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Background: Psoriasis is associated with significant morbidity and impaired quality of life. Identification of the host genes that influence disease susceptibility and can potentially guide future, targeted therapy is the need of the hour. Aims: The aim of the study was to investigate the associations of macrophage migration inhibitory factor (MIF) gene polymorphisms, that is, a 5–8-CATT tetra nucleotide repeats at -794 (-794*CATT5–8) and a single-nucleotide polymorphism at -173 (-173*G/C) with the risk of chronic plaque psoriasis and to observe the correlation, if any, of disease determinants with genetic functional variants and circulating MIF levels. Methods: Five hundred and seventeen individuals (265 psoriasis patients and 252 controls) were genotyped for MIF gene polymorphisms. Data were analyzed with respect to disease susceptibility, serum MIF levels, disease severity, age at onset, disease duration and presence of comorbidities. Results: The presence of co-morbidities was more frequently noted in patients with late onset disease (P = 0.01). No statistically significant differences were observed either in genotype (P = 0.680) or allele frequency (P = 0.69) with respect to distribution of MIF-173*G/C polymorphism between patients and controls. The frequencies of genotypes -794*CATT 5/7 and 7/7 were significantly lower in patients (P = 0.027* and 0.038*, respectively). CATT*5/MIF-173*C haplotype occurred at a higher frequency in patients (odds ratio 3.03, 95% confidence intervals 1.09–8.47, P = 0.02). The mean serum MIF levels were significantly higher in patients as compared to controls (P < 0.001). The presence of either extended MIF -794*CATT repeats or C allele did not reveal any significant association with serum MIF levels or age at onset. Analysis of effect of various disease determinants revealed no significant association with genetic variants and serum MIF levels. Limitations: The lesional expression of MIF could not be studied. Conclusion: Our results showed that CATT*5/MIF-173*C haplotype is associated with increased susceptibility to psoriasis vulgaris.
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Direct immunofluorescence (DIF) and indirect immunofluorescence (IIF) tests on skin biopsy are being done mostly in academic teaching hospitals. These tests provide a useful diagnostic aid to dermatologists. Immunohistology and serology can, in conjunction with histology, provide considerable help in delineation and diagnosis of various skin disorders as well as systemic diseases with skin involvement, e.g. systemic lupus erythematosus. Immunofluorescence (IF) studies have now become an invaluable supplement to clinical and histological examination in a variety of dermatological diseases. These skin diseases now include not only bullous and connective tissue disorders, vasculitides, and conditions such as lichen planus, but also the scaling dermatoses, notably psoriasis. In this review article, we share our experience of providing such a diagnostic facility for more than 30 years in a large tertiary care health center in North India and also help to outline the conditions, which can be diagnosed confidently, and others where IF can help in confirming a diagnosis or the immune component of the disease. The article also deals with handling of skin biopsy specimens and interpretation of biopsy findings on DIF and IIF examination.
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Background: By direct immunofluorescence (DIF), presence of immune complexes in the skin biopsy at various locations such as the dermo-epidermal junction, dermal blood vessels, etc. help to arrive at a diagnosis. Aims: (1) To study the role of DIF in confirmation or exclusion of diseases involving skin vis-à-vis histopathology and clinical diagnosis, (2) to describe the annual spectrum of dermatologic conditions that present to a tertiary referral center and require DIF examination of skin biopsy for confirmation of diagnosis. Methods: A total of 267 biopsies received over a period of 16 months in the Department of Immunopathology were analyzed along with clinical and histopathological details and the correlation between them was studied. Results: DIF was positive in 204 skin biopsies. Of these, 127 biopsies showed good clinico-immuno-histopathological correlation. In 10 cases, only DIF could clinch the diagnosis. In another nine cases, immune deposits were noted, which were unexpected in light of clinical and histopathological diagnosis. The most common skin involvement was seen in vasculitides. DIF was, however, non-contributory in lesions like erythema multiformè, post Kala-azar dermal leishmaniasis, sarcoidosis, lupus vulgaris, pyoderma gangrenosum and prurigo nodularis. Conclusion: The DIF of skin in conjunction with histopathology gives the best diagnostic yield. It is invaluable in confirming the diagnosis of small vessel vasculitides and bullous lesions of skin and can be used as an additional tool to pinpoint the diagnosis of systemic and localized autoimmune diseases involving the skin.