Transient Monoclonal Gammopathy Induced by Disseminated Staphylococcus aureus Infection

Diabetic Patient with CA-MRSA Pneumonia and Plasma Cell Neoplasm: A Case Report of Severe Complications and Prognosis

BACKGROUND The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has been increasing in recent years, becoming a cause of community-acquired infection. Interestingly, its role in malignancy recently started to be considered after a noticed increase in reported cases and studies discussing the potential association. CASE REPORT In the present case, the patient had known and uncontrolled diabetes mellitus and a history of multiple abscesses that were previously treated by incision and drainage. The patient received a diagnosis of severe pneumonia, and MRSA was found in blood cultures. Further tests for HIV, hemagglutinin type 1, and neuraminidase type 1 (H1N1) were negative. The D test was also performed for macrolide-inducible resistance and was negative, indicating the need for intravenous administration of clindamycin. An echocardiogram ruled out endocarditis. Subsequently, the patient experienced progressive back pain and weakness involving the lower limbs. A pathological fracture was discovered, along with nerve root compression. An urgent posterior spine fixation was then performed by a neurosurgeon. A biopsy was collected at the site of the pathological fracture, and histopathological tests indicated a plasma cell neoplasm. CONCLUSIONS MRSA is known to cause serious and dangerous infections, including necrotizing pneumonia. Furthermore, a link between MRSA and plasma cell dyscrasia has been considered in several reports. This necessitates the need for further studies to clarify this hidden association, which may help in the course and prognosis of these patients.

Monoclonal gammopathy of unknown significance in kidney transplanted patients: novel insights into long-term outcomes

BACKGROUND

Because of increased access to kidney transplantation in elderly subjects, the prevalence of monoclonal gammopathies of unknown significance (MGUS) in kidney transplantation (KT) is growing. However, little is known about the consequences of MGUS on long-term outcomes.

METHODS

We identified 70 recipients with MGUS present at transplantation (KTMG) and 114 patients with MGUS occurring after KT (DNMG), among 3059 patients who underwent a KT in two French kidney transplantation centers. We compared outcomes of KTMG with those of matched controls.

RESULTS

Baseline characteristics were similar except for an older age in KTMG compared with the DNMG group (62 vs 57 years, P = .03). Transient MGUS occurred more frequently in DNMG patients (45% vs 24%, P = .007). When compared with matched controls without MGUS, KTMG patients showed higher frequency and earlier post-transplant solid cancers (15% vs 5%, P = .04) and a trend for more bacterial infections (63% vs 48%, P = .08), without difference regarding patient and graft survival, rejection episodes or hematological complications. KTMG patients with an abnormal kappa/lambda ratio and/or severe hypogammaglobulinemia at the time of KT experienced shorter overall survival.

CONCLUSIONS

MGUS detection at the time of KT is neither associated with a higher occurrence of graft rejection, nor adversely affects graft or overall survival. MGUS should not contraindicate KT. However, MGUS at the time of KT may be associated with higher risk of early neoplastic and infectious complications and warrants prolonged surveillance. Measurement of serum free light chain should be performed before transplant to refine the risk evaluation of KTMG patients and propose personalized follow-up and immunosuppression.

Prevalence of monoclonal gammopathies and clinical outcomes in a high-risk US population screened by mass spectrometry: a multicentre cohort study

BACKGROUND

Prevalence estimates for monoclonal gammopathy of undetermined significance (MGUS) are based on predominantly White study populations screened by serum protein electrophoresis supplemented with immunofixation electrophoresis. A prevalence of 3% is reported for MGUS in the general population of European ancestry aged 50 years or older. MGUS prevalence is two times higher in individuals of African descent or with a family history of conditions related to multiple myeloma. We aimed to evaluate the prevalence and clinical implications of monoclonal gammopathies in a high-risk US population screened by quantitative mass spectrometry.

