Efficacy of Antiviral Treatment in Hepatitis C Virus (HCV)-Driven Monoclonal Gammopathies Including Myeloma

Short-Chain Fatty Acid Production by Gut Microbiota Predicts Treatment Response in Multiple Myeloma

PURPOSE

The gut microbiota plays important roles in health and disease. We questioned whether the gut microbiota and related metabolites are altered in monoclonal gammopathies and evaluated their potential role in multiple myeloma and its response to treatment.

EXPERIMENTAL DESIGN

We used 16S rRNA sequencing to characterize and compare the gut microbiota of patients with monoclonal gammopathy of undetermined significance (n = 11), smoldering multiple myeloma (n = 9), newly diagnosed multiple myeloma (n = 11), relapsed/refractory multiple myeloma (n = 6), or with complete remission (n = 9). Short-chain fatty acids (SCFA) were quantified in serum and tested in cell lines. Relevant metabolites were validated in a second cohort of 62 patients.

RESULTS

Significant differences in alpha- and beta diversity were present across the groups and both were lower in patients with relapse/refractory disease and higher in patients with complete remission after treatment. Differences were found in the abundance of several microbiota taxa across disease progression and in response to treatment. Bacteria involved in SCFA production, including Prevotella, Blautia, Weissella, and Agathobacter, were more represented in the premalignant or complete remission samples, and patients with higher levels of Agathobacter showed better overall survival. Serum levels of butyrate and propionate decreased across disease progression and butyrate was positively associated with a better response. Both metabolites had antiproliferative effects in multiple myeloma cell lines.

CONCLUSIONS

We demonstrate that SCFAs metabolites and the gut microbiota associated with their production might have beneficial effects in disease evolution and response to treatment, underscoring its therapeutic potential and value as a predictor.

Exploring the role of viral hepatitis in plasma cell disorders

Not available.

Impact of viral hepatitis therapy in multiple myeloma and other monoclonal gammopathies linked to hepatitis B or C viruses

Subsets of multiple myeloma (MM) and monoclonal gammopathies of undetermined significance (MGUS) present with a monoclonal immunoglobulin specific for hepatitis C virus (HCV), thus are presumably HCV-driven, and antiviral treatment can lead to the disappearance of antigen stimulation and improved control of clonal plasma cells. Here we studied the role of hepatitis B virus (HBV) in the pathogenesis of MGUS and MM in 45 HBV-infected patients with monoclonal gammopathy. We analyzed the specificity of recognition of the monoclonal immunoglobulin of these patients and validated the efficacy of antiviral treatment (AVT). For 18 of 45 (40%) HBV-infected patients, the target of the monoclonal immunoglobulin was identified: the most frequent target was HBV (n=11), followed by other infectious pathogens (n=6) and glucosylsphingosine (n=1). Two patients whose monoclonal immunoglobulin targeted HBV (HBx and HBcAg), implying that their gammopathy was HBV-driven, received AVT and the gammopathy did not progress. AVT efficacy was then investigated in a large cohort of HBV-infected MM patients (n=1367) who received or did not receive anti-HBV treatments and compared to a cohort of HCV-infected MM patients (n=1220). AVT significantly improved patient probability of overall survival (P=0.016 for the HBV-positive cohort, P=0.005 for the HCV-positive cohort). Altogether, MGUS and MM disease can be HBV- or HCV-driven in infected patients, and the study demonstrates the importance of AVT in such patients.

Determination of the target of monoclonal immunoglobulins: a novel diagnostic tool for individualized MGUS therapy, and prevention and therapy of smoldering and multiple myeloma

Subsets of patients diagnosed with a monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM) or multiple myeloma (MM), present with a monoclonal immunoglobulin (Ig) specific for an infectious pathogen, including hepatitis C and B viruses (HCV, HBV), Helicobacter pylori and several Herpesviruses. Such cases are likely initiated by infection, since in the context of HCV- or HBV-infected patients, antiviral therapy can lead to the disappearance of antigenic stimulation, control of clonal plasma cells, and reduced or suppressed monoclonal Ig production. Complete remission has been obtained with anti-HCV therapy in refractory MM with a HCV-specific monoclonal Ig, and antiviral treatments significantly improved the probability of survival of MM patients infected with HCV or HBV prior to the diagnosis of MM. Monoclonal Igs may also target glucolipids, particularly glucosylsphingosine (GlcSph), and GlcSph-reducing therapy can lead to complete remission in SMM and MM patients presenting with a GlcSph-specific monoclonal Ig. The present review describes the importance of determining the target of the monoclonal Ig of MGUS, SMM and MM patients, and discusses the efficacy of target-reducing treatments in the management of MGUS, SMM and MM cases who present with a monoclonal Ig reactive against a treatable infectious pathogen or GlcSph.

The Role of the Crosstalk Between Gut Microbiota and Immune Cells in the Pathogenesis and Treatment of Multiple Myeloma

Around 10% of all hematologic malignancies are classified as multiple myeloma (MM), the second most common malignancy within that group. Although massive progress in developing of new drugs against MM has been made in recent years, MM is still an incurable disease, and every patient eventually has relapse refractory to any known treatment. That is why further and non-conventional research elucidating the role of new factors in MM pathogenesis is needed, facilitating discoveries of the new drugs. One of these factors is the gut microbiota, whose role in health and disease is still being explored. This review presents the continuous changes in the gut microbiota composition during our whole life with a particular focus on its impact on our immune system. Additionally, it mainly focuses on the chronic antigenic stimulation of B-cells as the leading mechanism responsible for MM promotion. The sophisticated interactions between microorganisms colonizing our gut, immune cells (dendritic cells, macrophages, neutrophils, T/B cells, plasma cells), and intestinal epithelial cells will be shown. That article summarizes the current knowledge about the initiation of MM cells, emphasizing the role of microorganisms in that process.