To-Figueras J, Ozalla MD, Herrero C
Hospital Clinic i Provincial, Barcelona, Spain
Patients with overt porphyria cutanea tarda (PCT) show a very distinctive abnormal urinary profile of porphyrin excretion. It is not known, however, if the clinical remission of the disease does always conclude with a complete normalisation of this profile. We have selected 46 patients early diagnosed of PCT that after a period of treatment, present low values of total porphyrins in urine (<35 nmol/mmol creatinine). We have analyzed the urine by HPLC, identified and quantified the different porphyrins and compared the urinary profile with that of a group of healthy volunteers. The results showed that while the healthy volunteers presented a pattern dominated by the excretion of coproporphyrin III, a large proportion of the patients in clinical remission (80%) still presented a characteristic profile of PCT, with decrease of the coproporphyrin-to-uroporphyrin ratio and/or inversion of the normal coproporphyrin III-to-coproporphyrin I ratio. Detectability of uroporphyrin III and heptacarboxyl III intermediates was also significantly higher among these patients than among the controls (P<0.05). These results show that patients with PCT present persistent subtle changes in their urinary porphyrin profile even after a period of clinical remission and even if the total bulk of porphyrins excreted have fallen to low normal values