High pregnancy rates with administration of granulocyte colony-stimulating factor in ART-patients with repetitive implantation failure and lacking killer-cell immunglobulin-like receptors

Sir,

As early as the year 2000, we reported on the use of granulocyte colony-stimulating factor (G-CSF) for IVF patients who failed to become pregnant after repeated embryo transfers (Würfel, 2000; Würfel, 2003). At that time, we administered 300 µg of Molgramostin in a single dose on the day of the embryo transfer. The pregnancy rate of patients treated with transfer on day 2 (average two embryos) was almost 43% compared with almost 20% in the placebo group.

The study by Scarpellini et al. (2009) now reports on continuous administration of G-CSF, evidently without any identifiable negative effects on the infants. Given this, we decided to run a pilot study to investigate whether continuous administration of G-CSF to patients with RIF (repetitive implantation failure) would be beneficial or not.

However, the initial criterion—patients' failure to conceive after repeated IVF or ICSI treatments—appeared to us to be too vague. Taking the publication by Hiby et al. (2008) as a basis we initially performed killer-cell immunglobulin-like receptor (KIR) typing on patients with more than five unsuccessful IVF treatments or embryo transfers. Only patients who lacked the three activating receptors were accepted for the study; also included were patients suffering from long-term unexplained sterility (average 6.8 years) and lacking the three activating KIR genes. Groups overlapped to some extent as cases of unexplained sterility had often undergone (unsuccessful) IVF treatment.

The incidence of three lacking receptors (2 DS 1, 2 DS 3 and 3 DS 5) was very high in the group examined, at 78%. In addition, it was noted that patients lacked not only the three named activating receptors but also further receptors, so that in general the group was shown to lack five to seven receptors including the above-mentioned three activating receptors.

We performed IVF and ICSI treatment on the defined group with the target of a day 5 transfer. Patients received 13 million units of Granocyte^TM (Lanogrostim) every 3 days in addition to the usual luteal support. In cases where insufficient numbers of fertilized oocytes were available, the transfer was performed on day 2 (particularly in cases of ovarian insufficiency).

Results for d + 5: Exclusively transfer of two blastocysts/morulae or compacted morulae

Number of patients	40
Number of treatment cycles	42
Clinical pregnancies
(excluding biochemical)	31
of which abortions (clinical)	12
Pregnancy rate per treatment cycle/embryo transfer	73.8%
Abortion rate (clinical pregnancies)	38.7%

Results for transfer d + 2 (also including patients with significant ovarian insufficiency)

Number of patients	19
Number of treatment cycles	19
Clinical pregnancies	8
of which abortion (clinical)	3
Pregnancy rate per embryo transfer	42%
Abortion rate	37.5%

The group we selected and defined certainly had a very poor prognosis. The pregnancy rates achieved were extraordinarily high both in the day 5 transfers and the day 2 transfers. However, the rate of clinical abortions is also high (biochemical pregnancies were ignored). In the meantime, we have also conducted a further pilot study in which G-CSF was administered to patients with a history of multiple unsuccessful IVF treatments or unexplained sterility, who had no KIR defects. The results were very poor, with pregnancy rates currently below 10% per embryo transfer.

We conclude from this that the use of G-CSF is an extremely promising additional method of treatment in cases where defects in materno-embryonic implantation communication can be shown. This applies in particular to KIR defects and, in this, particularly to the lack of the three activating receptors as described by Hiby et al. Where such defects were not present, results of G-CSF treatment were disappointing.

On the basis of the results of these pilot studies, we are currently planning a prospective randomized double-blind study under the initial criteria given above.