PCR of immunoglobulin heavy-chain (IgH) complementary determining region III (CDRIII) for diagnosis of meningeal dissemination (MD) in primary CNS lymphoma (PCNSL): A prospective evaluation

Abstract

2082 Background: The prognostic impact of MD in PCNSL is unclear. Cytomorphological examination of cerebrospinal fluid (CSF) cells is the gold standard for detection of MD. PCR for detection of a clonal B-cell population may represent a more sensitive and specific method for MD detection. Methods: CSF was collected by lumbar puncture before treatment in patients with newly diagnosed PCNSL of B cell type, histologically proven. CSF cytomorphological examination was performed by an experienced hematopathologist or neurologist immediately after sampling at the treating institution. A sample of native CSF was sent for PCR examination to our central moleculargenetic laboratory. Here, DNA from CSF cell pellets was extracted using commercially available kits. A seminested PCR of the IgH chain CDR III region was performed using the primers LJH in the first, VLJH in the second and FR3A in both PCR reactions. PCR products were subjected to an automated fluorescent fragment analysis (ALF) to detect a monoclonal vs. polyclonal pattern, and results were compared to conventional cytology. Results: From January 2001 to August 2006 CSF from 215 patients was collected. Here, data from the first 146 patients examined is presented ( Table ). MD was detected in 15 of 106 examined patients (14%) by cytomorphological evaluation and in 17 of 146 patients (11.6%) using PCR. In 8 patients with negative cytology the PCR product was monoclonal, and in 7 patients with positive cytology a polyclonal PCR product was found. Conclusion: The frequency of MD in PCNSL detected by PCR of the IgH CDR III region is low and comparable to that detected by cytomorphological evaluation. However, discordant PCR and cytology results are frequent. Thus, PCR analysis appears to be an important adjunct for MD diagnosis. [Table: see text] No significant financial relationships to disclose.