'We have observed a number of patients who fail to develop coccidioidal complement fixing (CF) antibody (immunoglobulin [IgG]) after the initiation of early antifungal therapy. Although this is the first description of this phenomenon in mycology, a precedent for the abrogation of the immune response has been observed in other conditions, including primary syphilis and primary Lyme disease,' scientists writing in the journal Clinical Infectious Diseases report (see also Infectious Diseases).
'We conducted a retrospective case-control study to determine any patient-specific risk factors associated with this observation. Additionally, in vitro analysis of the coccidioidal CF (IgG) antigen (Cts1) was performed after Coccidioides was grown under escalating fluconazole concentrations. Seventeen patients persistently positive for coccidioidal IgM antibodies without developing an IgG response (cases) were compared with 64 consecutive patients who did develop coccidioidal CF (IgG) antibodies (controls). Early treatment with antifungals (within 2 weeks of symptom onset) was associated with an abrogation of IgG antibody production (P < .001). With immunodiffusion testing, control serum demonstrated a lack of IgG seroreactivity when Coccidioides posadasii grown in the presence of escalating fluconazole doses (0.5-128 mu g/mL) was used as the antigen; however, control serum remained seroreactive for the presence of IgM. The coccidioidal IgG antigen (Cts1) was shown to be diminished when cultures were grown in the presence of fluconazole, lending further in vitro plausibility to our findings,' wrote G.R. Thompson and colleagues, University of California.
The researchers concluded: 'The abrogation of an IgG response in patients treated early in the course of coccidioidal infection may complicate serodiagnosis and epidemiologic studies, and further study to determine the potential clinical implications should be performed.'
Thompson and colleagues published their study in Clinical Infectious Diseases (Early Treatment With Fluconazole May Abrogate the Development of IgG Antibodies in Coccidioidomycosis. Clinical Infectious Diseases, 2011;53(6):E20-E24).
Additional information can be obtained by contacting G.R. Thompson, University of California, Dept. of Public Health Science, Division Biostatistics, Davis, CA 95616, United States.
The publisher of the journal Clinical Infectious Diseases can be contacted at: Oxford University Press Inc., Journals Dept., 2001 Evans Rd., Cary, NC 27513, USA.
Keywords: City:Davis, State:California, Country:United States, Region:North and Central America, Antiinfectives, Pharmaceuticals, Drugs, Immunology, Blood Proteins, Azole Antifungals
This article was prepared by Biotech Week editors from staff and other reports. Copyright 2011, Biotech Week via NewsRx.com.
