Misinterpretation of allergic bronchopulmonary aspergillosis/allergic bronchopulmonary mycosis due to diverse characteristics in different clinical stages

Lung cancer resembling allergic bronchopulmonary mycosis with an asthma-like presentation

Allergic bronchopulmonary aspergillosis (ABPA) is a lung disorder caused by a hypersensitivity reaction to antigens of the Aspergillus species. Recently, allergic bronchopulmonary mycosis (ABPM) caused by fungi other than Aspergillus species but with the same symptoms has been described. ABPM commonly affects patients with allergic diseases including bronchial asthma. ABPM is characterized by radiographic appearance, with the most common findings being proximal bronchiectasis and signs of mucoid impaction. However, the differentiation of ABPM is often necessary to enable accurate diagnosis of lung cancer. A 73-year-old man visited the outpatient clinic with symptoms of exertional dyspnea. He was diagnosed with ABPM due to suspicious bronchiectasis and mucoid impaction observed in computed tomography (CT) of his chest. After 3 months, he visited our hospital with continued exertional dyspnea and suspicion of a possible tumor in his lung. Marked eosinophilia and high-attenuation mucus impaction were not taken into consideration as diagnosis was conducted as per clinical diagnostic criteria for ABPA/ABPM. We hereby report a case of lung cancer in a patient initially evaluated for suspected ABPM of the right lung. The diagnosis of lung cancer was established using bronchoscopy. If any definitive diagnosis is not achieved by following the clinical diagnostic criteria for ABPM, physicians should achieve a histological diagnosis by performing a prompt bronchoscopy.

Pentraxin-3 polymorphisms and pulmonary fungal disease in non-neutropenic patients

Background

Pentraxin 3 (PTX3) plays a non-redundant role in innate immunity against fungal diseases. Although single nucleotide polymorphisms (SNPs) of PTX3 are associated with a higher risk of invasive aspergillosis among the immunosuppressed population and chronic obstructive pulmonary disease patients, it is unknown whether PTX3 genetic variants influence the risk of pulmonary fungal disease in immunocompetent patients.

Methods

To investigate the association between PTX3 gene polymorphisms and pulmonary mycosis in non-neutropenic patients, we conducted a case-control study in a tertiary hospital department. Forty-five patients were identified using the criteria of the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC-MSG) and enrolled in the case group. Of these patients, 15 had allergic bronchopulmonary aspergillosis (ABPA), 10 had invasive pulmonary aspergillosis (IPA), 18 had pulmonary cryptococcosis, and 2 had other types of pulmonary mycosis. One hundred and twenty-two non-neutropenic inpatients not infected by fungal disease were randomly selected as the control group. We detected three SNPs (rs2305619, rs3816527, and rs1840680) within the PTX3 gene using polymerase chain reaction sequencing and compared their associations with different types of pulmonary fungal disease.

Results

Three SNPs were consistent with Hardy-Weinberg equilibrium (HWE). SNP rs2305619 was in linkage disequilibrium with rs3816527 (D’=0.85) and rs1840680 (D’=0.85), respectively. There was no difference in the genotypic distribution and haplotype frequency of the SNPs between the case group and the control group. When we focused on invasive mold infections as a subgroup, we found that the SNP rs3816527 CC homozygote was associated with a higher risk of IPA (OR, 7.37; 95% CI, 0.93–44.44; P=0.033), while the rs3816527 AA homozygote might lower the risk of pulmonary cryptococcosis (OR, 0.35; 95% CI, 0.11–0.96; P=0.047). No genotypic distribution differences were observed for the other two SNPs (rs2305619 and rs1840680). When it came to the comparison between ABPA subgroup and control group, no difference in single nucleotide polymorphism was observed.

Conclusions

This study showed that the SNP rs3816527 is associated with IPA in non-neutropenic patients. Further investigations in large populations are needed to validate this genetic predisposition. Functional studies are also required.