Remote and rapid pathological diagnosis in a resource challenged unit.

Malawi is one of the world's poorest countries, but despite this, has a dedicated paediatric oncology service. The service has been hampered by the inability to make a timely cytological diagnosis in the majority of patients. A telemedicine programme was commenced to help overcome this problem, and the results for the first 197 consecutive patients are described. The results are compared with the local reports where available. Most samples were fine needle aspirates (104/197-53%), but others included bone marrow aspirates, peripheral blood films and other fluid collections. A diagnosis was arrived at in 52% of the samples; there were 46 discordant results, 38 were when one or other of the local or distant teams were unable to make a diagnosis, and only 8 where the diagnoses of the 2 teams differed. Diagnoses were made and reports were compiled by the 'distant' team within 24 h and sent to the centre in Malawi. This simple telepathology initiative has had a positive impact on clinical management, and could be used in other less resourced centres twinned with better resourced ones.

Epidermal Langerhans cells in Actinic Prurigo: a comparison between lesional and non-lesional skin.

BACKGROUND: Actinic Prurigo (AP) is a chronic pruritic dermatosis of unknown cause affecting sun exposed skin in defined ethnic groups with characteristic MHC alleles. However, the cutaneous dendritic cells have not been assessed. OBJECTIVE: To assess in situ the epidermal Langerhans Cell (LC) status in Actinic Prurigo. STUDY DESIGN: Fresh skin samples from three AP patients were used to evaluate in situ the epidermal LC, comparing lesional and non-lesional sites in each subject. SETTING: AP patients attending the Dermatology Department at the Hospital M. Gea-Gonzalez in Mexico city. METHODS: Lesional and non-lesional skin samples were taken from each subject to prepare both epidermal sheets and conventional tissue sections. Three markers restricted to LC in epidermis (CD1a, ATPase, MHC-II) were used to quantify the LC per area in epidermal sheets. RESULTS: Compared to non-lesional skin from the same subject, a significant reduction in the number of LC per area of epidermis was found in lesional skin; with any of the three markers evaluated. CONCLUSION: The frequency of epidermal LC decreases importantly in lesional skin from AP patients.

TNFalpha and IL-6 are mediators in the blistering process of pemphigus.

BACKGROUND: Pemphigus is an autoimmune disease characterized by intraepidermal blisters induced by pemphigus IgG. In addition to autoantibodies, molecular mechanisms involved in acantholysis remain largely unknown. For this reason, we address a possible role of the inflammatory cytokines IL-6 and TNFalpha in pemphigus lesions. METHODS: Sixteen biopsies from patients with different types of pemphigus were studied by in situ hybridization using DNA fluorescent probes for IL-6 and TNFalpha mRNA. RESULTS: Fifty-six percent of lesional biopsies exhibited cytokine gene expression, which was poorly expressed in noninvolved skin. Deposits of TNFalpha and IL-6 were products of in situ transcription at the epidermal level. CONCLUSIONS: Inflammatory cytokine expression around the blister could play a mediator role in pemphigus lesions by increasing epithelial damage.

Further evidence of the role of HLA-DR4 in the genetic susceptibility to actinic prurigo.

BACKGROUND: Actinic prurigo (AP) is triggered by sun exposure. Its prevalence in Mexicans seems to be particularly high, which suggests a genetic susceptibility. OBJECTIVE: Our purpose was to determine the role of major histocompatibility complex (MHC) genes in the genetic susceptibility to AP. METHODS: Fifty-six Mexican Mestizo patients with AP underwent serologic typing for HLA class I and class II antigens. Class II MHC genes were also studied by DNA analysis. Findings in patients were compared with 100 ethnically matched healthy controls. RESULTS: We found that 92.8% of patients with AP were HLA-DR4 positive (corrected p = 0.002; odds ratio [OR] = 10.1). The class I antigens HLA-A28 and HLA-B39 (B16) were also significantly increased (p < or = 0.000001, OR = 20.9 and p = 0.0001, OR = 6.7, respectively) compared with normal controls. Allele-specific oligonucleotide DR4 subtyping showed that 80.7% of HLA-DR4+ patients with AP were also positive for the DRB1*0407 allele. CONCLUSION: These results confirm the role of HLA-DR4 (DRB1*0407) in the genetic susceptibility to AP and raise the possibility of a role for class I MHC antigens HLA-A28 and B16 in Mexican patients.

Pigmentary problems in the tropics.

Pigmentary problems are one of the most frequent causes of dermatologic consultation in the tropics. This article deals with diseases seen mostly in tropical countries (ashy dermatosis, lichen planus pigmentosus, frictional dermatitis, pityriasis versicolor, and pinta) and in which a combination of racial, ecologic, nutritional, and social factors all contribute. Other common dermatoses seen worldwide, such as vitiligo and melasma, sometimes acquire dramatic expressions in tropical countries, and their management is usually difficult even for the most experienced dermatologists.