[Viral C hepatitis in patients with end stage renal disease. II. Viral genotypes]

The hepatitis C virus infection is highly prevalent in patients on chronic dialysis. There are more than 10 variants of the hepatitis C virus, with 55 to 72% of identity among them at the amino acid level. However, we do not know the specific genotype in dialysis patients in Mexico. Thus, the aim of the present study was to know the specific genotypes of the C virus in infected dialysis patients, to know the distribution of genotypes in the different dialysis techniques and to know the relation between genotype and hepatic disease stage.

We performed a prospective, transversal and comparative study in patients in dialysis in three hospital centers in the south of Mexico City. The presence of C-type hepatitis infection was assessed by ELISA II and qualitative RT-PCR in blood samples. The genotype of the hepatitis C virus was determined by analysis of the restriction pattern of the RT-PCR product using Mva I, Hinf I, BstU I and ScrF I restriction enzymes. Variables analyzed were: age, gender, etiology of renal failure, kind and time in substitutive therapy, transfusion and hepatitis history, liver function test, blood urea, serum creatinine and blood cell count.

We studied 235 dialysis patients that were divided following their dialysis modality into: 132 in continue ambulatory peritoneal dialysis (CAPD), 17 in CAPD, but with history of hemodialysis (PD/HD) of at least one month and 86 on hemodialysis (HD). The hepatitis infection was detected in 24 of the 235 patients (CAPD = 4.5%, PD/HD = 41.1% and HD = 12.7%; p < 0.001). The most common genotype was 1B (12/24), followed by 1A and 2A (4/24 each one), and finally by 2B and 2C (2/24 each one). We detected no patients with genotypes 3 to 6. The patients with 2A genotype were older than those infected with 1A (p < 0.05). History of surgery, transfusions, and hepatitis was similar in all genotypes. Finally the time in dialysis was longer in patients with 2A genotype than others (2A = 60.5 +/- 71.5 months, vs. 1A = 11.5 +/- 11.3, 1B = 26 +/- 26.4 y 2B/C = 17.5 +/- 13.4), but the difference did not reach statistical significance. The genotype distribution between dialysis techniques showed that 1B genotype was the most frequent in all modalities. The 1A genotype was present in similar proportions in patients of the three dialysis groups, the 2C genotype was present only in patients with CAPD. Finally, the 2B was only found in hemodialysis patients.

The assessment of viral genotype revealed that 1B is the most common genotype in patients on chronic dialysis in Mexico City. The fact that the 1B and 1A genotypes were the most common types in our dialysis population suggest that transmission was similar to the general population, that is, probably by blood transfusions.