Characterization of Mesoamerican Nephropathy in a Kidney Failure Hotspot in Nicaragua.

BACKGROUND: Mesoamerican nephropathy (MeN) is a kidney disease of unknown cause that mainly affects working-age men in Central America. Despite being a major cause of morbidity and mortality in this region, its clinical characteristics have not been well defined. STUDY DESIGN: Cross-sectional family-based study. SETTING & PARTICIPANTS: 266 members of 24 families with high chronic kidney disease (CKD) burdens in a MeN hotspot in Northwestern Nicaragua. We compared clinical and biochemical characteristics of affected individuals first with their unaffected relatives and then with NHANES (National Health and Nutrition Examination Survey) participants with CKD in order to reveal identifying features of MeN. PREDICTOR: CKD defined as serum creatinine level ≥ 1.5mg/dL in men and ≥1.4mg/dL in women. OUTCOMES: Clinical and biochemical parameters, including serum sodium, potassium, bicarbonate, calcium, magnesium, phosphorus, and uric acid. RESULTS: Hyperuricemia, in many cases severe, was common among patients with MeN. Uric acid levels in patients with MeN were higher than those in NHANES participants (mean, 9.6 vs 7.4mg/dL for men in each group) despite more frequent use of uric acid-lowering medications in Nicaraguan individuals (71.7% vs 11.2%). In multivariable linear mixed-effects regression analysis, uric acid levels were 2.0mg/dL (95% CI, 1.0-3.0; P<0.001) higher in patients with MeN compared with their NHANES counterparts after adjusting for age, estimated glomerular filtration rate, and uric acid-lowering therapies. In contrast to prior reports, hyponatremia and hypokalemia were not common. LIMITATIONS: CKD defined by single serum creatinine measurement; population likely not representative of full MeN phenotype spectrum across Central America; major differences between MeN and NHANES groups in important characteristics such as age, ancestry, and recruitment method. CONCLUSIONS: Hyperuricemia out of proportion to the degree of decreased kidney function was common among Nicaraguan patients with MeN. Our results suggest that rather than being solely a consequence of CKD, hyperuricemia may play a role in MeN pathogenesis, a hypothesis that deserves further study.

Peripheral blood monocyte count is a dynamic prognostic biomarker in multiple myeloma.

With the growing knowledge of multiple myeloma (MM) pathobiology and the introduction of novel therapies, risk stratification continues to evolve. Myeloid-derived suppressor cells and tumor-associated macrophages, derived from peripheral blood monocytes, support malignant plasma cell proliferation in the bone marrow. Because peripheral blood absolute monocyte count (AMC) is thought to reflect the bone marrow microenvironment, we sought to evaluate the prognostic significance of AMC in MM. We retrospectively analyzed 10 822 patients newly diagnosed with MM between 2000 and 2019 at Veteran's Administration hospitals. We obtained AMC closest to diagnosis and every 3 months thereafter up to 2.5 years. Patients were stratified into 4 groups: low, normal, elevated, and severely elevated AMC (<0.2, 0.2-<0.8, 0.8-<1.25, and ≥1.25 × 103/mm3, respectively). Abnormal AMC at diagnosis was observed in 25.3% of the patients and was associated with an inferior overall survival (OS). In patients with low, severely elevated, elevated, and normal AMC, respectively, median OS at diagnosis was 2.3, 2.7, 3.1, and 3.6 years (P < .001) and at 2.5 years was 2.0, 2.6, 3.4, and 3.9 years (P < .001). Patients with normal AMC at diagnosis who developed an abnormal AMC >1 year after diagnosis also had an inferior OS relative to patients who maintained a normal AMC. Abnormal AMC was also associated with inferior OS independent of validated prognostic markers, including the international staging system and lactate dehydrogenase. Our findings provide novel clues for future prospective studies on the functional role of monocytes in MM, which could be a readily available metric for risk stratification.