Inter-Laboratory Concordance of Cerebrospinal Fluid and Serum Kappa Free Light Chain Measurements.

The kappa index (K-Index), calculated by dividing the cerebrospinal fluid (CSF)/serum kappa free light chain (KFLC) ratio by the CSF/serum albumin ratio, is gaining increasing interest as a marker of intrathecal immunoglobulin synthesis. However, data on inter-laboratory agreement of these measures is lacking. The aim was to assess the concordance of CSF and serum KFLC measurements, and of K-index values, across different laboratories. KFLC and albumin of 15 paired CSF and serum samples were analyzed by eight participating laboratories. Four centers used Binding Site instruments and assays (B), three used Siemens instruments and assays (S), and one center used a Siemens instrument with a Binding Site assay (mixed). Absolute individual agreement was calculated using a two-way mixed effects intraclass correlation coefficient (ICC). Cohen's kappa coefficient (k) was used to measure agreement on positive (≥5.8) K-index values. There was an excellent agreement in CSF KFLC measurements across all laboratories (ICC (95% confidence interval): 0.93 (0.87-0.97)) and of serum KFLC across B and S laboratories (ICC: 0.91 (0.73-0.97)), while ICC decreased (to 0.81 (0.53-0.93)) when including the mixed laboratory in the analysis. Concordance for a positive K-Index was substantial across all laboratories (k = 0.77) and within S laboratories (k = 0.71), and very good (k = 0.89) within B laboratories, meaning that patients rarely get discordant results on K-index positivity notwithstanding the testing in different laboratories and the use of different platforms/assays.

The contribute of cerebrospinal fluid free light-chain assay in the diagnosis of multiple sclerosis and other neurological diseases in an Italian multicenter study.

BACKGROUND: Cerebrospinal fluid (CSF) free light chains (FLCs) can be an alternative assay to oligoclonal bands (OCBs) in inflammatory neurological disorders, but threshold has no consensus. OBJECTIVE: To assess the diagnostic accuracy of CSF FLCs in multiple sclerosis (MS) and other neurological diseases. METHODS: A total of 406 patients from five Italian centers. FLCs were measured in CSF and serum using Freelite MX assays on Optilite. RESULTS: A total of 171 patients were diagnosed as MS, 154 non-inflammatory neurological diseases, 48 inflammatory central nervous system (CNS) diseases, and 33 peripheral neurological diseases. Both kFLC and λFLC indices were significantly higher in patients with MS compared to other groups (p < 0.0001). The kFLC index ⩾ 6.4 is comparable to OCB for MS diagnosis (area under the receiver operating characteristic curve (AUC) = 0.876; sensitivity 83.6% vs 84.2%; specificity 88.5% vs 90.6%). λFLC index ⩾ 5 showed an AUC of 0.616, sensitivity of 33.3% and specificity of 90.6%. In all, 12/27 (44.4%) MS patients with negative OCB had kFLC index ⩾ 6.4. Interestingly, 37.5% of 24 patients with a single CSF IgG band showed high kFLC index and 12.5% positive λFLC index. CONCLUSION: Our findings support the diagnostic utility of FLC indices in MS and other CNS inflammatory disorders, suggesting a combined use of FLC and OCB to help clinicians with complementary information.

Enhanced liver fibrosis test as a reliable tool for assessing fibrosis in nonalcoholic fatty liver disease in a clinical setting.

BACKGROUND: Liver fibrosis is the main determinant and predictor of the clinical course of nonalcoholic fatty liver disease (NAFLD). To date, a liver biopsy is still considered the gold standard for staging fibrosis. The aim of this study was to investigate the diagnostic accuracy of the commercial enhanced liver fibrosis (ELF) test manufacturer's cutoff value (≥9.8) in identifying severe fibrosis for adult patients with histologically confirmed NAFLD. METHODS: We tested the ELF test in a clinical practice, prospective cohort of 82 consecutive patients who consecutively underwent percutaneous liver biopsy. RESULTS: All stages of liver fibrosis were represented in our cohort, and severe fibrosis was present in 15 of 82 patients (18.3%). The stage of fibrosis was significantly associated with ELF score (Spearman's rho = 0.483, p<0.001). The commercial ELF test manufacturer's cutoff identified severe fibrosis with good sensitivity (86.7%; 95% confidence interval [95% CI], 0.69-1.04) and high specificity (92.5%; 95% CI, 0.86-0.99), with a positive predictive value of 72% and negative predictive value of 97%. CONCLUSIONS: Our data could support the use of the ELF test in clinical practice.