METHODS

We used quantitative matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF) mass spectrometry and EXENT-iQ software to screen for and quantify monoclonal gammopathies in serum from 7622 individuals who consented to the PROMISE screening study between Feb 26, 2019, and Nov 4, 2021, and the Mass General Brigham Biobank (MGBB) between July 28, 2010, and July 1, 2021. M-protein concentrations at the monoclonal gammopathy of indeterminate potential (MGIP) level were confirmed by liquid chromatography mass spectrometry testing. 6305 (83%; 2211 from PROMISE, 4094 from MGBB) of 7622 participants in the cohorts were at high risk for developing a monoclonal gammopathy on the basis of Black race or a family history of haematological malignancies and fell within the eligible high-risk age range (30 years or older for PROMISE cohort and 18 years or older for MGBB cohort); those over 18 years were also eligible if they had two or more family members with a blood cancer (PROMISE cohort). Participants with a plasma cell malignancy diagnosed before screening were excluded. Longitudinal clinical data were available for MGBB participants with a median follow-up time from serum sample screening of 4·5 years (IQR 2·4-6·7). The PROMISE study is registered with ClinicalTrials.gov, NCT03689595.

FINDINGS

The median age at time of screening was 56·0 years (IQR 46·8-64·1). 5013 (66%) of 7622 participants were female, 2570 (34%) male, and 39 (<1%) unknown. 2439 (32%) self-identified as Black, 4986 (65%) as White, 119 (2%) as other, and 78 (1%) unknown. Using serum protein electrophoresis with immunofixation electrophoresis, the MGUS prevalence was 6% (101 of 1714) in high-risk individuals aged 50 years or older. Using mass spectrometry, we observed a total prevalence of monoclonal gammopathies of 43% (1788 of 4207) in this group. We termed monoclonal gammopathies below the clinical immunofixation electrophoresis detection level (<0·2 g/L) MGIPs, to differentiate them from those with higher concentrations, termed mass-spectrometry MGUS, which had a 13% (592 of 4207) prevalence by mass spectrometry in high-risk individuals aged 50 years or older. MGIP was predominantly of immunoglobulin M isotype, and its prevalence increased with age (19% [488 of 2564] for individuals aged <50 years, 29% [1464 of 5058] for those aged ≥50 years, and 37% [347 of 946] for those aged ≥70 years). Mass-spectrometry MGUS prevalence increased with age (5% [127 of 2564] for individuals aged <50 years, 13% [678 of 5058] for those aged ≥50 years, and 18% [173 of 946] for those aged ≥70 years) and was higher in men (314 [12%] of 2570) compared with women (485 [10%] 5013; p=0·0002), whereas MGIP prevalence did not differ significantly by gender. In those aged 50 years or older, the prevalence of mass spectrometry was significantly higher in Black participants (224 [17%] of 1356) compared with the controls (p=0·0012) but not in those with family history (368 [13%] of 2851) compared with the controls (p=0·1008). Screen-detected monoclonal gammopathies correlated with increased all-cause mortality in MGBB participants (hazard ratio 1·55, 95% CI 1·16-2·08; p=0·0035). All monoclonal gammopathies were associated with an increased likelihood of comorbidities, including myocardial infarction (odds ratio 1·60, 95% CI 1·26-2·02; p=0·00016 for MGIP-high and 1·39, 1·07-1·80; p=0·015 for mass-spectrometry MGUS).

INTERPRETATION

We detected a high prevalence of monoclonal gammopathies, including age-associated MGIP, and made more precise estimates of mass-spectrometry MGUS compared with conventional gel-based methods. The use of mass spectrometry also highlighted the potential hidden clinical significance of MGIP. Our study suggests the association of monoclonal gammopathies with a variety of clinical phenotypes and decreased overall survival.

FUNDING

Stand Up To Cancer Dream Team, the Multiple Myeloma Research Foundation, and National Institutes of Health.

A multi-center retrospective cohort study defines the spectrum of kidney pathology in Coronavirus 2019 Disease (COVID-19)

