MHC class I deficiency-1 (MHC1D1) is an autosomal recessive immunologic disorder characterized by the onset of recurrent and chronic bacterial sinobronchial infections in the first or second decades of life, usually with progression to bronchiectasis. Nasal polyps are commonly observed, and chronic necrotizing granulomatous lesions affecting the nasal cavity, upper respiratory tract, and/or skin, which can be severe, may develop later. Patient cells have decreased or absent expression of MHC type I (HLA class I) antigens (HLA-A, HLA-B, and HLA-C) on the cell surface, leading to the alternative designation bare lymphocyte syndrome type I (BLS type I). Some patients may be asymptomatic (Sullivan et al., 1985; summary by Maeda et al., 1985; Moins-Teisserenc et al., 1999).
In an early review by de la Salle et al. (1999), only 9 well-documented cases of HLA class I deficiency with normal expression of class II molecules had been found. Contrary to MHC class II deficiency (see MHC2D1, 209920), which is characterized by the early onset of severe combined immunodeficiency (SCID), HLA class I antigen deficiencies are not accompanied by particular pathologic manifestations during the first years of life, although chronic lung disease develops in late childhood. Also in contrast to type II BLS, pathology of the gut (diarrhea) is not observed. Systemic infections have not been described in HLA class I-deficient patients. Chronic bacterial infections, often beginning in the first decade of life, are restricted to the respiratory tract and extend from the upper to the lower airway. Bronchiectasis, emphysema, panbronchiolitis, and bronchial obstruction have been described. There is a high frequency of nasal polyps and involvement of the nasal sinuses.
Genetic Heterogeneity of MHC Class I Deficiency
See also MHC1D2 (620813), caused by mutation in the TAP2 gene (170261), MHC1D3 (620814), caused by mutation in the TAPBP (601962) gene, and MHC1D4 (241600), caused by mutation in the B2M gene (109700).
See also MHC class II deficiency (see, e.g., MHC2D1; 209920). [from
OMIM]