Incidence and Type of Monoclonal or Biclonal Gammopathies in Scrub Typhus / 대한진단검사의학회지

BACKGROUND: Korea is an endemic area of scrub typhus and it is a common seasonal febrile illness. Although, various humoral immune responses to scrub typhus have been documented, no association between gammopathy and scrub typhus has ever been reported. We analyzed the incidences and types of monoclonal and biclonal gammopathies in scrub typhus for better coping with those gammopathies in scrub typhus. METHODS: Anti-Orientia tsutsugamushi antibody-positive sera identified by indirect immunofluorescence assay were acquired from 40 patients with confirmed scrub typhus. Monoclonal and biclonal gammopathies were screened by protein electrophoresis and were confirmed using immunofixation electrophoresis (IFE). Laboratory findings on admission of the patients with monoclonal or biclonal gammopathy were investigated retrospectively to characterize the gammopathies. RESULTS: Monoclonal or biclonal gammopathies were detected in 30% (12/40) of patients with scrub typhus (IgG-lambda, 40%; IgG-kappa, 30%; IgM-kappa, 10%; IgM-lambda, 10%; IgA-kappa, 5%; IgA-lambda, 5%). Concentrations of clonal immunoglobulin were less than 3 g/dL in all gammopathies, and hypercalcemia was not detected in any of the patients. CONCLUSIONS: Our results suggest possible association between gammopathies and scrub typhus. Further studies in larger series will be needed for exact incidence and clinical course of gammopathies in scrub typhus.

Serum Free Light Chains for Diagnosis and Follow-up of Multiple Myeloma / 대한진단검사의학회지

BACKGROUND: Free light chain (FLC) is widely used to evaluate B-cell proliferative diseases. Herein, we estimated the clinical usefulness of serum FLC in multiple myeloma (MM). METHODS: Fifty-one patients were enrolled. We performed FLC analysis, protein electrophoresis (PEP), and immunofixation electrophoresis (IFE). FLC was measured using Toshiba 200 FR Neo with FREELITE(TM), and kappa/lambda (kappa/lambda) ratio was calculated. We compared these parameters in 41 patients with increased FLC before and after bortezomib treatment. Complete response (CR) was defined as the disappearance of monoclonal (M) protein in serum and/or urine as measured by IFE. Partial response (PR) was defined as > or =50% reduction of serum M protein. Early objective response (EOR) included both CR and PR. Minimal response (MR) was defined as 25-49% reduction of M protein and stable disease (SD) as <25% reduction. RESULTS: Forty-one (80.4%) of the 51 patients studied revealed increment of FLC and the five patients with no increment revealed an abnormal kappa/lambda ratio. Especially, all of the light chain myeloma and non-secretory myeloma showed increased FLC concentrations. Among the patients with EOR, 72.4% (21/29) showed a normal or subnormal FLC concentration after the first cycle of treatment. Otherwise, PEP and IFE normalized in 24.1% (7/29) and 24.1% (7/29), respectively. The ratio of decreased FLC after the first cycle of treatment was significantly different between EOR and other response groups (MR, SD) (90.6% vs 51.8%, P=0.011). CONCLUSIONS: FLC was considered as a good diagnostic method in complement with PEP and IFE in MM, especially in light chain myeloma or non-secretory myeloma. Moreover, FLC is a useful monitoring tool because it reflects therapy results more rapidly owing to a short serum half-life.

Immunoglobulin heavy and light chain isotypes in multiple myeloma patients.

The frequency of expression of immunoglobulin (Ig) light and heavy chain isotypes was analyzed in myeloma proteins (M-proteins) from sera of 40 Indian patients with clinically established multiple myeloma. Patients samples were screened by a combination of electrophoresis, immunoelectrophoresis (IEP) and ELISA techniques in this study. We found that majority of the myeloma proteins (58%) were of the IgG isotype followed by IgA (24%) and biclonal gammopathy associated with IgG and IgA (5%). Both kappa and lambda light chains were associated with the heavy chain isotypes. We recommend the triangular combination for detection of M-proteins and biclonal gammopathy of cancerous plasma cells as biomarkers for diagnosis of myeloma.