Induction immunosuppression refers to potent immunosuppressive therapy used in the peritransplant and immediate posttransplant periods to deplete or modulate lymphocytes. The document discusses various induction agents including polyclonal antibodies (ATG), monoclonal antibodies (basiliximab, daclizumab), and alemtuzumab. ATG is derived from rabbits or horses immunized with human cells and contains antibodies against T cell markers. It causes prolonged depletion of T cells. Basiliximab blocks the IL-2 receptor on activated T cells. Studies show ATG reduces rejection rates compared to no induction, while IL-2RA induction has fewer adverse effects than ATG. Induction therapy is recommended routinely by guidelines, with

1. INDUCTION
IMMUNOSUPPRESSION

2. What is Induction immunosuppression?
• Classify Immunosuppressive therapies based on timing ?
• Induction immunosuppression is a prophylactic treatment using
biologic agents that deplete or modulate the activation of
lymphocytes in the peritransplant and immediate posttransplant
periods.
• Intense (potent ) / Potentially toxic on long term use

3. Basis for Induction immunosuppression ?
1. Non-physiologically high donor-specific T-cell precursor frequency present in
most recipients
2. Association of transplant with tissue injury
Injurious aspects of transplantation such as endothelial damage, complement
activation, ischemia and reperfusion, surgical wounding to the recipient, and
donor injury or brain death all impact the intensity of an immune response
These factors impel immunity and increase the effective precursor frequency by
lowering the threshold of T cell activation, improving the efficiency of antigen
presentation, and increasing the trafficking of cells to the organ and its draining
lymph nodes.

5. Advantages of Induction immunosuppression
• Improved graft survival for high-risk patients
• Period of delayed graft function may be foreshortened
• Onset of first rejection is delayed
• Obviates early use of calcineurin inhibitor
• May permit less aggressive maintenance regimen

6. Disadvantages of Induction
immunosuppression
• Risk for first-dose reactions
• May prolong hospital admission stay
• Greater cost
• Higher incidence of infections like cytomegalovirus infection
• Increased risk of post-transplant lymphoma
• Increased short- and long-term mortality reported

7. Timeline of Induction therapy
• ATG / ALG - 1970’s – induction and rejection
• OKT3 – 1985 - introduced for both treatment of rejection and
induction in kTx -1st monoclonal Ab to be approved for humans .
• Basiliximab and daclizumab – approved by FDA in 1998 for kidney
transplant – induction agent

10. Induction agents – Classification
• Monoclonal agents versus Polyclonal
Basiliximab versus ATG
• T-cell depleting versus Non T cell depleting
ATG versus basiliximab
Alemtuzumab ??

11. Mono clonal Antibodies

13. Basiliximab / Anti CD 25 inhibitors

14. • The IL-2 receptor is upregulated only on activated T cells, and as a result of the binding of the
antibody, IL-2-mediated responses are blocked. The anti-CD25 monoclonal antibodies thus complement
the effect of the CNIs, which reduce the production of IL-2.
• Originate as murine monoclonal antibodies, which are then genetically engineered so that large parts of
the molecule are replaced by human IgG. Basiliximab – 75% human and 25 % murine
• Compounds have low immunogenicity because they do not induce production of significant amounts
of human antimurine antibody  prolonged half life and no first dose reaction
• Half life – 7 days ; 2 doses 4 days apart (day 0 and day 4) ; saturation of IL2 receptor sites for 30-45
days
• Less adverse effects in comparative studies with ATG (anaphylaxis , first dose effect / infections )

15. Why not use Basiliximab for treatment of
rejection ??
• Previously activated T cells that are responding in an anamnestic response are
less dependent on IL-2 for proliferation. Heterologous responses (cross-
reactive responses between a previously encountered pathogen and an
alloantigen) or memory alloimmune responses seem not to be affected
significantly by CD25 interruption.
• Given this biology, primarily focused on naïve T cell early activation, CD25-
directed antibodies have found a role in induction, but have no role in the
treatment of established rejection.

