Poster Display Immune dysregulation & autoimmunity

SEVERE CLONAL GAMMA-DELTA T-LYMPHOCYTOSIS WITH UNUSUAL IMMUNE PHENOTYPE IN COMBINED IMMUNODEFICIENCY WITHOUT MALIGNANT TRANSFORMATION

Lecture Time
10:45 - 10:46
Presenter
  • George Shubinsky, Israel
Room
Poster Area
Date
19.09.2019, Thursday
Session Time
10:00 - 17:00
Board Number
119
Presentation Topic
Immune dysregulation & autoimmunity

Abstract

Background and Aims

Severe γδT-lymphocytosis (γδTL) in patients with primary immunodeficiency (PID) is suggestive of T-cell lymphoma but is also found in rare cases of atypical combined immunodeficiency (CID). We report two closely related patients with CID and γδTL.

Methods

Retrospective analysis

Results

Patient 1: 21-year old male with recurrent diarrhea, hypoalbuminemia, recurrent pneumonia and bronchiectasis. He is receiving intravenous immunoglobulin (IVIG) therapy since age 6 months. At age 15 years autoimmune hemolytic anemia (AIHA), occasional neutropenia and thrombocytopenia ensued. Flow cytometry (FC) of peripheral blood detected CD8-positive absolute (970-1,310 γδT-cells) γδTL with irregular immunophenotype and decreased number of switched B-memory cells (SBMC). Clonal expansion of T cells was recorded, and T-cell receptor excision circles (TRECs) were absent. FC of bone marrow revealed significant decrease of mature and increase of immature B-cells. Patient responded to systemic steroids and increased frequency of IVIG. He showed no evidence for malignancy with a 6-year follow-up period.

Patient 2: 5-year old male who had since birth recurrent respiratory distress. At 10 months he developed severe AIHA with a partial response to steroids and IVIG. FC showed severe T-lymphopenia with relative γδTL (26-31%/T-cells) and low number of SBMC. Complete absence of TRECs was found. He received myeloablative matched sibling hematopoietic stem cell transplant and recovered.

Whole exome sequencing was unrevealing in both patients.

Conclusions

This report supports the assumption that severe clonal γδTL in patients with PID can directly result from disordered lymphopoiesis and exist without malignant transformation. The cases may be related to CID with immunophenotypically rare clonal γδTL.

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