Microfluidic chip technology applied to fine-needle aspiration cytology samples for IGH clonality assessment

Background: Most cases of non-Hodgkin lymphoma (NHL) can be diagnosed using a combination of fine-needle cytology (FNC) and flow cytometry together with immunoglobulin light chain restriction and/or specific phenotypic profiles. However, 5%-15% of B-cell NHLs lack these specific diagnostic features. In such cases, the diagnosis of NHL may be supported by molecular clonality testing based on the immunoglobulin heavy chain (IGH) assay of clonality by polyacrylamide heteroduplex analysis or by automated capillary electrophoresis via GeneScan analysis. Chip-based microfluidic technology (MT), based on miniaturized parallel capillary electrophoresis structures, is a viable alternative to capillary electrophoresis analysis, being less costly and cumbersome. In this study, we evaluated the performance of MT platform in IGH clonality assessment in a series of lymph node FNC samples.

Methods: Thirty-five consecutive lymph node FNCs were evaluated. In all cases, the first and the second passes were used to prepare a conventional smear and to collect material for flow cytometry analysis; residual material was collected for molecular clonality assessment, and PCR products were analyzed both by MT and GeneScan platforms.

Results: Molecular clonality assessment by MT had a sensitivity of 84.2% and a specificity of 76.9%; GeneScan analysis had a sensitivity of 88.8% and a specificity of 92.8%. The overall agreement between the two platforms was 85.7% (30/35).

Conclusions: MT analysis proved to be a viable technique for IGH clonality assessment on FNC samples. Should our data be confirmed in larger studies, the MT procedure may be suitable for routine diagnostic practice, even on cytological samples.