Graded defects in cytotoxicity determine severity of hemophagocytic lymphohistiocytosis in humans and mice

Frontiers in Immunology

Volumn 4, Issue DEC, 2013, Pages

  Jessen, Birthe ^a   Kögl, Tamara ^a   Sepulveda, Fernando E ^b,c   de Saint Basile, Genevieve ^b,c,d   Aichele, Peter ^a   Ehl, Stephan ^a  

^a UNIVERSITY OF FREIBURG   (Germany)

^b INSERM   (France)

^c IMAGINE INSTITUTE   (France)

^d HÔPITAL NECKER ENFANTS MALADES   (France)

Author keywords

Antigen persistence; CTL; Cytotoxicity; Hemophagocytic lymphohistiocytosis; Inflammation; Virus persistence

Indexed keywords

EID: 84892143506     PISSN: None     EISSN: 16643224     Source Type: Journal    
DOI: 10.3389/fimmu.2013.00448     Document Type: Article

References (87)

1. de Saint Basile G, Menasche G, Fischer A. Molecular mechanisms of biogenesis and exocytosis of cytotoxic granules. Nat Rev Immunol (2010) 10(8):568-79. doi: 10.1038/nri2803.
2. Filipovich AH. Hemophagocytic lymphohistiocytosis and related disorders. Curr Opin Allergy Clin Immunol (2006) 6(6):410-5. doi:10.1097/01.all.0000246626.57118.d9.
3. Janka GE. Familial and acquired hemophagocytic lymphohistiocytosis. Eur J Pediatr (2007) 166(2):95-109. doi:10.1007/s00431-006-0258-1.
4. Janka GE. Familial and acquired hemophagocytic lymphohistiocytosis. Annu Rev Med (2012) 63:233-46. doi:10.1146/annurev-med-041610-134208.
5. Henter JI, Elinder G, Soder O, Hansson M, Andersson B, Andersson U. Hypercytokinemia in familial hemophagocytic lymphohistiocytosis. Blood (1991) 78(11):2918-22.
6. Osugi Y, Hara J, Tagawa S, Takai K, Hosoi G, Matsuda Y, et al. Cytokine production regulating Th1 and Th2 cytokines in hemophagocytic lymphohistiocytosis. Blood (1997) 89(11):4100-3.
7. Takada H, Ohga S, Mizuno Y, Suminoe A, Matsuzaki A, Ihara K, et al. Oversecretion of IL-18 in haemophagocytic lymphohistiocytosis: a novel marker of disease activity. Br J Haematol (1999) 106(1):182-9. doi:10.1046/j.1365-2141.1999.01504.x.
8. Henter JI, Horne A, Arico M, Egeler RM, Filipovich AH, Imashuku S, et al. HLH-2004: diagnostic and therapeutic guidelines for hemophagocytic lymphohistiocytosis. Pediatr Blood Cancer (2007) 48(2):124-31. doi:10.1002/pbc.21039.
9. Henter JI, Samuelsson-Horne A, Arico M, Egeler RM, Elinder G, Filipovich AH, et al. Treatment of hemophagocytic lymphohistiocytosis with HLH-94 immunochemotherapy and bone marrow transplantation. Blood (2002) 100(7):2367-73. doi:10.1182/blood-2002-01-0172.
10. Janka GE. Hemophagocytic syndromes. Blood Rev (2007) 21(5):245-53. doi:10.1016/j.blre.2007.05.001.
11. Jordan MB, Allen CE, Weitzman S, Filipovich AH, McClain KL. How I treat hemophagocytic lymphohistiocytosis. Blood (2011) 118(15):4041-52. doi:10.1182/blood-2011-03-278127.
12. Bryceson YT, Rudd E, Zheng C, Edner J, Ma D, Wood SM, et al. Defective cytotoxic lymphocyte degranulation in syntaxin-11 deficient familial hemophagocytic lymphohistiocytosis 4 (FHL4) patients. Blood (2007) 110(6):1906-15. doi:10.1182/blood-2007-02-074468.
13. Feldmann J, Callebaut I, Raposo G, Certain S, Bacq D, Dumont C, et al. Munc13-4 is essential for cytolytic granules fusion and is mutated in a form of familial hemophagocytic lymphohistiocytosis (FHL3). Cell (2003) 115(4):461-73. doi:10.1016/S0092-8674(03)00855-9.
14. Stepp SE, Dufourcq-Lagelouse R, Le Deist F, Bhawan S, Certain S, Mathew PA, et al. Perforin gene defects in familial hemophagocytic lymphohistiocytosis. Science (1999) 286(5446):1957-9. doi:10.1126/science.286.5446.1957.
