Protective role of humoral immune responses during an outbreak of hepatitis E in Egypt

Abstract

Although the seroprevalence of hepatitis E virus (HEV) is approximately 80% in adult Egyptians living in rural areas, symptomatic HEV-caused acute viral hepatitis (AVH) is sporadic and relatively uncommon. To investigate the dichotomy between HEV infection and clinical AVH, HEV-specific immune responses in patients with symptomatic and asymptomatic HEV infection during a waterborne outbreak in Egypt were examined. Of 235 acute hepatitis patients in Assiut hospitals screened for HEV infection, 42 (17.9%) were acute hepatitis patients confirmed as HEV-caused AVH; 37 (88%) of the 42 patients were residents of rural areas, and 14 (33%) were from one village (Kom El-Mansoura). Another 200 contacts of AVH cases in this village were screened for HEV and 14 (7.0%), all of whom were family members of AVH cases, were asymptomatic HEV IgM-positive. HEV infections in this village peaked during the summer. Asymptomatic HEV seroconverters had significantly higher levels of epitope-specific neutralising (p=0.006) and high avidity (p=0.04) anti-HEV antibodies than the corresponding AVH cases. In conclusion, naturally acquired humoral immune responses appear to protect HEV-exposed subjects from AVH during an HEV outbreak in Egypt.

Clinicolaboratory Study of Mother-to-Neonate Transmission of Hepatitis E Virus in Egypt

“…These responses are not changed or boosted like the avidity of the anti-HEV responses. 33 Previous reports 31,36 from studies in Egyptian patients have confirmed the protective role of cellmediated immunity and cytokines 37 in the morbidity of HEV infection. 31,36 It is difficult to determine whether differences in antibody responses are causally related to reduction of the severity of liver damage or can be considered a surrogate marker for other protective factors.…”

“…3 Not surprisingly, neutralizing antibodies to certain epitopes protect against HEV infection in animals [28][29][30] and humans. 31,32 However, the effect of either anti-HEV avidity or epitope-specific neutralizing antibody levels on the modulation of HEV morbidity has not been reported except in a study carried out by Shata et al 33 in Egyptian patients from our region. Anti-HEV avidity and ORF2 452-617 epitopespecific neutralizing capacity in HEV-infected AVH cases were significantly lower than in asymptomatic HEV-infected family members, supporting their roles in protection from symptomatic AVH.…”

“…31,36 It is difficult to determine whether differences in antibody responses are causally related to reduction of the severity of liver damage or can be considered a surrogate marker for other protective factors. 33 Additional studies are required, particularly in pregnant patients and their neonates, to elucidate the role of the humoral immune response in controlling disease severity in both groups.…”

The global burden of hepatitis E outbreaks: a systematic review

“…HEV outbreaks have been reported from 14 countries: Egypt, 66 Kenya, 67,68 Sudan and South Sudan, [69][70][71][72][73][74][75][76] Central African Republic (CAR), [77][78][79] Uganda, [80][81][82][83][84] Chad, 73,76,[85][86][87][88][89] Republic of Djibouti, 90 Algeria, 85,86,89,91 Namibia, 92,93 Morocco, 94,95 Somalia, 96,97 Ethiopia, 98 South Africa, 99 and Cameroon 100 (Fig. 2 and Table S2).…”

Immunity against hepatitis E virus infection: Implications for therapy and vaccine development

“…The protective role of naturally acquired antibody responses has been demonstrated in outbreak and non-outbreak settings. [53][54][55][56] Similarly, passive anti-HEV IgG immunization is also protective for pregnant women in endemic settings. 57 Persistence of anti-HEV IgG has been observed at 5 to 14 years after the occurrence of an outbreak.…”