[Validity of intrathecal secretion formulas of IgG in the follow-up of the response to neurosyphilis treatment].

The different formulas on intrathecal secretion of IgG were evaluated in patients with active neurosyphillis (NS) who did not have HIV infection with the aim of knowing their usefulness and sensitivity in the follow up of response to treatment. Five HIV negative patients with defined criteria of active NS were analyzed. The QAib ratio (albumin LCR/serum x 1,000) and Tourtellotte, Schuller and Reiber formulas of intrathecal secretion and the Link's index were studied prior to and at 15 days and three months following treatment with high intravenous doses of penicillin G over 12 days. A decrease in the QAlb ratio and all the formulas of intrathecal secretion of IgG was observed after treatment. The mean decrease was statistically significant on the third month after treatment for the Tourtellotte formula (116.6 +/- 44 mg/dl in basal control, 60.7 +/- 38 mg/dl at 15 days and 46.5 +/- 59 mg/dl at three months) (p < 0.05). The same evolutive pattern was not observed with the Link's index 1.75 +/- 9 mg/dl in basal control, 1.16 +/- 5 mg/dl at 15 days and 1.79 +/- 1 mg/dl at 3 months) in this series. The formulas of intrathecal secretion of IgG are useful to evaluate the response to treatment of patients with active neurosyphilis. The Tourtellotte formula was shown to be better than the Link index in this evaluation.