[Disturbed neutrophil activation in pneumonia during medicinal immunosuppression]

In medically immunosuppressed patients with pneumonia, the BAL cell differential and neutrophils secretion products were determined and compared to patients with pneumonia without defined immunodeficiency in order to define a possibly deficient neutrophil function.

Forty-eight medically immunosuppressed patients were studied: 24 pts. after renal transplantation receiving threefold immunosuppression (cyclosporine, azathioprine, prednisolone), 14 pts. with non-Hodgkin-lymphoma receiving polychemotherapy and 10 pts. with rheumatologic disorders (rheumatoid arthritis n = 3, M. Wegener n = 5 und SLE n = 2) receiving cyclophosphamide or methotrexate. For comparison, 116 patients without defined immunodeficiency and pneumonia and 16 healthy adults were studied. In addition to the cell differential the BALF concentrations of the neutrophil degranulation products myeloperoxidase (MPO) and lactoferrin were determined using immunoluminometric assays. For identification of microorganisms semiquantitative cultures were used.

Neutrophilia > 5% in BAL was present in only 36% of the immunosuppressed pts. in contrast to 91.3% of the immunocompetent pts. (p < 0.01). The same pathogen was found in 14 pts. of each group, so that a pathogen matched comparison was possible. The neutrophil percentage and the BALF concentration of lactoferrin was significantly lower in the immunosuppressed group. In blood there was no difference with regard to the neutrophil count between the groups.

BAL characteristics of immunosuppressed pts. are different from those of immunocompetent pts. with pneumonia. The pathogen-matched comparison proved that this is not due to different pathogens. Medically immunosuppressed patients with pneumonia exhibit a disturbed neutrophil recruitment. A neutrophil percentage < 5% in BAL of medically immunosuppressed patients does not preclude a bacterial infection.