Serum neopterin after lung transplantation.
OBJECTIVE
Neopterin (N), a marker for activated cell-mediated immunity, was assayed in the sera of 44 lung recipients early and late after transplantation. The study was a prospective, blind clinical trial designed to evaluate the following: (1) the daily dynamics of the serum neopterin/creatinine (N/C) ratio during the first 3 weeks after transplantation; (2) the correlation between changes in the serum N/C ratio and episodes of rejection or infection; (3) the correlation between the serum N/C ratio and the concentration of serum soluble interleukin 2 receptor (sIL-2R), a marker of T-cell activation; and (4) the potential value of monitoring the serum N/C ratio during noninvasive long-term follow-up of lung recipients.


METHODS
Sera from lung recipients were collected every day or every 2 days for the first 3 weeks after transplantation (22 patients) and before fiberoptic bronchoscopy and routine consultation (44 patients). The N concentrations were determined by radioimmunoassay and sIL-2R levels were measured using a sandwich enzyme immunoassay.


RESULTS
Serum N/C is an early and sensitive marker of immune activation in the 21 days following transplantation. The N/C ratios during early rejections (815 +/- 182 mumol/mol) and infections (677 +/- 75 mumol/mol) were higher than those in patients with no complications (160 +/- 32 mumol/mol). In contrast, the N/C ratio did not increase during rejection later after transplantation. More than 3 weeks after transplantation, an increase in the N/C ratio was specifically correlated with infections, mainly those due to cytomegalovirus (CMV) (control subjects, 132 +/- 12 mumol/mol; rejections, 163 +/- 25 mumol/mol; CMV pneumonia, 786 +/- 103 mumol/mol, p < 0.001). The N/C ratio correlated with sIL-2R serum levels (r = 0.625, p < 0.001).


CONCLUSIONS
Our results indicate that more than 3 weeks after transplantation, the serum N/C ratio increases only in cases of infection, mostly CMV pneumonia. In contrast, both rejection and infectious complications are associated with an increased N production in the early postoperative period.
Humbert
M
M
Laboratoire d'Immunopathologie et d'Immunologie Virale, Inserm U131, Clamart, France.
Delattre
R M
RM
Cerrina
J
J
Dartevelle
P
P
Simonneau
G
G
Emilie
D
D
D000293:Adolescent; D000328:Adult; D001708:Biopterins / Q000031:analogs & derivatives* / Q000097:blood; D003404:Creatinine / Q000097:blood; D006084:Graft Rejection; D006801:Humans; D007239:Infections / Q000097:blood / Q000209:etiology; D016040:Lung Transplantation / Q000276:immunology; D008875:Middle Aged; D019798:Neopterin; D011183:Postoperative Complications; D011446:Prospective Studies; D015375:Receptors, Interleukin-2 / Q000032:analysis; D013997:Time Factors
D015375:Receptors, Interleukin-2; D001708:Biopterins; D019798:Neopterin; D003404:Creatinine