16. EVIDENCE FOR USE OF BASILIXIMAB / ANTI CD 25
ANTIBODIES
Basiliximab versus Placebo
Modestly reduce the incidence of acute cellular rejection compared
with methylprednisolone induction when used in triple or double
immunosuppressive regimens
Acute cellular rejection among renal allograft recipients treated with basiliximab, a chimeric anti-interleukin-2-receptor
monoclonal antibody. Transplantation 1999;67:276–84.
Nashan B, Light S, Hardie I, et al. Reduction of acute renal allograft rejection by daclizumab. Transplantation
1999;67:110–5.
Nashan B, Moore R, Amlot P, et al. Randomised trial of basiliximab versus placebo for control of acute cellular rejection
in renal allograft recipients. CHIB. 201 international study group. Lancet 1997;350:1193–8.

17. • Basiliximab verus Polyclonal antibodies
Studies comparing basiliximab with
polyclonal antibodies in regimens using cyclosporine, MMF,
and steroids have shown comparable outcomes
Lebranchu Y, Bridoux F, Buchler M, et al. Immunoprophylaxis with basiliximab compared with antithymocyte globulin in renal
transplant patients receiving MMF-containing triple therapy. Am J Transplant 2002;2:48–56.
163. Mourad G, Rostaing L, Legendre C, et al. Sequential protocols using basiliximab versus antithymocyte globulins in renal-
transplant patients receiving mycophenolate mofetil and steroids. Transplantation 2004;78:584–90.
164. Sollinger H, Kaplan B, Pescovitz M, et al. Basiliximab versus antithymocyte globulin for prevention of acute renal allograft
rejection. Transplantation 2001;72:1915–9

18. • Antirejection effect seen with anti-CD25 therapy depends to some extent on the
intensity of the maintenance regimen, with earlier trials using cyclosporine-based and
azathioprine-based regimens showing a 25% reduction and later trials in the
tacrolimus/MMF era showing a more modest 10% improvement

19. ATG – Anti thymocyte globulin
• Belong to the group of polyclonal antibodies
• Animals immunized with human tissues cells (e.g.human lymphocytes),
or cell lines (e.g., Jurkatt cells) . Most polyclonal preparations are derived
from rabbit or horse immunizations
• These preparations are produced through whole-cell immunization, the
resulting preparations contain a vast array of antibodies binding many
epitopes expressed on the immunogen cells—some intended, and some
not.

20. • 3 dominant commercial preparations of ATG
- two rabbit-derived antibody preparations, antithymocyte globulin–rabbit
(ATG-R, Thymoglobulin, Genzyme-Sanofi) and antithymocyte globulin–
Fresenius (ATG-F, Fresenius),
- one horse-derived product (ATGAM, Pfizer )
• Polyclonal preparations are composed of a wide variety of antibodies, and
complete characterization has remained elusive
- T cell molecules involved in antigen recognition (CD3, CD4, CD8, and TCR),
adhesion (CD2, lymphocyte function antigen (LFA)-1, and intracellular
adhesion molecule (ICAM)-1), costimulation (CD28,CD40, CD80, CD86, and
CD154), non-T cell molecules (CD16, CD38, CD138, and CD20) and class I
and II major histocompatibility complex (MHC) molecules

21. Mechanism of action
• Antibodies directed against a variety of T cell markers
• lymphocytes, T cells in particular, are either lysed or cleared by the
reticuloendothelial system, and their surface antigens may be
masked by the antibody
• Also has action on B cells and plasma cells causing their depletion
• Thymoglobulin causes sustained and rapid expansion of CD4+, CD25+,
FOXP3+ regulatory T cells that play an important part in maintaining
immune homeostasis (role in immunologic tolerance )

23. Duration of action
• Prolonged serum half-lives of several weeks.
Nondepleted cells have been shown to be coated with heterologous
antibody for months, suggesting that these preparations could influence
the function of lymphocytes long after treatment has stopped
CD4 T-cell subsets maybe low for years

24. Dosage and administration
• rATG - Varies from centre to centre . Upto 6-9 mg/kg total dose initial studies .
Now more conservative 3 – 6 mg/kg
• More effective when started intraoperatively
• It is mixed in 500 mL of dextrose or saline and infused over 4 to 8 hours into a
central vein or arteriovenous fistula. Use of a peripheral vein is sometimes
followed by vein thrombosis or thrombophlebitis, although this may be prevented
by adding hydrocortisone 20 mg, and heparin, 1,000U, to the infusion solution.
• To avoid allergic reactions, the patient should receive intravenous premedication
consisting of methylprednisolone, 30 mg, and diphenhydramine hydrochloride 50
mg given 30 minutes before injection.
• Acetaminophen should be given before and 4 hours after commencement of the
infusion for fever control. Vital signs should be monitored every 15 minutes
during the first hour of infusion and then hourly until the infusion is complete.

