Pneumocystis jirovecii and SARS-CoV-2 Coinfection as Presentation of X-linked Severe Combined Immunodeficiency

Excerpt

To the Editor: A 6-mo-old boy was admitted to the Pediatric Intensive Care Unit due to severe hypoxemia secondary to bilateral pneumonia, with a positive SARS-CoV-2 PCR in the nasopharyngeal swab. He developed a pediatric acute respiratory distress syndrome (PARDS) requiring endotracheal intubation within the first hours after admission. The transthoracic echocardiography showed no signs of pulmonary hypertension or congenital heart disease. Due to the atypical clinical course and recent history of persistent cough and weight loss, a complete immune function test was performed, showing absence of CD3+ cells and CD3-CD16/CD56+ cells with normal CD19+ cell count, but associating hypogammaglobulinemia and absence of memory B cells, compatible with a T−B+NK− severe combined immunodeficiency (SCID) phenotype. Given the possibility of a Pneumocystis jirovecii pneumonia (PJP), empirical treatment with intravenous trimethoprim-sulfamethoxazole was started, with a subsequent positive result for P. jirovecii in a tracheal aspirate sample. He also received methylprednisolone (2 mg/kg/d). The patient’s status progressively improved, receiving 4 wk of trimethoprim-sulfamethoxazole treatment and being extubated after 5 wk. The next-generation sequence study of the 200 immunodeficiency gene panel identified a frameshift variant in hemizygosis (p. Ser113LeufsTer34) in exon 3 of the IL2RG gene, compatible with the clinical manifestations and phenotype of the patient. He was finally transplanted from a matched unrelated donor four months after the diagnosis of SCID, with a good outcome. …