Cytomegalovirus pneumonia as the first manifestation of severe combined immunodeficiency

Szczawinska-Poplonyk, Aleksandra; Jonczyk-Potoczna, Katarzyna; Ossowska, Lidia; Breborowicz, Anna; Bartkowska-Sniatkowska, Alicja; Wachowiak, Jacek

Severe combined immunodeficiency (SCID) is a group of inherited, genetically heterogeneous disorders characterized by a defective T lymphocyte development, leading to their absence or dysfunction that affects both cellular and humoral arms of adaptive immunity. Depending on the genetic defect influencing the presence or absence of B lymph cells and NK cells, SCID may be conventionally categorized as T-B+ and T-B-SCID, the first being caused by mutations in cytokine-mediated signaling and defective V(D)J (variable, diversity, joining) recombination necessary for the rearrangement of the B and T cell receptor genes in the latter [1] . A defective T-cell mediated immune response and the subsequent inability to clear viral infections makes SCID infants susceptible to inflammatory lung damage due to infections with paramyxoviruses and adenoviruses, with high rates of respiratory failure and mortality [2] . Progressive interstitial pneumonitis with hyper-inflation reflecting the impairment of peripheral ventilation are common features of an infection with Pneumocystis jiroveci, as a co-pathogen with respiratory viruses [1, 3] .