Previous studies have found that iNKT cells have a constant TCRα receptor and they cannot develop without SAP protein, thus iNKT cells will not be detected in XLP-1 patients when SAP protein is deficient.[21,22] Additionally, iNKT can be labeled with CD3, TCRVα24 and TCRVβ11 antibodies that offer convenience in the detection.[23] Overall, combination of sequencing technology and flow cytometry provides a more efficient and accurate way in the diagnosis and classification of XLP. Here, SH2D1A is linked to X-linked lymphoproliferative disease.