Immunogenetics of drug-induced skin blistering disorders. Part II: synthesis.

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon examining the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events including Stevens-Johnson syndrome and Toxic epidermal necrolysis). New results from an exemplar study on shared precipitating and perpetuating inner causes with other related disease phenotypes including aphtous stomatitis, Behçets, erythema multiforme, Hashimoto's thyroiditis, pemphigus, periodic fevers, Sweet's syndrome and drug-induced multisystem hypersensitivity are presented. A call for a collaborative, wider demographic profiling and deeper immunotyping in suggested future work is made.

TNF, LTA, HSPA1L and HLA-DR gene polymorphisms in HIV-positive patients with hypersensitivity to cotrimoxazole.

AIMS: Sulfamethoxazole in combination with trimethoprim (cotrimoxazole) is used for prophylaxis and treatment of several opportunistic infections in HIV-infected patients. It is associated with a high incidence of hypersensitivity reactions, which is thought to have an immune basis. Genetic polymorphisms in MHC are known to predispose to hypersensitivity reactions to a structurally diverse group of drugs in HIV-positive patients. The aim of the study was to determine whether functional polymorphisms in TNF, LTA, HSPA1L and HLA-DRB1 genes influence the risk of cotrimoxazole hypersensitivity in HIV-infected patients. METHODS: We genotyped 136 HIV-positive patients with (n = 53) and without (n = 83) cotrimoxazole hypersensitivity using a combination of PCR-based techniques, including PCR-restriction fragment length polymorphisms, PCR-sequence specific oligonucleotides and real-time PCR. Genotypes and the haplotype frequencies were analyzed using the chi(2) test in the Haploview and CLUMP programs. RESULTS: No statistically significant difference in SNP or haplotype frequencies were found in HIV-infected sulfamethoxazole hypersensitive patients compared with controls. CONCLUSION: Our data show that MHC polymorphisms are not major predisposing factors for cotrimoxazole hypersensitivity, although we cannot exclude a minor contribution. An environmental factor (i.e., HIV infection) seems to predominate over any of the genetic factors so far investigated in increasing the risk of cotrimoxazole hypersensitivity.

Immunogenetics of drug-induced skin blistering disorders. Part I: Perspective.

The overall immunopathogenesis relevant to a large series of disorders caused by a drug or its associated hyperimmune condition is discussed based upon the examination of the genetics of severe drug-induced bullous skin problems (sporadic idiosyncratic adverse events, including Stevens-Johnson syndrome and toxic epidermal necrolysis). An overarching pharmacogenetic schema is proposed. Immune cognition and early-effector processes are focused upon and a challenging synthesis around systems evolution is explained by a variety of projective analogies. Etiology, human leukocyte antigen-B, immune stability, dysregulation, pharmacomimicry, viruses and an aggressive ethnically differentiated 'karmic' response are discussed.

Investigation into the multidimensional genetic basis of drug-induced Stevens-Johnson syndrome and toxic epidermal necrolysis.

OBJECTIVE: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare severe blistering skin diseases, which are mainly caused by drugs. The two idiosyncratic conditions are distinguished on the basis of the degree of blistering, possibly representing diseases at different ends of the same spectrum. A genetic predisposition has been postulated. METHOD: We have retrospectively identified a heterogeneous group of patients with SJS and TEN (n = 73 cases, 141 matched controls) induced by a number of marketed drugs and evaluated effector candidate genetic predisposition. We have used a multivariate genetic analysis method for the first time to handle the heterogeneity of clinical presentation, drug etiology, ethnicity and gender in these adverse events. RESULTS: Our results show that predisposition varied according to ethnicity. There was a correlation for SJS with HLA-B*44, DRB1*07 and with the MHC ancestral 57.1 haplotype (and its constituents) in subjects who self-reported as Caucasians, which did not differ with gender. The HLA-DRB and -DRQ genetic predisposition to SJS seemed to be distinct from that of TEN, but further work is needed for both conditions to identify the causal variants. No conclusion concerning correlations with different drugs could be made because of small numbers in each drug group. CONCLUSION: This study stresses the importance of accurate clinical phenotyping, exemplifies a novel analysis method to dissect complicated samples and calls for collaborative prospective studies.

Visualizing gene determinants of disease in drug discovery.

Target discovery, subphenotype detection and the detection of human heterogeneity are major challenges in drug discovery and development on which genetic markers can have an impact. Visualizing gene determinants of traits in case-control study individuals during drug discovery using contrasts of empirically-derived log Bayes factors (LBFs) from whole-genome scan single nucleotide polymorphism (SNP) data is presented to aid this. Examples of the use of eigen analysis, covariate overlays and individualized aggregation to ontologies are included from disease research studies. Displays of individuals, or exposures of biological features of interest, can encompass unlimited numbers of markers in a single multivariate analysis without multiple testing. This filtering approach is aimed at nonspecialists who find themselves asked to undertake work such as that performed by the authors.