7 research outputs found
Model selection in logistic regression
This paper is devoted to model selection in logistic regression. We extend
the model selection principle introduced by Birg\'e and Massart (2001) to
logistic regression model. This selection is done by using penalized maximum
likelihood criteria. We propose in this context a completely data-driven
criteria based on the slope heuristics. We prove non asymptotic oracle
inequalities for selected estimators. Theoretical results are illustrated
through simulation studies
Non-asymptotic Oracle Inequalities for the Lasso and Group Lasso in high dimensional logistic model
We consider the problem of estimating a function in logistic regression model. We propose to estimate this function by a sparse approximation build as a linear combination of elements of a given dictionary of functions. This sparse approximation is selected by the Lasso or Group Lasso procedure. In this context, we state non asymptotic oracle inequalities for Lasso and Group Lasso under restricted eigenvalues assumption as introduced in \cite{BRT}
Non-asymptotic oracle inequalities for the Lasso and Group Lasso in high dimensional logistic model
We consider the problem of estimating a function f(0) in logistic regression model. We propose to estimate this function f(0) by a sparse approximation build as a linear combination of elements of a given dictionary of p functions. This sparse approximation is selected by the Lasso or Group Lasso procedure. In this context, we state non asymptotic oracle inequalities for Lasso and Group Lasso under restricted eigenvalue assumption as introduced in [P.J. Bickel, Y. Ritov and A.B. Tsybakov, Ann. Statist. 37 (2009) 1705-1732]
Matching for the non-conventional MHC-I MICA gene significantly reduces the incidence of acute and chronic GVHD
Graft-versus-host disease (GVHD) is among the most challenging complications in unrelated donor hematopoietic cell transplantation (HCT). The highly polymorphic "MHC class I chain-related gene A", MICA, encodes a stress-induced glycoprotein expressed primarily on epithelia. MICA interacts with the invariant activating receptor NKG2D; expressed by cytotoxic lymphocytes. The MICA gene is located in the MHC, next to HLA-B; hence MICA has the requisite attributes of a bona fide transplantation antigen. Using high-resolution sequence-based genotyping of MICA, we retrospectively analyzed the clinical impact of MICA mismatches in a multicenter cohort of 922 unrelated donor HLA-A, -B, -C, -DRB1, and -DQB1 10/10 allele-matched HCT. Among the 922 pairs, 113 (12.3%) were mismatched in MICA MICA mismatches were significantly associated with an increased incidence of grade III-IV acute GVHD (HR, 1.83; 95% CI, 1.50 to 2.23; P<0.001), chronic GVHD (HR, 1.50; 95% CI, 1.45 to 1.55; P<0.001) and non-relapse mortality (HR, 1.35; 95% CI, 1.24 to 1.46; P<0.001). The increased risk of GVHD was mirrored by a lower risk of relapse (HR, 0.50; 95% CI, 0.43 to 0.59; P<0.001), indicating a possible graft-versus-leukemia effect. In conclusion, when possible, selecting a MICA-matched donor significantly influences key clinical outcomes of HCT in which a marked reduction of GVHD is paramount. The tight linkage disequilibrium between MICA and HLA-B renders identifying a MICA-matched donor readily feasible in clinical practice
Matching for the nonconventional MHC-I MICA gene significantly reduces the incidence of acute and chronic GVHD
Graft-versus-host disease (GVHD) is among the most challenging complications in unrelated donor hematopoietic cell transplantation (HCT). The highly polymorphic MHC class I chain-related gene A, MICA, encodes a stress-induced glycoprotein expressed primarily on epithelia. MICA interacts with the invariant activating receptor NKG2D, expressed by cytotoxic lymphocytes, and is located in the MHC, next to HLA-B. Hence, MICA has the requisite attributes of a bona fide transplantation antigen. Using high-resolution sequence-based genotyping of MICA, we retrospectively analyzed the clinical effect of MICA mismatches in a multicenter cohort of 922 unrelated donor HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1 10/10 allele-matched HCT pairs. Among the 922 pairs, 113 (12.3%) were mismatched in MICA. MICA mismatches were significantly associated with an increased incidence of grade III-IV acute GVHD (hazard ratio [HR], 1.83; 95% confidence interval [CI], 1.50-2.23; P < .001), chronic GVHD (HR, 1.50; 95% CI