My name is Dr. Lorenzo Bereta, and for most of my life I believed a slide could tell the truth more faithfully than any human being.
For 29 years, I worked as a clinical microbiologist in the central hematology laboratory of San Rafaele Hospital in Milan. I handled pediatric oncology samples so often that grief became almost procedural.
I knew how blood behaved when disease had exhausted it. I knew how leukemic cells degraded, how membranes ruptured, how nuclei fragmented, how even carefully preserved material lost the freshness of life.
By the time Dr. Marco Galli called me in October 2010, I had analyzed more than 62,000 samples from children with cancer. That number is not a boast. It is a weight.
Galli was head of molecular pathology at San Gerardo Hospital in Monza. He asked me to consult on an archived case of acute promyelocytic leukemia, subtype M3, from a patient who had died 4 years earlier.
The patient was Carlo Acutis, 15 years old, deceased on October 12, 2006. His family had requested the conservation of peripheral blood and bone marrow samples for scientific purposes.
The Vatican, Galli explained, had begun the beatification process. The postulation wanted an independent microbiological examination of the preserved biological material. Not to prove sanctity. Not to stage wonder.
The question was practical: before any future exhumation, could contamination or abnormal degradation be ruled out? I accepted the assignment on October 18, 2010.
On November 22 at 9:20 a.m., I arrived at San Gerardo. Galli met me near the pathology block, and we descended into the cold basement corridors.
Every laboratory has a smell. This one smelled of disinfectant, metal, filtered air, and the faint chemical sterility that clings to places where human suffering is measured by machines.
The biobank held three liquid nitrogen chambers at -196ºC. Carlo Acutis’s samples were catalogued as B2006-0847: four 1 ml cryopreservation vials, three heparinized peripheral blood samples, and one bone marrow aspirate.
The protocol was ordinary. Water bath at 37ºC for 90 seconds. Dilution 1 to 10 in RPMI 1640. Smear on a clean slide. May-Grünwald-Giemsa stain. Microscopy at 1000x.
While I prepared the laminar-flow cabinet, Antonia Salzano entered. She was Carlo’s mother. Galli had not told me she would be there.
She spoke softly and said she only wanted to watch from a distance. Then she handed me a cream-colored envelope sealed with red wax.
“My son asked me two days before he died,” she said, “that if a scientist ever examined his blood again, I should give him this envelope.”
I remember the envelope’s weight. It did not feel like paper alone. Something small, flat, and rectangular seemed to rest inside it.
“Do not open it today,” she told me. “Do not open it until science runs out of answers. When that moment comes, you will know.”
I placed it inside the inner pocket of my white coat. I thanked her. Then I returned to the cabinet and began working.
At 10:14 a.m., I thawed the first vial. The temperature was exactly as expected. I transferred 50 microliters to the slide, spread the sample, dried it, stained it, washed it, and lowered it beneath the microscope.
The first wrong thing was not visual. It was tactile. When my finger brushed the glass, the slide felt too warm.
The basement laboratory was calibrated at 21ºC. The slide had been sitting at room temperature long enough to cool. Thermodynamically, it should have been nearly the same temperature as the table.
I retrieved a Fluke 52-2 surface thermometer, calibrated 3 weeks earlier. It read 29.4ºC. I checked again with a Testo 830-T1 infrared thermometer. It read 29.6ºC.
Galli measured it himself. The slide was 29.5ºC. The table beside it was 21.1ºC. The surrounding instruments were 21.2ºC.
Only Carlo Acutis’s blood slide radiated heat.
Then I looked through the microscope. The promyelocytes were there, as expected. Carlo’s disease had been M3 leukemia, and the sample had been taken on October 10, 2006, during a blast crisis.
But the morphology was not expected. The cell membranes were intact. The nuclei retained their chromatin structure. Azurophilic granules remained sharp. Auer rods were visible in approximately 12% of cells.
At the center of the smear, over roughly 2 mm², the malignant cells looked impossibly fresh. No nuclear fragmentation. No obvious loss of granulation. No partial membrane lysis.
I counted 200 cells. One hundred ninety-four were completely intact. Six showed minimal cryodamage.
After 4 years of cryopreservation, that number should not have existed. Scientific literature places expected morphological alteration far higher, even with excellent preservation.
Galli performed his own count. Two hundred cells. One hundred ninety-eight intact. Two mildly damaged.
He asked whether I might have contaminated the sample with fresh cells. I showed him the sterile cabinet, sealed slide, new pipettes, new gloves, and the exact time log.
