Delayed Diagnosis of Chronic Necrotizing Granulomatous Skin Lesions due to TAP2 Deficiency.
J Clin Immunol 2023;
43:217-228. [PMID:
36227411 DOI:
10.1007/s10875-022-01374-7]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 09/23/2022] [Indexed: 01/18/2023]
Abstract
Major histocompatibility complex class I (MHC-I) deficiency, also known as bare lymphocyte syndrome type 1 (BLS-1), is a rare autosomal recessively inherited immunodeficiency disorder with remarkable clinical and biological heterogeneity. Transporter associated with antigen processing (TAP) is a member of the ATP-binding cassette superfamily of transporters and consists of two subunits, TAP1 or TAP2. Any defect resulting from a mutation or deletion of these two subunits may adversely affect the peptide translocation in the endoplasmic reticulum, which is an important process for properly assembling MHC-I molecules. To date, only 12 TAP2-deficient patients were reported in the literature. Herein, we described two Iranian cases with 2 and 3 decades of delayed diagnosis of chronic necrotizing granulomatous skin lesions due to TAP2 deficiency without pulmonary involvement. Segregation analysis in family members identified 3 additional homozygous asymptomatic carriers. In both asymptomatic and symptomatic carriers, HLA-I expression was only 4-15% of the one observed in healthy controls. We performed the first deep immunophenotyping in TAP2-deficient patients. While total CD8 T cell counts were normal as previously reported, the patients showed strongly impaired naïve CD8 T cell counts. Mucosal-associated invariant T (MAIT) cells and invariant natural killer T (iNKT) cell counts were increased.
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