The relationship between immunosuppressive therapy and clinical isolates for patients diagnosed with...

Immunosuppressive therapy is the main treatment for patients with interstitial lung diseases (ILD) secondary to dermatomyositis (DM). Microbial colonization or infection might be very common for these patients. However, the relationship between immunotherapy and microorganism isolates are not fully understood in these patients.

This study retrospectively analyzed on the clinical features in DM-ILD patients who had positive microbiological results during immunosuppressive therapy in our hospital.

Patients were divided into two groups, according to the result of microbiological study. Comparisons in infection-related data in various contexts were carried out.

As a result, patients who had positive microbiological findings were manifested as higher fever degree [p = 0.01; positive group: mean ± SEM: 38.83 ± 0.15 °C, N = 28; negative group: mean ± SEM: 38.27 ± 0.15 °C; N = 28], higher serum C-reactive protein (CRP) [p less than 0.001, positive group (mean ± SEM: 31.6 ± 5.2 mg/L; N = 43); negative (mean ± SEM: 11.1 ± 1.6 mg/L; N = 86)], and lower CD3⁺CD4⁺ T cells counts than that of negative populations [p = 0.03, positive group (mean ± SEM: 0.27 ± 0.05 × 109/L; N = 31); negative group (mean ± SEM: 0.400 ± 0.03 × 109/L; N = 44)]. Longer hospital stay [p = 0.005; 21/36 vs 31/99] and higher serum FK506 concentrations [p = 0.02, positive group: 9.80 ± 1.87 ng/ml; N = 7; negative group: 5.76 ± 0.73 ng/ml; N = 27] were related to the occurrence of microorganism in the airway. Meanwhile, short-term investigation of in-hospital mortality related to airway microbial carry had no statistical difference between the both groups [p = 0.21, Log-rank (Mantel-Cox) Test].

Occurrence of positive isolates in DM-ILD patients may relate to higher inflammatory markers CRP, lower CD4 + T cells counts, high concentration of serum FK-506, and longer hospital stay.