Science is not embarrassed by uncertainty. It is embarrassed by carelessness. So we repeated the entire procedure with the second vial.
The second slide warmed too. Minute 4: 27ºC. Minute 17: 27.8ºC. Minute 39: 28.6ºC. Minute 52: 29.1ºC.
The room remained at 21.0ºC. The slide did not cool toward the room. It warmed away from it.
My hands began to tremble. I was not praying. I was not interpreting. I was only watching a measurement refuse to behave.
Galli asked whether I believed in God. I told him the truth: I did not know. In that moment, I believed only what I could measure, and what I could measure had become impossible.
At 5:10 p.m., Dr. Federico Ricci from the Mario Negri Institute arrived. He had 41 years of molecular hematology experience. We gave him the slide without telling him whose sample it was.
He studied it for 23 minutes in silence. When he lifted his face, he said, “This sample is not 4 years old. This sample is 4 hours old at most.”
Then he added that the malignant cells preserved an impossible architecture. Membrane, nucleus, cytoplasm, and cellular organization were present in a way he could not reconcile with the sample history.
When we asked him to measure the temperature, the slide read 30.2ºC.
Only then did he ask the patient’s name. I said, “Carlo Acutis.” Ricci stood, touched the wall with his open palm, and said only, “Allora.”
Then he left the laboratory without signing the report.
That night I arrived home in Monza at 1:28 a.m. The sealed envelope from Antonia Salzano was still in my coat pocket.
I did not open it. She had said, “When science runs out of answers.” I still believed science would find one.
I placed the envelope in my home office safe behind my father’s black Pelikan fountain pen. That pen had belonged to the world of measurements, ink, record books, and proof.
Three days later, on November 25, the molecular results arrived from the Mario Negri Institute. Flow cytometry. Quantitative PCR. PML-RARA sequencing. Annexin V and propidium iodide viability markers.
The result was 87% viable cells.
For blood cryopreserved for 4 years, expected viability is commonly far lower, often between 15% and 25% even under excellent conditions. Eighty-seven percent belonged to fresh blood.
PML-RARA confirmed the T(15;17) chromosomal translocation characteristic of Carlo’s leukemia. These were not substitute cells. They were his malignant cells.
The chain of custody remained intact: barcode records, biobank log, uninterrupted storage temperature, matching identifiers, and sealed vials. I had artifact after artifact and no explanation.
On December 14, 2010, I met Antonia Salzano in a small café on Via Manzoni in Milan. She brought Carlo’s blue school notebook.
On a page dated September 28, 2006, two weeks before his death, Carlo had written: “My blood will remain alive when my body is no longer here.”
He also wrote that what the scientist would see in 2010 could not be explained in Milan. The answer, he wrote, would be where Thérèse wrote on July 21 in Lisieux.
I read the words and felt the room narrow around me. Carlo had written them 4 years before I placed his blood under my microscope.
Antonia told me the sealed envelope contained a letter Carlo had prepared before his death. It was to be opened only by the scientist, only in the right place, only on the right date.
“Doctor Bereta,” she said, “my son knew you would go to Lisieux. But he knew it would take years.”
For 12 years, I did not go. I worked. I published. I attended conferences in Boston, Singapore, and Stockholm. I directed research on hematopoietic cell cryopreservation.
Carlo was beatified on October 10, 2020, in Assisi. I watched the ceremony on television. The envelope remained in my safe.
My mother died in March 2021 of a sudden heart attack. Her death broke something in me that professional discipline could not repair.
In January 2023, at 57 years old, I was diagnosed with stage 2 follicular non-Hodgkin lymphoma. A cervical lymph node appeared after Christmas and led to the testing.
The irony was not lost on me. I had spent 29 years examining blood from oncology patients. Now I was the patient.
My oncologist, Dr. Francesca Lorenzon, recommended R-CHOP immunochemotherapy: six cycles every 21 days. I began on February 6, 2023.
The first cycles were tolerable. Fatigue stayed with me like a second body. Nausea came and went. By April, the lymph node markers had decreased by 70%.
In June, after the sixth cycle, I was told the disease was in complete remission. The medicine had done its work, but I could barely walk more than three streets.
My sister Paola suggested a short rest trip. Provence, she said. Somewhere quiet.
I answered, “Normandy.”
I booked a flight to Paris for July 18, 2023. I rented a car at Charles de Gaulle Airport and drove 200 km west to Lisieux.