25. ATG – F (GRAFALON )
• Home work

26. Adverse Effects
• Acute : Chills, fever, and arthralgias are common. Rarer anaphylaxis
• Sub acute : serum sickness – 1-2 weeks after infusion . Immune complex deposition – arthralgias
, fever , rash . Rx – increase dose of prednisolone .
• Leucopenias / Thrombocytopenias – 50% . Drug dose is usually halved for patients with either a
platelet count of 50,000 to 75,000 cells/mL or a white blood cell count of less than 3,000
cells/mL.
-Administration should be stopped if the counts fall further.
- Target ALC - <0.1%
• Long term / chronic – Infections / malignancy

27. CMV infection
• Common . Frequency varies with dosing and other concomitant
immunosuppression
• CMV prophylaxis necessary post use of ATG / other depletional agents
• American Society of Transplant guidelines

28. PTLD
• Fulminant and typically rapidly fatal B-cell lymphoma develops within
the first few months after transplantation. Epstein–Barr virus (EBV)
antibody-negative patients receiving a graft from an EBV-positive
donor appear to be at greatest risk.
• Repeated dosing of ATG / other depletional agents

29. Can ATG cause rejection ?

30. Indications for ATG
• Induction Agent –
- Lower rejection rates
- Early steroid withdrawal
‘mild’ rejections, which are easy to treat, and steroid-resistant rejections in
highly immunized patients are prevented.
Many studies on ATG were in the Pre Tac/MMF era .

31. • A 2010 Cochrane meta-analysis showed better 1-year allograft survival
with IL-2Ra induction versus no induction, but when IL-2Ra was
compared to ATG (16 studies, 2211 participants), there was no difference
in graft loss but there was a benefit for ATG in biopsy-proven acute
rejection at 1 year {eight studies: relative risk [RR] 1.30; [confidence
interval (CI) 1.01–1.67]}.
• However this was at the cost of a 75% increase in malignancy [7 studies:
RR 0.25 (95% CI 0.07–0.87)] and a 32% increase in cytomegalovirus (CMV)
disease[13 studies: RR 0.68 (95% CI 0.50–0.93)

32. • In the total cohort, consisting primarily of recipients at low immunological risk
(72% being firs transplants), ATG was no more effective in preventing rejection
than IL2RA agents, and the safety profile favored IL2RA induction.

33. KDIGO 2009
• Based largely on these findings, the 2009 Kidney Disease Improving Global
Outcomes (KDIGO) guidelines for the care of kidney transplant patients
recommended (i) that induction therapy with a biological agent be a routine
part of the initial immune suppressive regimen (grade 1B) and (ii) that an IL2R
agent be the first-line therapy (grade 1B).
• lymphocyte-depleting agents be used selectively in patients at high
immunological risk (grade2B)

34. High risk as per KDIGO
• high number of HLA mismatches,
• younger recipient age,
• older donor age,
• black ethnicity (in the United States),
• panel reactive antibodies >0%,
• presence of a donor-specific antibody,
• blood group incompatibility,
• delayed onset of graft function and
• cold ischemia time >24 h.

35. What the KDIGO 2009 guidelines do not tell ???
• Studies forming part of 2009 guidelines largely done in 1990’s and
early 2000s – double immunosuppression / AZA / Cyclosporine
based regimens and not the current Tac/MMF/steroids regimen
• After shift to standard Triple regimen , rejection rates reduced from
50 percent to around 10 -15 percent irrespective of induction agent
• No large RCT comparing IL-2 versus ATG in a regimen consisting of
Standard Triple immunosuppression ( most evidence only form
retrospective / observational data )

36. What about IL-2RA for low risk patients ?
• Gralla and Wiseman performed a retrospective analysis using U.S.
registry data from primary kidney transplants performed during
2000–2008, comparing patients who received initial
immunosuppression consisting of tacrolimus, MPA and prednisone
with or without IL2RA induction
• The 1-year acute rejection rate was 11.6% with IL2RA induction
versus 13.0% with no induction.
• No difference in graft or patient survival

