Biochemical index and immunological function in the peripheral blood of patients with idiopathic pulmonary alveolar proteinosis.

Idiopathic pulmonary alveolar proteinosis (PAP) has recently been recognized as a disease of impaired alveolar macrophage function caused by the neutralizing granulocyte-macrophage colony stimulating factor (GM-CSF) autoantibody. However, the change of immunological function and biochemical index in the peripheral blood of patients with idiopathic PAP remains unclear. The clinical data of 29 patients with idiopathic PAP and 30 normal subjects were retrospectively analyzed. Biochemical indices, immunoglobulin and complement of all participants, and immunocytes in 19 patients and 30 normal subjects were evaluated. The peripheral blood of the patients showed a decrease in CD4+/CD8+ (P<0.05) and the percentage of the CD4+ T lymphocyte and helper T lymphocyte (both P<0.01), whereas an increase was observed in the percentage of the suppressor T lymphocyte (P<0.01) compared to the normal subjects. No significant differences were found in the concentration of IgG, IgA, IgM, C3 and C4 between the two groups. An increase was observed in LDH (P<0.01) and cytokeratin fragment antigen (CYFR) 211 (P<0.01) in the peripheral blood of the patients compared to that of normal subjects. The serum level of LDH was negatively correlated with FVC% Pred (P<0.05), DLCO% Pred (P<0.05), PaO2 (P<0.05) and positively associated with the dyspnea score (P<0.05) of 29 patients, and positively correlated with the score of high-resolution computed tomography (HRCT) of the chest of 21 patients (P<0.05). The serum level of CYFR211 was negatively correlated with DLCO% Pred (P<0.05) and positively associated with the dyspnea score (P<0.05). Findings of the present study suggest that hypofunction of cellular immunity may exist in the patients with idiopathic PAP. LDH and CYFRA211 may be considered as important indices to monitor the severity of idiopathic PAP.