I stayed in a small guesthouse about 500 meters from the Basilica of Saint Thérèse. The cream envelope came with me in my luggage. I still had not opened it.
On July 21, 2023, at 9:28 a.m., I entered the basilica. It was exactly the date Carlo had written in his notebook 13 years earlier.
The stone floor was cool. Light fell through the windows in clean pale bands. Somewhere nearby, rosary beads clicked softly between fingers.
I walked toward the relicary of Saint Thérèse of the Child Jesus. Then my legs weakened. I knelt, not because I had decided to pray, but because my body no longer held me.
The envelope pressed against the inside of my jacket. For the first time since 2010, I removed it and broke the red wax seal.
Inside were two things: a folded handwritten sheet and a small holy card of Saint Thérèse. The sheet was written in Carlo’s hand.
“Dear doctor or doctora who is reading this,” it began, “if you have arrived in Lisieux, it is because my blood spoke under the microscope.”
I read further. Carlo wrote that he had prayed for the scientist who would one day hold his blood on a slide. He wrote that when that scientist’s own illness came, he should not be afraid.
“The illness will probably arrive around the year 2023,” he wrote, “when you are approximately 57 years old. But you will live. Medicine will cure you.”
He wrote that I would come to Lisieux on July 21 because Saint Thérèse had first sustained him in prayer while he was ill, and would also sustain the scientist who studied his blood.
Carlo had dated the letter October 3, 2006. Nine days before his death.
I was born on March 14, 1966. On July 21, 2023, I was 57 years, 4 months, and 7 days old.
My lymphoma had been diagnosed in January 2023. I had completed treatment in June. I was in Lisieux on July 21.
In 2006, Carlo could not have known me. I was a healthy 40-year-old microbiologist with no connection to him, no cancer history, and no place in his family circle.
Yet he had written my illness, my age, my treatment, my journey, and the date.
I fell to my knees again. This time it was not lymphoma fatigue. I cried for the first time since my mother died.
An elderly French woman approached and placed her hand on my shoulder. She said nothing. She stayed until my sobbing eased.
When I turned over the holy card of Saint Thérèse, there was one line written in pencil: “The blood you analyzed in Milan is alive because Saint Thérèse prayed for me in heaven while I was dying in Monza.”
I left the basilica at 11:42 a.m. and sat on a stone bench in the garden. I read the letter three times.
Then I took out my father’s Pelikan pen, which I had brought without knowing why, and wrote the date and hour in my notebook.
That notebook became part of my testimony. The original letter was later placed in a bank security box. A notarized copy was attached to my laboratory records from November 22, 2010.
My microbiological report on Carlo Acutis’s blood was submitted to the postulation on March 12, 2024, signed by me, Dr. Galli, and Dr. Ricci.
I later testified in five canonization causes opened through the Congregation for the Causes of Saints. I spoke in Boston in October 2024, Madrid in February 2025, and Rome in June 2025.
The scientific community treated me with a mixture of respect and skepticism. Some called me credulous. Others sent private letters describing similar anomalies they had never dared publish.
Dr. Vincenzo Esposito, the cryobiology specialist from the CNR in Naples, eventually published a short 2024 paper in Cryobiology on anomalous cellular integrity in tissues associated with canonization processes. Three pages. Data, not theology.
On September 7, 2025, during the jubilee, I went to Rome. I stood in St. Peter’s Square and watched Pope Leo XIV canonize Carlo Acutis.
Antonia Salzano recognized me. She came over with tears in her eyes and said Carlo had always known I would be there.
I carry the holy card of Saint Thérèse in the inner pocket of my lab coat whenever I go down to the San Rafaele laboratory. I also carry my father’s Pelikan pen.
I use it to sign reports by hand, the way he did.
For 15 years, I was silent. For 15 years, I believed I would be able to explain scientifically what I had seen. I could not.
The science did not become false. The measurements did not become less important. But the blood stayed warm, the cells remained viable, the letter was real, and the date matched.
My name is Dr. Lorenzo Bereta. What I saw on the slide 4 years after the death of Carlo Acutis should not have been possible under any law of microbiology I had ever studied.
I do not ask anyone to believe because I say so. I only say what I saw, what I measured, what two other specialists confirmed, and what I found in a letter written by a dying 15-year-old boy.
The Eucharist was Carlo Acutis’s highway to heaven. And perhaps the prayer of a sick child in October 2006 traveled farther than any microscope could see.
Sometimes the footprints of heaven do not arrive as thunder. Sometimes they remain on a glass slide, waiting 4 years to speak.
