Seroprevalence and prognostic value of Aspergillus-specific IgG among non-neutropenic invasive pulmonary aspergillosis patients: a prospective multicenter study.

Background: This study aimed to assess the diagnostic and prognostic value of Aspergillus-specific IgG (Asp-IgG) for invasive pulmonary aspergillosis (IPA) in non-neutropenic non-hematologic patients.

Methods: Between November 2019 and February 2022, we recruited 40 non-neutropenic, non-hematologic IPA patients from Taiwan and measured serum Asp-IgG levels using Phadia, Thermofisher. A positive Asp-IgG test was defined as a level > 40 mgA/L. We evaluated the association between Asp-IgG levels and overall survival, as well 90-day mortality rate of IPA patients.

Results: Of the 40 participants, 11 (27.5%) tested positive for Asp-IgG, while 16 (40%) had positive galactomannan antigen (optical density > 1). Higher Asp-IgG levels were associated with improved overall survival (HR: 0.22, 95% CI: 0.05-0.99, p = 0.035) in multivariable Cox regression. The overall 90-day mortality rate was 65% (26/40). We found that patients with low Asp-IgG levels (≤ 40 mgA/L) had a borderline higher 90-day mortality rate compared to patients with high Asp-IgG levels (OR: 3.15, 95% CI: 0.75-13.28, p = 0.118). Stratifying by serum galactomannan and Aspergillus IgG levels, patients with elevated serum GM and low Asp-IgG had the highest 90-day mortality (80%, 8/10), followed by patients with low serum GM and low Asp-IgG (68.4%, 13/19).

Conclusions: Asp-IgG was positive in approximately one-fourth of non-neutropenic IPA patients. Asp-IgG may hold potential as a clinical prognostic factor for IPA. Further studies are required to validate this finding.