Compared with those in the CTD-non-ILD-PJP group, patients in the CTD-ILD-PJP group had higher white blood cell count [7.7 (5.6, 10.9) × 109/L vs. 6.4 (4.1, 8.9) × 109/L, p = 0.030], neutrophil count [6.6 (4.8, 9.4) × 109/L vs. 5.4 (3.4, 7.9) × 109/L, p = 0.002], platelet (PLT) [183.0 (129.0, 226.0) × 109/L vs. 128.0 (94.0, 213.5) × 109/L, p = 0.003], immunoglobulin A (1.9 ± 1.0 g/L vs. 1.6 ± 1.2 g/L, p = 0.043), and CD4+T/CD8+ T-cell [0.9 (0.4, 1.8) vs. 0.6 (0.4, 1.0), p < 0.015]. Here, CD8A is linked to pneumocystosis.