Fecal but not serum calprotectin is a potential marker of GVHD after stem cell transplantation.

Gastrointestinal graft-versus-host disease (GvHD) represents a life-threatening complication after stem cell transplantation. Differential diagnosis between gut GvHD and other causes of diarrhea after HSCT is still subjected to endoscopy and histological findings. The research for a reliable biomarker for gut GvHD might allow an early diagnosis of this condition and a consequent prompt treatment that could reduce unfavorable outcomes. Recently, fecal calprotectin was reported as reliable marker of gut involvement. We would evaluate if serum instead of fecal calprotectin could be considered a possible biomarker of gut GvHD. Serum calprotectin was measured in a cohort of 54 patients submitted to allogeneic stem cell transplantation using ELISA assay. For a subset of 21 patients, calprotectin serum levels were compared with fecal calprotectin detection. Contrary to fecal calprotectin, we found only a trend to high level of serum calprotectin for GvHD development and gut involvement, but statistical difference was not reached. Fecal but not serum calprotectin could be considered as possible biomarker for gut GvHD.

A Critical Approach to Clinical Biochemistry of Chromogranin A.

Chromogranin A (CGA) is a member of the granin family of proteins which are widespread in endocrine, neuroendocrine, peripheral, and central nervous tissues, where they are typically found in secretory granules. It is well accepted that CGA cooperates to regulate synthesis and secretion of these various granule signaling molecules.Because of its ubiquitous distribution within neuroendocrine tissues, CGA can be a useful diagnostic marker for neuroendocrine neoplasms, including carcinoids, pheochromocytomas, neuroblastomas, medullary thyroid carcinomas (MTC), some pituitary tumors, functioning and nonfunctioning islet cell tumors and other amine precursor uptake and decarboxylation (APUD) tumors. It is also useful as a prognostic marker for detection of recurrence and monitoring of response to different treatments. As other tumor markers, it is imperative to know its physiology and pathophysiology, its sensitivity and specificity in different neuroendocrine tumors (NETs), and carefully integrate these data with the clinical data of the single patient, to maximize its diagnostic/prognostic index.

Worsening of the clinical-hematological picture in a patient with a rare PK-LR compound heterozygosis after mitral replacement.

We report a case of a patient affected by compound heterozygosis for two PK-LR gene mutations: p.R486W (c.1456C>T) and p.M403I (c.1209G>A). Our patient suffered from an initial moderate hemolytic anemia which subsequently evolved into a severe form after mitral prosthetic valve replacement for valve regurgitation. Thereafter, the clinical features evolved into a worsening of anemia, heart failure and pulmonary hypertension, in the absence of valve dysfunction. This clinical picture improved only after an intensive transfusion regimen. This case highlights aspects concerning the intricate balance between the risks and benefits of a mechanical prosthetic valve implant in PK-deficient patients.

Prospective evaluation of epstein-barr virus reactivation after stem cell transplantation: association with monoclonal gammopathy.

Epstein-Barr Virus (EBV) reactivation and EBV-related post-transplant lymphoproliferative disease (PTLD) have emerged as a severe complication after stem cell transplantation (SCT). We prospectively evaluated 104 consecutive patients receiving SCT either autologous or allogeneic. Fifty-two patients (50%) presented EBV DNA-emia and five of them developed PTLD proven or probable. PTLD rate was 9.6% among patients with EBV DNA-emia. One patient developed PTLD without EBV DNA-emia (0.96%). Overall PTLD incidence was 5.7%. No PTLD developed after autologous SCT. EBV DNA-emia was significantly more frequent after allogeneic than autologous SCT (60.7% vs 17.4%, p = 0.0002). At EBV reactivation, serum protein electrophoresis and immunofixation were assessed. Global incidence of γ-peak after allogeneic SCT with EBV reactivation was 65.3% (32/49 patients) and monoclonal gammopathy (MG) was identified in 23/28 evaluable patients (82%). All patients with PTLD developed γ-peak and in five of them MG was identified. MG is consistently associated with EBV DNA-emia and may help identification of progression to PTLD after allogeneic SCT.