Kidney transplant recipients see lower IgG production after COVID-19 vaccine | Latest news for doctors, nurses and pharmacists

Vaccination against COVID-19 appears to be less effective in kidney transplant recipients, according to a recent study. Stopping or reducing immunosuppressive therapy may contribute to increased immunoglobulin (Ig)G production in these patients.

In 151 kidney transplant recipients, the mean anti-Spike protein IgG level was 1377 AU/mL. This was significantly lower than that of the 74 living kidney donors and 50 healthy volunteers enrolled as comparators (8310 and 9908 AU/mL, respectively; pInt J Urol 2022;doi:10.1111/iju.15027]

Of note, none of the participants in the two comparison groups were considered to have negative antibody levels, while 32.7% of transplant recipients were classified as such. Meanwhile, 100% and 98.6% of healthy volunteers and donors had strong positive antibody levels, respectively, while only 26.7% of recipients met those criteria.

A crude analysis showed that women were more likely to test positive for antibodies after vaccination against COVID-19. Discontinuation of mycophenolate mofetil (MMF) immunosuppressive therapy was correlated with better antibody response, as were younger age, higher lymphocyte counts, and better kidney function.

Additionally, having a history of antithymocyte globulin (ATG) therapy was associated with poor response after vaccination.

Multivariate nominal logistic regression analysis was then performed to identify independent predictors of anti-spike IgG positivity. Stopping or reducing the dose of MMF remained a significant predictor of better vaccine response, increasing the odds of antibody positivity nearly fourfold (odds ratio [OR]3.78, 95% confidence interval [CI], 1.59–9.01; p=0.003).

High IgG positivity, defined as titers ≥1000 AU/mL, was also influenced by reducing or stopping MMF, which improved its odds more than eight-fold (OR, 8.24, 95 %, 2.27–24.45; p

“Although withdrawal of MMF for a prolonged period increases the risk of rejection and deterioration of graft survival, discontinuation of MMF for 3 to 7 days resulted in no episodes of rejection within 6 months of the second vaccination,” the researchers said, warning that the long-term effects of reduced immunosuppression remain unknown.

Renal function, as measured by estimated glomerular filtration rate, also remained significantly and positively associated with general (OR, 16.1, 95% CI, 1.08 to 238.95; p=0.01) and strong (OR, 47.9, 95% CI, 2.20 to 1044.93; p=0.01) IgG positivity. These results indicate that poor graft function also compromises the patient’s immunity and therefore the production of antibodies after vaccination.

Lymphocyte count also remained a positive predictor of a strong IgG response, while having no history of ATG or rituximab treatment correlated with a better overall response.

“A higher antibody titer is needed to protect against infection with the Omicron variant; it is therefore important to find ways to improve antibody production in kidney transplant recipients,” the researchers said. “Approaches to achieve efficient antibody production after additional doses of vaccine may also be important, and our MMF dose modification strategy is helpful in this regard.”

Such a strategy could also help improve patient response to other existing vaccines or vaccines that may be developed in the future, they added.

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