1. IMMUNITY IN VULNERABLE GROUP(NEONATES & ELDERLY) Assist Prof Dr. Syed Yousaf Kazmi

2. OBJECTIVES Discuss the immune status of neonates & elderly Identify the common infections in these two age groups Describe some of the preventive strategies

3. IMMUNE STATUS IN NEONATES AND ELDERLY-GENERAL INTRO Immune system is immature in neonates while it has waned in elderly Both extremes of life are susceptible to infections Elders have increase incidence of autoimmune disease, cancers and tolerance to transplants Fetus lived in sterile environment-no past exposure to pathogen, no memory cells; face challenge The neonate immune system is diminished in quantity & quality

4. IMMUNE STATUS NEONATE- INNATE ARM Physical barriers are immature e.g. thin skin, low sebum production etc. No microbial flora to guard against pathogens Short length & small diameter of respiratory tree-easy access of pathogens Plugging of respiratory tree by mucus-trap pathogens Cough & sneeze reflex Acid pH

5. IMMUNE STATUS NEONATE- INNATE ARM Neutrophils, Macrophage, Monocytes have reduced functions in neonates Chemotaxis-reduced Neutrophils L-selectins reduced in number ↓ Phagocytosis, Opsonization ↓ complement (C9) predisposes to E. coli infection Macrophage response to IFN-  by activated T-helper cells is reduced-intracellular pathogens killing ↓

6. IMMUNE STATUS NEONATE- ADAPTIVE ARM Humoral response in neonate is decreased Secretion of cytokines decreased e.g. IL-4, IL-10 etc. IgG and IgA responses to pathogens, although inducible, are relatively weak Neonate is almost wholly dependent upon passive transfer of Immunoglobulin from mother

7. IMMUNE STATUS NEONATE- ADAPTIVE ARM During intrauterine life, tolerance to fetal allo-antigens due to immune hypo-responsiveness Fetal immune system is directed to TH2 arm than TH1 (protect against placental & fetal damage) Suppression of TH1 arm of immune system continues in neonate period Cytotoxic T cell functions are diminished esp against viruses (e.g. RSV) than adult children

8. INFECTIONS IN NEONATES NEONATAL SEPSIS  Group B streptococci  Escherichia coli  Listeria monocytogenes  Respiratory syncytial virus (RSV)  Herpes simplex virus (HSV)  Cytomegalovirus (CMV)  Varicella-zoster virus (VZV)  Candida species INTRAUTERINE INFECTIONS Toxoplasma gondii Others (Syphilis) Rubella Cytomegalovirus Herpes simplex virus NEONATAL CONJUNCTIVITIS Staph aureus UMBILICAL SEPSIS (OMPHALITIS) COMMUNITY ACQUIRED(3-6 wks) Streptococcus pneumoniae Streptococcus pyogenes

9. AGE RELATED CHANGES IN ELDERLY Poor cough/ sneeze reflex Stiff respiratory cage Poor mucociliary function Prostate hypertrophy-urine stagnation Replacement of red marrow with fat Deteriorating function of multiple organs e.g. kidney, liver Poor blood supply to peripheral tissue

10. SHIFT OF IMMUNE STATUS IN ELDERLY Decrease number of HLA class I and II antigenic sites on lymphocytes Decreased proportion of T, B, cells NK cells increased density per cell Decreased number of monocytes Decreased ability of dendritic cells to stimulate T-cell secretion of IFN-  and IL2 Functional impairment of macrophages and granulocytes Macrophages produce less IFN- 

11. IMMUNE STATUS OF ELDERLY B-CELLS FUNCTION Decreased number of circulating and peripheral blood B cells Decreased generation of primary and secondary memory B cells General decline in lympho- proliferative capacity General decrease in humoral responsiveness: Decline in high affinity protective antibody production of Germinal center-site of B lymphocytes production

12. IMMUNE STATUS OF ELDERLY T-CELLS FUNCTION General decline in cell mediated immunity T-cell population become hyporesponsive Decline in new T-cell production Increase in proportion of memory T-cells Decrease in new T-cells production Diminished functional capacity of new T-cells T cytotoxic cells attacking cancer cell

13. INFECTIONS IN ELDERLY Increased incidence of following infections occur in elderly E. Coli Streptococcus pneumonia Mycobacterium tuberculosis Pseudomonas aeruginosa Herpes virus Influenza virus pneumonia Reappearance of latent viral infections e.g. Varicella zoster

14. PREVENTION OF INFECTIONS IN NEONATES & ELDERLY CARE OF NEONATES (DELIVERY) Deliveries carried out by expert midwives Observation of hand hygiene Observation of universal precautions/ barrier nursing Use of clean sterilized equipments in hospital/ labor rooms etc. ELDERLY PERSONS Geriatric care Care of old age related diseases Pharmacological management of old age diseases like BPH, DM etc.

15. PREVENTION OF INFECTIONS IN NEONATES & ELDERLY IMMUNIZATION Follow EPI program of the country Old age specific immunization e.g. pneumovax, Influenza virus, etc. MANAGEMENT OF INFECTION Prompt identification of pathogen & appropriate treatment Use of microbiological lab (C/S testing etc.) INFRASTRUCTURE & TRAINING Strengthen public health infrastructures to support surveillance, response, and research to implement prevention and control of infections