Antineutrophil cytoplasmic antibody (C-ANCA) levels in relation to the treatment of Wegener's granulomatosis

We assessed the clinical significance of cANCA in relation to the diagnosis and follow-up of Wegener's granulomatosis patients using NephroScholor C-ANC, the ELISA kit for the detection of cANCA. The NephroScholor C-ANC test for cANCA was revealed to be useful for the diagnosis of Wegener's granulomatosis, but slightly less sensitive than the indirect immunofluorescence assay using human neutrophils, which has been in widespread use for the detection of ANCAs. With NephroScholor C-ANC, the cANCA titer can be estimated conveniently and expressed quantitatively. When conventional immunosuppressive therapy with prednisolone and cyclophosphamide was applied, the patients' symptoms subsided as the cANCA titer decreased, and thus it also seemed useful for the follow-up of Wegener's granulomatosis patients. However, a rising ANCA titer during the course of the disease was not always correlated with the occurrence of a relapse as previously reported. Based on these findings, it is not recommended that treatment be changed immediately because of elevation of the ANCA titer alone, and it never seemed too late to increase immunosuppressive therapy, even after a clinical exacerbation was observed. Several treatments other than the conventional immunosuppressive therapy have often been applied for our patients, especially in the limited type of this disease, and these treatments, including sulfamethoxazole-trimethoprim alone, low-dose prednisolone alone, and cyclophosphamide alone, have often been useful. We conclude that the choice of therapy must depend on the severity or the condition of the individual patient, and this therapeutic policy should reduce unnecessary side effects of potentially toxic drugs.