15. zur Stadt U, Schmidt S, Kasper B, Beutel K, Diler AS, Henter JI, et al. Linkage of familial hemophagocytic lymphohistiocytosis (FHL) type-4 to chromosome 6q24 and identification of mutations in syntaxin 11. Hum Mol Genet (2005) 14(6):827-34. doi:10.1093/hmg/ddi076.
16. Cote M, Menager MM, Burgess A, Mahlaoui N, Picard C, Schaffner C, et al. Munc18-2 deficiency causes familial hemophagocytic lymphohistiocytosis type 5 and impairs cytotoxic granule exocytosis in patient NK cells. J Clin Invest (2009) 119(12):3765-73. doi:10.1172/JCI40732.
17. zur Stadt U, Rohr J, Seifert W, Koch F, Grieve S, Pagel J, et al. Familial hemophagocytic lymphohistiocytosis type 5 (FHL-5) is caused by mutations in Munc18-2 and impaired binding to syntaxin 11. Am J Hum Genet (2009) 85(4):482-92. doi:10.1016/j.ajhg.2009.09.005.
18. Barbosa MD, Nguyen QA, Tchernev VT, Ashley JA, Detter JC, Blaydes SM, et al. Identification of the homologous beige and Chediak-Higashi syndrome genes. Nature (1996) 382(6588):262-5. doi:10.1038/382262a0.
19. Enders A, Zieger B, Schwarz K, Yoshimi A, Speckmann C, Knoepfle EM, et al. Lethal hemophagocytic lymphohistiocytosis in Hermansky-Pudlak syndrome type II. Blood (2006) 108(1):81-7. doi:10.1182/blood-2005-11-4413.
20. Jessen B, Bode SF, Ammann S, Chakravorty S, Davies G, Diestelhorst J, et al. The risk of hemophagocytic lymphohistiocytosis in Hermansky-Pudlak syndrome type 2. Blood (2013) 121(15):2943-51. doi:10.1182/blood-2012-10-463166.
21. Menasche G, Pastural E, Feldmann J, Certain S, Ersoy F, Dupuis S, et al. Mutations in RAB27A cause Griscelli syndrome associated with haemophagocytic syndrome. Nat Genet (2000) 25(2):173-6. doi:10.1038/76024.
22. Nagle DL, Karim MA, Woolf EA, Holmgren L, Bork P, Misumi DJ, et al. Identification and mutation analysis of the complete gene for Chediak-Higashi syndrome. Nat Genet (1996) 14(3):307-11. doi:10.1038/ng1196-307.
23. Badolato R, Parolini S. Novel insights from adaptor protein 3 complex deficiency. J Allergy Clin Immunol (2007) 120(4):735-41. doi:10.1016/j.jaci.2007.08.039.
24. Benson KF, Li FQ, Person RE, Albani D, Duan Z, Wechsler J, et al. Mutations associated with neutropenia in dogs and humans disrupt intracellular transport of neutrophil elastase. Nat Genet (2003) 35(1):90-6. doi:10.1038/ng1224.
25. Dell'Angelica EC, Shotelersuk V, Aguilar RC, Gahl WA, Bonifacino JS. Altered trafficking of lysosomal proteins in Hermansky-Pudlak syndrome due to mutations in the beta 3A subunit of the AP-3 adaptor. Mol Cell (1999) 3(1):11-21. doi:10.1016/S1097-2765(00)80170-7.
26. Jancic C, Savina A, Wasmeier C, Tolmachova T, El-Benna J, Dang PM, et al. Rab27a regulates phagosomal pH and NADPH oxidase recruitment to dendritic cell phagosomes. Nat Cell Biol (2007) 9(4):367-78. doi:10.1038/ncb1552.
27. Stinchcombe J, Bossi G, Griffiths GM. Linking albinism and immunity: the secrets of secretory lysosomes. Science (2004) 305(5680):55-9. doi:10.1126/science.1095291.
28. Zhen L, Jiang S, Feng L, Bright NA, Peden AA, Seymour AB, et al. Abnormal expression and subcellular distribution of subunit proteins of the AP-3 adaptor complex lead to platelet storage pool deficiency in the pearl mouse. Blood (1999) 94(1):146-55.
