title: Estimation of serum level of interleukin-17 and interleukin-4 in leprosy, towards more understanding of leprosy immunopathogenesis.
abstract: BACKGROUND
  Combating Mycobacterium leprae is known to be via T-helper1 response. However, other T-helper effector cells; T-helper17 and T-helper2; play a role, particularly in the context of disease type.
  
  
  OBJECTIVE
  We aimed to evaluate serum levels of interleukin (IL)-17 (T-helper17 cytokine) and IL-4 (T-helper2 cytokine) in untreated patients with different types of leprosy, compared to controls.
  
  
  METHODS
  Using enzyme-linked immunosorbent assay, serum IL-17 and IL-4 levels were estimated in 43 leprotic patients and 43 controls. Patients were divided into six groups; tuberculoid, borderline cases, lepromatous, erythema nodosum leprosum (ENL), type 1 reactional leprosy, and pure neural leprosy. Patients were also categorized according to bacillary load and the presence or absence of reactions.
  
  
  RESULTS
  Serum IL-17 was significantly lower in cases (4-61.5 pg/mL; median 19), compared to controls (26-55 pg/mL; median 36) (P < 0.001), and was significantly lower in each type of leprosy compared to controls, with the lowest level in lepromatous leprosy (4-61.5 pg/mL; median 12.5). Significantly elevated serum IL-4 was found in patients (1.31-122.4 pg/mL; median 2.31) compared to controls (1.45-5.72 pg/mL; median 2.02) (P = 0.008), with the highest level among lepromatous leprosy patients (2-87.2 pg/mL; median 28.9), and the lowest in type 1 reactional leprosy (1.4-2.5 pg/mL; median 1.87) (P = 0.006).
  
  
  CONCLUSIONS
  Defective secretion of IL-17 is related to disease acquisition as well as progression toward lepromatous pole in leprosy patients. The overproduction of IL-4 in patients with lepromatous leprosy may infer their liability to develop ENL. Nevertheless, the small number of the studied population is a limitation.
authors.affiliation: Department of Dermatology, Venereology and Andrology, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
authors.forename: Marwa
authors.initials: M
authors.lastname: Abdallah
authors.forename: Hanaa
authors.initials: H
authors.lastname: Emam
authors.forename: Enas
authors.initials: E
authors.lastname: Attia
authors.forename: Jihan
authors.initials: J
authors.lastname: Hussein
authors.forename: Noha
authors.initials: N
authors.lastname: Mohamed
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D032882:Comprehension; D018450:Disease Progression; D005260:Female; D006801:Humans; D020381:Interleukin-17 / Q000097:blood* / Q000378:metabolism; D015847:Interleukin-4 / Q000097:blood*; D007918:Leprosy / Q000097:blood* / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D015415:Biomarkers; C508598:IL4 protein, human; D020381:Interleukin-17; D015847:Interleukin-4