Risk factors and characteristics influencing humoral response to COVID-19 vaccination in patients after allogeneic stem cell transplantation.

Introduction: Vaccination against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is approved and recommended for immunocompromised patients such as patients after allogeneic stem cell transplantation (allo-SCT). Since infections represent a relevant cause of transplant related mortality we analyzed the advent of immunization to SARS-CoV-2 vaccination in a bicentric population of allogeneic transplanted patients. Methods: We retrospectively analyzed data of allo-SCT recipients in two German transplantation centers for safety and serologic response after two and three SARS-CoV-2 vaccinations. Patients received mRNA vaccines or vector-based vaccines. All patients were monitored for antibodies against SARS-CoV2-spike protein (anti-S-IgG) with an IgG ELISA assay or an EIA Assay after two and three doses of vaccination. Results: A total of 243 allo-SCT patients underwent SARS-CoV-2 vaccination. The median age was 59 years (range 22-81). While 85% of patients received two doses of mRNA vaccines, 10% had vector-based vaccines and 5% received a mixed vaccination. The two vaccine doses were well tolerated with only 3% patients developing a reactivation of graft versus host disease (GvHD). Overall, 72% of patients showed a humoral response after two vaccinations. In the multivariate analysis age at time of allo-SCT (p=0.0065), ongoing immunosuppressive therapy (p= 0.029) and lack of immune reconstitution (CD4-T-cell counts <200/µl, p< 0.001) were associated with no response. Sex, intensity of conditioning and the use of ATG showed no influence on seroconversion. Finally, 44 out of 69 patients that did not respond after the second dose received a booster and 57% (25/44) showed a seroconversion. Discussion: We showed in our bicentric allo-SCT patient cohort, that a humoral response could be achieve after the regular approved schedule, especially for those patients who underwent immune reconstitution and were free from immunosuppressive drugs. In over 50% of the initial non-responders after 2-dose vaccination, a seroconversion can be achieved by boostering with a third dose.

Fecal transplant in refractory Clostridium difficile colitis.

BACKGROUND: Clostridium difficile infections are becoming more common, more severe, and more likely to recur. Conventional treatment with antibiotics often fails to eradicate the infection; even when it succeeds, recurrent infection is common. Complementary treatment with probiotic agents to reconstitute the physiological intestinal flora does not yield any consistent benefit. In recent years, fecal transplantation has been used in the English-speaking countries with cure rates of about 87%, but the available evidence is limited to large case series. No randomized controlled trials have been performed. We present the case of a 73-year-old woman with intractable, recurrent enterocolitis due to Clostridium difficile who was successfully treated with fecal transplantation via colonoscopy. CASE DESCRIPTION: Upon the completion of antibiotic treatment for a second recurrence of enterocolitis, stool in liquid suspension was introduced into the patient's colon through a colonoscope. Prior testing had shown the stool donor to be free of acute infection or stool pathogens. The patient was given loperamide to prolong contact of the stool transplant with the colonic mucosa. She was also treated with Saccharomyces cerevisiae for four weeks. COURSE: There was no clinical or microbiological evidence of a further recurrence of enterocolitis for 6 months after transplantation. Stool transplantation had no adverse effects. CONCLUSION: This patient had a lasting remission of enterocolitis due to Clostridium difficile after the treatment described above. Fecal transplantation seems to be a safe and highly effective treatment for recurrent Clostridium difficile infection. It is unclear whether the administration of Saccharomyces cerevisiae confers any additional benefit.

Naturally occurring fragments from two distinct regions of the prostatic acid phosphatase form amyloidogenic enhancers of HIV infection.

Semen is the major vector for HIV-1 transmission. We previously isolated C-proximal fragments of the prostatic acid phosphatase (PAP) from semen which formed amyloid fibrils that potently enhanced HIV infection. Here, we used the same methodology and identified another amyloidogenic peptide. Surprisingly, this peptide is derived from an N-proximal fragment of PAP (PAP85-120) and forms, similar to the C-proximal fragments, positively charged fibrillar structures that increase virion attachment to cells. Our results provide a first example for amyloid formation by fragments of distinct regions of the same precursor and further emphasize the possible importance of amyloidogenic peptides in HIV transmission.