29. D'Orlando O, Zhao F, Kasper B, Orinska Z, Muller J, Hermans-Borgmeyer I, et al. Syntaxin 11 is required for NK and CD8(+) T-cell cytotoxicity and neutrophil degranulation. Eur J Immunol (2013) 43(1):194-208. doi:10.1002/eji.201142343.
30. Martin-Verdeaux S, Pombo I, Iannascoli B, Roa M, Varin-Blank N, Rivera J, et al. Evidence of a role for Munc18-2 and microtubules in mast cell granule exocytosis. J Cell Sci (2003) 116(Pt 2):325-34. doi:10.1242/jcs.00216.
31. Meeths M, Entesarian M, Al-Herz W, Chiang SC, Wood SM, Al-Ateeqi W, et al. Spectrum of clinical presentations in familial hemophagocytic lymphohistiocytosis type 5 patients with mutations in STXBP2. Blood (2010) 116(15):2635-43. doi:10.1182/blood-2010-05-282541.
32. Sandrock K, Nakamura L, Vraetz T, Beutel K, Ehl S, Zieger B. Platelet secretion defect in patients with familial hemophagocytic lymphohistiocytosis type 5 (FHL-5). Blood (2010) 116(26):6148-50. doi:10.1182/blood-2010-08-302943.
33. Ye S, Karim ZA, Al Hawas R, Pessin JE, Filipovich AH, Whiteheart SW. Syntaxin-11, but not syntaxin-2 or syntaxin-4, is required for platelet secretion. Blood (2012) 120(12):2484-92. doi:10.1182/blood-2012-05-430603.
34. Pachlopnik Schmid J, Cote M, Menager MM, Burgess A, Nehme N, Menasche G, et al. Inherited defects in lymphocyte cytotoxic activity. Immunol Rev (2010) 235(1):10-23. doi:10.1111/j.0105-2896.2010.00890.x.
35. Rudd E, Goransdotter Ericson K, Zheng C, Uysal Z, Ozkan A, Gurgey A, et al. Spectrum and clinical implications of syntaxin 11 gene mutations in familial haemophagocytic lymphohistiocytosis: association with disease-free remissions and haematopoietic malignancies. J Med Genet (2006) 43(4):e14. doi:10.1136/jmg.2005.035253.
36. Zhang K, Jordan MB, Marsh RA, Johnson JA, Kissell D, Meller J, et al. Hypomorphic mutations in PRF1, MUNC13-4, and STXBP2 are associated with adult-onset familial HLH. Blood (2011) 118(22):5794-8. doi:10.1182/blood-2011-07-370148.
37. Beutel K, Gross-Wieltsch U, Wiesel T, Stadt UZ, Janka G, Wagner HJ. Infection of T lymphocytes in Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis in children of non-Asian origin. Pediatr Blood Cancer (2009) 53(2):184-90. doi:10.1002/pbc.22037.
38. Booth C, Gilmour KC, Veys P, Gennery AR, Slatter MA, Chapel H, et al. X-linked lymphoproliferative disease due to SAP/SH2D1A deficiency: a multicenter study on the manifestations, management and outcome of the disease. Blood (2011) 117(1):53-62. doi:10.1182/blood-2010-06-284935.
39. Henter JI, Ehrnst A, Andersson J, Elinder G. Familial hemophagocytic lymphohistiocytosis and viral infections. Acta Paediatr (1993) 82(4):369-72. doi:10.1111/j.1651-2227.1993.tb12699.x.
40. Suzuki N, Morimoto A, Ohga S, Kudo K, Ishida Y, Ishii E. Characteristics of hemophagocytic lymphohistiocytosis in neonates: a nationwide survey in Japan. J Pediatr (2009) 155(2):235.e-8.e. doi:10.1016/j.jpeds.2009.02.050.
41. Jordan MB, Hildeman D, Kappler J, Marrack P. An animal model of hemophagocytic lymphohistiocytosis (HLH): CD8+ T cells and interferon gamma are essential for the disorder. Blood (2004) 104(3):735-43. doi:10.1182/blood-2003-10-3413.
42. Crozat K, Hoebe K, Ugolini S, Hong NA, Janssen E, Rutschmann S, et al. Jinx, an MCMV susceptibility phenotype caused by disruption of Unc13d: a mouse model of type 3 familial hemophagocytic lymphohistiocytosis. J Exp Med (2007) 204(4):853-63. doi:10.1084/jem.20062447.
