Contributions
Abstract: PB2139
Type: Publication Only
Background
The thermodynamic stability of biofluids is currently extensively studied by means of differential scanning calorimetry (DSC), a biophysical technique that measures thermally induced conformational transitions of biomolecules in solution.
Aims
With the aim to develop a novel strategy for monitoring of patients with multiple myeloma (MM) that underwent autologous stem cells transplantation (ASCT) we have explored the potential of differential scanning calorimetry (DSC).
Methods
Blood sera were derived from 11 patients, defined as eligible for ASCT – 8 secretory, 2 non secretory(NS) and 1 with Free Light Chain (FLC) MM before and at 1; 2; 3; 6; 9; 12;16 months after the ASCT. In addition, 21 age matched control samples were studied. The quantification of immunoglobulin heavy/light chains (HLC) and the ratio FLC (rFLC) was performed by “Hevylite immunoassay” and “Freelite” R test, with SPAPLUS (Binding Site, UK) analyzer. Blood sera were heated with constant scanning rate (1 °C/min) in the range 20–95 °C by means of highly sensitive DASM 4 (Privalov, BioPribor)-built-in calorimeter. Origin software package was used to evaluate the calorimetric parameters: transition temperature (Tm) and excess heat capacity (CPex) of the successive thermal transitions; temperature of the major peak (Tmmp) and weighted average center of the thermogram, TFM (TFM = T1∫T2 T CPex (T) dT/ CPex (T) dT), where T1 and T2 are the initial and final temperatures of the thermogram. We applied linear correlation in the thermogram’s shape (Pearson's correlation coefficient) and non-parametric statistical test.
Results
Before and after ASCT however the M protein concentration, rFLC and HLC varied in very large intervals. The calorimetric profiles and the thermodynamic parameters before the ASCT derived from the thermograms deviated strongly from the control thermogram. The excess heat capacity at and above 70 °C was clearly larger in the MM cases than in the control samples. The Tmmp shifts from 61.9 °C in the control samples to 72.6–76. 3 °C and the TFM, shifts from 64 to 68.0–74.5 °C, for all MM samples before ASCT. These changes in the CPex and the denaturation temperatures of the individual transitions resulted in greatly reduced values of the shape similarity parameter, r, (0.09–0.9) as compared to those typical for healthy thermograms (0.97). Before the ASCT the CpHSA value is ca. 1.5–2.0 times, lower than that of the control. For NS MM and FLC MM cases before ASCT, CpHSA is lower by 1.5–2.3 times than the control, r was 0.74–0.90 and Tmmp was 62–64 °C. After ASCT there was a trend for strong reduction in the M protein content and the HLC for all secretory cases. There was also an inverse correlation between the changes in the M protein level and in the thermogram’s shape similarity parameter, r. The decrease in M protein concentration was also related to strong reduction in Tmmp from 78 °C to 62 °C as well as in TFM, but less pronounced – from 76 °C to 68 °C; those correlations are less strong than that between the M protein level and r. The calorimetric scans recorded for the two NS MM cases both before and after ASCT deviated strongly from those of healthy controls.
Conclusion
We established that the change in the paraprotein level and thus the patient’s clinical status is clearly reflected in the serum thermogram. Hence, DSC can be used as complementary bioanalytical tool for the monitoring of MM remission/progression in a fast and cheap way.
Session topic: 13. Myeloma and other monoclonal gammopathies – Biology & Translational Research
Keyword(s): Autologous hematopoietic stem cell transplantation, Multiple Myeloma
Abstract: PB2139
Type: Publication Only
Background
The thermodynamic stability of biofluids is currently extensively studied by means of differential scanning calorimetry (DSC), a biophysical technique that measures thermally induced conformational transitions of biomolecules in solution.
Aims
With the aim to develop a novel strategy for monitoring of patients with multiple myeloma (MM) that underwent autologous stem cells transplantation (ASCT) we have explored the potential of differential scanning calorimetry (DSC).
Methods
Blood sera were derived from 11 patients, defined as eligible for ASCT – 8 secretory, 2 non secretory(NS) and 1 with Free Light Chain (FLC) MM before and at 1; 2; 3; 6; 9; 12;16 months after the ASCT. In addition, 21 age matched control samples were studied. The quantification of immunoglobulin heavy/light chains (HLC) and the ratio FLC (rFLC) was performed by “Hevylite immunoassay” and “Freelite” R test, with SPAPLUS (Binding Site, UK) analyzer. Blood sera were heated with constant scanning rate (1 °C/min) in the range 20–95 °C by means of highly sensitive DASM 4 (Privalov, BioPribor)-built-in calorimeter. Origin software package was used to evaluate the calorimetric parameters: transition temperature (Tm) and excess heat capacity (CPex) of the successive thermal transitions; temperature of the major peak (Tmmp) and weighted average center of the thermogram, TFM (TFM = T1∫T2 T CPex (T) dT/ CPex (T) dT), where T1 and T2 are the initial and final temperatures of the thermogram. We applied linear correlation in the thermogram’s shape (Pearson's correlation coefficient) and non-parametric statistical test.
Results
Before and after ASCT however the M protein concentration, rFLC and HLC varied in very large intervals. The calorimetric profiles and the thermodynamic parameters before the ASCT derived from the thermograms deviated strongly from the control thermogram. The excess heat capacity at and above 70 °C was clearly larger in the MM cases than in the control samples. The Tmmp shifts from 61.9 °C in the control samples to 72.6–76. 3 °C and the TFM, shifts from 64 to 68.0–74.5 °C, for all MM samples before ASCT. These changes in the CPex and the denaturation temperatures of the individual transitions resulted in greatly reduced values of the shape similarity parameter, r, (0.09–0.9) as compared to those typical for healthy thermograms (0.97). Before the ASCT the CpHSA value is ca. 1.5–2.0 times, lower than that of the control. For NS MM and FLC MM cases before ASCT, CpHSA is lower by 1.5–2.3 times than the control, r was 0.74–0.90 and Tmmp was 62–64 °C. After ASCT there was a trend for strong reduction in the M protein content and the HLC for all secretory cases. There was also an inverse correlation between the changes in the M protein level and in the thermogram’s shape similarity parameter, r. The decrease in M protein concentration was also related to strong reduction in Tmmp from 78 °C to 62 °C as well as in TFM, but less pronounced – from 76 °C to 68 °C; those correlations are less strong than that between the M protein level and r. The calorimetric scans recorded for the two NS MM cases both before and after ASCT deviated strongly from those of healthy controls.
Conclusion
We established that the change in the paraprotein level and thus the patient’s clinical status is clearly reflected in the serum thermogram. Hence, DSC can be used as complementary bioanalytical tool for the monitoring of MM remission/progression in a fast and cheap way.
Session topic: 13. Myeloma and other monoclonal gammopathies – Biology & Translational Research
Keyword(s): Autologous hematopoietic stem cell transplantation, Multiple Myeloma