37. • Data from the Australia and New Zealand Dialysis and Transplant Registry
(ANZDATA) on renal transplant recipients between 1995 and 2005 also
showed no reduction in rejection risk with IL2RA either in low-risk
recipients or in tacrolimus-treated patients with intermediate
immunological risk (RR 0.90, 95% CI 0.68–1.20; p = 0.48)
• In summary, the available data suggest that for kidney transplant patients
at standard immunological risk treated with tacrolimus, MPA and
maintenance steroids, the benefit of IL2RA is very modest or nonexistent
in terms of reducing acute rejection and does not confer a graft or patient
survival advantage.

38. 25. Woodle ES, First MR, Pirsch J et al. A prospective, randomized, double- blind, placebo-controlled multicenter trial
comparing early (7 day) cortico- steroid cessation versus long-term, low-dose corticosteroid therapy. Ann Surg 2008; 248: 564–
577
26. Mourad G, Morelon E, No€el C et al. The role of thymoglobulin induction in kidney transplantation: an update. Clin
Transplant 2012; 26: E450–E464
27. Lentine KL, Schnitzler MA, Xiao H et al. Long-term safety and efficacy of antithymocyte globulin induction: use of integrated
national registry data to achieve ten-year follow-up of 10-10 Study participants. Trials 2015; 16: 365; erratum 2015; 16: 412
28. Brennan DC, Daller JA, Lake KD et al. Rabbit antithymocyte globulin versus basiliximab in renal transplantation. N Engl J
Med 2006; 355: 1967–1977
29. No€el C, Abramowicz D, Durand D et al. Daclizumab versus antithymocyte
globulin in high-immunological-risk renal transplant recipients. J Am Soc
Nephrol 2009; 20: 1385–1392
31. Tian JH, Wang X, Yang KH et al. Induction with and without antithymocyte globulin combined with cyclosporine/tacrolimus-
based immunosuppression in renal transplantation: a meta-analysis of randomized controlled trials. Transplant Proc 2009; 41:
3671–3676
32. Liu Y, Zhou P, Han M et al. Basiliximab or antithymocyte globulin for induction therapy in kidney transplantation: a meta-
analysis. Transplant Proc 2010; 42: 1667–1670
33. Hao WJ, Zong HT, Cui YS et al. The efficacy and safety of alemtuzumab and daclizumab versus antithymocyte globulin during
organ transplantation: a meta-analysis. Transplant Proc 2012; 44: 2955–2960
34. Yin H, Xu Y, Zhang Q et al. Safety and efficacy of preoperative induction therapy using a single high dose ATG-F in renal
transplantation: a meta- analysis of randomized controlled trials. Zhonghua Yi Xue Za Zhi 2016; 96: 1773–1777
35. Malvezzi P, Jouve T, Rostaing L. Induction by anti-thymocyte globulins in kidney transplantation: a review of the literature
and current usage. J Nephropathol 2015; 4: 110–115

39. High Immunological Risk transplants
• Advantage of induction therapy appears to be more clear cut in high-risk
kidney transplant recipients.
• Only two large randomized trials have compared IL2RA versus rATG
induction specifically in this setting.

40. • Brennan and colleagues found rejection rates to be almost halved in
high-risk patients given rATG versus IL2RA at 1 year (16% vs. 26%, p =
0.02) and at 5 years (15% vs. 27%, p = 0.03)

41. • Noel et al enrolled 227 patients at high immunological risk (mean current
panel reactive antibodies 35%), of whom almost three-quarters were
receiving a second, third or fourth transplant (17). Maintenance therapy
comprised tacrolimus, MPA and steroids.
• Again, both the incidence and severity of acute rejection were significantly
lower with rATG versus IL2RA.

42. • Both studies failed to show a difference in long-term graft- or patient
survival benefit with rATG compared with IL2RA
• However acute rejection is associated with risk of graft loss /
dysfunction / treatment is costly and has a psychological effect

43. Other indications for Induction therapy
• Steroid avoidance / Steroid withdrawal and steroid free transplant

44. Additional Reading
• OKT3
• Alemtuzumab
• Rituximab in Induction regimes – especially ABO incompatible and
steroid avoidance regimes .