergy

Factors Favoring the Th1 Response • • • • •

Healthy intestinal flora Presence of older siblings Childhood infections Rural environment Probiotics

Factors Favoring the Th2 Response • • • •

Limited bacterial exposure Urban/Western lifestyle Indiscriminate antibiotic use Early exposure to allergenic food proteins

Bacteria

Antigens

Th1

Th2

Protective Immunity

Allergy

mean log10 CFU/g stool

Bifidobacteria in Stool of Infants After 7 Days of Feeding 11 10 9 8 7 6

Standard Formula

Formula + Probiotic

Breastmilk

Adapted from Langhendries JP., et al. JPGN 1995;21:177-186.

% Infants with Bifidobacteriain Stool After 1 Month of Feeding

Bifidobacteria Supplementation can Increase Enteric Bifidobacteria (1 month follow up) 70%

*

60% 50% 40% 30% 20% 10% 0% Supplemented

*P<0.05 compared to standard formula.

Standard formula

Breastmilk

Adapted from Langhendries JP., et al. JPGN 1995;21:177-186.

Immune Benefits

• Cellular • Humoral

B. lactis and Innate Cellular Immune Response in Adults % Tumor cell killing

90

*

*

3 wks intake

3 wks after intake

80

70 60 50

Baseline *P<0.05; compared to baseline.

Chiang BL., et al. European J Clin Nutr 2000;54;849-855.

Probiotics and Vaccination

typhi IgA Antibody Titre

Serum specific Anti-Salmonella

Mix of Bifidobacteria (B. lactis) and Lactobacillus Improves Response to Salmonella Vaccine in Adults 120.0 100.0

*

Control Probiotics

80.0

*

60.0 40.0 20.0 0.0 Pre-vaccine

day 14

day 24

*P< 0.001 compared to pre-vaccine Link-Amster H., et al. Immunol Med Microbiol 1994;10:55-64.

% of infants that developed diarrhea

B. lactis Enriched Formula and Incidence of Diarrhea 40 30 20

31 10

7

0 *P=0.035

*

Not supplemented

Supplemented

Saavedra JM, et al., Lancet 1994;344:1046-1049.

% of Infants that Shed Rotavirus

B. lactis Enriched Formula and Incidence of Rotaviral Shedding 50 40 30 20

39

*

10 10 0 *P=0.025

Not supplemented

Supplemented

Saavedra JM, et al., Lancet 1994;344:1046-1049.

Incidence Risk Reduction %

Meta-analyses of Randomized Clinical Trials on Probiotic Treatment of Acute Diarrhea Incidence of Diarrhea > 3 days 70 60 50

95% CI = 0.3 – 0.5

40

95% CI = 0.6 – 0.8

30 20

8 RCTs

15 RCTs

10 0 Szajewska, 2001

Allen, 2003

Adapted from: Szajewska H., et al. JPGN 2006;42:454-475.

Trends in Atopic Dermatitis Prevalence*

% Prevalence

25 20 15 10 5 0 1946

1958

1970

1994

*Secular trends in the UK Eichenfield L., et al. Pediatrics 2003; 111: 608-616.

Immunologic Management of Antigens Tolerance

Genetics + Antigens Environment Sensitization

Allergy

Antigenic Exposure

• ~ 1 Ton of nutrients pass through GI tract per year

• ~ 10

circulating intact proteins are found 2-5 hrs after a meal (eg 3-10 ng/ml beta lactoglobulin, ovalbumin, etc) free of immune complexes 5

Should we expect more sensitization and allergies? Paganelli R. and Levinsky, RJ. J Immunol Methods 1980; 37:333-341. Husby S., et .al. Scand J Immunol 1985; 22:83-92.

Odds Ratio of factors on incidence of allergic symptoms

Risk Factors for Allergy 5

**

4

95% CI = 1.0-14.2

3 2

* 95% CI = 0.9-7.7

95% CI = 0.8-4.2 95% CI = 0.3-0.9

1 0 Breast Feeding

*P<0.05; **P<0.0005

Parental Asthma

Intact Protein Formula (1st week)

Intact Protein Formula (any time)

Marini A., et. al. Acta Paediatr Suppl 1996; 414:1-22.

Prevalence of Bifidobacteria in Stools of Atopic and Healthy Infants 70%

% of infants

60% 50%

Atopic Non-atopic

**

***

*

40% 30% 20% 10% 0% 1 week

3 months

1 year

*P=0.02; **P=0.03; ***P=0.05 comparing prevalence at a given age Björksten B., et al. J Allergy Clin Immunol 2001;108:516-520.

Conclusions • The immune system is determined by: – genetic factors – environmental factors

• Any deviation from the “natural” life style is adversely associated with life-long immune responses

• These findings impose more responsibility on

neonatologists / pediatricians during management