Kidney failure is common in patients with Coronavirus Disease-19 (COVID-19) resulting in increased morbidity and mortality. In an international collaboration, 284 kidney biopsies were evaluated to improve understanding of kidney disease in COVID-19. Diagnoses were compared to five years of 63,575 native biopsies prior to the pandemic and 13,955 allograft biopsies to identify diseases increased in patients with COVID-19. Genotyping for APOL1 G1 and G2 alleles was performed in 107 African American and Hispanic patients. Immunohistochemistry for SARS-CoV-2 was utilized to assess direct viral infection in 273 cases along with clinical information at the time of biopsy. The leading indication for native biopsy was acute kidney injury (45.4%), followed by proteinuria with or without concurrent acute kidney injury (42.6%). There were more African American patients (44.6%) than patients of other ethnicities. The most common diagnosis in native biopsies was collapsing glomerulopathy (25.8%) which associated with high-risk APOL1 genotypes in 91.7% of cases. Compared to the five-year biopsy database, the frequency of myoglobin cast nephropathy and proliferative glomerulonephritis with monoclonal IgG deposits was also increased in patients with COVID-19 (3.3% and 1.7%, respectively), while there was a reduced frequency of chronic conditions (including diabetes mellitus, IgA nephropathy, and arterionephrosclerosis) as the primary diagnosis. In transplants, the leading indication was acute kidney injury (86.4%), for which rejection was the predominant diagnosis (61.4%). Direct SARS-CoV-2 viral infection was not identified. Thus, our multi-center large case series identified kidney diseases that disproportionately affect patients with COVID-19, demonstrated a high frequency of APOL1 high-risk genotypes within this group, with no evidence of direct viral infection within the kidney.

Case Report: Monoclonal Gammopathy of Undetermined Significance is Associated with Loa loa Infection

A 63-year-old woman who migrated from Nigeria to the United States was found to have an elevated total serum protein, anemia, and eosinophilia. Serum protein electrophoresis (SPEP) and serum protein immunofixation electrophoresis (SPIFE) demonstrated monoclonal immunoglobulin G (IgG) κ restricted bands (IgG 3,820 mg/dL; κ/λ ratio 4.47), indicative of monoclonal gammopathy of unknown significance (MGUS). A rapid diagnostic test (RDT) for malaria was positive for Plasmodium falciparum (BinaxNOW^®; Alere Scarborough Inc., Scarborough, ME). Giemsa-stained blood smears were negative for malarial parasites, however, Loa loa microfilariae were identified. Reverse transcription polymerase chain reaction for P. falciparum, Plasmodium ovale, Plasmodium malariae, and Plasmodium vivax yielded a negative result. She was treated for loiasis with diethylcarbamazine and received no malaria medication. Treatment resulted in a resolution of the microfilaremia and eosinophilia, a negative RDT for malaria, and marked reduction in the monoclonal gammopathy. This is the first reported human case of MGUS associated with loiasis and its resolution after antiparasitic treatment.

Transient monoclonal gammopathy induced by Candida fungemia

A 41-year-old woman was admitted for Candida fungemia. On hospital day 4, a routine complete blood count and peripheral smear showed circulating plasma cells. Initial workup showed an M-component on serum protein electrophoresis with 6% λ-predominate plasma cells by flow cytometry. The patient was treated with intravenous antifungal therapy. Her 6-month follow-up laboratory evaluation revealed resolution of the M-component and only rare polyclonal plasma cells in peripheral blood by flow cytometry. This case illustrates that transient monoclonal gammopathy can be induced by fungal infection. It is important to exclude a plasma cell neoplasm or a B-cell lymphoma and to follow the patient until resolution of abnormal findings.

Morphologic Confounders and CD19 Negativity in a Case of Hairy Cell Leukemia

OBJECTIVES

We report a case of hairy cell leukemia (HCL) initially misdiagnosed as plasma cell dyscrasia due to various clinical, morphological and immunophenotypic confounders.

METHODS AND RESULTS

In a patient diagnosed of marrow plasmacytosis and serum monoclonal protein elsewhere and referred to our hospital, morphological evaluation of bone marrow aspirate smears and trephine biopsy, immunophenotyping, and molecular testing (BRAFV600E mutation) were done. Clinically, the patient was asymptomatic; bone marrow revealed plasmacytosis, mastocytosis, and lymphocytosis with a few "hairy" cells. Immunophenotyping showed features of HCL with aberrant CD10 expression and a large subclone of CD19^neg cells. A diagnosis of HCL with reactive plasmacytosis and mast cell hyperplasia was made and confirmed by immunophenotyping and molecular studies.

CONCLUSION

Hematopathologists must be aware of various confounding factors and should judiciously use flow cytometric and molecular studies for attaining a proper diagnosis of HCL. We also report a very rare immunophenotypic aberrancy (CD 19 negativity) in HCL.