3.1 | Clinical characteristics and pathogens
The clinical features of the children are summarized in Table 1 . These were seven boys with age ranging from 4-20 months (median age, 13 months). All children had respiratory infections, including fever and cough. All patients had at least one episode of respiratory tract infection. Of the seven patients, four (P1, P5, P6, and P7) hadTalaromyces marneffei(T. marneffei) infection and two (P2 and P3) were identified to have cytomegalovirus (CMV) and human adenovirus (HAdV) infections, respectively; Only P2 was confirmed to have a mixed infection caused byPneumocystis carinii(P. carinii) and CMV. From a pulmonary imaging perspective, four patients developed lymphadenopathy and diffuse infiltration with T. marneffei infection on high-resolution computed tomography (HRCT) (Figure 1A ). The other three patients (P2, P3, and P4) showed ground-glass opacities on HRCT (Figure 1B ). Specifically, seven patients were followed up for 3-10 years. During the follow-up period, only one patient (P3) died of respiratory failure, whereas the others survived with regular infusions of intravenous immunoglobulin (IVIg) (as checked till before manuscript submission).
3.2 | Hematological andimmunological parameters
Immunological evaluations of the seven patients at the time of diagnosis are listed in Table 2 . Almost all patients had reduced serum IgG levels, except for one child (P6) treated with IVIg before the examination. Serum IgM levels of P3, P4, and P5 were slightly elevated, while serum IgM levels of the other patients (P1, P2, P6, and P7) were normal. High or normal T and B lymphocyte counts were observed in all patients. The counts of CD19+ B cells were elevated in P1, P2, P3, P4, and P7, whereas the other two patients (P5 and P6) had normal CD19+ B cell counts. Nitro blue tetrazolium test results were normal in all patients.