43. Kögl T, Muller J, Jessen B, Schmitt-Graeff A, Janka G, Ehl S, et al. Hemophagocytic lymphohistiocytosis in syntaxin-11-deficient mice: T-cell exhaustion limits fatal disease. Blood (2013) 121(4):604-13. doi:10.1182/blood-2012-07-441139.
44. Sepulveda FE, Debeurme F, Menasche G, Kurowska M, Cote M, Pachlopnik Schmid J, et al. Distinct severity of HLH in both human and murine mutants with complete loss of cytotoxic effector PRF1, RAB27A, and STX11. Blood (2013) 121(4):595-603. doi:10.1182/blood-2012-07-440339.
45. Pachlopnik Schmid J, Ho CH, Diana J, Pivert G, Lehuen A, Geissmann F, et al. A Griscelli syndrome type 2 murine model of hemophagocytic lymphohistiocytosis (HLH). Eur J Immunol (2008) 38(11):3219-25. doi:10.1002/eji.200838488.
46. Jessen B, Maul-Pavicic A, Ufheil H, Vraetz T, Enders A, Lehmberg K, et al. Subtle differences in CTL cytotoxicity determine susceptibility to hemophagocytic lymphohistiocytosis in mice and humans with Chediak-Higashi syndrome. Blood (2011) 118(17):4620-9. doi:10.1182/blood-2011-05-356113.
47. Kagi D, Ledermann B, Burki K, Seiler P, Odermatt B, Olsen KJ, et al. Cytotoxicity mediated by T cells and natural killer cells is greatly impaired in perforin-deficient mice. Nature (1994) 369(6475):31-7. doi:10.1038/369031a0.
48. Pachlopnik Schmid J, Ho CH, Chretien F, Lefebvre JM, Pivert G, Kosco-Vilbois M, et al. Neutralization of IFNgamma defeats haemophagocytosis in LCMV-infected perforin-and Rab27a-deficient mice. EMBO Mol Med (2009) 1(2):112-24. doi:10.1002/emmm.200900009.
49. Barber DL, Wherry EJ, Ahmed R. Cutting edge: rapid in vivo killing by memory CD8 T cells. J Immunol (2003) 171(1):27-31.
50. Ehl S, Klenerman P, Aichele P, Hengartner H, Zinkernagel RM. A functional and kinetic comparison of antiviral effector and memory cytotoxic T lymphocyte populations in vivo and in vitro. Eur J Immunol (1997) 27(12):3404-13. doi:10.1002/eji.1830271240.
51. Fung-Leung WP, Kundig TM, Zinkernagel RM, Mak TW. Immune response against lymphocytic choriomeningitis virus infection in mice without CD8 expression. J Exp Med (1991) 174(6):1425-9. doi:10.1084/jem.174.6.1425.
52. Lehmann-Grube F, Lohler J, Utermohlen O, Gegin C. Antiviral immune responses of lymphocytic choriomeningitis virus-infected mice lacking CD8+ T lymphocytes because of disruption of the beta 2-microglobulin gene. J Virol (1993) 67(1):332-9.
53. Zinkernagel RM, Leist T, Hengartner H, Althage A. Susceptibility to lymphocytic choriomeningitis virus isolates correlates directly with early and high cytotoxic T cell activity, as well as with footpad swelling reaction, and all three are regulated by H-2D. J Exp Med (1985) 162(6):2125-41. doi:10.1084/jem.162.6.2125.
54. Feldmann J, Le Deist F, Ouachee-Chardin M, Certain S, Alexander S, Quartier P, et al. Functional consequences of perforin gene mutations in 22 patients with familial haemophagocytic lymphohistiocytosis. Br J Haematol (2002) 117(4):965-72. doi:10.1046/j.1365-2141.2002.03534.x.
55. Voskoboinik I, Smyth MJ, Trapani JA. Perforin-mediated target-cell death and immune homeostasis. Nat Rev Immunol (2006) 6(12):940-52. doi:10.1038/nri1983.
56. van Dommelen SL, Sumaria N, Schreiber RD, Scalzo AA, Smyth MJ, Degli-Esposti MA. Perforin and granzymes have distinct roles in defensive immunity and immunopathology. Immunity (2006) 25(5):835-48. doi:10.1016/j.immuni.2006.09.010.
