Differential humoral responses against heat-shock proteins after autologous stem cell transplantation in multiple myeloma

Prospective Identification of Oligoclonal/Abnormal Band of the Same Immunoglobulin Type as the Malignant Clone by Differential Location of M-Spike and Oligoclonal Band

Background

Serum and urine protein electrophoreses and immunofixation electrophoreses are the gold standards in diagnosing monoclonal gammopathy. Identification of oligoclonal bands in post-treatment patients has emerged as an important issue and recording the location of the malignant monoclonal peak may facilitate prospective identification of a new “monoclonal” spike as being distinct from the malignant peak.

Methods

We recorded the locations of monoclonal spikes in descriptive terms, such as being in the cathodal region, mid-gamma region, anodal region, and beta region. The location of monoclonal or restricted heterogeneity bands in subsequent protein electrophoreses was compared to the location of the original malignant spike.

Results

In a patient with plasma cell myeloma, the original monoclonal IgG kappa band was located at the anodal end of gamma region. Post-treatment, an IgG kappa band was noted in mid-gamma region and the primary malignant clone was not detectable by serum protein immunofixation electrophoresis (SIFE) in post-treatment sample. Even though the κ/λ ratio remained abnormal, we were able to recognize stringent complete response by noting the different location of the new IgG kappa band as a benign regenerative process.

Conclusions

Recording the location of the malignant monoclonal spike facilitates the identification of post-treatment oligoclonal bands, prospectively. Recognizing the regenerative, benign, bands in post-transplant patients facilitates the determination of stringent complete response despite an abnormal κ/λ ratio.

Oligoclonal Pattern/Abnormal Protein Bands in Post-Treatment Plasma Cell Myeloma Patients: Implications for Protein Electrophoresis and Serum Free Light Chain Assay Results

BACKGROUND

The impact of autologous stem cell transplantation (ASCT) in plasma cell myeloma patients on the frequency, quality, and timing of oligoclonal pattern in serum protein electrophoresis/immunofixation electrophoresis (SPEP/SIFE) and serum free light chain assay (SFLCA) was evaluated.

METHODS

Laboratory results and clinical data for 251 patients with plasma cell myeloma, who had SPEP/SIFE and/or SFLCA performed between January 2010 and December 2016 were reviewed. The results for SPEP/SIFE and SFLCA were compared in patients with ASCT to those without ASCT. The implications of oligoclonal pattern in interpretation of SPEP/SIFE and SFLCA - κ/λ ratio were addressed.

RESULTS

In 251 patients, a total of 3,134 observations, of either SPEP/SIFE and/or SFLCA, were reviewed. One hundred fifty-nine patients received ASCT. The incidence of oligoclonal patterns was significantly higher after ASCT. More than half of the oligoclonal patterns developed in the first year after transplantation. In 13 of the 84 patients with lambda chain restricted plasma cell myeloma, the κ/λ ratio was kappa dominant in the presence of oligoclonal pattern. There was no reversal of κ/λ ratio in patients with kappa chain restricted plasma cell myelomas.

CONCLUSIONS

ASCT is associated with significantly higher incidence of oligoclonal patterns than with chemotherapy alone. The presence of oligoclonal patterns has the potential to interfere with the interpretation of SPEP/SIFE and ascertainment of complete remission. At a minimum, the oligoclonal pattern caused an incorrect kappa dominant κ/λ ratio in 15.5% of patients with lambda chain restricted plasma cell myeloma. If a similar rate were to be applied to the 167 kappa chain myeloma patients, about 26 of these would have displayed an erroneous kappa chain dominant κ/λ ratio. The presence of oligoclonal pattern further degrades the performance of already dubious SFLCA. The need for recording the location of monoclonal spike in SPEP/SIFE and higher resolution protein electrophoresis methods are highlighted.

A transplant “immunome” screening platform defines a targetable epitope fingerprint of multiple myeloma

The myeloma transplant B-cell immunome is predictive for response to treatment. It may be exploited by immunosequencing and library technology as a source for unique target structures and antibodies for immunotherapy.