90P - Flowcytometric expression of LAIR-1 inhibitory immune-receptor in pediatric Acute Lymphoblastic Leukemia cases does not correlate with standard ris...

Date 08 December 2017
Event ESMO Immuno-Oncology Congress 2017
Session Lunch & Poster Display session
Topics Cancer Immunology and Immunotherapy
Translational Research
Presenter PRATEEK Bhatia
Citation Annals of Oncology (2017) 28 (suppl_11): xi6-xi29. 10.1093/annonc/mdx711
Authors P. Bhatia1, M. Singh1, J. Shandilya2, N. Varma3, M.S. Sachdeva3, A. Trehan1, D. Bansal1, R. Jain1, S. Totadri1
  • 1Pediatrics, PGIMER, Chandigarh, 160012 - Chandigarh/IN
  • 2Pediatrics Immunology Unit, PGIMER, Chandigarh, 160012 - Chandigarh/IN
  • 3Hematology, PGIMER, Chandigarh, 160012 - Chandigarh/IN

Abstract

Background

Immunophenotypic markers play significant role in prognostication in different cancers. Recently identified one such marker is Leukocyte-associated Ig-like receptor (LAIR-1) which is an inhibitory immuno-receptor. Few studies done worldwide have shown controversial expression of this marker in different leukemias.

Methods

We measured the LAIR-1 expression in paediatric ALL patients (n-42) by flow cytometry gating of CD45 and CD3/19 positive lymphoblasts. Median Fluorescence intensities were calculated after appropriate compensation using controls and isotype samples. Demographic, clinical variables and early treatment outcome parameters of patients were noted and correlated with expression level of LAIR-1.

Results

The age of ALL cohort 1 - 11 y & M:F ratio 2.5:1. 64% had WBC count 50x109/L. 52% were standard risk and 48% high risk. 6 were T-ALL and 36 B-ALL. AML1-TEL, E2A-PBX, BCR-ABL & MLL-AF4 transcripts were noted in 3, 6, 2 and 1 patient respectively. Day 8 ABC was 1000 in 8 cases. 30 had low MRD (0.01) at day 35 of treatment. The median of MFIs of LAIR-1 expression in control cases was 8.2 (range of 7.76-11.69) & in ALL cases 4.02 (range of 0.56 to 11.87). 74% (n-31) of ALL cases showed lower expression while 26% (n-11) had normal expression. However, on correlating the standard ALL risk factors and MRD, no significant correlation was found. Out of 42 patients, 4 patients died during induction treatment and one left therapy. 60% (n-3/5) with above event had low expression of LAIR-1. Also ALL patients with low LAIR-1 expression had t(12;21), t(1;19) and t(4;11) translocations in 2, 4 and 1 samples respectively but none had t(9;22). While patients with high LAIR-1 expression, 2 had t(9;22) (MFIs-14.43 & 11.87).

Conclusions

This is one of the first studies on LAIR-1expression in ALL and suggests low expression of the inhibitory molecule on leukemic cells. However, the findings need to be confirmed in larger cohort along with study of pathophysiological role in leukemic clone survival and immune system escape.

Clinical trial identification

Legal entity responsible for the study

Dr. Prateek Bhatia

Funding

PGIMER Chandigarh

Disclosure

All authors have declared no conflicts of interest.