<prompt> Child admitted with meningitis. Examination reveals gram negative diplococci. History of previous similar infection is present with same organism. Which of the following should be suspected?Complement deficiencyImmunoglobulin deficiencyT cell8 cell  <response>: Ans: A Complement deficiency Ref: Harrisons Principles of Internal Medicine, 17th edition, 2008, Chapter 136, pg: 911 and Nelson Textbook of Pediatrics, 19th editionExplanation:Defects in Complement SystemHost DefectDisease or Therapy Associated With DefectCommon Etioiogic Agent of InfectionC3 Congenital liver disease SLE Nephrotic syndrome S. aureus S. pneumoniae Pseudomonas spp Proteus spc.C5 Congenital Neisseria spp. Gram-negative rodsC6,C7,C8 Congenital, SLE Neisseria meningitidis N. qonorrhoeaeAlternativepathway Sickie cell disease S. pneumonia Salmonella spp. 