A novel approach for more precise quantification of M-protein using variables derived from immunosubtraction electropherogram and associated biochemistry analytes.

Introduction: Due to limitations in currently used methodologies, the widely acknowledged approach for quantifying M-protein (MP) is not available. If employed as a source of quantitative data, the immunosubtraction electropherogram (IS-EPG), a qualitative analysis of MP, has the potential to overcome known analytical issues. The aim of this study is to explore measured and derived variables obtained from immunosubtraction electropherogram as a tool for quantifying MP and to compare the derived results to currently available methods. Materials and methods: Measurands were amplitudes of MP and albumin fractions. Assessed derived variables included also immunoglobulin (Ig) G, IgA, IgM and total protein data. Capillary electrophoresis was used for determination of MP (in % of total protein concentration, or concentration of MP in g/L) by perpendicular drop and tangent skimming method. Results: Passing-Bablok analysis showed the most comparable results in D1Ig and D1nIg variables, and the largest discrepancies in AD1nIg and AD2nIg variables. The background presence had greater impact on D1nIg comparison results than did on D1Ig results. The contribution of albumin fraction data did not improve the comparability of the results. The coefficients of variation of derived variables were lower (maximum 3.1%) than those obtained by densitometric measurements, regardless of MP concentration, polyclonal background, or migration pattern (2.3-37.7%). Conclusion: The amplitude of MP spike in IS-EPG is an valuable measurand to compute derived variables for quantifying MP. The most comparable results were achieved with the D1Ig variable. Patients with monoclonal gammopathy can benefit from increased precision employing an objective and background independent measurand, especially during longitudinal follow-up.

Immunoglobulin heavy/light chain analysis enhances the detection of residual disease and monitoring of multiple myeloma patients.

AIM: To evaluate the clinical utility of incorporating a novel heavy/light chain immunoassay (HLC) into the existing methods for the assessment of multiple myeloma (MM) patients. METHODS: Convenience sera samples from 90 previously treated IgG and IgA MM patients in different disease stages were analyzed. The study was conducted in Clinical Hospital Center Zagreb between 2011 and 2013. The collected sera were analyzed by standard laboratory techniques (serum protein electrophoresis, quantification of total immunoglobulins, serum immunofixation, serum free light chain [FLC] assay) and HLC assay. RESULTS: HLC ratios outside the normal range were found in 58 of 90 patients, including 28 out of 61 patients with total immunoglobulin measurements within the normal range and 5 out of 23 patients in complete response. Both elevated HLC isotype level and abnormal HLC ratio correlated with the parameters of tumor burden, including percentage of plasma cells in the bone marrow (P<0.001 and P=0.002, respectively) and an abnormal serum FLC ratio (for both P<0.001). In addition, abnormal HLC isotype level correlated with serum beta-2-microglobulin level (P=0.038). In terms of prognosis, abnormal HLC isotype level and abnormal HLC ratio were significantly associated with shorter overall survival (P<0.001 and P=0.002, respectively). Interestingly, suppression of the uninvolved (polyclonal) isotype pair, but not other non-myeloma immunoglobulin isotypes, was also associated with a shorter overall survival (P=0.021). In a multivariate analysis, an abnormal HLC ratio and ß2-microglobulin level >3.5mg/L were independent risk factors for survival. CONCLUSION: The new HLC assay has greater sensitivity in detecting monoclonal protein, correlates with tumor burden markers, and affects patients' outcome.

Factitious proteinuria - the most dominant feature in a young female patient with Munchausen syndrome.

Munchausen syndrome is a factitious disorder with predominantly physical signs and symptoms, resulting from the patient's high motivation for assuming a sick role, without any external incentives or boundaries. We report the case of a young female patient with factitious proteinuria in the nephrotic range and a fairly eventful medical history. After performing many expensive and unnecessary investigations and procedures,the real origin of the proteinuria was determined;it was found to be caused by the patient carefully adding calibrated egg albumin to her urine samples. This discovery roused suspicions about multiple, non-corroborated conditions from her history (e.g., multiple miscarriages, breast cancer, and thyroid disorders).The diversity of diseases presented by a single Munchausen patient tends to be bizarre,and thus is a challenge for health care providers to diagnose the condition. Teamwork is therefore of the utmost necessity to diagnose Munchausen syndrome.

[Three-year-old boy--a homozygote for familiar hypercholesterolemia]. / Trogodisnji djecak--homozigot za porodicnu hiperkolesterolemiju.

Homozygous familial hypercholesterolemia (FH) is a rare autosomal dominant disorder caused by mutations in the low-density-lipoprotein (LDL) receptor gene. It occurs with a frequency of approximately 1 per million persons world-wide. Clinically, homozygous FH is associated with extremely elevated levels of LDL cholesterol and cutaneous xanthomas that develop in early childhood. These children are at risk of extremely early coronary events and death from myocardial infarction caused by premature generalized atherosclerosis. Their medical treatment is very complex, associated with various problems and complications. We describe a 3-year-old boy with clinical signs of homozygous FH (elevated LDL-cholesterol levels and xanthomas). Heterozygous hypercholesterolemia was found in his parents and some other family members. The boy has been treated with simvastatin and atorvastatin, but without reaching the treatment goals. LDL apheresis is planned as the treatment of choice for homozygous children with FH.

Aberrant glycosylation of Igg heavy chain in multiple myeloma.

Although the majority of eukaryotic proteins are glycosylated, there is a dearth of knowledge regarding protein sugar moieties and their changes in disease. Most multiple myeloma cases are characterized by production of monoclonal immunoglobulins (Ig). We studied galactosylation and sialylation of IgG heavy chains in 16 patients with IgG myeloma using lectin blotting and densitometry. In comparison to age and sex matched controls, galactosylation was reduced in multiple myeloma (median 317 vs. 362, range 153-410 vs. 309-447 relative units, p = 0.015, Student's t-test). Sialylation was stage dependent; samples from patients with stage IIA had lowest amounts of sialic acid, IIIA intermediate and IIIB highest (142.6 vs. 185.9 vs. 248.5 relative units, correlation coefficient r = 0.55). Both galactosylation and sialylation levels were independent of age, sex, treatment type, response to treatment, disease duration and IgG and b2 microglobulin concentration. These data indicate that multiple myeloma is characterized by aberrant immunoglobulin glycosylation.