57. Chiossone L, Audonnet S, Chetaille B, Chasson L, Farnarier C, Berda-Haddad Y, et al. Protection from inflammatory organ damage in a murine model of hemophagocytic lymphohistiocytosis using treatment with IL-18 binding protein. Front immunol (2012) 3:239. doi:10.3389/fimmu.2012.00239.
58. Shellam GR, Allan JE, Papadimitriou JM, Bancroft GJ. Increased susceptibility to cytomegalovirus infection in beige mutant mice. Proc Natl Acad Sci USA (1981) 78(8):5104-8. doi:10.1073/pnas.78.8.5104.
59. Certain S, Barrat F, Pastural E, Le Deist F, Goyo-Rivas J, Jabado N, et al. Protein truncation test of LYST reveals heterogenous mutations in patients with Chediak-Higashi syndrome. Blood (2000) 95(3):979-83.
60. Scherber E, Beutel K, Ganschow R, Schulz A, Janka G, Stadt U. Molecular analysis and clinical aspects of four patients with Chediak-Higashi syndrome (CHS). Clin Genet (2009) 76(4):409-12. doi:10.1111/j.1399-0004.2009.01205.x.
61. Kaya Z, Ehl S, Albayrak M, Maul-Pavicic A, Schwarz K, Kocak U, et al. A novel single point mutation of the LYST gene in two siblings with different phenotypic features of Chediak Higashi syndrome. Pediatr Blood Cancer (2011) 56(7):1136-9. doi:10.1002/pbc.22878.
62. Karim MA, Suzuki K, Fukai K, Oh J, Nagle DL, Moore KJ, et al. Apparent genotype-phenotype correlation in childhood, adolescent, and adult Chediak-Higashi syndrome. Am J Med Genet (2002) 108(1):16-22. doi:10.1002/ajmg.10184.abs.
63. Macal M, Lewis GM, Kunz S, Flavell R, Harker JA, Zuniga EI. Plasmacytoid dendritic cells are productively infected and activated through TLR-7 early after arenavirus infection. Cell Host Microbe (2012) 11(6):617-30. doi:10.1016/j.chom.2012.04.017.
64. Hislop AD, Taylor GS, Sauce D, Rickinson AB. Cellular responses to viral infection in humans: lessons from Epstein-Barr virus. Annu Rev Immunol (2007) 25:587-617. doi:10.1146/annurev.immunol.25.022106.141553.
65. Bidere N, Su HC, Lenardo MJ. Genetic disorders of programmed cell death in the immune system. Annu Rev Immunol (2006) 24:321-52. doi:10.1146/annurev.immunol.24.021605.090513.
66. Chen M, Felix K, Wang J. Critical role for perforin and Fas-dependent killing of dendritic cells in the control of inflammation. Blood (2012) 119(1):127-36. doi:10.1182/blood-2011-06-363994.
67. Biron CA. Yet another role for natural killer cells: cytotoxicity in immune regulation and viral persistence. Proc Natl Acad Sci U S A (2012) 109(6):1814-5. doi:10.1073/pnas.1120528109.
68. Davis DM. Intercellular transfer of cell-surface proteins is common and can affect many stages of an immune response. Nat Rev Immunol (2007) 7(3):238-43. doi:10.1038/nri2020.
69. Lang PA, Lang KS, Xu HC, Grusdat M, Parish IA, Recher M, et al. Natural killer cell activation enhances immune pathology and promotes chronic infection by limiting CD8+ T-cell immunity. Proc Natl Acad Sci U S A (2012) 109(4):1210-5. doi:10.1073/pnas.1118834109.
70. Marcenaro E, Ferranti B, Moretta A. NK-DC interaction: on the usefulness of auto-aggression. Autoimmun Rev (2005) 4(8):520-5. doi:10.1016/j.autrev.2005.04.015.
71. Menasche G, Feldmann J, Fischer A, de Saint Basile G. Primary hemophagocytic syndromes point to a direct link between lymphocyte cytotoxicity and homeostasis. Immunol Rev (2005) 203:165-79. doi:10.1111/j.0105-2896.2005.00224.x.
72. Su MW, Walden PR, Golan DB, Eisen HN. Cognate peptide-induced destruction of CD8+ cytotoxic T lymphocytes is due to fratricide. J Immunol (1993) 151(2):658-67.
