Pre- vs. post-pubertal onset of vitiligo: multivariate analysis indicates atopic diathesis association in pre-pubertal onset vitiligo

BACKGROUND

Limited epidemiological data exist that compare clinical features of pre- and post-pubertal nonsegmental vitiligo.

OBJECTIVES

To compare factors associated with pre- and post-pubertal onset vitiligo.

PATIENTS AND METHODS

A prospective observational study was conducted of patients with vitiligo attending the clinic between 1 January 2006 and 1 July 2011. The Vitiligo European Task Force questionnaire was completed for each patient and thyroid function and antithyroid antibodies were screened. Other forms of vitiligo (segmental, focal, mucosal, not classifiable) were excluded.

RESULTS

A total of 679 patients were included; 422 had post-pubertal and 257 pre-pubertal onset of vitiligo. Vitiligo universalis was seen only in post-pubertal onset. In univariate analysis, there was no significant statistical difference for sex, Koebner phenomenon or disease activity between both groups; thyroid disease or presence of thyroid antibodies was more frequent in post-pubertal onset [odds ratio (OR) 0·31, P < 0·003] whereas atopic dermatitis was more often associated with or preceding pre-pubertal onset (OR 2·42, P = 0·006). In multivariate analysis, halo naevi, family history of vitiligo, premature hair greying, atopic dermatitis and previous episode of spontaneous repigmentation were independently associated with pre-pubertal onset. In contrast, stress as onset factor, personal history of thyroid disease and acrofacial type were associated with post-pubertal onset.

CONCLUSIONS

Pre-pubertal onset vitiligo is strongly associated with personal and family history of atopy, suggesting that the predisposing immune background in vitiligo is not limited to autoimmunity, as also noted in alopecia areata. This study also suggests reconsidering the epidemiological data on sex ratio in vitiligo.

Mechanism of extracellular thiol nitrosylation by N(2)O(3) produced by activated macrophages

Reactive nitrogen intermediates are synthesized by activated macrophages. These molecules, and nitrous anhydride (N(2)O(3)) in particular, are known to be potent nitrosylating species. We investigated the role of macrophage-derived N(2)O(3) in extracellular nitrosylation. We used dilution experiments to demonstrate the intracellular production of N(2)O(3) and its export into the extracellular medium, with a rate constant k(ex) = 6.8 x 10(6) M s(-1). The kinetics of the competition between extracellular hydrolysis of N(2)O(3) and its reaction with added glutathione were also studied. We obtained a value of the rate constant k(GSH) for the latter reaction of 4.4 x 10(7) M(-1) s(-1), consistent with earlier determinations in cell-free systems. The implications of these results in human albumin nitrosylation were investigated. Nitrosylated albumin was detected in activated macrophages supernatants using an anti-NO-acetylated cysteine antibody. It was estimated that 10% of N(2)O(3) produced by activated cells participate in extracellular nitrosylation. N(2)O(3) thus appears to be a new effector molecule of the immune system, as an agent for the nitrosylation of albumin, the main nitric oxide carrier in vivo.

Evidence for a role of Fc epsilon RII/CD23 in the IL-4-induced nitric oxide production by normal human mononuclear phagocytes

IL-4 stimulates NO production by human monocytes. After 6 days of culture with IL-4, human monocytes released detectable amounts of nitrite and L-citrulline that were inhibited in the presence of nitro-L-arginine (1 mM). Incubation with an anti-CD23 mAb Fab fragment that suppressed the biological effect of CD23 led to a strong reduction (50 to 70%) of the IL-4-induced nitrite and L-citrulline production. Ligation of membrane-associated CD23 or stimulation with recombinant soluble CD23 elicited monocytes to release nitrite and L-citrulline that was suppressed by nitro-L-arginine. Preactivation of human monocytes with IFN-gamma led to subsequent increased IL-4- and CD23-driven nitrite and L-citrulline productions that were also suppressed in the presence of either nitro-L-arginine or the anti-CD23 mAb Fab fragment. The CD23 molecule under its membrane or soluble form thus regulates NO generation by human monocytes. In addition, the IL-4-induced NO production could be mediated, at least in part, by CD23.

The differentiation of human pro-thymocytes along the TCR-alpha/beta pathway in vitro is accompanied by the site-specific deletion of the TCR-delta locus

The nested location of the TCR-delta gene within the TCR-alpha locus is a common feature of both mouse and human. Yet alpha/beta and gamma/delta T cells represent two separate lineages. We have previously proposed that a specific rearrangement event (delta Rec--psi J alpha) resulting in the specific deletion of the TCR-delta gene could be responsible for the independent usage of these two loci. We used an in vitro model of T cell differentiation to test this hypothesis. We show that in culture conditions (IL-1 + sCD23) which promote the development of alpha/beta expressing T cells exclusively, the specific deletion of the TCR-delta locus occurs very rapidly, probably before the productive rearrangement of the TCR-alpha gene. These results clearly demonstrate that the specific deletion of the TCR-delta gene could be the initial regulatory event that imprints the irreversible commitment of T cell differentiation along the alpha/beta pathway.

Origin of malignant centrofacial granulomas: surface markers and gene rearrangement of malignant cells

Malignant centrofacial granuloma (MCFG) is a clinical entity characterized by a relentless ulceration of the upper airway involving the nose, palate, and face, without any demonstrable etiology. The origin of 11 cases were analyzed with the help of cell-surface immunostaining in all and with T-cell receptor gene (TCR) rearrangement in 3. The results show that most of the cases of MCFG are in fact T-cell lymphomas with cell-surface antigens (CD2, CD7, CD3) consistent with either early or mature T lymphocytes. However, some cases exhibit B-lymphoid (CD19, CD20) or histiomonocytic (CD13, CD14) lineage-specific markers. In conclusion, despite its remarkable clinical unity, MCFG is a heterogeneous group of neoplastic diseases, most but not all of which may be classified as T-cell lymphoma.