Influence of MBL-2 mutations in the infection risk of patients with follicular lymphoma treated with rituximab, fludarabine, and cyclophosphamide

Identification of gene-environment interactions in cancer studies using penalization

High-throughput cancer studies have been extensively conducted, searching for genetic markers associated with outcomes beyond clinical and environmental risk factors. Gene-environment interactions can have important implications beyond main effects. The commonly-adopted single-marker analysis cannot accommodate the joint effects of a large number of markers. The existing joint-effects methods also have limitations. Specifically, they may suffer from high computational cost, do not respect the "main effect, interaction" hierarchical structure, or use ineffective techniques. We develop a penalization method for the identification of important G × E interactions and main effects. It has an intuitive formulation, respects the hierarchical structure, accommodates the joint effects of multiple markers, and is computationally affordable. In numerical study, we analyze prognosis data under the AFT (accelerated failure time) model. Simulation shows satisfactory performance of the proposed method. Analysis of an NHL (non-Hodgkin lymphoma) study with SNP measurements shows that the proposed method identifies markers with important implications and satisfactory prediction performance.

Mannan-binding lectin in malignancy

Complement may play a dual role in cancer: it may contribute either to the development or to the inhibition of tumour growth. Its components may be candidate biomarkers facilitating the disease detection, its progress or effectiveness of therapy. Additionally, complement deficiencies may increase the risk of infections and contribute to the higher mortality, especially in patients undergoing aggressive chemotherapy. In this paper, possible cancer associations of one of the factors activating complement via the lectin pathway, mannan-binding lectin (MBL), are discussed.

Mannose-binding lectin 2 polymorphisms do not influence frequency or type of infection in adults with chemotherapy induced neutropaenia

Background

Mannose-binding Lectin protein (MBL) has been suggested to be relevant in the defence against infections in immunosuppressed individuals. In a Swedish adult cohort immunosuppressed from both the underlying disease and from iatrogenic treatments for their underlying disease we investigated the role of MBL in susceptibility to infection.

Methods

In this cross sectional, prospective study, blood samples obtained from 96 neutropaenic febrile episodes, representing 82 individuals were analysed for single nucleotide polymorphism (SNP) in the MBL2 gene. Concurrent measurement of plasma MBL protein concentrations was also performed for observation of acute response during febrile episodes.

Findings

No association was observed between MBL2 genotype or plasma MBL concentrations, and the type or frequency of infection. Adding to the literature, we found no evidence that viral infections or co-infections with virus and bacteria would be predisposed by MBL deficiency. We further saw no correlation between MBL2 genotype and the risk of fever. However, fever duration in febrile neutropaenic episodes was negatively associated with MBL2 SNP mutations (p<0.05). Patients with MBL2 SNP mutations presented a median febrile duration of 1.8 days compared with 3 days amongst patients with wildtype MBL2 genotype.

Interpretation

We found no clear association between infection, or infection type to MBL2 genotypes or plasma MBL concentration, and add to the reports casting doubts on the benefit of recombinant MBL replacement therapy use during iatrogenic neutropaenia.

The mild inflammatory response in febrile neutropenic lymphoma patients with low risk of complications is more pronounced in patients receiving tobramycin once daily compared with three times daily

We evaluated inflammatory markers in febrile neutropenic lymphoma patients undergoing high-dose chemotherapy with autologous stem cell support. Based on MASCC scores, our patients had a low risk of serious complications and a perspective of a benign initial clinical course of the febrile neutropenia. We also studied the impact of tobramycin given once versus three times daily on these immune markers. Sixty-one patients participating in a Norwegian multicentre prospective randomized clinical trial, comparing tobramycin once daily versus three times daily, given with penicillin G to febrile neutropenic patients, constituted a clinically homogenous group. Four patients had bacteraemia, all isolates being Gram-positive. Thirty-two patients received tobramycin once daily, and 29 patients received tobramycin three times daily. Blood samples were taken at the onset of febrile neutropenia and 1-2 days later. All samples were frozen at -70 °C and analysed at the end of the clinical trial for C-reactive protein (CRP), procalcitonin (PCT), complement activation products, mannose-binding lectin (MBL) and 17 cytokines. We found a mild proinflammatory response in this series of patients. CRP was non-specifically elevated. Ten patients with decreased MBL levels showed the same mild clinical and proinflammatory response. Patients receiving tobramycin once daily showed a more pronounced proinflammatory response compared with patients receiving tobramycin three times daily. Overall, febrile neutropenic cancer patients with a benign clinical course show a mild proinflammatory immune response.