The database contains raw, anonymized demographic data (sex, age, ethnicity) and histological data (number of glomeruli, lupus nephritis class, total NIH AI score, active lesion scores, total NIH CI score, chronic lesion scores) for two patient cohorts, presented in two separate sheets. Ethnicity data was only available for cohort 2 (Legend: 1: caucasian, 2: afro-caribbean, 3: asian, 4: other). The first cohort contains data of patients from Meyer Children’s Hospital (Florence, Italy) and the University Medical Center of Groningen (Groningen, the Netherlands). The second cohort contains data of patients from the University College London Hospitals NHS Foundation Trust (London, United Kingdom). This data was used to analyse the distribution of the NIH AI and CI and identify the ‘real world’ ranges of the indices. We also explored their relationship with the histological ISN/RPS classes and evaluate which lesions most significantly contribute to these scores. Analyses were performed by our statistician using SAS statistical software version 9.4. A pdf file contains a summary of the statistical analysis.