Distribution of CALR mutations among cell-types in peripheral blood

Transcription

1 Distribution of CALR mutations among cell-types in peripheral blood Lasse Kjær, Dept. of Hematology, Zealand University Hospital MPN&MPNr-EuroNet Eleventh meeting Poznan, Poland

2 Overview Introduction to CALR mutations Are homozygous subclones present in CALR mutated patients? Are CALR mutations present in lymphoid cell lineages?

3 CALR mutation distribution in MPNs PV ET PMF Klampfl T., NEJM (2013)

4 Mutations and clinical characteristics CALR vs JAK2V617F Lower age Higher platelet count Lower hemoglobin Lower leukocyte count Lower risk of thrombosis Type 1 Myelofibrotic transformation - prevalent in PMF patients Klampfl T., NEJM (2013) Type 2 Higher platelet count Lower risk of thrombosis prevalent in ET patients Pietra D., Leukemia (2015)

5 Survival according to mutation Tefferi A., Blood (2014)

6 Survival of ET patients according to mutation Elala YC., AJH (2016)

7 Survival according to mutation type in PMF Type 1 N=110 Type 1 N=53 Type 2 N=21 Type 2 N=21 Type 2 N=8 Type 1 N=33 Tefferi A., Blood (2014) Guglielmelli P., Blood Canc. Jour. (2015) Cabagnols X., Leukemia (2015)

8 Many functions of CALR Ca 2+ homeostasis Chaperone Phagocytosis Differentiation Regulating cell surface expresson Transport JAK/STAT signalling

9 Protein sequence changes Pietra D., Leukemia (2015)

10 Calcium mobilisation according to mutation type Pietra D., Leukemia (2015)

11 Cytokine independence through TPO receptor (c-mpl) Araki M., Blood (2016) Chachoua I., Blood (2016)

12 Mutant specific domain required for c-mpl/tpo binding Araki M., Blood (2016)

13 Actions of mutated calreticulin Reduced calcium binding capacity Cytokine independency involves extracellular part of TPO receptor (c-mpl) Gain of function of calreticulin in c-mpl activation

14 Mutant CALR allele burden N=685 Schnittger S., Leukemia (2015)

15 Mutant allele burden and blood counts N=31 Higher CALR allelic burden: -Lower hemoglobin -higher leukocyte count -higher platelet count Andrikovics H., Haematologica (2014)

16 Allele burden of mutant CALR and progression of disease? Andrikovics H., Haematologica (2014)

17 JAK2V617F allele burden Biological continuum JAK2V617F allele burden ET PV MF Kralovics R., NEJM (2005) Godfrey AL., Blood (2012)

18 JAK2V617F mutation in haematopoietic stem cell Larsen TS., BJH (2007)

19 Cazzola M., Blood (2014)

20 Isolation of CALR clones 15 CALR mutated patients: 4 ET 3 pre-pmf 7 PMF 1 Post-ET MF 4 type 2 11 type 1

21 qpcr assay for type 1 og type 2 CALR Sens. : <0.02% Slopes: Y-intercept: %CALR mutant allele burden pt1 pt2 Type 1 pt3 pt4 pt5 %CALR mutant allele burden pt1 pt2 pt3 pt4 pt5 Type 1: Range: % Cov: % Type 2: Range: % Cov: %

22 Heterozygote CALR patienter PMF PMF Pre-PMF PMF PMF Pre-PMF ET ET PMF PMF ET Pre-PMF PMF Post-ET MF ET 0/10/0 0/10/0 0/14/0 0/20/0 0/20/0 0/20/0 0/20/0 2/18/0 17/3/0 0/10/0 4/16/0 2/18/0 0/20/0 0/20/0 17/3/0 Homozygous Heterozygous negative 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% wildtype hetero homo CALR type 1, type 2

23 Cell sorting Is the CALR mutations present in both myeloid and lymphoid lineages? CD16 positive granulocytes CD14 positive monocytes CD3 positive T-lymphocytes CD8 positive B-lymphocytes

24 Gating strategy CD16 + granulocytes CD16 FITC CD3 + T cells CD3 PE

25 Gating strategy CD19 + B cells CD16 FITC CD14 + Monocytes CD3 PE

26 CALR mutations are present in lymphoid cells CD3: 7.8% CD3: 16% CD19: 18% CD3: 5% CD19: 31% PMF4 PMF5 PMF3 ET1 ET2 ET3 ET4 pre-pmf Post ET MF PMF1 PMF2 %CALR mutant allele burden

27 Summary Irrespectable of diagnosis homozygous subclones appear to be rare The CALR mutations are present in both myeloid and lymphoid lineages

28 Thanks to: Department of Hematology Zealand University Hospital, Roskilde Morten Holmström Vibe Skov Mette Grymer Jensen Hans Hasselbalch Center for Cancer Immune Therapy (CCIT)/Department of Hematology Herlev Hospital Mads Hald Kirsten Nikolajsen Department of Clinical Biochemistry Zealand University Hospital, Roskilde Lone Vandsø Jørgensen Cathrine Linde