In the present study, punch biopsy specimens form 85 patients with psoriasis, 20 patients with other erythemato-squamous lesions, and five healthy individuals were studied with DIF and IIF for the detection of in vivo deposit of SCab and complement in the keratin layer. Routine histology with HE served to classify the lesions. Fifty well developed typical psoriatic plaques, 15 pin point lesions, ten receding lesions, and ten lesions of K6bner phenomenon were studied. In addition, ten lesions with eczema, five with seborrheic dermatitis, and five with pityriasis rosea were also studied.
Fresh normal human sera afforded a source for both SCab (titer > 80) and complement, diluted I: IO in PBS. Sera heated to 56 ~ for 30 min served as negative controls for complement fixation studies. IIF tests for IgG antibodies using heated sera as positive controls were also studied. Pretreatment of sections with PBS and staining with anti-IgG conjugate absorbed with normal human serum to remove antMgG antibody, served to exclude sections with non specific staining. Fluorescein-conjugated goat antihuman IgG, F/P ratio: 2.9 was used throughout the study, diluted 1:10 in PBS. Similarly diluted goat antihuman C3 and C4 conjugates were also used (F/P ratio:l.8).
The aims of DIF and IIF tests was to study (a) if some or all of the S C antigenic sites which can react with SCab, as revealed by IIF, are in vivo saturated with IgG and complement (DIF test) and (b) if the fluorescent pattern in the IIF test is similar that in the DIF test, suggesting that the in vivo bound IgG and complement occupy similar SC-antigenic sites to the autoantibody sites revealed by IIF.