Kaposi's sarcoma: Genetic subtypes and clinical correlation in a South African population

Human herpes virus 8 (HHV8) is the aetiological agent of all forms of Kaposi's sarcoma (KS). Seven major subtypes (A, B, C, D, E, F, Z) based on genetic variability of open reading frame (ORF)-K1, have been identified. Numerous studies point to differing tumorigenic and pathogenic properties of the HHV8 subtypes. The study objective was to determine the prevalence of the HHV8 subtypes in a cohort of clinical and histologically confirmed KS in Cape Town, South Africa, and analyse associations between the different subtypes, clinico- epidemiological forms and clinical presentation of KS. The clinical data was prospectively collected and recorded on a body diagram and with photographs. Demographic data was retrospectively collected from clinical records. Tissue biopsies were taken for ORF-K1 subtyping. Out of a cohort of 103, eighty six patients were subtyped; 81 AIDS (aquired immune deficiency syndrome)-KS and 5 African endemic. Subtype A5 (42/86) and B2 (16/86) predominated. B1, B3, A1 and A4 subtypes were identified in 10/86, 9/86, 4/86 and 1/86 patients respectively. A5, B1, B2 and B3 were found in African blacks and individuals of mixed ancestry, while subtypes A1 and A4 are found only in whites and individuals of mixed ancestry. Subtype A5 was associated with >10 KS lesions at presentation in the AIDS-cohort (32/38, p=0,050), but not in the African endemic patients (2/4, p=0,600). Subtypes A1 and A4 were less likely to be associated with poor risk tumour extension (p=0,031) and A1 was associated with lower likelihood of lower limb involvement (p=0,004)

Case Report: Stevens-Johnson syndrome following a single double dosing of nevirapine-containing regimen once in an HIV-infected woman on long-term antiretroviral therapy. [version 1; referees: 1 approved, 2 approved with reservations]

A 31-year old HIV-infected African woman on nevirapine, tenofovir and lamivudine for more than 4 years presented with an 8-day history of symptoms and signs of Stevens-Johnson syndrome. She was on no other medication. Her viral load was undetectable and she had maintained a CD4 count of between 356 and 387cells/mm3 in the preceding 2½ years. She missed her antiretrovirals 10 days before the onset of her symptoms and subsequently doubled her daily dose the following day. She had been on no other medication in the preceding 8 weeks. Her ARVs were stopped and she fully re-epithelialized with the exception of the lips, over the following 10 days. She was started on a daily single tablet of Odimune® (a fixed drug combination antiretroviral containing tenofovir, emtricitabine and efavirenz).   Nevirapine is the most common offender in cases of antiretroviral-associated SJS in published literature. Lamivudine is very rarely implicated while there are no similar reports with tenofovir.  We concluded that nevirapine was by far the most likely offender in this case. Nevirapine toxicity is associated with high CD4 counts, undetectable viral load and high drug plasma level. We postulate that the sudden increase of the plasma levels of nevirapine in a patient with a high CD4 count and undetectable viral load created a perfect storm for the development of SJS in our patient, who had been on the NVP-containing regimen for many years. Clinicians should be aware that severe adverse drug reactions are dynamic and can occur even when the drug has been in use for a long time

Comment on: Proposal for a new diagnostic classification of photodistributed Stevens–Johnson syndrome and toxic epidermal necrolysis

Abstract Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and SJS/TEN overlap (SJS/TEN), collectively referred to SJS/TEN, form a spectrum of severe life-threatening adverse drug reactions whose pathomechanism is not fully understood. The article "Photodistributed Stevens–Johnson Syndrome and Toxic Epidermal Necrolysis: A Systematic Review and Proposal for a New Diagnostic Classification" by McKinley et. al., discusses a distinct distribution of epidermal necrosis in SJS/TEN, attributable to preceding exposure to ultraviolet radiation (UVR), and relative sparing of photo-protected areas. After reviewing numerous cases within the Immune-mediated Adverse drug Reactions in African HIV endemic setting Register and Biorepository (IMARI-SA) at the University of Cape Town with a similar clinical pattern as those published by McKinley et. al., we propose that the relative sparing of some areas giving an impression of photo-distribution is due to localised increase in skin pressure that reduces the blood supply in that area below a critical threshold. A dip in blood supply below this critical threshold quantitively limited T lymphocytes and cytokines that drive SJS/TEN to reach and damage the skin