Early and rapid detection of X-linked lymphoproliferative syndrome with SH2D1A mutations by flow cytometry.
BACKGROUND
X-linked lymphoproliferative syndrome (XLP) is a rare immunodeficiency with extreme vulnerability to Epstein-Barr virus (EBV) infection. It presents with fatal infectious mononucleosis, lymphoproliferative disorder, or dysgammaglobulinemia. The majority of affected males have mutations in the SH2D1A/SLAM-associated protein (SAP) gene. We previously generated an antihuman SAP monoclonal antibody (KST-3) for a flow cytometric assay and described the activation of T cells to be necessary for the flow cytometric assessment of the SAP expression using an FITC-conjugated secondary antibody.


METHODS
Between 2005 and 2008, we recruited 23 male patients with suspected XLP, including mainly EBV-associated hemophagocytic lymphohistiocytosis (HLH), and attempted to evaluate SAP expression in fresh lymphoid cells using Alexa Fluor 488-conjugated secondary antibody instead of an FITC-conjugated one.


RESULTS
The method demonstrated that SAP was intensely expressed in CD8(+) T cells and NK cells in normal fresh blood samples, thus suggesting the possible rapid identification of individuals with SAP deficiency. SH2D1A mutations were identified in six patients with SAP deficiency, but not in patients with normal SAP expression.


CONCLUSIONS
The outcomes from this trial were verified by a flow cytometric assay using KST-3 and Alexa Fluor 488 secondary antibody. Based on the demonstration SAP deficiency in patients with suspected XLP, including mainly EBV-associated HLH, this approach could serve as a method for the early and rapid detection of patients with XLP-1.
Zhao
Meina
M
Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama, Japan.
Kanegane
Hirokazu
H
Kobayashi
Chie
C
Nakazawa
Yozo
Y
Ishii
Eizaburo
E
Kasai
Mikio
M
Terui
Kiminori
K
Gocho
Yoshihiro
Y
Imai
Kohsuke
K
Kiyasu
Junichi
J
Nonoyama
Shigeaki
S
Miyawaki
Toshio
T
D000293:Adolescent; D000328:Adult; D001483:Base Sequence; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005434:Flow Cytometry; D016368:Frameshift Mutation; D018380:Hematopoietic Stem Cell Transplantation; D004854:Herpesvirus 4, Human; D006801:Humans; D007223:Infant; D047908:Intracellular Signaling Peptides and Proteins / Q000097:blood / Q000235:genetics*; D051359:Lymphohistiocytosis, Hemophagocytic / Q000097:blood / Q000821:virology; D008232:Lymphoproliferative Disorders / Q000097:blood / Q000175:diagnosis* / Q000628:therapy; D008297:Male; D017354:Point Mutation; D017384:Sequence Deletion; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D055815:Young Adult
D047908:Intracellular Signaling Peptides and Proteins; C114953:SH2D1A protein, human; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein