Particular phenotypic profile of blood lymphocytes during obliterative bronchiolitis syndrome following lung...

Bronchiolitis obliterans syndrome (OBS) remains the major complication in long-term survivors with heart-lung transplants, occurring in up to 50% of patients who survived the first year postsurgery. Until now, a significant decrease in small airway flow parameters has represented the most sensitive index for the detection of early OBS. Using immunocytofluorometric analysis, in a prospective study we have analysed the phenotype of peripheral blood lymphocyte effector and regulatory subsets in seven patients with inactive well-established OBS as compared with lung transplant recipients without any complication. We found a particular phenotypic profile during well-established OBS characterized by: (1) the disappearance of the CD19+ B cell population despite normal or increased immunoglobulin blood levels; (2) a marked decrease in the CD4+/CD8+ ratio; (3) a dramatic increase in phenotypic cytotoxic effector T cells CD8+S6F1+high and CD3+CD4-CD8-; (4) a dramatic increase in the CD4+CD29+/CD4+CD45RA+ ratio associated with the loss of the phenotypic suppressor/inducer CD4+CD45RA+T cells. The results of this preliminary study suggest that, using this selected combination of lymphocyte membrane markers, sequential phenotyping could be useful in the noninvasive follow-up of lung transplant recipients. The predictive value of this phenotypic profile for the early diagnosis of OBS is under investigation.