Comparison of Monoclonal Gammopathies Linked to Poliovirus or Coxsackievirus vs. Other Infectious Pathogens

Abstract

Chronic stimulation by infectious pathogens or self-antigen glucosylsphingosine (GlcSph) can lead to monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM). Novel assays such as the multiplex infectious antigen microarray (MIAA) and GlcSph assays, permit identification of targets for >60% purified monoclonal immunoglobulins (Igs). Searching for additional targets, we selected 28 purified monoclonal Igs whose antigen was not represented on the MIAA and GlcSph assays; their specificity of recognition was then analyzed using microarrays consisting of 3760 B-cell epitopes from 196 pathogens. The peptide sequences PALTAVETG and PALTAAETG of the VP1 coat proteins of human poliovirus 1/3 and coxsackievirus B1/B3, respectively, were specifically recognized by 6/28 monoclonal Igs. Re-analysis of patient cohorts showed that purified monoclonal Igs from 10/155 MGUS/SM (6.5%) and 3/147 MM (2.0%) bound to the PALTAVETG or PALTAAETG epitopes. Altogether, PALTAV/AETG-initiated MGUS are not rare and few seem to evolve toward myeloma.

Keywords: MGUS; antigen specificity; coxsackievirus; infection; monoclonal gammopathy; monoclonal immunoglobulin; multiple myeloma; pathogen; poliovirus.

Figure 1

Results of PEPperCHIP^® Infectious Epitope MicroArrays obtained for Monoclonal IgGs Specific for VP1 Coat Protein of Human Polioviruses.Microarrays were incubated with the patient monoclonal IgG (50 or 100 µg/mL), stained with secondary and control antibodies, then read out at scanning intensities of 7/7 (red/ green) (see Materials and Methods). Antibody response against peptides is annotated next to corresponding signals in the intensity plot (left panel). Well-defined staining of HA control peptides appear in green; PV control peptides appear in red.

Figure 2

Results of PEPperCHIP^® Infectious Epitope MicroArrays obtained for Monoclonal IgGs Specific for VP1 Coat Protein of Human Coxsackieviruses. Microarrays were incubated with the patient monoclonal IgG (50 or 100 µg/mL), stained with secondary and control antibodies, then read out at scanning intensities of 7/7 (red/green) (see Materials and Methods). Antibody response against peptides is annotated next to corresponding signals in intensity plots (left panels). Well-defined staining of HA control peptides appear in green, PV control peptides appear in red.

Figure 3

Results of the “PV/CVB” Dot Blotting Assays obtained for the 6 Monoclonal Igs found to be Specific for the PALTAV/AETG Epitopes with the PEPperCHIP^® Infectious Epitope Arrays. Membranes were spotted with the following peptides: (a) HP-1a, HP-3a and HC-a, respectively relevant to PV1, PV3 and CVB1/B3; (b) irrelevant HP-1b, HP-3b and HC-b peptides; (c) irrelevant HP-1c, HP-3c and HC-c peptides (see Supplementary Table S2), then incubated with positive or negative controls or samples of serum from patients. After validation that no signal was obtained with irrelevant peptides for serum samples, purified monoclonal Igs were incubated with relevant peptides only. Immunoblot revelation with secondary antibodies (Materials & Methods). The assay confirmed that the purified monoclonal IgG of MGUS patients 4_38, 4_51 and 4_52 (in bold, left panel) bound specifically to PALTAVETG or PALTAAETG epitopes.

Figure 4

Results of the “PV/CVB” Dot Blotting Assays obtained for the 10 Additional Patients Who Presented a Monoclonal Ig Specific for PV1, PV3 or CVB1/3 Peptides. Membranes were spotted with nine peptides: (a) HP-1a, HP-3a and HC-a, respectively relevant to PV1, PV3 and CVB1/B3; (b) irrelevant HP-1b, HP-3b and HC-b peptides; (c) irrelevant HP-1c, HP-3c and HC-c peptides (see Supplementary Table S2), then incubated with serum (left) or purified monoclonal Ig (right), followed by revelation (see Materials and Methods). After validation that no signal was obtained with irrelevant peptides for serum samples, purified monoclonal Igs were incubated with relevant peptides only. Patients 2_49, 2_79, 5_15 are NDMM; all others are MGUS.

Figure 5

Percentages of Patients with a Monoclonal Ig Specific for GlcSph or an Infectious Pathogen in Cohorts of MGUS/SM, newly diagnosed MM (NDMM) or refractory MM (RRMM). Targets of Monoclonal Igs: GlcSph, glucosylsphingosine; EBNA-1, EBV Nuclear Antigen 1; PV/CVB: PALTAVETG or PALTAAETG sequences of human PV1/3 and CVB1/B3; Other pathogen: HSV-1, CMV or H. pylori. The Chi-2 test was used to compare the percentages of patients in the MGUS/SM group and in NDMM and RRMM groups; p < 0.05 was considered significant. NS: Not significant.