Chronic hepatitis C represents an important cause of morbidity and mortality because of its widespread prevalence (1). Liver involvement is only one side of the coin, as extrahepatic manifestations may complicate the course of disease in over 70% of hepatitis C virus (HCV)-infected individuals (2–4). A wide variety of extrahepatic manifestations have been described in association with HCV infection, including lymphoproliferative disorders, cardiovascular disease, metabolic derangements, renal involvement, dermatologic manifestations, neuropsychiatric alterations, and autoimmune diseases (2–12). Many of the extrahepatic manifestations of HCV infection may be considered as the consequence of an aberrant immune response, among which mixed cryoglobulinemia is the most frequent and best studied (13). Indeed, since the immune response against HCV is not effective owing to the virus’ ability to modify its antigenicity, chronic engagement of initially activated and then exhausted immune cells may turn deleterious to the infected individual (14). Serological evidence of chronic immune stimulation is usually reflected by the occurrence of a wide variety of autoantibodies, including anti-nuclear antibodies (ANA), anti-smooth muscle antibodies (ASMA), rheumatoid factor, etc., which may be just the laboratory “signature” of this immune effort to clear the viral infection or even be accompanied by clinical features of autoimmunity (15). Recently, the introduction of direct-acting antivirals (DAAs) into the therapeutic armamentarium has revolutionized the treatment of HCV infection (16). Indeed, DAAs allow nearly all HCV-infected patients to obtain quick and curative resolution of the disease, with excellent treatment tolerability (16). Aims of this study were, therefore, to assess the prevalence of and DAAs impact on serum autoantibodies in a cohort of chronic hepatitis C patients referred to our dedicated outpatient clinic.

In this retrospective study, we aimed at determining the impact of DAA treatment on serum autoantibodies in chronic hepatitis C patients. Specifically, we showed that a significant proportion of patients with serum autoantibodies turned out to be negative or displayed a significant titer reduction following successful eradication of HCV infection. Indeed, nearly two thirds of ANA-positive patients and more than 70% of ASMA-positive patients did not either show detectable autoantibodies or had serum titers reduced at the 24-week follow-up after DAA treatment initiation. These observations are in line with the notion that chronic immune stimulation induced by HCV may lead to dysregulated immune responses possibly resulting in frank autoimmune phenomena (23–25). Consistently, HCV clearance may stop chronic immune stimulation thus reverting the likelihood of subclinical or overt autoimmunity (26). The significance of persistently positive serum autoantibodies in the small fraction of patients who did not show disappearance of these autoreactive immunoglobulins following DAA treatment may require careful long-term follow-up (27, 28); in these patients, autoreactivity may not be linked to HCV infection (i.e., is independent of) or it may have become disengaged from the triggering viral infection. This latter hypothesis is supported by the observation of persistent cryoglobulinemia in a significant proportion of patients with HCV-related cryoglobulinemic vasculitis, despite achievement of a sustained viral response following DAA treatment (29, 30). Moreover, relapses of cryoglobulinemic vasculitis in these patients have been reported within 2 years of a sustained viral response to DAA therapy (30). Thus, a vigilant eye must be kept in order to recognize early in their development possible extrahepatic autoimmune manifestations in patients who still display positive autoantibody titers despite successful DAA therapy (27, 28). Notwithstanding, at the latest follow-up (at least 35 months after sustained viral clearance), we have not recorded yet any frank autoimmune diseases in our cohort of HCV-eradicated patients with persistence of serum autoantibodies. Unfortunately, at the moment, it is not clear why certain patients remain positive for serum autoantibodies long after SVR as opposed to others who become quickly seronegative after sustained HCV clearance. As there is no formal need for therapy in the former group in the absence of clinical manifestations, long-term follow-up should be the recommended strategy.

There are only a few reports in the literature addressing the role of DAAs in clearing autoimmune serology in chronic hepatitis C patients and our results are in full accordance with these previous investigations (27, 28, 31). As only small case series have been published on this topic thus far (27, 28, 31), our report further contributes to and strengthens the notion of HCV being responsible for undermining immune tolerance in chronically infected patients. Besides, more than half of the patients (no. 11) have been followed up for more than 5 years, while for the remaining ones at least nearly three years (35 months) have thus far elapsed since end of DAA treatment. There are no other papers in the literature reporting such a long follow-up.

It should be noted that the rate of DAA-induced autoantibody clearance could have been even higher in our experience, had we excluded from the analyses patients with centromeric and rod and ring patterns. The centromeric pattern is highly suggestive of systemic sclerosis, limited variant (32), whereas the rod and ring pattern is known to be associated with a previous treatment with IFN-α and RBV (33, 34). Thus, we would have not expected clearance of these antibodies following DAA treatment anyway, as they were not closely related to HCV infection.

Clearly, this study has some limitations. First, because of the relatively small patient population, our results need to be confirmed in larger cohorts; second, the study was conducted in a single center, therefore, validation in different geographic areas would be desirable; finally, due to the retrospective nature of the study, potential bias may have not been recognized.

In conclusion, DAA did favorably impact on serum autoantibodies in our patient population. As our HCV-cleared patients with persistently positive autoantibody serology have not been shown to have developed clinical autoimmunity despite the quite long follow-up thus far, we would be tempted to affirm the benign nature of these alterations (provided cryoglobulins are excluded from the evaluation)!; however, to definitively confirm the benign outcome of patients with persistent serum autoantibodies, we would cautiously suggest waiting for a further follow-up extension.

Raw data are available from the corresponding author upon reasonable request.

The study was carried out in accordance with the Declaration of Helsinki and its later amendments; because of its retrospective nature, formal consent was not required.

CR and AM provided substantial contributions to the conception and design of the study and in the writing of the article; AM, CR, OT, AS, and LDM contributed to the acquisition and the interpretation of the data; LEA and DDS carried out the statistical analyses. All authors were involved in the critical revision of the manuscript and approved the final version of the article.

Funds from open access publication fees come from the Department of Advanced Medical and Surgical Sciences.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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