AUTHOR=Zhang Fei Zhou , Yuan Jie Xin , Qin Lu , Tang Lan Fang 

TITLE=Pulmonary Alveolar Proteinosis Due to Pneumocystis carinii in Type 1 Hyper-IgM Syndrome: A Case Report

JOURNAL=Frontiers in Pediatrics

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2020.00264

DOI=10.3389/fped.2020.00264

ISSN=2296-2360

ABSTRACT=<p><bold>Background:</bold> Pulmonary alveolar proteinosis (PAP) is a rare diffuse lung disease. Reports of rare cases of PAP due to <italic>Pneumocystis jirovecii</italic> (<italic>P. jirovecii</italic>) exist in infants with immunodeficiency diseases, but no cases have been reported to date in pediatric patients with type 1 hyper-IgM syndrome (HIGM1).</p><p><bold>Case Presentation:</bold> Herein, we present a case of PAP secondary to <italic>P. jirovecii</italic> on an infant with HIGM1. He was admitted to our unit because of cough and tachypnea. Lung biopsy confirmed the diagnosis of PAP, whereas hexamine-silver staining of the bronchoalveolar lavage fluid identified <italic>P. jirovecii</italic> infection. No other probable cause of PAP was observed. Whole exome sequencing indicated a novel c.511dupA (p.I171N<sup>*</sup>30) hemizygous mutation in the CD40 ligand (CD40LG) gene. He was cured with bronchoalveolar lavage and compound sulfamethoxazole tablets.</p><p><bold>Conclusions:</bold> To our knowledge, this is the first reported case of <italic>P. jirovecii</italic> infection as a reversible cause of PAP in an infant with HIGM1.</p>