73. Waggoner SN, Cornberg M, Selin LK, Welsh RM. Natural killer cells act as rheostats modulating antiviral T cells. Nature (2011) 481(7381):394-8. doi:10.1038/nature10624.
74. Chellapandian D, Das R, Zelley K, Wiener SJ, Zhao H, Teachey DT, et al. Treatment of Epstein-Barr virus-induced haemophagocytic lymphohistiocytosis with rituximab-containing chemo-immunotherapeutic regimens. Br J Haematol (2013) 162(3):376-82. doi:10.1111/bjh.12386.
75. Imashuku S. Treatment of Epstein-Barr virus-related hemophagocytic lymphohistiocytosis (EBV-HLH); update 2010. J Pediatr Hematol Oncol (2010) 33(1):35-9. doi:10.1097/MPH.0b013e3181f84a52.
76. Lykens JE, Terrell CE, Zoller EE, Risma K, Jordan MB. Perforin is a critical physiologic regulator of T-cell activation. Blood (2011) 118(3):618-26. doi:10.1182/blood-2010-12-324533.
77. Zinkernagel RM, Ehl S, Aichele P, Oehen S, Kundig T, Hengartner H. Antigen localisation regulates immune responses in a dose-and time-dependent fashion: a geographical view of immune reactivity. Immunol Rev (1997) 156:199-209. doi:10.1111/j.1600-065X.1997.tb00969.x.
78. Badovinac VP, Tvinnereim AR, Harty JT. Regulation of antigen-specific CD8+ T cell homeostasis by perforin and interferon-gamma. Science (2000) 290(5495):1354-8. doi:10.1126/science.290.5495.1354.
79. Odermatt B, Eppler M, Leist TP, Hengartner H, Zinkernagel RM. Virus-triggered acquired immunodeficiency by cytotoxic T-cell-dependent destruction of antigen-presenting cells and lymph follicle structure. Proc Natl Acad Sci U S A (1991) 88(18):8252-6. doi:10.1073/pnas.88.18.8252.
80. Wong P, Pamer EG. Feedback regulation of pathogen-specific T cell priming. Immunity (2003) 18(4):499-511. doi:10.1016/S1074-7613(03)00081-5.
81. Yang J, Huck SP, McHugh RS, Hermans IF, Ronchese F. Perforin-dependent elimination of dendritic cells regulates the expansion of antigen-specific CD8+ T cells in vivo. Proc Natl Acad Sci U S A (2006) 103(1):147-52. doi:10.1073/pnas.0509054103.
82. Terrell CE, Jordan MB. Perforin deficiency impairs a critical immunoregulatory loop involving murine CD8(+) T cells and dendritic cells. Blood (2013) 121(26):5184-91. doi:10.1182/blood-2013-04-495309.
83. Sasai M, Linehan MM, Iwasaki A. Bifurcation of Toll-like receptor 9 signaling by adaptor protein 3. Science (2010) 329(5998):1530-4. doi:10.1126/science.1187029.
84. Sugita M, Cao X, Watts GF, Rogers RA, Bonifacino JS, Brenner MB. Failure of trafficking and antigen presentation by CD1 in AP-3-deficient cells. Immunity (2002) 16(5):697-706. doi:10.1016/S1074-7613(02)00311-4.
85. Iannacone M, Sitia G, Isogawa M, Whitmire JK, Marchese P, Chisari FV, et al. Platelets prevent IFN-alpha/beta-induced lethal hemorrhage promoting CTL-dependent clearance of lymphocytic choriomeningitis virus. Proc Natl Acad Sci U S A (2008) 105(2):629-34. doi:10.1073/pnas.0711200105.
86. Loria GD, Romagnoli PA, Moseley NB, Rucavado A, Altman JD. Platelets support a protective immune response to LCMV by preventing splenic necrosis. Blood (2013) 121(6):940-50. doi:10.1182/blood-2011-08-376822.
87. Battegay M, Cooper S, Althage A, Banziger J, Hengartner H, Zinkernagel RM. Quantification of lymphocytic choriomeningitis virus with an immunological focus assay in 24-or 96-well plates. J Virol Methods (1991) 33(1-2):191-8. doi:10.1016/0166-0934(91)90018-U.