A new C1q solid-phase assay for the detection of IgM immune complexes: application to the follow-up of kidney graft recipients with recurrent cytomegalovirus infection.
A C1q solid-phase enzyme assay for detecting circulating immune complexes (CIC) containing immunoglobulins M was developed. IgM immune complexes (IgM-CIC) bind to purified C1q-coated microplates. The amount of bound IgM-CIC is determined by adding anti-mu-alkaline phosphatase conjugate. This assay proved IgM-CIC specific; it does not detect IgG-CIC nor free anti-CMV IgM. Furthermore Rheumatoid Factor (RF) does not interfere with this test. Then, 119 renal allograft recipients were followed-up for the presence of seric IgM-CIC. Among them, 86 patients developed a recurrent Cytomegalovirus (CMV) infection and 33 did not. In the non-infected population, IgM-CIC were detected in only 15.2% of the patients. In contrast, patients with recurrent CMV infection showed a significantly higher frequency of detectable IgM-CIC (62.8%) (p less than 0.01). These IgM-CIC were detected: (a) during the first two or three weeks after graft; (b) in the course of the second month post graft. This second peak of IgM-CIC was never observed in subjects non-infected with CMV. IgM-CIC occurred before or at the same time as the detectable anti-CMV IgM and virus excretion in urines. Presence of IgM-CIC was not influenced by graft rejection episodes. Such a marker might help in discriminating immune response to viral infection from immune graft rejection.
Basson
J
J
Laboratoire de Virologie, Centre Hospitalier Universitaire, Lyon, France.
Tardy
J C
JC
Aymard
M
M
D000914:Antibodies, Viral / Q000097:blood*; D000936:Antigen-Antibody Complex / Q000097:blood*; D015415:Biomarkers; D015922:Complement C1q; D003586:Cytomegalovirus Infections / Q000209:etiology / Q000276:immunology*; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D007075:Immunoglobulin M / Q000097:blood* / Q000276:immunology; D016030:Kidney Transplantation / Q000009:adverse effects / Q000276:immunology*; D012008:Recurrence
D000914:Antibodies, Viral; D000936:Antigen-Antibody Complex; D015415:Biomarkers; D007075:Immunoglobulin M; D015922:Complement C1q